[PATCH v2 08/10] block: Don't query all block devices at hmp_nbd_server_start

[Fabiano Rosas <farosas@suse.de>]

We're currently doing a full query-block just to enumerate the devices
for qmp_nbd_server_add and then discarding the BlockInfoList
afterwards. Alter hmp_nbd_server_start to instead iterate explicitly
over the block_backends list.

This allows the removal of the dependency on qmp_query_block from
hmp_nbd_server_start. This is desirable because we're about to move
qmp_query_block into a coroutine and don't need to change the NBD code
at the same time.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 block/monitor/block-hmp-cmds.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/block/monitor/block-hmp-cmds.c b/block/monitor/block-hmp-cmds.c
index ca2599de44..26116fe831 100644
--- a/block/monitor/block-hmp-cmds.c
+++ b/block/monitor/block-hmp-cmds.c
@@ -394,7 +394,7 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
     bool writable = qdict_get_try_bool(qdict, "writable", false);
     bool all = qdict_get_try_bool(qdict, "all", false);
     Error *local_err = NULL;
-    BlockInfoList *block_list, *info;
+    BlockBackend *blk;
     SocketAddress *addr;
     NbdServerAddOptions export;
 
@@ -419,18 +419,24 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
         return;
     }
 
-    /* Then try adding all block devices.  If one fails, close all and
+    /*
+     * Then try adding all block devices.  If one fails, close all and
      * exit.
      */
-    block_list = qmp_query_block(NULL);
+    for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) {
+        BlockDriverState *bs = blk_bs(blk);
 
-    for (info = block_list; info; info = info->next) {
-        if (!info->value->inserted) {
+        if (!*blk_name(blk) && !blk_get_attached_dev(blk)) {
+            continue;
+        }
+
+        bs = bdrv_skip_implicit_filters(bs);
+        if (!bs || !bs->drv) {
             continue;
         }
 
         export = (NbdServerAddOptions) {
-            .device         = info->value->device,
+            .device         = g_strdup(blk_name(blk)),
             .has_writable   = true,
             .writable       = writable,
         };
@@ -443,8 +449,6 @@ void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
         }
     }
 
-    qapi_free_BlockInfoList(block_list);
-
 exit:
     hmp_handle_error(mon, local_err);
 }
-- 
2.35.3