Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 668128e9 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
Browse files

autofs4: don't take spinlock when not needed in autofs4_lookup_expiring 



If the expiring_list is empty, we can avoid a costly spinlock in the
rcu-walk path through autofs4_d_manage (once the rest of the path
becomes rcu-walk friendly).

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarIan Kent <raven@themaw.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c312442f

fs/autofs4/root.c

+6 −2
Original line number Diff line number Diff line
@@ -166,8 +166,10 @@ static struct dentry *autofs4_lookup_active(struct dentry *dentry) 
	const unsigned char *str = name->name;

	struct list_head *p, *head;



	spin_lock(&sbi->lookup_lock);

	head = &sbi->active_list;

	if (list_empty(head))

		return NULL;

	spin_lock(&sbi->lookup_lock);

	list_for_each(p, head) {

		struct autofs_info *ino;

		struct dentry *active;
@@ -218,8 +220,10 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) 
	const unsigned char *str = name->name;

	struct list_head *p, *head;



	spin_lock(&sbi->lookup_lock);

	head = &sbi->expiring_list;

	if (list_empty(head))

		return NULL;

	spin_lock(&sbi->lookup_lock);

	list_for_each(p, head) {

		struct autofs_info *ino;

		struct dentry *expiring;