Re: [PATCH 1/2] audit: Quit audit_free_names() early if name list empty

Al Viro
2026-01-21T05:24:47Z

On Tue, Jan 20, 2026 at 11:08:45PM -0500, Waiman Long wrote:
>
> On 1/20/26 10:11 PM, Al Viro wrote:
> > On Tue, Jan 20, 2026 at 09:35:08PM -0500, Waiman Long wrote:
> > > Optimize audit_free_names() by quitting early if the name list is empty.
> > > This eliminates the need to acquire and release the fs_struct spinlock
> > > in path_put().
> > Why would path_put() go anywhere need fs_struct spinlock???
> >
> path_put() is defined in include/linux/fs_struct.h. It calls
> read_seq{un}lock_excl(&fs->seq) which, in turn, acquires the releases the
> spinlock underneath the seqlock_t.

Really? Which kernel would that be? On mainline we have

; git grep -n -w path_put include/linux/fs_struct.h
; $ git grep -C 6 'void path_put\>' fs/namei.c
fs/namei.c-/**
fs/namei.c- * path_put - put a reference to a path
fs/namei.c- * @path: path to put the reference to
fs/namei.c- *
fs/namei.c- * Given a path decrement the reference count to the dentry and the vfsmount.
fs/namei.c- */
fs/namei.c:void path_put(const struct path *path)
fs/namei.c-{
fs/namei.c- dput(path->dentry);
fs/namei.c- mntput(path->mnt);
fs/namei.c-}
fs/namei.c-EXPORT_SYMBOL(path_put);
fs/namei.c-
;