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Commit e56ed358 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
Browse files

kernfs: make kernfs_walk_ns() use kernfs_pr_cont_buf[] 



kernfs_walk_ns() uses a static path_buf[PATH_MAX] to separate out path
components.  Keeping around the 4k buffer just for kernfs_walk_ns() is
wasteful.  This patch makes it piggyback on kernfs_pr_cont_buf[]
instead.  This requires kernfs_walk_ns() to hold kernfs_rename_lock.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 388f7b1d

fs/kernfs/dir.c

+14 −5
Original line number Diff line number Diff line
@@ -691,15 +691,22 @@ static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, 
					  const unsigned char *path,

					  const void *ns)

{

	static char path_buf[PATH_MAX];	/* protected by kernfs_mutex */

	size_t len = strlcpy(path_buf, path, PATH_MAX);

	char *p = path_buf;

	char *name;

	size_t len;

	char *p, *name;



	lockdep_assert_held(&kernfs_mutex);



	if (len >= PATH_MAX)

	/* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */

	spin_lock_irq(&kernfs_rename_lock);



	len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf));



	if (len >= sizeof(kernfs_pr_cont_buf)) {

		spin_unlock_irq(&kernfs_rename_lock);

		return NULL;

	}



	p = kernfs_pr_cont_buf;



	while ((name = strsep(&p, "/")) && parent) {

		if (*name == '\0')
@@ -707,6 +714,8 @@ static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, 
		parent = kernfs_find_ns(parent, name, ns);

	}



	spin_unlock_irq(&kernfs_rename_lock);



	return parent;

}