linux-kernel - [PATCH 1/4] vfs: Remove useless loop in mntput_no

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Message-ID: <87sipguzos.fsf_-_@x220.int.ebiederm.org>
Date:	Mon, 14 Apr 2014 00:40:03 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Al Viro <viro@...IV.linux.org.uk>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Serge E. Hallyn" <serge@...lyn.com>,
	Linux-Fsdevel <linux-fsdevel@...r.kernel.org>,
	Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Andy Lutomirski <luto@...capital.net>,
	Rob Landley <rob@...dley.net>,
	Miklos Szeredi <miklos@...redi.hu>,
	Christoph Hellwig <hch@...radead.org>,
	Karel Zak <kzak@...hat.com>,
	"J. Bruce Fields" <bfields@...ldses.org>,
	Fengguang Wu <fengguang.wu@...el.com>, tytso@....edu
Subject: [PATCH 1/4] vfs: Remove useless loop in mntput_no_expire


Remove the extra reference added to mnt_count by the mnt_pinned code,
and stop jumping to the top of mntput_no_expire.

When fput synchronously called mntput that extra reference count and
the loop ensured that after acct_auto_close_mnt closed all of the
pinned references mntput_no_expire would then proceed actually
unmount the filesystem.

As fput is asynchronous today there is no point in looping.

Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>
---
 fs/namespace.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 9d0eb6b4e7d5..2abd5a2416d0 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -985,7 +985,6 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
 
 static void mntput_no_expire(struct mount *mnt)
 {
-put_again:
 	rcu_read_lock();
 	mnt_add_count(mnt, -1);
 	if (likely(mnt->mnt_ns)) { /* shouldn't be the last one */
@@ -999,12 +998,12 @@ put_again:
 		return;
 	}
 	if (unlikely(mnt->mnt_pinned)) {
-		mnt_add_count(mnt, mnt->mnt_pinned + 1);
+		mnt_add_count(mnt, mnt->mnt_pinned);
 		mnt->mnt_pinned = 0;
 		rcu_read_unlock();
 		unlock_mount_hash();
 		acct_auto_close_mnt(&mnt->mnt);
-		goto put_again;
+		return;
 	}
 	if (unlikely(mnt->mnt.mnt_flags & MNT_DOOMED)) {
 		rcu_read_unlock();
-- 
1.9.1

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