From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47037) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ag8PS-0007Ly-TF for qemu-devel@nongnu.org; Wed, 16 Mar 2016 06:10:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ag8PN-0005eA-Bo for qemu-devel@nongnu.org; Wed, 16 Mar 2016 06:10:34 -0400 From: Fam Zheng Date: Wed, 16 Mar 2016 18:10:15 +0800 Message-Id: <1458123018-18651-2-git-send-email-famz@redhat.com> In-Reply-To: <1458123018-18651-1-git-send-email-famz@redhat.com> References: <1458123018-18651-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_context List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , qemu-block@nongnu.org, "Michael S. Tsirkin" , tubo@linux.vnet.ibm.com, Stefan Hajnoczi , cornelia.huck@de.ibm.com, pbonzini@redhat.com, borntraeger@de.ibm.com An empty begin/end pair is almost the same as a bare bdrv_drain except the aio_poll inside is wrapped by aio_disable_external/aio_enable_external. This is safer, and is the only way to achieve quiescence in this aio_poll(), because bdrv_drained_begin/end pair cannot span across context detach/attach options, so it's not possible to do by the caller. Signed-off-by: Fam Zheng --- block.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 59a18a3..31f4a9f 100644 --- a/block.c +++ b/block.c @@ -3747,7 +3747,9 @@ void bdrv_attach_aio_context(BlockDriverState *bs, void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) { - bdrv_drain(bs); /* ensure there are no in-flight requests */ + /* ensure there are no in-flight requests */ + bdrv_drained_begin(bs); + bdrv_drained_end(bs); bdrv_detach_aio_context(bs); -- 2.4.3