linux-kernel - [PATCH 6/6] autofs4: don't take spinlock when not needed in autofs4_lookup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140709234114.4525.70534.stgit@notabene.brown>
Date:	Thu, 10 Jul 2014 09:41:14 +1000
From:	NeilBrown <neilb@...e.de>
To:	Ian Kent <raven@...maw.net>
Cc:	autofs@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 6/6] 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 authfs4_d_manage.

Signed-off-by: NeilBrown <neilb@...e.de>
---
 fs/autofs4/root.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 1ad119407e2f..774c2dab331b 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -219,6 +219,8 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry,
 	const unsigned char *str = name->name;
 	struct list_head *p, *head;
 
+	if (list_empty(&sbi->expiring_list))
+		return NULL;
 	spin_lock(&sbi->lookup_lock);
 	head = &sbi->expiring_list;
 	list_for_each(p, head) {


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/