The patch titled
Subject: proc: faster open/close of files without ->release hook
has been added to the -mm tree. Its filename is
proc-faster-open-close-of-files-without-release-hook.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-faster-open-close-of-files-without-release-hook.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-faster-open-close-of-files-without-release-hook.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: proc: faster open/close of files without ->release hook
The whole point of code in fs/proc/inode.c is to make sure ->release hook
is called either at close() or at rmmod time.
All if it is unnecessary if there is no ->release hook.
Save allocation+list manipulations under spinlock in that case.
Link: http://lkml.kernel.org/r/20180214063033.GA15579@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/inode.c | 41 +++++++++++++++++++++++------------------
1 file changed, 23 insertions(+), 18 deletions(-)
diff -puN fs/proc/inode.c~proc-faster-open-close-of-files-without-release-hook fs/proc/inode.c
--- a/fs/proc/inode.c~proc-faster-open-close-of-files-without-release-hook
+++ a/fs/proc/inode.c
@@ -342,31 +342,36 @@ static int proc_reg_open(struct inode *i
*
* Save every "struct file" with custom ->release hook.
*/
- pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
- if (!pdeo)
- return -ENOMEM;
-
- if (!use_pde(pde)) {
- kfree(pdeo);
+ if (!use_pde(pde))
return -ENOENT;
- }
- open = pde->proc_fops->open;
+
release = pde->proc_fops->release;
+ if (release) {
+ pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
+ if (!pdeo) {
+ rv = -ENOMEM;
+ goto out_unuse;
+ }
+ }
+ open = pde->proc_fops->open;
if (open)
rv = open(inode, file);
- if (rv == 0 && release) {
- /* To know what to release. */
- pdeo->file = file;
- pdeo->closing = false;
- pdeo->c = NULL;
- spin_lock(&pde->pde_unload_lock);
- list_add(&pdeo->lh, &pde->pde_openers);
- spin_unlock(&pde->pde_unload_lock);
- } else
- kfree(pdeo);
+ if (release) {
+ if (rv == 0) {
+ /* To know what to release. */
+ pdeo->file = file;
+ pdeo->closing = false;
+ pdeo->c = NULL;
+ spin_lock(&pde->pde_unload_lock);
+ list_add(&pdeo->lh, &pde->pde_openers);
+ spin_unlock(&pde->pde_unload_lock);
+ } else
+ kfree(pdeo);
+ }
+out_unuse:
unuse_pde(pde);
return rv;
}
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
proc-do-less-stuff-under-pde_unload_lock.patch
proc-move-proc-sysvipc-creation-to-where-it-belongs.patch
proc-faster-open-close-of-files-without-release-hook.patch
proc-randomize-struct-pde_opener.patch
proc-move-struct-pde_opener-to-kmem-cache.patch
proc-account-struct-pde_opener.patch
seq_file-delete-small-value-optimization.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
