From bbfb7c2f350262f893642433dea66352fc168295 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 10 Jun 2021 13:08:02 +0300 Subject: [PATCH] block/nbd: safer transition to receiving request req->receiving is a flag of request being in one concrete yield point in nbd_co_do_receive_one_chunk(). Such kind of boolean flag is always better to unset before scheduling the coroutine, to avoid double scheduling. So, let's be more careful. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20210610100802.5888-33-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/nbd.c b/block/nbd.c index 5cfb749e08..3cbee762de 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -150,6 +150,7 @@ static void nbd_recv_coroutines_wake_all(BDRVNBDState *s) NBDClientRequest *req = &s->requests[i]; if (req->coroutine && req->receiving) { + req->receiving = false; aio_co_wake(req->coroutine); } } @@ -548,6 +549,7 @@ static coroutine_fn void nbd_connection_entry(void *opaque) * connection_co happens through a bottom half, which can only * run after we yield. */ + s->requests[i].receiving = false; aio_co_wake(s->requests[i].coroutine); qemu_coroutine_yield(); } @@ -934,7 +936,7 @@ static coroutine_fn int nbd_co_do_receive_one_chunk( /* Wait until we're woken up by nbd_connection_entry. */ s->requests[i].receiving = true; qemu_coroutine_yield(); - s->requests[i].receiving = false; + assert(!s->requests[i].receiving); if (!nbd_client_connected(s)) { error_setg(errp, "Connection closed"); return -EIO;