From 9a9800bbe9e2a38adaccc98314fff2354a52037e Mon Sep 17 00:00:00 2001

From: Jeffrey Cody <jcody@redhat.com>

Date: Tue, 16 Sep 2014 20:11:50 +0200

Subject: [PATCH 12/20] block: allow bdrv_unref() to be passed NULL pointers

Message-id: <aadda07926a2fbf063041cd73b68b8846ff677ed.1410897407.git.jcody@redhat.com>

Patchwork-id: 61216

O-Subject: [PATCH qemu-kvm-rhel RHEL7.1 11/15] block: allow bdrv_unref() to be passed NULL pointers

Bugzilla: 1098086

RH-Acked-by: Fam Zheng <famz@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Max Reitz <mreitz@redhat.com>

If bdrv_unref() is passed a NULL BDS pointer, it is safe to

exit with no operation.  This will allow cleanup code to blindly

call bdrv_unref() on a BDS that has been initialized to NULL.

Reviewed-by: Max Reitz <mreitz@redhat.com>

Signed-off-by: Jeff Cody <jcody@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit 9a4d5ca60772e09d0cbac01f1b4778aa68e00eaa)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 block.c |    3 +++

 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/block.c b/block.c

index a2e95f6..af162fe 100644

--- a/block.c

+++ b/block.c

@@ -5083,6 +5083,9 @@ void bdrv_ref(BlockDriverState *bs)

  * deleted. */

 void bdrv_unref(BlockDriverState *bs)

 {

+    if (!bs) {

+        return;

+    }

     assert(bs->refcnt > 0);

     if (--bs->refcnt == 0) {

         bdrv_delete(bs);

-- 

1.7.1