block: Add bdrv_next_monitor_owned()

Add a function for iterating over all monitor-owned BlockDriverStates so
the generic block layer can do so.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

blockdev.c

@@ -723,6 +723,13 @@ void blockdev_close_all_bdrv_states(void)
     }
 }
 
+/* Iterates over the list of monitor-owned BlockDriverStates */
+BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs)
+{
+    return bs ? QTAILQ_NEXT(bs, monitor_list)
+              : QTAILQ_FIRST(&monitor_bdrv_states);
+}
+
 static void qemu_opt_rename(QemuOpts *opts, const char *from, const char *to,
                             Error **errp)
 {

include/block/block.h

@@ -412,6 +412,7 @@ BlockDriverState *bdrv_lookup_bs(const char *device,
 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base);
 BlockDriverState *bdrv_next_node(BlockDriverState *bs);
 BlockDriverState *bdrv_next(BlockDriverState *bs);
+BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs);
 int bdrv_is_encrypted(BlockDriverState *bs);
 int bdrv_key_required(BlockDriverState *bs);
 int bdrv_set_key(BlockDriverState *bs, const char *key);

stubs/Makefile.objs

 stub-obj-y += arch-query-cpu-def.o
+stub-obj-y += bdrv-next-monitor-owned.o
 stub-obj-y += blk-commit-all.o
 stub-obj-y += blockdev-close-all-bdrv-states.o
 stub-obj-y += clock-warp.o

stubs/bdrv-next-monitor-owned.c

+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "block/block.h"
+
+BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs)
+{
+    return NULL;
+}