2019-05-19 20:08:55 +08:00
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// SPDX-License-Identifier: GPL-2.0-only
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2005-04-17 06:20:36 +08:00
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/*
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* proc/fs/generic.c --- generic routines for the proc-fs
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*
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* This file contains generic proc-fs routines for handling
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* directories and files.
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*
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* Copyright (C) 1991, 1992 Linus Torvalds.
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* Copyright (C) 1997 Theodore Ts'o
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*/
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2018-04-11 07:31:52 +08:00
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#include <linux/cache.h>
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2005-04-17 06:20:36 +08:00
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#include <linux/errno.h>
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#include <linux/time.h>
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#include <linux/proc_fs.h>
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#include <linux/stat.h>
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2010-06-04 17:30:02 +08:00
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#include <linux/mm.h>
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2005-04-17 06:20:36 +08:00
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#include <linux/module.h>
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2018-04-14 06:35:42 +08:00
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#include <linux/namei.h>
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include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
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#include <linux/slab.h>
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2013-02-28 09:03:16 +08:00
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#include <linux/printk.h>
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2005-04-17 06:20:36 +08:00
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#include <linux/mount.h>
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#include <linux/init.h>
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#include <linux/idr.h>
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#include <linux/bitops.h>
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2006-03-26 17:36:55 +08:00
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#include <linux/spinlock.h>
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Fix rmmod/read/write races in /proc entries
Fix following races:
===========================================
1. Write via ->write_proc sleeps in copy_from_user(). Module disappears
meanwhile. Or, more generically, system call done on /proc file, method
supplied by module is called, module dissapeares meanwhile.
pde = create_proc_entry()
if (!pde)
return -ENOMEM;
pde->write_proc = ...
open
write
copy_from_user
pde = create_proc_entry();
if (!pde) {
remove_proc_entry();
return -ENOMEM;
/* module unloaded */
}
*boom*
==========================================
2. bogo-revoke aka proc_kill_inodes()
remove_proc_entry vfs_read
proc_kill_inodes [check ->f_op validness]
[check ->f_op->read validness]
[verify_area, security permissions checks]
->f_op = NULL;
if (file->f_op->read)
/* ->f_op dereference, boom */
NOTE, NOTE, NOTE: file_operations are proxied for regular files only. Let's
see how this scheme behaves, then extend if needed for directories.
Directories creators in /proc only set ->owner for them, so proxying for
directories may be unneeded.
NOTE, NOTE, NOTE: methods being proxied are ->llseek, ->read, ->write,
->poll, ->unlocked_ioctl, ->ioctl, ->compat_ioctl, ->open, ->release.
If your in-tree module uses something else, yell on me. Full audit pending.
[akpm@linux-foundation.org: build fix]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 14:39:00 +08:00
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#include <linux/completion.h>
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2016-12-25 03:46:01 +08:00
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#include <linux/uaccess.h>
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2018-04-14 01:44:18 +08:00
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#include <linux/seq_file.h>
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2005-04-17 06:20:36 +08:00
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2006-01-08 17:04:16 +08:00
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#include "internal.h"
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2015-09-10 06:35:57 +08:00
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static DEFINE_RWLOCK(proc_subdir_lock);
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2006-03-26 17:36:55 +08:00
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2018-04-11 07:31:52 +08:00
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struct kmem_cache *proc_dir_entry_cache __ro_after_init;
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void pde_free(struct proc_dir_entry *pde)
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{
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if (S_ISLNK(pde->mode))
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kfree(pde->data);
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if (pde->name != pde->inline_name)
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kfree(pde->name);
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kmem_cache_free(proc_dir_entry_cache, pde);
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}
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2018-02-07 07:37:31 +08:00
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static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
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2005-04-17 06:20:36 +08:00
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{
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2014-12-11 07:45:01 +08:00
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if (len < de->namelen)
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return -1;
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if (len > de->namelen)
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return 1;
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return memcmp(name, de->name, len);
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}
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static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
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{
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2018-04-11 07:32:20 +08:00
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return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
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subdir_node);
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2014-12-11 07:45:01 +08:00
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}
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static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
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{
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2014-12-11 07:45:07 +08:00
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return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
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subdir_node);
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2014-12-11 07:45:01 +08:00
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}
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static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
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const char *name,
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unsigned int len)
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{
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2018-04-11 07:32:20 +08:00
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struct rb_node *node = dir->subdir.rb_node;
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2014-12-11 07:45:01 +08:00
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while (node) {
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2017-02-25 07:00:17 +08:00
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struct proc_dir_entry *de = rb_entry(node,
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struct proc_dir_entry,
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subdir_node);
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2018-02-07 07:37:31 +08:00
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int result = proc_match(name, de, len);
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2014-12-11 07:45:01 +08:00
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if (result < 0)
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node = node->rb_left;
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else if (result > 0)
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node = node->rb_right;
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else
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return de;
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}
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return NULL;
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}
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static bool pde_subdir_insert(struct proc_dir_entry *dir,
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struct proc_dir_entry *de)
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{
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2018-04-11 07:32:20 +08:00
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struct rb_root *root = &dir->subdir;
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struct rb_node **new = &root->rb_node, *parent = NULL;
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2014-12-11 07:45:01 +08:00
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/* Figure out where to put new node */
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while (*new) {
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2017-02-25 07:00:17 +08:00
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struct proc_dir_entry *this = rb_entry(*new,
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struct proc_dir_entry,
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subdir_node);
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2018-02-07 07:37:31 +08:00
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int result = proc_match(de->name, this, de->namelen);
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2014-12-11 07:45:01 +08:00
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parent = *new;
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if (result < 0)
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new = &(*new)->rb_left;
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2018-04-11 07:32:20 +08:00
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else if (result > 0)
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2014-12-11 07:45:01 +08:00
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new = &(*new)->rb_right;
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2018-04-11 07:32:20 +08:00
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else
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2014-12-11 07:45:01 +08:00
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return false;
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}
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/* Add new node and rebalance tree. */
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rb_link_node(&de->subdir_node, parent, new);
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2018-04-11 07:32:20 +08:00
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rb_insert_color(&de->subdir_node, root);
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2014-12-11 07:45:01 +08:00
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return true;
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2005-04-17 06:20:36 +08:00
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}
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static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
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{
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2015-03-18 06:25:59 +08:00
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struct inode *inode = d_inode(dentry);
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2005-04-17 06:20:36 +08:00
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struct proc_dir_entry *de = PDE(inode);
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int error;
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2016-05-26 22:55:18 +08:00
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error = setattr_prepare(dentry, iattr);
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2005-04-17 06:20:36 +08:00
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if (error)
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2010-06-04 17:30:02 +08:00
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return error;
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2005-04-17 06:20:36 +08:00
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2010-06-04 17:30:02 +08:00
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setattr_copy(inode, iattr);
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mark_inode_dirty(inode);
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2012-12-15 18:48:48 +08:00
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2014-01-24 07:55:41 +08:00
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proc_set_user(de, inode->i_uid, inode->i_gid);
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2005-04-17 06:20:36 +08:00
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de->mode = inode->i_mode;
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2010-06-04 17:30:02 +08:00
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return 0;
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2005-04-17 06:20:36 +08:00
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}
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statx: Add a system call to make enhanced file info available
Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.
The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.
Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.
========
OVERVIEW
========
The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.
A number of requests were gathered for features to be included. The
following have been included:
(1) Make the fields a consistent size on all arches and make them large.
(2) Spare space, request flags and information flags are provided for
future expansion.
(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).
(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).
This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].
(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).
(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).
And the following have been left out for future extension:
(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].
Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.
(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).
(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].
(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].
(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).
(10) Extra coherency data may be useful in making backups [Andreas Dilger].
(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).
(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...
(This requires a separate system call - I have an fsinfo() call idea
for this).
(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].
(Deferred to fsinfo).
(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].
(Deferred to fsinfo).
(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).
(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).
(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].
(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).
(16) Femtosecond-resolution timestamps [Dave Chinner].
(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).
(17) A set multiple attributes syscall to go with this.
===============
NEW SYSTEM CALL
===============
The new system call is:
int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);
The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.
Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):
(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.
(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.
(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.
mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.
buffer points to the destination for the data. This must be 256 bytes in
size.
======================
MAIN ATTRIBUTES RECORD
======================
The following structures are defined in which to return the main attribute
set:
struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};
struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};
The defined bits in request_mask and stx_mask are:
STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]
stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.
Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.
The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:
STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs
Within the kernel, the supported flags are listed by:
KSTAT_ATTR_FS_IOC_FLAGS
[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]
New flags include:
STATX_ATTR_AUTOMOUNT Object is an automount trigger
These are for the use of GUI tools that might want to mark files specially,
depending on what they are.
Fields in struct statx come in a number of classes:
(0) stx_dev_*, stx_blksize.
These are local system information and are always available.
(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.
These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.
If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.
If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.
Note that there are instances where the type might not be valid, for
instance Windows reparse points.
(2) stx_rdev_*.
This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.
(3) stx_btime.
Similar to (1), except this will be set to 0 if it doesn't exist.
=======
TESTING
=======
The following test program can be used to test the statx system call:
samples/statx/test-statx.c
Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.
Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.
[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)
Secondly, the result of automounting on that directory.
[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-02-01 00:46:22 +08:00
|
|
|
static int proc_getattr(const struct path *path, struct kstat *stat,
|
|
|
|
u32 request_mask, unsigned int query_flags)
|
2005-09-07 06:17:18 +08:00
|
|
|
{
|
statx: Add a system call to make enhanced file info available
Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.
The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.
Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.
========
OVERVIEW
========
The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.
A number of requests were gathered for features to be included. The
following have been included:
(1) Make the fields a consistent size on all arches and make them large.
(2) Spare space, request flags and information flags are provided for
future expansion.
(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).
(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).
This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].
(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).
(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).
And the following have been left out for future extension:
(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].
Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.
(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).
(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].
(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].
(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).
(10) Extra coherency data may be useful in making backups [Andreas Dilger].
(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).
(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...
(This requires a separate system call - I have an fsinfo() call idea
for this).
(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].
(Deferred to fsinfo).
(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].
(Deferred to fsinfo).
(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).
(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).
(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].
(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).
(16) Femtosecond-resolution timestamps [Dave Chinner].
(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).
(17) A set multiple attributes syscall to go with this.
===============
NEW SYSTEM CALL
===============
The new system call is:
int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);
The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.
Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):
(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.
(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.
(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.
mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.
buffer points to the destination for the data. This must be 256 bytes in
size.
======================
MAIN ATTRIBUTES RECORD
======================
The following structures are defined in which to return the main attribute
set:
struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};
struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};
The defined bits in request_mask and stx_mask are:
STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]
stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.
Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.
The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:
STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs
Within the kernel, the supported flags are listed by:
KSTAT_ATTR_FS_IOC_FLAGS
[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]
New flags include:
STATX_ATTR_AUTOMOUNT Object is an automount trigger
These are for the use of GUI tools that might want to mark files specially,
depending on what they are.
Fields in struct statx come in a number of classes:
(0) stx_dev_*, stx_blksize.
These are local system information and are always available.
(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.
These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.
If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.
If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.
Note that there are instances where the type might not be valid, for
instance Windows reparse points.
(2) stx_rdev_*.
This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.
(3) stx_btime.
Similar to (1), except this will be set to 0 if it doesn't exist.
=======
TESTING
=======
The following test program can be used to test the statx system call:
samples/statx/test-statx.c
Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.
Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.
[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)
Secondly, the result of automounting on that directory.
[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-02-01 00:46:22 +08:00
|
|
|
struct inode *inode = d_inode(path->dentry);
|
2015-02-13 07:01:03 +08:00
|
|
|
struct proc_dir_entry *de = PDE(inode);
|
2019-12-05 08:49:59 +08:00
|
|
|
if (de) {
|
|
|
|
nlink_t nlink = READ_ONCE(de->nlink);
|
|
|
|
if (nlink > 0) {
|
|
|
|
set_nlink(inode, nlink);
|
|
|
|
}
|
|
|
|
}
|
2005-09-07 06:17:18 +08:00
|
|
|
|
|
|
|
generic_fillattr(inode, stat);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-02-12 16:55:40 +08:00
|
|
|
static const struct inode_operations proc_file_inode_operations = {
|
2005-04-17 06:20:36 +08:00
|
|
|
.setattr = proc_notify_change,
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This function parses a name such as "tty/driver/serial", and
|
|
|
|
* returns the struct proc_dir_entry for "/proc/tty/driver", and
|
|
|
|
* returns "serial" in residual.
|
|
|
|
*/
|
2010-03-06 05:43:59 +08:00
|
|
|
static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
|
|
|
|
const char **residual)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
const char *cp = name, *next;
|
|
|
|
struct proc_dir_entry *de;
|
|
|
|
|
proc: less special case in xlate code
If valid "parent" is passed to proc_create/remove_proc_entry(), then name of
PDE should consist of only one path component, otherwise creation or or
removal will fail. However, if NULL is passed as parent then create/remove
accept full path as a argument. This is arbitrary restriction -- all
infrastructure is in place.
So, patch allows the following to succeed:
create_proc_entry("foo/bar", 0, pde_baz);
remove_proc_entry("baz/foo/bar", &proc_root);
Also makes the following to behave identically:
create_proc_entry("foo/bar", 0, NULL);
create_proc_entry("foo/bar", 0, &proc_root);
Discrepancy noticed by Den Lunev (IIRC).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 16:01:40 +08:00
|
|
|
de = *ret;
|
|
|
|
if (!de)
|
|
|
|
de = &proc_root;
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
while (1) {
|
|
|
|
next = strchr(cp, '/');
|
|
|
|
if (!next)
|
|
|
|
break;
|
|
|
|
|
2019-12-05 08:50:02 +08:00
|
|
|
de = pde_subdir_find(de, cp, next - cp);
|
2010-03-06 05:44:00 +08:00
|
|
|
if (!de) {
|
|
|
|
WARN(1, "name '%s'\n", name);
|
2010-03-06 05:43:59 +08:00
|
|
|
return -ENOENT;
|
2010-03-06 05:44:00 +08:00
|
|
|
}
|
2019-12-05 08:50:02 +08:00
|
|
|
cp = next + 1;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
*residual = cp;
|
|
|
|
*ret = de;
|
2010-03-06 05:43:59 +08:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
|
|
|
|
const char **residual)
|
|
|
|
{
|
|
|
|
int rv;
|
|
|
|
|
2015-09-10 06:35:57 +08:00
|
|
|
read_lock(&proc_subdir_lock);
|
2010-03-06 05:43:59 +08:00
|
|
|
rv = __xlate_proc_name(name, ret, residual);
|
2015-09-10 06:35:57 +08:00
|
|
|
read_unlock(&proc_subdir_lock);
|
2010-03-06 05:43:59 +08:00
|
|
|
return rv;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2008-07-26 15:21:37 +08:00
|
|
|
static DEFINE_IDA(proc_inum_ida);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-07-26 15:18:28 +08:00
|
|
|
#define PROC_DYNAMIC_FIRST 0xF0000000U
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Return an inode number between PROC_DYNAMIC_FIRST and
|
|
|
|
* 0xffffffff, or zero on failure.
|
|
|
|
*/
|
2011-06-18 04:33:20 +08:00
|
|
|
int proc_alloc_inum(unsigned int *inum)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2017-07-11 06:50:52 +08:00
|
|
|
int i;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2017-07-11 06:50:52 +08:00
|
|
|
i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
|
|
|
|
GFP_KERNEL);
|
|
|
|
if (i < 0)
|
|
|
|
return i;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2017-07-11 06:50:52 +08:00
|
|
|
*inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
|
2011-06-18 04:33:20 +08:00
|
|
|
return 0;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2011-06-18 04:33:20 +08:00
|
|
|
void proc_free_inum(unsigned int inum)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2017-07-11 06:50:52 +08:00
|
|
|
ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2018-04-14 06:35:42 +08:00
|
|
|
static int proc_misc_d_revalidate(struct dentry *dentry, unsigned int flags)
|
|
|
|
{
|
|
|
|
if (flags & LOOKUP_RCU)
|
|
|
|
return -ECHILD;
|
|
|
|
|
|
|
|
if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
|
|
|
|
return 0; /* revalidate */
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int proc_misc_d_delete(const struct dentry *dentry)
|
|
|
|
{
|
|
|
|
return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static const struct dentry_operations proc_misc_dentry_ops = {
|
|
|
|
.d_revalidate = proc_misc_d_revalidate,
|
|
|
|
.d_delete = proc_misc_d_delete,
|
|
|
|
};
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
* Don't create negative dentries here, return -ENOENT by hand
|
|
|
|
* instead.
|
|
|
|
*/
|
2018-02-07 07:37:31 +08:00
|
|
|
struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
|
|
|
|
struct proc_dir_entry *de)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2013-01-26 09:11:22 +08:00
|
|
|
struct inode *inode;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2015-09-10 06:35:57 +08:00
|
|
|
read_lock(&proc_subdir_lock);
|
2014-12-11 07:45:01 +08:00
|
|
|
de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
|
|
|
|
if (de) {
|
|
|
|
pde_get(de);
|
2015-09-10 06:35:57 +08:00
|
|
|
read_unlock(&proc_subdir_lock);
|
2014-12-11 07:45:01 +08:00
|
|
|
inode = proc_get_inode(dir->i_sb, de);
|
|
|
|
if (!inode)
|
|
|
|
return ERR_PTR(-ENOMEM);
|
2019-02-02 06:20:01 +08:00
|
|
|
d_set_d_op(dentry, de->proc_dops);
|
2018-05-03 21:45:06 +08:00
|
|
|
return d_splice_alias(inode, dentry);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2015-09-10 06:35:57 +08:00
|
|
|
read_unlock(&proc_subdir_lock);
|
2013-01-26 09:11:22 +08:00
|
|
|
return ERR_PTR(-ENOENT);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
[NET]: Make /proc/net a symlink on /proc/self/net (v3)
Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.
The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.
The proposed fix is to turn /proc/net into a symlink, which points
to /proc/self/net, which in turn shows what previously was in
/proc/net - the network-related info, from the net namespace the
appropriate task lives in.
# ls -l /proc/net
lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net
In other words - this behaves like /proc/mounts, but unlike
"mounts", "net" is not a file, but a directory.
Changes from v2:
* Fixed discrepancy of /proc/net nlink count and selinux labeling
screwup pointed out by Stephen.
To get the correct nlink count the ->getattr callback for /proc/net
is overridden to read one from the net->proc_net entry.
To make selinux still work the net->proc_net entry is initialized
properly, i.e. with the "net" name and the proc_net parent.
Selinux fixes are
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Changes from v1:
* Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-08 03:08:40 +08:00
|
|
|
struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
|
2012-06-11 05:13:09 +08:00
|
|
|
unsigned int flags)
|
[NET]: Make /proc/net a symlink on /proc/self/net (v3)
Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.
The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.
The proposed fix is to turn /proc/net into a symlink, which points
to /proc/self/net, which in turn shows what previously was in
/proc/net - the network-related info, from the net namespace the
appropriate task lives in.
# ls -l /proc/net
lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net
In other words - this behaves like /proc/mounts, but unlike
"mounts", "net" is not a file, but a directory.
Changes from v2:
* Fixed discrepancy of /proc/net nlink count and selinux labeling
screwup pointed out by Stephen.
To get the correct nlink count the ->getattr callback for /proc/net
is overridden to read one from the net->proc_net entry.
To make selinux still work the net->proc_net entry is initialized
properly, i.e. with the "net" name and the proc_net parent.
Selinux fixes are
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Changes from v1:
* Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-08 03:08:40 +08:00
|
|
|
{
|
2020-04-19 22:10:54 +08:00
|
|
|
struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb);
|
|
|
|
|
|
|
|
if (fs_info->pidonly == PROC_PIDONLY_ON)
|
|
|
|
return ERR_PTR(-ENOENT);
|
|
|
|
|
2018-02-07 07:37:31 +08:00
|
|
|
return proc_lookup_de(dir, dentry, PDE(dir));
|
[NET]: Make /proc/net a symlink on /proc/self/net (v3)
Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.
The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.
The proposed fix is to turn /proc/net into a symlink, which points
to /proc/self/net, which in turn shows what previously was in
/proc/net - the network-related info, from the net namespace the
appropriate task lives in.
# ls -l /proc/net
lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net
In other words - this behaves like /proc/mounts, but unlike
"mounts", "net" is not a file, but a directory.
Changes from v2:
* Fixed discrepancy of /proc/net nlink count and selinux labeling
screwup pointed out by Stephen.
To get the correct nlink count the ->getattr callback for /proc/net
is overridden to read one from the net->proc_net entry.
To make selinux still work the net->proc_net entry is initialized
properly, i.e. with the "net" name and the proc_net parent.
Selinux fixes are
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Changes from v1:
* Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-08 03:08:40 +08:00
|
|
|
}
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
* This returns non-zero if at EOF, so that the /proc
|
|
|
|
* root directory can use this and check if it should
|
|
|
|
* continue with the <pid> entries..
|
|
|
|
*
|
|
|
|
* Note that the VFS-layer doesn't care about the return
|
|
|
|
* value of the readdir() call, as long as it's non-negative
|
|
|
|
* for success..
|
|
|
|
*/
|
2018-02-07 07:37:31 +08:00
|
|
|
int proc_readdir_de(struct file *file, struct dir_context *ctx,
|
|
|
|
struct proc_dir_entry *de)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
int i;
|
2013-05-17 00:07:31 +08:00
|
|
|
|
|
|
|
if (!dir_emit_dots(file, ctx))
|
|
|
|
return 0;
|
|
|
|
|
2018-08-22 12:54:23 +08:00
|
|
|
i = ctx->pos - 2;
|
2015-09-10 06:35:57 +08:00
|
|
|
read_lock(&proc_subdir_lock);
|
2014-12-11 07:45:01 +08:00
|
|
|
de = pde_subdir_first(de);
|
2013-05-17 00:07:31 +08:00
|
|
|
for (;;) {
|
|
|
|
if (!de) {
|
2015-09-10 06:35:57 +08:00
|
|
|
read_unlock(&proc_subdir_lock);
|
2013-05-17 00:07:31 +08:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
if (!i)
|
|
|
|
break;
|
2014-12-11 07:45:01 +08:00
|
|
|
de = pde_subdir_next(de);
|
2013-05-17 00:07:31 +08:00
|
|
|
i--;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2013-05-17 00:07:31 +08:00
|
|
|
|
|
|
|
do {
|
|
|
|
struct proc_dir_entry *next;
|
|
|
|
pde_get(de);
|
2015-09-10 06:35:57 +08:00
|
|
|
read_unlock(&proc_subdir_lock);
|
2013-05-17 00:07:31 +08:00
|
|
|
if (!dir_emit(ctx, de->name, de->namelen,
|
|
|
|
de->low_ino, de->mode >> 12)) {
|
|
|
|
pde_put(de);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
ctx->pos++;
|
2018-08-22 12:54:23 +08:00
|
|
|
read_lock(&proc_subdir_lock);
|
2014-12-11 07:45:01 +08:00
|
|
|
next = pde_subdir_next(de);
|
2013-05-17 00:07:31 +08:00
|
|
|
pde_put(de);
|
|
|
|
de = next;
|
|
|
|
} while (de);
|
2015-09-10 06:35:57 +08:00
|
|
|
read_unlock(&proc_subdir_lock);
|
2013-08-20 07:26:12 +08:00
|
|
|
return 1;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2013-05-17 00:07:31 +08:00
|
|
|
int proc_readdir(struct file *file, struct dir_context *ctx)
|
[NET]: Make /proc/net a symlink on /proc/self/net (v3)
Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.
The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.
The proposed fix is to turn /proc/net into a symlink, which points
to /proc/self/net, which in turn shows what previously was in
/proc/net - the network-related info, from the net namespace the
appropriate task lives in.
# ls -l /proc/net
lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net
In other words - this behaves like /proc/mounts, but unlike
"mounts", "net" is not a file, but a directory.
Changes from v2:
* Fixed discrepancy of /proc/net nlink count and selinux labeling
screwup pointed out by Stephen.
To get the correct nlink count the ->getattr callback for /proc/net
is overridden to read one from the net->proc_net entry.
To make selinux still work the net->proc_net entry is initialized
properly, i.e. with the "net" name and the proc_net parent.
Selinux fixes are
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Changes from v1:
* Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-08 03:08:40 +08:00
|
|
|
{
|
2013-05-17 00:07:31 +08:00
|
|
|
struct inode *inode = file_inode(file);
|
2020-04-19 22:10:54 +08:00
|
|
|
struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
|
|
|
|
|
|
|
|
if (fs_info->pidonly == PROC_PIDONLY_ON)
|
|
|
|
return 1;
|
[NET]: Make /proc/net a symlink on /proc/self/net (v3)
Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.
The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.
The proposed fix is to turn /proc/net into a symlink, which points
to /proc/self/net, which in turn shows what previously was in
/proc/net - the network-related info, from the net namespace the
appropriate task lives in.
# ls -l /proc/net
lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net
In other words - this behaves like /proc/mounts, but unlike
"mounts", "net" is not a file, but a directory.
Changes from v2:
* Fixed discrepancy of /proc/net nlink count and selinux labeling
screwup pointed out by Stephen.
To get the correct nlink count the ->getattr callback for /proc/net
is overridden to read one from the net->proc_net entry.
To make selinux still work the net->proc_net entry is initialized
properly, i.e. with the "net" name and the proc_net parent.
Selinux fixes are
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Changes from v1:
* Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-08 03:08:40 +08:00
|
|
|
|
2018-02-07 07:37:31 +08:00
|
|
|
return proc_readdir_de(file, ctx, PDE(inode));
|
[NET]: Make /proc/net a symlink on /proc/self/net (v3)
Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.
The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.
The proposed fix is to turn /proc/net into a symlink, which points
to /proc/self/net, which in turn shows what previously was in
/proc/net - the network-related info, from the net namespace the
appropriate task lives in.
# ls -l /proc/net
lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net
In other words - this behaves like /proc/mounts, but unlike
"mounts", "net" is not a file, but a directory.
Changes from v2:
* Fixed discrepancy of /proc/net nlink count and selinux labeling
screwup pointed out by Stephen.
To get the correct nlink count the ->getattr callback for /proc/net
is overridden to read one from the net->proc_net entry.
To make selinux still work the net->proc_net entry is initialized
properly, i.e. with the "net" name and the proc_net parent.
Selinux fixes are
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Changes from v1:
* Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-08 03:08:40 +08:00
|
|
|
}
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
* These are the generic /proc directory operations. They
|
|
|
|
* use the in-memory "struct proc_dir_entry" tree to parse
|
|
|
|
* the /proc directory.
|
|
|
|
*/
|
2007-02-12 16:55:34 +08:00
|
|
|
static const struct file_operations proc_dir_operations = {
|
proc: stop using BKL
There are four BKL users in proc: de_put(), proc_lookup_de(),
proc_readdir_de(), proc_root_readdir(),
1) de_put()
-----------
de_put() is classic atomic_dec_and_test() refcount wrapper -- no BKL
needed. BKL doesn't matter to possible refcount leak as well.
2) proc_lookup_de()
-------------------
Walking PDE list is protected by proc_subdir_lock(), proc_get_inode() is
potentially blocking, all callers of proc_lookup_de() eventually end up
from ->lookup hooks which is protected by directory's ->i_mutex -- BKL
doesn't protect anything.
3) proc_readdir_de()
--------------------
"." and ".." part doesn't need BKL, walking PDE list is under
proc_subdir_lock, calling filldir callback is potentially blocking
because it writes to luserspace. All proc_readdir_de() callers
eventually come from ->readdir hook which is under directory's
->i_mutex -- BKL doesn't protect anything.
4) proc_root_readdir_de()
-------------------------
proc_root_readdir_de is ->readdir hook, see (3).
Since readdir hooks doesn't use BKL anymore, switch to
generic_file_llseek, since it also takes directory's i_mutex.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-28 03:48:36 +08:00
|
|
|
.llseek = generic_file_llseek,
|
2005-04-17 06:20:36 +08:00
|
|
|
.read = generic_read_dir,
|
2016-04-21 05:13:54 +08:00
|
|
|
.iterate_shared = proc_readdir,
|
2005-04-17 06:20:36 +08:00
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* proc directories can do almost nothing..
|
|
|
|
*/
|
2007-02-12 16:55:40 +08:00
|
|
|
static const struct inode_operations proc_dir_inode_operations = {
|
2005-04-17 06:20:36 +08:00
|
|
|
.lookup = proc_lookup,
|
2005-09-07 06:17:18 +08:00
|
|
|
.getattr = proc_getattr,
|
2005-04-17 06:20:36 +08:00
|
|
|
.setattr = proc_notify_change,
|
|
|
|
};
|
|
|
|
|
2018-04-24 23:00:52 +08:00
|
|
|
/* returns the registered entry, or frees dp and returns NULL on failure */
|
|
|
|
struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
|
|
|
|
struct proc_dir_entry *dp)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2018-04-24 23:00:52 +08:00
|
|
|
if (proc_alloc_inum(&dp->low_ino))
|
|
|
|
goto out_free_entry;
|
2006-03-26 17:36:55 +08:00
|
|
|
|
2015-09-10 06:35:57 +08:00
|
|
|
write_lock(&proc_subdir_lock);
|
2007-07-16 14:40:09 +08:00
|
|
|
dp->parent = dir;
|
2014-12-11 07:45:04 +08:00
|
|
|
if (pde_subdir_insert(dir, dp) == false) {
|
2014-12-11 07:45:01 +08:00
|
|
|
WARN(1, "proc_dir_entry '%s/%s' already registered\n",
|
|
|
|
dir->name, dp->name);
|
2015-09-10 06:35:57 +08:00
|
|
|
write_unlock(&proc_subdir_lock);
|
2018-04-24 23:00:52 +08:00
|
|
|
goto out_free_inum;
|
2014-12-11 07:45:04 +08:00
|
|
|
}
|
2019-12-05 08:49:59 +08:00
|
|
|
dir->nlink++;
|
2015-09-10 06:35:57 +08:00
|
|
|
write_unlock(&proc_subdir_lock);
|
2007-07-16 14:40:09 +08:00
|
|
|
|
2018-04-24 23:00:52 +08:00
|
|
|
return dp;
|
|
|
|
out_free_inum:
|
|
|
|
proc_free_inum(dp->low_ino);
|
|
|
|
out_free_entry:
|
|
|
|
pde_free(dp);
|
|
|
|
return NULL;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] destroy_inode+0x24/0x33
=======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 20:18:37 +08:00
|
|
|
static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
|
2005-04-17 06:20:36 +08:00
|
|
|
const char *name,
|
2011-07-24 15:36:29 +08:00
|
|
|
umode_t mode,
|
2005-04-17 06:20:36 +08:00
|
|
|
nlink_t nlink)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *ent = NULL;
|
2014-08-09 05:21:25 +08:00
|
|
|
const char *fn;
|
|
|
|
struct qstr qstr;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
proc: less special case in xlate code
If valid "parent" is passed to proc_create/remove_proc_entry(), then name of
PDE should consist of only one path component, otherwise creation or or
removal will fail. However, if NULL is passed as parent then create/remove
accept full path as a argument. This is arbitrary restriction -- all
infrastructure is in place.
So, patch allows the following to succeed:
create_proc_entry("foo/bar", 0, pde_baz);
remove_proc_entry("baz/foo/bar", &proc_root);
Also makes the following to behave identically:
create_proc_entry("foo/bar", 0, NULL);
create_proc_entry("foo/bar", 0, &proc_root);
Discrepancy noticed by Den Lunev (IIRC).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 16:01:40 +08:00
|
|
|
if (xlate_proc_name(name, parent, &fn) != 0)
|
2005-04-17 06:20:36 +08:00
|
|
|
goto out;
|
2014-08-09 05:21:25 +08:00
|
|
|
qstr.name = fn;
|
|
|
|
qstr.len = strlen(fn);
|
|
|
|
if (qstr.len == 0 || qstr.len >= 256) {
|
|
|
|
WARN(1, "name len %u\n", qstr.len);
|
|
|
|
return NULL;
|
|
|
|
}
|
2018-04-11 07:32:11 +08:00
|
|
|
if (qstr.len == 1 && fn[0] == '.') {
|
|
|
|
WARN(1, "name '.'\n");
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
|
|
|
|
WARN(1, "name '..'\n");
|
|
|
|
return NULL;
|
|
|
|
}
|
2014-08-09 05:21:25 +08:00
|
|
|
if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
|
|
|
|
WARN(1, "create '/proc/%s' by hand\n", qstr.name);
|
|
|
|
return NULL;
|
|
|
|
}
|
2015-05-12 05:44:25 +08:00
|
|
|
if (is_empty_pde(*parent)) {
|
|
|
|
WARN(1, "attempt to add to permanently empty directory");
|
|
|
|
return NULL;
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2018-04-11 07:31:52 +08:00
|
|
|
ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
|
2012-10-05 08:15:43 +08:00
|
|
|
if (!ent)
|
|
|
|
goto out;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2018-06-14 02:43:19 +08:00
|
|
|
if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
|
2018-04-11 07:31:52 +08:00
|
|
|
ent->name = ent->inline_name;
|
|
|
|
} else {
|
|
|
|
ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
|
|
|
|
if (!ent->name) {
|
|
|
|
pde_free(ent);
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-08-09 05:21:25 +08:00
|
|
|
memcpy(ent->name, fn, qstr.len + 1);
|
|
|
|
ent->namelen = qstr.len;
|
2005-04-17 06:20:36 +08:00
|
|
|
ent->mode = mode;
|
|
|
|
ent->nlink = nlink;
|
2018-04-11 07:32:20 +08:00
|
|
|
ent->subdir = RB_ROOT;
|
2018-04-11 07:32:14 +08:00
|
|
|
refcount_set(&ent->refcnt, 1);
|
Fix rmmod/read/write races in /proc entries
Fix following races:
===========================================
1. Write via ->write_proc sleeps in copy_from_user(). Module disappears
meanwhile. Or, more generically, system call done on /proc file, method
supplied by module is called, module dissapeares meanwhile.
pde = create_proc_entry()
if (!pde)
return -ENOMEM;
pde->write_proc = ...
open
write
copy_from_user
pde = create_proc_entry();
if (!pde) {
remove_proc_entry();
return -ENOMEM;
/* module unloaded */
}
*boom*
==========================================
2. bogo-revoke aka proc_kill_inodes()
remove_proc_entry vfs_read
proc_kill_inodes [check ->f_op validness]
[check ->f_op->read validness]
[verify_area, security permissions checks]
->f_op = NULL;
if (file->f_op->read)
/* ->f_op dereference, boom */
NOTE, NOTE, NOTE: file_operations are proxied for regular files only. Let's
see how this scheme behaves, then extend if needed for directories.
Directories creators in /proc only set ->owner for them, so proxying for
directories may be unneeded.
NOTE, NOTE, NOTE: methods being proxied are ->llseek, ->read, ->write,
->poll, ->unlocked_ioctl, ->ioctl, ->compat_ioctl, ->open, ->release.
If your in-tree module uses something else, yell on me. Full audit pending.
[akpm@linux-foundation.org: build fix]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 14:39:00 +08:00
|
|
|
spin_lock_init(&ent->pde_unload_lock);
|
2008-07-25 16:48:29 +08:00
|
|
|
INIT_LIST_HEAD(&ent->pde_openers);
|
2016-08-11 05:36:01 +08:00
|
|
|
proc_set_user(ent, (*parent)->uid, (*parent)->gid);
|
|
|
|
|
2019-02-02 06:20:01 +08:00
|
|
|
ent->proc_dops = &proc_misc_dentry_ops;
|
|
|
|
|
2012-10-05 08:15:43 +08:00
|
|
|
out:
|
2005-04-17 06:20:36 +08:00
|
|
|
return ent;
|
|
|
|
}
|
|
|
|
|
|
|
|
struct proc_dir_entry *proc_symlink(const char *name,
|
|
|
|
struct proc_dir_entry *parent, const char *dest)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *ent;
|
|
|
|
|
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] destroy_inode+0x24/0x33
=======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 20:18:37 +08:00
|
|
|
ent = __proc_create(&parent, name,
|
2005-04-17 06:20:36 +08:00
|
|
|
(S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
|
|
|
|
|
|
|
|
if (ent) {
|
|
|
|
ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
|
|
|
|
if (ent->data) {
|
|
|
|
strcpy((char*)ent->data,dest);
|
2014-12-26 05:47:49 +08:00
|
|
|
ent->proc_iops = &proc_link_inode_operations;
|
2018-04-24 23:00:52 +08:00
|
|
|
ent = proc_register(parent, ent);
|
2005-04-17 06:20:36 +08:00
|
|
|
} else {
|
2018-04-11 07:31:52 +08:00
|
|
|
pde_free(ent);
|
2005-04-17 06:20:36 +08:00
|
|
|
ent = NULL;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return ent;
|
|
|
|
}
|
2009-12-30 13:24:41 +08:00
|
|
|
EXPORT_SYMBOL(proc_symlink);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-04-12 09:48:30 +08:00
|
|
|
struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
|
|
|
|
struct proc_dir_entry *parent, void *data)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
struct proc_dir_entry *ent;
|
|
|
|
|
2013-04-12 09:48:30 +08:00
|
|
|
if (mode == 0)
|
|
|
|
mode = S_IRUGO | S_IXUGO;
|
|
|
|
|
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] destroy_inode+0x24/0x33
=======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 20:18:37 +08:00
|
|
|
ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (ent) {
|
2013-04-12 09:48:30 +08:00
|
|
|
ent->data = data;
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
ent->proc_dir_ops = &proc_dir_operations;
|
2014-12-26 05:47:49 +08:00
|
|
|
ent->proc_iops = &proc_dir_inode_operations;
|
2018-04-24 23:00:52 +08:00
|
|
|
ent = proc_register(parent, ent);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
return ent;
|
|
|
|
}
|
2013-04-12 09:48:30 +08:00
|
|
|
EXPORT_SYMBOL_GPL(proc_mkdir_data);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-04-12 09:48:30 +08:00
|
|
|
struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
|
|
|
|
struct proc_dir_entry *parent)
|
2008-05-02 19:12:41 +08:00
|
|
|
{
|
2013-04-12 09:48:30 +08:00
|
|
|
return proc_mkdir_data(name, mode, parent, NULL);
|
2008-05-02 19:12:41 +08:00
|
|
|
}
|
2013-04-12 09:48:30 +08:00
|
|
|
EXPORT_SYMBOL(proc_mkdir_mode);
|
2008-05-02 19:12:41 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
struct proc_dir_entry *proc_mkdir(const char *name,
|
|
|
|
struct proc_dir_entry *parent)
|
|
|
|
{
|
2013-04-12 09:48:30 +08:00
|
|
|
return proc_mkdir_data(name, 0, parent, NULL);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2009-12-30 13:24:41 +08:00
|
|
|
EXPORT_SYMBOL(proc_mkdir);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2015-05-12 05:44:25 +08:00
|
|
|
struct proc_dir_entry *proc_create_mount_point(const char *name)
|
|
|
|
{
|
|
|
|
umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
|
|
|
|
struct proc_dir_entry *ent, *parent = NULL;
|
|
|
|
|
|
|
|
ent = __proc_create(&parent, name, mode, 2);
|
|
|
|
if (ent) {
|
|
|
|
ent->data = NULL;
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
ent->proc_dir_ops = NULL;
|
2015-05-12 05:44:25 +08:00
|
|
|
ent->proc_iops = NULL;
|
2018-04-24 23:00:52 +08:00
|
|
|
ent = proc_register(parent, ent);
|
2015-05-12 05:44:25 +08:00
|
|
|
}
|
|
|
|
return ent;
|
|
|
|
}
|
2016-11-14 19:12:56 +08:00
|
|
|
EXPORT_SYMBOL(proc_create_mount_point);
|
2015-05-12 05:44:25 +08:00
|
|
|
|
2018-04-24 23:08:36 +08:00
|
|
|
struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
|
|
|
|
struct proc_dir_entry **parent, void *data)
|
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] destroy_inode+0x24/0x33
=======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 20:18:37 +08:00
|
|
|
{
|
2018-04-24 23:08:36 +08:00
|
|
|
struct proc_dir_entry *p;
|
|
|
|
|
2013-03-31 09:20:14 +08:00
|
|
|
if ((mode & S_IFMT) == 0)
|
|
|
|
mode |= S_IFREG;
|
2018-04-24 23:08:36 +08:00
|
|
|
if ((mode & S_IALLUGO) == 0)
|
|
|
|
mode |= S_IRUGO;
|
|
|
|
if (WARN_ON_ONCE(!S_ISREG(mode)))
|
2013-03-31 09:20:14 +08:00
|
|
|
return NULL;
|
2018-04-24 23:08:36 +08:00
|
|
|
|
|
|
|
p = __proc_create(parent, name, mode, 1);
|
|
|
|
if (p) {
|
|
|
|
p->proc_iops = &proc_file_inode_operations;
|
|
|
|
p->data = data;
|
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] destroy_inode+0x24/0x33
=======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 20:18:37 +08:00
|
|
|
}
|
2018-04-24 23:08:36 +08:00
|
|
|
return p;
|
|
|
|
}
|
|
|
|
|
proc: faster open/read/close with "permanent" files
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:09:01 +08:00
|
|
|
static inline void pde_set_flags(struct proc_dir_entry *pde)
|
|
|
|
{
|
|
|
|
if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT)
|
|
|
|
pde->flags |= PROC_ENTRY_PERMANENT;
|
|
|
|
}
|
|
|
|
|
2018-04-24 23:08:36 +08:00
|
|
|
struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
|
|
|
|
struct proc_dir_entry *parent,
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
const struct proc_ops *proc_ops, void *data)
|
2018-04-24 23:08:36 +08:00
|
|
|
{
|
|
|
|
struct proc_dir_entry *p;
|
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] destroy_inode+0x24/0x33
=======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 20:18:37 +08:00
|
|
|
|
2018-04-24 23:08:36 +08:00
|
|
|
p = proc_create_reg(name, mode, &parent, data);
|
|
|
|
if (!p)
|
|
|
|
return NULL;
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
p->proc_ops = proc_ops;
|
proc: faster open/read/close with "permanent" files
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:09:01 +08:00
|
|
|
pde_set_flags(p);
|
2018-04-24 23:08:36 +08:00
|
|
|
return proc_register(parent, p);
|
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] destroy_inode+0x24/0x33
=======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 20:18:37 +08:00
|
|
|
}
|
2009-12-30 13:24:41 +08:00
|
|
|
EXPORT_SYMBOL(proc_create_data);
|
2013-04-12 07:38:51 +08:00
|
|
|
|
2017-09-09 07:13:38 +08:00
|
|
|
struct proc_dir_entry *proc_create(const char *name, umode_t mode,
|
|
|
|
struct proc_dir_entry *parent,
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
const struct proc_ops *proc_ops)
|
2017-09-09 07:13:38 +08:00
|
|
|
{
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
return proc_create_data(name, mode, parent, proc_ops, NULL);
|
2017-09-09 07:13:38 +08:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(proc_create);
|
|
|
|
|
2018-04-14 01:44:18 +08:00
|
|
|
static int proc_seq_open(struct inode *inode, struct file *file)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *de = PDE(inode);
|
|
|
|
|
2018-04-24 23:05:17 +08:00
|
|
|
if (de->state_size)
|
|
|
|
return seq_open_private(file, de->seq_ops, de->state_size);
|
2018-04-14 01:44:18 +08:00
|
|
|
return seq_open(file, de->seq_ops);
|
|
|
|
}
|
|
|
|
|
2018-06-10 03:51:24 +08:00
|
|
|
static int proc_seq_release(struct inode *inode, struct file *file)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *de = PDE(inode);
|
|
|
|
|
|
|
|
if (de->state_size)
|
|
|
|
return seq_release_private(inode, file);
|
|
|
|
return seq_release(inode, file);
|
|
|
|
}
|
|
|
|
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
static const struct proc_ops proc_seq_ops = {
|
proc: faster open/read/close with "permanent" files
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:09:01 +08:00
|
|
|
/* not permanent -- can call into arbitrary seq_operations */
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
.proc_open = proc_seq_open,
|
|
|
|
.proc_read = seq_read,
|
|
|
|
.proc_lseek = seq_lseek,
|
|
|
|
.proc_release = proc_seq_release,
|
2018-04-14 01:44:18 +08:00
|
|
|
};
|
|
|
|
|
2018-04-24 23:05:17 +08:00
|
|
|
struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
|
2018-04-14 01:44:18 +08:00
|
|
|
struct proc_dir_entry *parent, const struct seq_operations *ops,
|
2018-04-24 23:05:17 +08:00
|
|
|
unsigned int state_size, void *data)
|
2018-04-14 01:44:18 +08:00
|
|
|
{
|
|
|
|
struct proc_dir_entry *p;
|
|
|
|
|
|
|
|
p = proc_create_reg(name, mode, &parent, data);
|
|
|
|
if (!p)
|
|
|
|
return NULL;
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
p->proc_ops = &proc_seq_ops;
|
2018-04-14 01:44:18 +08:00
|
|
|
p->seq_ops = ops;
|
2018-04-24 23:05:17 +08:00
|
|
|
p->state_size = state_size;
|
2018-04-14 01:44:18 +08:00
|
|
|
return proc_register(parent, p);
|
|
|
|
}
|
2018-04-24 23:05:17 +08:00
|
|
|
EXPORT_SYMBOL(proc_create_seq_private);
|
2018-04-14 01:44:18 +08:00
|
|
|
|
2018-05-15 21:57:23 +08:00
|
|
|
static int proc_single_open(struct inode *inode, struct file *file)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *de = PDE(inode);
|
|
|
|
|
|
|
|
return single_open(file, de->single_show, de->data);
|
|
|
|
}
|
|
|
|
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
static const struct proc_ops proc_single_ops = {
|
proc: faster open/read/close with "permanent" files
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:09:01 +08:00
|
|
|
/* not permanent -- can call into arbitrary ->single_show */
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
.proc_open = proc_single_open,
|
|
|
|
.proc_read = seq_read,
|
|
|
|
.proc_lseek = seq_lseek,
|
|
|
|
.proc_release = single_release,
|
2018-05-15 21:57:23 +08:00
|
|
|
};
|
|
|
|
|
|
|
|
struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
|
|
|
|
struct proc_dir_entry *parent,
|
|
|
|
int (*show)(struct seq_file *, void *), void *data)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *p;
|
|
|
|
|
|
|
|
p = proc_create_reg(name, mode, &parent, data);
|
|
|
|
if (!p)
|
|
|
|
return NULL;
|
proc: decouple proc from VFS with "struct proc_ops"
Currently core /proc code uses "struct file_operations" for custom hooks,
however, VFS doesn't directly call them. Every time VFS expands
file_operations hook set, /proc code bloats for no reason.
Introduce "struct proc_ops" which contains only those hooks which /proc
allows to call into (open, release, read, write, ioctl, mmap, poll). It
doesn't contain module pointer as well.
Save ~184 bytes per usage:
add/remove: 26/26 grow/shrink: 1/4 up/down: 1922/-6674 (-4752)
Function old new delta
sysvipc_proc_ops - 72 +72
...
config_gz_proc_ops - 72 +72
proc_get_inode 289 339 +50
proc_reg_get_unmapped_area 110 107 -3
close_pdeo 227 224 -3
proc_reg_open 289 284 -5
proc_create_data 60 53 -7
rt_cpu_seq_fops 256 - -256
...
default_affinity_proc_fops 256 - -256
Total: Before=5430095, After=5425343, chg -0.09%
Link: http://lkml.kernel.org/r/20191225172228.GA13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 09:37:14 +08:00
|
|
|
p->proc_ops = &proc_single_ops;
|
2018-05-15 21:57:23 +08:00
|
|
|
p->single_show = show;
|
|
|
|
return proc_register(parent, p);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(proc_create_single_data);
|
|
|
|
|
2013-04-12 07:38:51 +08:00
|
|
|
void proc_set_size(struct proc_dir_entry *de, loff_t size)
|
|
|
|
{
|
|
|
|
de->size = size;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(proc_set_size);
|
|
|
|
|
|
|
|
void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
|
|
|
|
{
|
|
|
|
de->uid = uid;
|
|
|
|
de->gid = gid;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(proc_set_user);
|
proc: fix ->open'less usage due to ->proc_fops flip
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[<c1188c1b>] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] destroy_inode+0x24/0x33
=======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 20:18:37 +08:00
|
|
|
|
2009-12-16 08:45:39 +08:00
|
|
|
void pde_put(struct proc_dir_entry *pde)
|
|
|
|
{
|
2018-04-11 07:32:14 +08:00
|
|
|
if (refcount_dec_and_test(&pde->refcnt)) {
|
2018-04-11 07:31:52 +08:00
|
|
|
proc_free_inum(pde->low_ino);
|
|
|
|
pde_free(pde);
|
|
|
|
}
|
2009-12-16 08:45:39 +08:00
|
|
|
}
|
|
|
|
|
2013-03-31 08:13:46 +08:00
|
|
|
/*
|
|
|
|
* Remove a /proc entry and free it if it's not currently in use.
|
|
|
|
*/
|
|
|
|
void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *de = NULL;
|
|
|
|
const char *fn = name;
|
|
|
|
unsigned int len;
|
|
|
|
|
2015-09-10 06:35:57 +08:00
|
|
|
write_lock(&proc_subdir_lock);
|
2013-03-31 08:13:46 +08:00
|
|
|
if (__xlate_proc_name(name, &parent, &fn) != 0) {
|
2015-09-10 06:35:57 +08:00
|
|
|
write_unlock(&proc_subdir_lock);
|
2013-03-31 08:13:46 +08:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
len = strlen(fn);
|
|
|
|
|
2014-12-11 07:45:01 +08:00
|
|
|
de = pde_subdir_find(parent, fn, len);
|
2019-12-05 08:49:59 +08:00
|
|
|
if (de) {
|
proc: faster open/read/close with "permanent" files
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:09:01 +08:00
|
|
|
if (unlikely(pde_is_permanent(de))) {
|
|
|
|
WARN(1, "removing permanent /proc entry '%s'", de->name);
|
|
|
|
de = NULL;
|
|
|
|
} else {
|
|
|
|
rb_erase(&de->subdir_node, &parent->subdir);
|
|
|
|
if (S_ISDIR(de->mode))
|
|
|
|
parent->nlink--;
|
2019-12-05 08:49:59 +08:00
|
|
|
}
|
|
|
|
}
|
2015-09-10 06:35:57 +08:00
|
|
|
write_unlock(&proc_subdir_lock);
|
2013-03-31 08:13:46 +08:00
|
|
|
if (!de) {
|
|
|
|
WARN(1, "name '%s'\n", name);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2013-04-04 07:07:30 +08:00
|
|
|
proc_entry_rundown(de);
|
2008-07-25 16:48:29 +08:00
|
|
|
|
2014-12-11 07:45:01 +08:00
|
|
|
WARN(pde_subdir_first(de),
|
|
|
|
"%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
|
|
|
|
__func__, de->parent->name, de->name, pde_subdir_first(de)->name);
|
2009-12-16 08:45:39 +08:00
|
|
|
pde_put(de);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2009-12-30 13:24:41 +08:00
|
|
|
EXPORT_SYMBOL(remove_proc_entry);
|
2013-03-31 08:13:46 +08:00
|
|
|
|
|
|
|
int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *root = NULL, *de, *next;
|
|
|
|
const char *fn = name;
|
|
|
|
unsigned int len;
|
|
|
|
|
2015-09-10 06:35:57 +08:00
|
|
|
write_lock(&proc_subdir_lock);
|
2013-03-31 08:13:46 +08:00
|
|
|
if (__xlate_proc_name(name, &parent, &fn) != 0) {
|
2015-09-10 06:35:57 +08:00
|
|
|
write_unlock(&proc_subdir_lock);
|
2013-03-31 08:13:46 +08:00
|
|
|
return -ENOENT;
|
|
|
|
}
|
|
|
|
len = strlen(fn);
|
|
|
|
|
2014-12-11 07:45:01 +08:00
|
|
|
root = pde_subdir_find(parent, fn, len);
|
2013-03-31 08:13:46 +08:00
|
|
|
if (!root) {
|
2015-09-10 06:35:57 +08:00
|
|
|
write_unlock(&proc_subdir_lock);
|
2013-03-31 08:13:46 +08:00
|
|
|
return -ENOENT;
|
|
|
|
}
|
proc: faster open/read/close with "permanent" files
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:09:01 +08:00
|
|
|
if (unlikely(pde_is_permanent(root))) {
|
|
|
|
write_unlock(&proc_subdir_lock);
|
|
|
|
WARN(1, "removing permanent /proc entry '%s/%s'",
|
|
|
|
root->parent->name, root->name);
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
2018-04-11 07:32:20 +08:00
|
|
|
rb_erase(&root->subdir_node, &parent->subdir);
|
2014-12-11 07:45:01 +08:00
|
|
|
|
2013-03-31 08:13:46 +08:00
|
|
|
de = root;
|
|
|
|
while (1) {
|
2014-12-11 07:45:01 +08:00
|
|
|
next = pde_subdir_first(de);
|
2013-03-31 08:13:46 +08:00
|
|
|
if (next) {
|
proc: faster open/read/close with "permanent" files
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 11:09:01 +08:00
|
|
|
if (unlikely(pde_is_permanent(root))) {
|
|
|
|
write_unlock(&proc_subdir_lock);
|
|
|
|
WARN(1, "removing permanent /proc entry '%s/%s'",
|
|
|
|
next->parent->name, next->name);
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
2018-04-11 07:32:20 +08:00
|
|
|
rb_erase(&next->subdir_node, &de->subdir);
|
2013-03-31 08:13:46 +08:00
|
|
|
de = next;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
next = de->parent;
|
|
|
|
if (S_ISDIR(de->mode))
|
|
|
|
next->nlink--;
|
2019-12-05 08:49:59 +08:00
|
|
|
write_unlock(&proc_subdir_lock);
|
|
|
|
|
|
|
|
proc_entry_rundown(de);
|
2013-03-31 08:13:46 +08:00
|
|
|
if (de == root)
|
|
|
|
break;
|
|
|
|
pde_put(de);
|
|
|
|
|
2015-09-10 06:35:57 +08:00
|
|
|
write_lock(&proc_subdir_lock);
|
2013-03-31 08:13:46 +08:00
|
|
|
de = next;
|
|
|
|
}
|
|
|
|
pde_put(root);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(remove_proc_subtree);
|
2013-04-12 21:06:01 +08:00
|
|
|
|
|
|
|
void *proc_get_parent_data(const struct inode *inode)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *de = PDE(inode);
|
|
|
|
return de->parent->data;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(proc_get_parent_data);
|
2013-04-13 00:27:28 +08:00
|
|
|
|
|
|
|
void proc_remove(struct proc_dir_entry *de)
|
|
|
|
{
|
|
|
|
if (de)
|
|
|
|
remove_proc_subtree(de->name, de->parent);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(proc_remove);
|
2013-04-13 01:03:36 +08:00
|
|
|
|
|
|
|
void *PDE_DATA(const struct inode *inode)
|
|
|
|
{
|
|
|
|
return __PDE_DATA(inode);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(PDE_DATA);
|
2018-05-18 18:46:15 +08:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Pull a user buffer into memory and pass it to the file's write handler if
|
|
|
|
* one is supplied. The ->write() method is permitted to modify the
|
|
|
|
* kernel-side buffer.
|
|
|
|
*/
|
|
|
|
ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
|
|
|
|
loff_t *_pos)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(file_inode(f));
|
|
|
|
char *buf;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!pde->write)
|
|
|
|
return -EACCES;
|
|
|
|
if (size == 0 || size > PAGE_SIZE - 1)
|
|
|
|
return -EINVAL;
|
|
|
|
buf = memdup_user_nul(ubuf, size);
|
|
|
|
if (IS_ERR(buf))
|
|
|
|
return PTR_ERR(buf);
|
|
|
|
ret = pde->write(f, buf, size);
|
|
|
|
kfree(buf);
|
|
|
|
return ret == 0 ? size : ret;
|
|
|
|
}
|