From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46281) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dEKqY-0002Tf-PI for qemu-devel@nongnu.org; Fri, 26 May 2017 15:24:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dEKqX-0005xs-NN for qemu-devel@nongnu.org; Fri, 26 May 2017 15:24:26 -0400 From: Jeff Cody Date: Fri, 26 May 2017 15:23:59 -0400 Message-Id: <20170526192404.32186-8-jcody@redhat.com> In-Reply-To: <20170526192404.32186-1-jcody@redhat.com> References: <20170526192404.32186-1-jcody@redhat.com> Subject: [Qemu-devel] [PULL 07/12] blockjob: introduce block_job_cancel_async, check iostatus invariants List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: peter.maydell@linaro.org, jcody@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, Paolo Bonzini From: Paolo Bonzini 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. Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini Message-id: 20170508141310.8674-8-pbonzini@redhat.com Signed-off-by: Jeff Cody --- blockjob.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/blockjob.c b/blockjob.c index cd1f4c0..eae8fe7 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