block: Fix bdrv_next() memory leak

The bdrv_next() users all leaked the BdrvNextIterator after completing
the iteration. Simply changing bdrv_next() to free the iterator before
returning NULL at the end of list doesn't work because some callers exit
the loop before looking at all BDSes.

This patch moves the BdrvNextIterator from the heap to the stack of
the caller and switches to a bdrv_first()/bdrv_next() interface for
initialising the iterator.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/qmp.c b/qmp.c
index 8f8ae3a79d..3165f8726b 100644
--- a/qmp.c
+++ b/qmp.c
@@ -181,7 +181,7 @@ void qmp_cont(Error **errp)
     Error *local_err = NULL;
     BlockBackend *blk;
     BlockDriverState *bs;
-    BdrvNextIterator *it;
+    BdrvNextIterator it;
 
     /* if there is a dump in background, we should wait until the dump
      * finished */
@@ -201,8 +201,7 @@ void qmp_cont(Error **errp)
         blk_iostatus_reset(blk);
     }
 
-    it = NULL;
-    while ((it = bdrv_next(it, &bs))) {
+    for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
         bdrv_add_key(bs, NULL, &local_err);
         if (local_err) {
             error_propagate(errp, local_err);