qemu/queue.h: add QLIST_SAFE_REMOVE()

QLIST_REMOVE() assumes the element is in a list.  It also leaves the
element's linked list pointers dangling.

Introduce a safe version of QLIST_REMOVE() and convert open-coded
instances of this pattern.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Message-id: 20200214171712.541358-4-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/block.c b/block.c
index 308a91c96b..1bdb9c679d 100644
--- a/block.c
+++ b/block.c
@@ -2636,10 +2636,7 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
 
 static void bdrv_detach_child(BdrvChild *child)
 {
-    if (child->next.le_prev) {
-        QLIST_REMOVE(child, next);
-        child->next.le_prev = NULL;
-    }
+    QLIST_SAFE_REMOVE(child, next);
 
     bdrv_replace_child(child, NULL);