diff options
| author | Alexey Dobriyan | 2018-04-10 16:31:01 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2018-04-11 10:28:33 -0700 |
| commit | e7a6e291e30a00061c356bbcba0d9380943a1671 (patch) | |
| tree | 896f6dbe0a8e1b1aee688b4bd61da4cb21dd7ec4 /fs | |
| parent | e74a0effffbbea75fe2b6770948f84fcb0917cdd (diff) | |
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@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/proc/inode.c | 41 |
1 files changed, 23 insertions, 18 deletions
diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 8118ce5df5c6..0331ddbee4f6 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -342,31 +342,36 @@ static int proc_reg_open(struct inode *inode, struct file *file) * * 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; } |