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From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <fam@euphon.net>,
	Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	Wen Congyang <wencongyang2@huawei.com>,
	Xie Changlong <xiechanglong.d@gmail.com>,
	Emanuele Giuseppe Esposito <eesposit@redhat.com>,
	Markus Armbruster <armbru@redhat.com>,
	qemu-devel@nongnu.org, Hanna Reitz <hreitz@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>, John Snow <jsnow@redhat.com>
Subject: [RFC PATCH 11/15] jobs: remove aiocontext locks since the functions are under BQL
Date: Fri, 29 Oct 2021 12:39:10 -0400	[thread overview]
Message-ID: <20211029163914.4044794-12-eesposit@redhat.com> (raw)
In-Reply-To: <20211029163914.4044794-1-eesposit@redhat.com>

In preparation to the job_lock/unlock patch, remove these
aiocontext locks.
The main reason these two locks are removed here is because
they are inside a loop iterating on the jobs list. Once the
job_lock is added, it will have to protect the whole loop,
wrapping also the aiocontext acquire/release.

We don't want this, as job_lock can only be *wrapped by*
the aiocontext lock, and not vice-versa, to avoid deadlocks.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 blockdev.c | 4 ----
 job-qmp.c  | 4 ----
 2 files changed, 8 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index d9bf842a81..67b55eec11 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3719,15 +3719,11 @@ BlockJobInfoList *qmp_query_block_jobs(Error **errp)
 
     for (job = block_job_next(NULL); job; job = block_job_next(job)) {
         BlockJobInfo *value;
-        AioContext *aio_context;
 
         if (block_job_is_internal(job)) {
             continue;
         }
-        aio_context = blk_get_aio_context(job->blk);
-        aio_context_acquire(aio_context);
         value = block_job_query(job, errp);
-        aio_context_release(aio_context);
         if (!value) {
             qapi_free_BlockJobInfoList(head);
             return NULL;
diff --git a/job-qmp.c b/job-qmp.c
index 829a28aa70..a6774aaaa5 100644
--- a/job-qmp.c
+++ b/job-qmp.c
@@ -173,15 +173,11 @@ JobInfoList *qmp_query_jobs(Error **errp)
 
     for (job = job_next(NULL); job; job = job_next(job)) {
         JobInfo *value;
-        AioContext *aio_context;
 
         if (job_is_internal(job)) {
             continue;
         }
-        aio_context = job->aio_context;
-        aio_context_acquire(aio_context);
         value = job_query_single(job, errp);
-        aio_context_release(aio_context);
         if (!value) {
             qapi_free_JobInfoList(head);
             return NULL;
-- 
2.27.0



  parent reply	other threads:[~2021-10-29 16:57 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-29 16:38 [RFC PATCH 00/15] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
2021-10-29 16:39 ` [RFC PATCH 01/15] jobs: add job-common.h Emanuele Giuseppe Esposito
2021-11-02 10:07   ` Stefan Hajnoczi
2021-10-29 16:39 ` [RFC PATCH 02/15] job.c: make job_lock/unlock public Emanuele Giuseppe Esposito
2021-11-02 10:10   ` Stefan Hajnoczi
2021-10-29 16:39 ` [RFC PATCH 03/15] job-common.h: categorize fields in struct Job Emanuele Giuseppe Esposito
2021-11-02 10:19   ` Stefan Hajnoczi
2021-10-29 16:39 ` [RFC PATCH 04/15] jobs: add job-monitor.h Emanuele Giuseppe Esposito
2021-10-29 16:39 ` [RFC PATCH 05/15] job-monitor.h: define the job monitor API Emanuele Giuseppe Esposito
2021-10-29 16:39 ` [RFC PATCH 06/15] jobs: add job-driver.h Emanuele Giuseppe Esposito
2021-10-29 16:39 ` [RFC PATCH 07/15] job-driver.h: add helper functions Emanuele Giuseppe Esposito
2021-11-02 10:54   ` Vladimir Sementsov-Ogievskiy
2021-10-29 16:39 ` [RFC PATCH 08/15] job.c: minor adjustments in preparation to job-driver Emanuele Giuseppe Esposito
2021-11-02 10:51   ` Vladimir Sementsov-Ogievskiy
2021-10-29 16:39 ` [RFC PATCH 09/15] job.c: move inner aiocontext lock in callbacks Emanuele Giuseppe Esposito
2021-10-29 16:39 ` [RFC PATCH 10/15] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED Emanuele Giuseppe Esposito
2021-10-29 16:39 ` Emanuele Giuseppe Esposito [this message]
2021-11-02 12:41   ` [RFC PATCH 11/15] jobs: remove aiocontext locks since the functions are under BQL Vladimir Sementsov-Ogievskiy
2021-11-03 15:56     ` Emanuele Giuseppe Esposito
2021-10-29 16:39 ` [RFC PATCH 12/15] jobs: protect jobs with job_lock/unlock Emanuele Giuseppe Esposito
2021-11-02 12:53   ` Vladimir Sementsov-Ogievskiy
2021-10-29 16:39 ` [RFC PATCH 13/15] jobs: use job locks and helpers also in the unit tests Emanuele Giuseppe Esposito
2021-10-29 16:39 ` [RFC PATCH 14/15] jobs: add missing job locks to replace aiocontext lock Emanuele Giuseppe Esposito
2021-10-29 16:39 ` [RFC PATCH 15/15] jobs: remove all unnecessary AioContext locks Emanuele Giuseppe Esposito
2021-11-02 10:06 ` [RFC PATCH 00/15] job: replace AioContext lock with job_mutex Stefan Hajnoczi
2021-11-02 13:08 ` Vladimir Sementsov-Ogievskiy
2021-11-02 14:13   ` Emanuele Giuseppe Esposito
2021-11-02 14:58     ` Vladimir Sementsov-Ogievskiy

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