From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 29 Aug 2012 13:00:01 +0000 (-0400)
Subject: close the race in nlmsvc_free_block()
X-Git-Tag: v3.6~6^2
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=c5aa1e554a20fb3542c62688ae46049c9225a965;p=~emulex%2Finfiniband.git

close the race in nlmsvc_free_block()

we need to grab mutex before the reference counter reaches 0

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index fb1a2bedbe9..8d80c990dff 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -289,7 +289,6 @@ static void nlmsvc_free_block(struct kref *kref)
 	dprintk("lockd: freeing block %p...\n", block);
 
 	/* Remove block from file's list of blocks */
-	mutex_lock(&file->f_mutex);
 	list_del_init(&block->b_flist);
 	mutex_unlock(&file->f_mutex);
 
@@ -303,7 +302,7 @@ static void nlmsvc_free_block(struct kref *kref)
 static void nlmsvc_release_block(struct nlm_block *block)
 {
 	if (block != NULL)
-		kref_put(&block->b_count, nlmsvc_free_block);
+		kref_put_mutex(&block->b_count, nlmsvc_free_block, &block->b_file->f_mutex);
 }
 
 /*