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fs/proc: calculate /proc/* and /proc/*/task/* nlink at init time 

Runtime nlink calculation works but meh.  I don't know how to do it at
compile time, but I know how to do it at init time.

Shift "2+" part into init time as a bonus.

Link: http://lkml.kernel.org/r/20161122195549.GB29812@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan 2016-12-12 16:45:32 -08:00 committed by Linus Torvalds
parent bac5f5d56b
commit 1270dd8d99
3 changed files with 15 additions and 6 deletions
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19
fs/proc/base.c
View File

@ -104,6 +104,9 @@
* in /proc for a task before it execs a suid executable.
*/
static u8 nlink_tid;
static u8 nlink_tgid;
struct pid_entry {
const char *name;
unsigned int len;
@ -139,13 +142,13 @@ struct pid_entry {
* Count the number of hardlinks for the pid_entry table, excluding the .
* and .. links.
*/
static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
unsigned int n)
{
unsigned int i;
unsigned int count;
count = 0;
count = 2;
for (i = 0; i < n; ++i) {
if (S_ISDIR(entries[i].mode))
++count;
@ -3068,8 +3071,7 @@ static int proc_pid_instantiate(struct inode *dir,
inode->i_fop = &proc_tgid_base_operations;
inode->i_flags|=S_IMMUTABLE;
set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,
ARRAY_SIZE(tgid_base_stuff)));
set_nlink(inode, nlink_tgid);
d_set_d_op(dentry, &pid_dentry_operations);
@ -3361,8 +3363,7 @@ static int proc_task_instantiate(struct inode *dir,
inode->i_fop = &proc_tid_base_operations;
inode->i_flags|=S_IMMUTABLE;
set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,
ARRAY_SIZE(tid_base_stuff)));
set_nlink(inode, nlink_tid);
d_set_d_op(dentry, &pid_dentry_operations);
@ -3552,3 +3553,9 @@ static const struct file_operations proc_task_operations = {
.iterate_shared = proc_task_readdir,
.llseek = generic_file_llseek,
};
void __init set_proc_pid_nlink(void)
{
nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
}

1
fs/proc/internal.h
View File

@ -211,6 +211,7 @@ extern const struct inode_operations proc_link_inode_operations;
extern const struct inode_operations proc_pid_link_inode_operations;
extern void proc_init_inodecache(void);
void set_proc_pid_nlink(void);
extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
extern int proc_fill_super(struct super_block *, void *data, int flags);
extern void proc_entry_rundown(struct proc_dir_entry *);

1
fs/proc/root.c
View File

@ -122,6 +122,7 @@ void __init proc_root_init(void)
int err;
proc_init_inodecache();
set_proc_pid_nlink();
err = register_filesystem(&proc_fs_type);
if (err)
return;