diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2023-06-05 10:57:10 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2023-06-28 08:46:23 +0200 |
| commit | 31b2ddfea304afc498aca8cac171020ef33eb89b (patch) | |
| tree | 3d0f42e0e2539c0f354169ffc2678456e8653190 /include/block | |
| parent | 22dd9405446f5301f32be4f9e88db6d9b582fd03 (diff) | |
graph-lock: Unlock the AioContext while polling
If the caller keeps the AioContext lock for a block node in an iothread,
polling in bdrv_graph_wrlock() deadlocks if the condition isn't
fulfilled immediately.
Now that all callers make sure to actually have the AioContext locked
when they call bdrv_replace_child_noperm() like they should, we can
change bdrv_graph_wrlock() to take a BlockDriverState whose AioContext
lock the caller holds (NULL if it doesn't) and unlock it temporarily
while polling.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230605085711.21261-11-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'include/block')
| -rw-r--r-- | include/block/graph-lock.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h index 7574a2de5b..7e04f98ff0 100644 --- a/include/block/graph-lock.h +++ b/include/block/graph-lock.h @@ -111,10 +111,12 @@ void unregister_aiocontext(AioContext *ctx); * The wrlock can only be taken from the main loop, with BQL held, as only the * main loop is allowed to modify the graph. * + * If @bs is non-NULL, its AioContext is temporarily released. + * * This function polls. Callers must not hold the lock of any AioContext other - * than the current one. + * than the current one and the one of @bs. */ -void bdrv_graph_wrlock(void) TSA_ACQUIRE(graph_lock) TSA_NO_TSA; +void bdrv_graph_wrlock(BlockDriverState *bs) TSA_ACQUIRE(graph_lock) TSA_NO_TSA; /* * bdrv_graph_wrunlock: |