From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 13 Oct 2015 12:09:44 +0000 (+0200)
Subject: block: Allow bdrv_unref_child(bs, NULL)
X-Git-Tag: v2.5.0-rc0~70^2~8
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=779020cbdc67011026c10fb620f701bfc6b85547;p=thirdparty%2Fqemu.git

block: Allow bdrv_unref_child(bs, NULL)

bdrv_unref() can be called with a NULL argument and doesn't do anything
then. Make bdrv_unref_child() consistent with it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
---

diff --git a/block.c b/block.c
index f38146e2e86..6490040b43a 100644
--- a/block.c
+++ b/block.c
@@ -1104,12 +1104,17 @@ static void bdrv_detach_child(BdrvChild *child)
 
 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child)
 {
-    BlockDriverState *child_bs = child->bs;
+    BlockDriverState *child_bs;
+
+    if (child == NULL) {
+        return;
+    }
 
     if (child->bs->inherits_from == parent) {
         child->bs->inherits_from = NULL;
     }
 
+    child_bs = child->bs;
     bdrv_detach_child(child);
     bdrv_unref(child_bs);
 }