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seq_file: allocate seq_file from kmem_cache 

For fine-grained debugging and usercopy protection.

Link: http://lkml.kernel.org/r/20180310085027.GA17121@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.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 2018-04-10 16:34:45 -07:00 committed by Linus Torvalds
parent 9ad553abe6
commit 0965232035
3 changed files with 12 additions and 2 deletions
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12
fs/seq_file.c
View File

@ -6,6 +6,7 @@
* initial implementation -- AV, Oct 2001. * initial implementation -- AV, Oct 2001.
*/ */
#include <linux/cache.h>
#include <linux/fs.h> #include <linux/fs.h>
#include <linux/export.h> #include <linux/export.h>
#include <linux/seq_file.h> #include <linux/seq_file.h>
@ -19,6 +20,8 @@
#include <linux/uaccess.h> #include <linux/uaccess.h>
#include <asm/page.h> #include <asm/page.h>
static struct kmem_cache *seq_file_cache __ro_after_init;
static void seq_set_overflow(struct seq_file *m) static void seq_set_overflow(struct seq_file *m)
{ {
m->count = m->size; m->count = m->size;
@ -51,7 +54,7 @@ int seq_open(struct file *file, const struct seq_operations *op)
WARN_ON(file->private_data); WARN_ON(file->private_data);
p = kzalloc(sizeof(*p), GFP_KERNEL); p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL);
if (!p) if (!p)
return -ENOMEM; return -ENOMEM;
@ -366,7 +369,7 @@ int seq_release(struct inode *inode, struct file *file)
{ {
struct seq_file *m = file->private_data; struct seq_file *m = file->private_data;
kvfree(m->buf); kvfree(m->buf);
kfree(m); kmem_cache_free(seq_file_cache, m);
return 0; return 0;
} }
EXPORT_SYMBOL(seq_release); EXPORT_SYMBOL(seq_release);
@ -1106,3 +1109,8 @@ seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
return NULL; return NULL;
} }
EXPORT_SYMBOL(seq_hlist_next_percpu); EXPORT_SYMBOL(seq_hlist_next_percpu);
void __init seq_file_init(void)
{
seq_file_cache = KMEM_CACHE(seq_file, SLAB_PANIC);
}

1
include/linux/seq_file.h
View File

@ -240,4 +240,5 @@ extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *hea
extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos); extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);
void seq_file_init(void);
#endif #endif

1
init/main.c
View File

@ -715,6 +715,7 @@ asmlinkage __visible void __init start_kernel(void)
vfs_caches_init(); vfs_caches_init();
pagecache_init(); pagecache_init();
signals_init(); signals_init();
seq_file_init();
proc_root_init(); proc_root_init();
nsfs_init(); nsfs_init();
cpuset_init(); cpuset_init();