[PATCH v4 41/48] block: mark bdrv_new() as GRAPH_UNLOCKED

[Fiona Ebner]

The function bdrv_new() calls bdrv_drained_begin(), which must be
called with the graph unlocked.

Marking bdrv_new() as GRAPH_UNLOCKED requires making the locked
section in bdrv_open_inherit() shorter.

Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
---

I'm not sure if the TODO comment is only intended for the
lower half of the function, i.e. is moving it like this okay?

 block.c                            | 7 ++++---
 include/block/block-global-state.h | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/block.c b/block.c
index 6f470aac2f..1b9c99dda9 100644
--- a/block.c
+++ b/block.c
@@ -3995,10 +3995,8 @@ bdrv_open_inherit(const char *filename, const char 
*reference, QDict *options,
     GLOBAL_STATE_CODE();
     assert(!qemu_in_coroutine());
 
-    /* TODO We'll eventually have to take a writer lock in this function */
-    GRAPH_RDLOCK_GUARD_MAINLOOP();
-
     if (reference) {
+        GRAPH_RDLOCK_GUARD_MAINLOOP();
         bool options_non_empty = options ? qdict_size(options) : false;
         qobject_unref(options);
 
@@ -4019,6 +4017,9 @@ bdrv_open_inherit(const char *filename, const char 
*reference, QDict *options,
 
     bs = bdrv_new();
 
+    /* TODO We'll eventually have to take a writer lock in this function */
+    GRAPH_RDLOCK_GUARD_MAINLOOP();
+
     /* NULL means an empty set of options */
     if (options == NULL) {
         options = qdict_new();
diff --git a/include/block/block-global-state.h 
b/include/block/block-global-state.h
index eec92a98da..b1f826dca6 100644
--- a/include/block/block-global-state.h
+++ b/include/block/block-global-state.h
@@ -67,7 +67,7 @@ int co_wrapper bdrv_create(BlockDriver *drv, const char 
*filename,
 int coroutine_fn GRAPH_UNLOCKED
 bdrv_co_create_file(const char *filename, QemuOpts *opts, Error **errp);
 
-BlockDriverState *bdrv_new(void);
+BlockDriverState * GRAPH_UNLOCKED bdrv_new(void);
 int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
                 Error **errp);
 
-- 
2.39.5