From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42032) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1agCG8-0002tu-Mc for qemu-devel@nongnu.org; Wed, 16 Mar 2016 10:17:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1agCG5-0005wK-I6 for qemu-devel@nongnu.org; Wed, 16 Mar 2016 10:17:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37441) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1agCG5-0005w4-Ck for qemu-devel@nongnu.org; Wed, 16 Mar 2016 10:17:09 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 1FA7646266 for ; Wed, 16 Mar 2016 14:17:09 +0000 (UTC) From: Paolo Bonzini Date: Wed, 16 Mar 2016 15:16:46 +0100 Message-Id: <1458137817-15383-6-git-send-email-pbonzini@redhat.com> In-Reply-To: <1458137817-15383-1-git-send-email-pbonzini@redhat.com> References: <1458137817-15383-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH v2 05/16] mirror: use bottom half to re-enter coroutine List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: famz@redhat.com, stefanha@redhat.com Signed-off-by: Paolo Bonzini --- v1->v2: use aio_bh_new() [Fam] block/mirror.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 9635fa8..2c7874d 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -72,6 +72,7 @@ typedef struct MirrorOp { QEMUIOVector qiov; int64_t sector_num; int nb_sectors; + QEMUBH *co_enter_bh; } MirrorOp; static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, @@ -87,6 +88,18 @@ static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, } } +static void mirror_bh_cb(void *opaque) +{ + MirrorOp *op = opaque; + MirrorBlockJob *s = op->s; + + qemu_bh_delete(op->co_enter_bh); + g_free(op); + if (s->waiting_for_io) { + qemu_coroutine_enter(s->common.co, NULL); + } +} + static void mirror_iteration_done(MirrorOp *op, int ret) { MirrorBlockJob *s = op->s; @@ -117,11 +130,14 @@ static void mirror_iteration_done(MirrorOp *op, int ret) } qemu_iovec_destroy(&op->qiov); - g_free(op); - if (s->waiting_for_io) { - qemu_coroutine_enter(s->common.co, NULL); - } + /* The I/O operation is not finished until the callback returns. + * If we call qemu_coroutine_enter here, there is the possibility + * of a deadlock when the coroutine calls bdrv_drained_begin. + */ + op->co_enter_bh = aio_bh_new(bdrv_get_aio_context(s->target), + mirror_bh_cb, op); + qemu_bh_schedule(op->co_enter_bh); } static void mirror_write_complete(void *opaque, int ret) -- 1.8.3.1