From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34262) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d0qoR-0004ZL-Ol for qemu-devel@nongnu.org; Wed, 19 Apr 2017 10:42:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d0qoQ-0001VT-HO for qemu-devel@nongnu.org; Wed, 19 Apr 2017 10:42:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53454) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d0qoQ-0001Uc-7t for qemu-devel@nongnu.org; Wed, 19 Apr 2017 10:42:30 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2058C81244 for ; Wed, 19 Apr 2017 14:42:29 +0000 (UTC) Received: from donizetti.redhat.com (ovpn-118-57.ams2.redhat.com [10.36.118.57] (may be forged)) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v3JEgK5G001048 for ; Wed, 19 Apr 2017 10:42:28 -0400 From: Paolo Bonzini Date: Wed, 19 Apr 2017 16:42:15 +0200 Message-Id: <20170419144219.20371-8-pbonzini@redhat.com> In-Reply-To: <20170419144219.20371-1-pbonzini@redhat.com> References: <20170419144219.20371-1-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 07/11] blockjob: introduce block_job_cancel_async, check iostatus invariants List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org The new functions helps respecting the invariant that the coroutine is entered with false user_resume, zero pause count and no error recorded in the iostatus. Resetting the iostatus is now common to all of block_job_cancel_async, block_job_user_resume and block_job_iostatus_reset, albeit with slight differences: - block_job_cancel_async resets the iostatus, and resumes the job if there was an error, but the coroutine is not restarted immediately. For example the caller may continue with a call to block_job_finish_sync. - block_job_user_resume resets the iostatus. It wants to resume the job unconditionally, even if there was no error. - block_job_iostatus_reset doesn't resume the job at all. Maybe that's a bug but it should be fixed separately. block_job_iostatus_reset does the least common denominator, so add some checking but otherwise leave it as the entry point for resetting the iostatus. Signed-off-by: Paolo Bonzini --- v1->v2: rewritten blockjob.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/blockjob.c b/blockjob.c index 5906266..1756153 100644 --- a/blockjob.c +++ b/blockjob.c @@ -304,6 +304,19 @@ static void block_job_completed_single(BlockJob *job) block_job_unref(job); } +static void block_job_cancel_async(BlockJob *job) +{ + if (job->iostatus != BLOCK_DEVICE_IO_STATUS_OK) { + block_job_iostatus_reset(job); + } + if (job->user_paused) { + /* Do not call block_job_enter here, the caller will handle it. */ + job->user_paused = false; + job->pause_count--; + } + job->cancelled = true; +} + static void block_job_completed_txn_abort(BlockJob *job) { AioContext *ctx; @@ -328,7 +341,7 @@ static void block_job_completed_txn_abort(BlockJob *job) * them; this job, however, may or may not be cancelled, depending * on the caller, so leave it. */ if (other_job != job) { - other_job->cancelled = true; + block_job_cancel_async(other_job); } continue; } @@ -411,8 +424,8 @@ bool block_job_user_paused(BlockJob *job) void block_job_user_resume(BlockJob *job) { if (job && job->user_paused && job->pause_count > 0) { - job->user_paused = false; block_job_iostatus_reset(job); + job->user_paused = false; block_job_resume(job); } } @@ -420,8 +433,7 @@ void block_job_user_resume(BlockJob *job) void block_job_cancel(BlockJob *job) { if (block_job_started(job)) { - job->cancelled = true; - block_job_iostatus_reset(job); + block_job_cancel_async(job); block_job_enter(job); } else { block_job_completed(job, -ECANCELED); @@ -765,6 +777,10 @@ void block_job_yield(BlockJob *job) void block_job_iostatus_reset(BlockJob *job) { + if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { + return; + } + assert(job->user_paused && job->pause_count > 0); job->iostatus = BLOCK_DEVICE_IO_STATUS_OK; } -- 2.9.3