Message ID | 20180913125217.23173-15-kwolf@redhat.com |
---|---|
State | New |
Headers | show |
Series | Fix some jobs/drain/aio_poll related hangs | expand |
On 13.09.18 14:52, Kevin Wolf wrote: > bdrv_drain_poll_top_level() was buggy because it didn't release the > AioContext lock of the node to be drained before calling aio_poll(). > This way, callbacks called by aio_poll() would possibly take the lock a > second time and run into a deadlock with a nested AIO_WAIT_WHILE() call. > > However, it turns out that the aio_poll() call isn't actually needed any > more. It was introduced in commit 91af091f923, which is effectively > reverted by this patch. The cases it was supposed to fix are now covered > by bdrv_drain_poll(), which waits for block jobs to reach a quiescent > state. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > Reviewed-by: Fam Zheng <famz@redhat.com> > --- > block/io.c | 8 -------- > 1 file changed, 8 deletions(-) Reviewed-by: Max Reitz <mreitz@redhat.com>
diff --git a/block/io.c b/block/io.c index 914ba78f1a..8b81ff3913 100644 --- a/block/io.c +++ b/block/io.c @@ -268,10 +268,6 @@ bool bdrv_drain_poll(BlockDriverState *bs, bool recursive, static bool bdrv_drain_poll_top_level(BlockDriverState *bs, bool recursive, BdrvChild *ignore_parent) { - /* Execute pending BHs first and check everything else only after the BHs - * have executed. */ - while (aio_poll(bs->aio_context, false)); - return bdrv_drain_poll(bs, recursive, ignore_parent, false); } @@ -511,10 +507,6 @@ static bool bdrv_drain_all_poll(void) BlockDriverState *bs = NULL; bool result = false; - /* Execute pending BHs first (may modify the graph) and check everything - * else only after the BHs have executed. */ - while (aio_poll(qemu_get_aio_context(), false)); - /* bdrv_drain_poll() can't make changes to the graph and we are holding the * main AioContext lock, so iterating bdrv_next_all_states() is safe. */ while ((bs = bdrv_next_all_states(bs))) {