[RFC PATCH 4/6] Convert query-block/info_block to coroutine

[Fabiano Rosas <farosas@suse.de>]

From: Lin Ma <lma@suse.com>

Sometimes the query-block performs time-consuming I/O(say waiting for
the fstat of NFS complete), So let's make this QMP handler runs in a
coroutine.

The following patch moves the fstat() into a thread pool.

Signed-off-by: Lin Ma <lma@suse.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 blockdev.c           | 6 +++---
 qapi/block-core.json | 3 ++-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 5d56b79df4..6412548662 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2804,9 +2804,9 @@ void qmp_drive_backup(DriveBackup *backup, Error **errp)
     blockdev_do_action(&action, errp);
 }
 
-BlockDeviceInfoList *qmp_query_named_block_nodes(bool has_flat,
-                                                 bool flat,
-                                                 Error **errp)
+BlockDeviceInfoList *coroutine_fn qmp_query_named_block_nodes(bool has_flat,
+                                                              bool flat,
+                                                              Error **errp)
 {
     bool return_flat = has_flat && flat;
 
diff --git a/qapi/block-core.json b/qapi/block-core.json
index da95fe456c..0559c38412 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1972,7 +1972,8 @@
 { 'command': 'query-named-block-nodes',
   'returns': [ 'BlockDeviceInfo' ],
   'data': { '*flat': 'bool' },
-  'allow-preconfig': true }
+  'allow-preconfig': true,
+  'coroutine': true}
 
 ##
 # @XDbgBlockGraphNodeType:
-- 
2.35.3