From patchwork Wed Jan 16 18:11:33 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 212914 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id EAED82C0093 for ; Thu, 17 Jan 2013 05:11:52 +1100 (EST) Received: from localhost ([::1]:40085 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TvXSp-0006Wq-3G for incoming@patchwork.ozlabs.org; Wed, 16 Jan 2013 13:11:51 -0500 Received: from eggs.gnu.org ([208.118.235.92]:38330) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TvXSc-0006SJ-Ri for qemu-devel@nongnu.org; Wed, 16 Jan 2013 13:11:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TvXSb-0003rk-Na for qemu-devel@nongnu.org; Wed, 16 Jan 2013 13:11:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:27684) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TvXSb-0003rZ-Fp for qemu-devel@nongnu.org; Wed, 16 Jan 2013 13:11:37 -0500 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r0GIBaa3029364 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 16 Jan 2013 13:11:36 -0500 Received: from dhcp-5-188.str.redhat.com (vpn1-6-32.ams2.redhat.com [10.36.6.32]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r0GIBYWP002123; Wed, 16 Jan 2013 13:11:35 -0500 From: Kevin Wolf To: qemu-devel@nongnu.org Date: Wed, 16 Jan 2013 19:11:33 +0100 Message-Id: <1358359893-718-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, pbonzini@redhat.com, stefanha@redhat.com Subject: [Qemu-devel] [PATCH] aio-posix: Fix return value of aio_poll() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org aio_poll() must return true if any work is still pending, even if it didn't make progress, so that qemu_aio_wait() doesn't return too early. The possibility of returning early occasionally lead to a failed assertion in bdrv_drain_all(), when some in-flight request was missed and the function didn't really drain all requests. In order to make that change, the return value as specified in the function comment must change for blocking = false; fortunately, the return value of blocking = false callers is only used in test cases, so this change shouldn't cause any trouble. Signed-off-by: Kevin Wolf --- aio-posix.c | 3 ++- include/block/aio.h | 6 ++---- tests/test-aio.c | 4 ++-- 3 files changed, 6 insertions(+), 7 deletions(-) diff --git a/aio-posix.c b/aio-posix.c index 88d09e1..fe4dbb4 100644 --- a/aio-posix.c +++ b/aio-posix.c @@ -264,5 +264,6 @@ bool aio_poll(AioContext *ctx, bool blocking) } } - return progress; + assert(progress || busy); + return true; } diff --git a/include/block/aio.h b/include/block/aio.h index 0933f05..8eda924 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -173,16 +173,14 @@ bool aio_pending(AioContext *ctx); * aio as a result of executing I/O completion or bh callbacks. * * If there is no pending AIO operation or completion (bottom half), - * return false. If there are pending bottom halves, return true. + * return false. If there are pending AIO operations of bottom halves, + * return true. * * If there are no pending bottom halves, but there are pending AIO * operations, it may not be possible to make any progress without * blocking. If @blocking is true, this function will wait until one * or more AIO events have completed, to ensure something has moved * before returning. - * - * If @blocking is false, this function will also return false if the - * function cannot make any progress without blocking. */ bool aio_poll(AioContext *ctx, bool blocking); diff --git a/tests/test-aio.c b/tests/test-aio.c index e4ebef7..c173870 100644 --- a/tests/test-aio.c +++ b/tests/test-aio.c @@ -315,13 +315,13 @@ static void test_wait_event_notifier_noflush(void) event_notifier_set(&data.e); g_assert(aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 1); - g_assert(!aio_poll(ctx, false)); + g_assert(aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 1); event_notifier_set(&data.e); g_assert(aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 2); - g_assert(!aio_poll(ctx, false)); + g_assert(aio_poll(ctx, false)); g_assert_cmpint(data.n, ==, 2); event_notifier_set(&dummy.e);