From: Stefan Hajnoczi Date: Tue, 8 Aug 2023 15:58:51 +0000 (-0400) Subject: block: minimize bs->reqs_lock section in tracked_request_end() X-Git-Tag: pull-xenfv-stable-20231106~102^2~12 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=3480ce69a9c7ee956323c45269d21b6905488904;p=users%2Fdwmw2%2Fqemu.git block: minimize bs->reqs_lock section in tracked_request_end() Signed-off-by: Stefan Hajnoczi Message-ID: <20230808155852.2745350-2-stefanha@redhat.com> Reviewed-by: Eric Blake Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- diff --git a/block/io.c b/block/io.c index 76e7df18d8..4f32d6aa6e 100644 --- a/block/io.c +++ b/block/io.c @@ -593,8 +593,14 @@ static void coroutine_fn tracked_request_end(BdrvTrackedRequest *req) qemu_co_mutex_lock(&req->bs->reqs_lock); QLIST_REMOVE(req, list); - qemu_co_queue_restart_all(&req->wait_queue); qemu_co_mutex_unlock(&req->bs->reqs_lock); + + /* + * At this point qemu_co_queue_wait(&req->wait_queue, ...) won't be called + * anymore because the request has been removed from the list, so it's safe + * to restart the queue outside reqs_lock to minimize the critical section. + */ + qemu_co_queue_restart_all(&req->wait_queue); } /**