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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 v2 09/14] jobs: remove aiocontext locks since the functions are under BQL
Date: Thu,  4 Nov 2021 10:53:29 -0400	[thread overview]
Message-ID: <20211104145334.1346363-10-eesposit@redhat.com> (raw)
In-Reply-To: <20211104145334.1346363-1-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:[~2021-11-04 15:06 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-04 14:53 [RFC PATCH v2 00/14] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
2021-11-04 14:53 ` [RFC PATCH v2 01/14] job.c: make job_lock/unlock public Emanuele Giuseppe Esposito
2021-12-16 16:18   ` Stefan Hajnoczi
2021-11-04 14:53 ` [RFC PATCH v2 02/14] job.h: categorize fields in struct Job Emanuele Giuseppe Esposito
2021-12-16 16:21   ` Stefan Hajnoczi
2021-12-21 14:23     ` Emanuele Giuseppe Esposito
2021-11-04 14:53 ` [RFC PATCH v2 03/14] job.h: define locked functions Emanuele Giuseppe Esposito
2021-12-16 16:48   ` Stefan Hajnoczi
2021-12-16 17:11     ` Vladimir Sementsov-Ogievskiy
2021-12-20 10:15       ` Emanuele Giuseppe Esposito
2021-11-04 14:53 ` [RFC PATCH v2 04/14] job.h: define unlocked functions Emanuele Giuseppe Esposito
2021-12-16 16:51   ` Stefan Hajnoczi
2021-11-04 14:53 ` [RFC PATCH v2 05/14] block/mirror.c: use of job helpers in drivers to avoid TOC/TOU Emanuele Giuseppe Esposito
2021-12-18 11:53   ` Vladimir Sementsov-Ogievskiy
2021-12-20 10:34     ` Emanuele Giuseppe Esposito
2021-12-20 10:47       ` Vladimir Sementsov-Ogievskiy
2021-12-23 11:37         ` Emanuele Giuseppe Esposito
2021-11-04 14:53 ` [RFC PATCH v2 06/14] job.c: make job_event_* functions static Emanuele Giuseppe Esposito
2021-12-16 16:54   ` Stefan Hajnoczi
2021-11-04 14:53 ` [RFC PATCH v2 07/14] job.c: move inner aiocontext lock in callbacks Emanuele Giuseppe Esposito
2021-11-04 14:53 ` [RFC PATCH v2 08/14] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED Emanuele Giuseppe Esposito
2021-11-04 14:53 ` Emanuele Giuseppe Esposito [this message]
2021-11-04 14:53 ` [RFC PATCH v2 10/14] jobs: protect jobs with job_lock/unlock Emanuele Giuseppe Esposito
2021-12-18 11:57   ` Vladimir Sementsov-Ogievskiy
2021-11-04 14:53 ` [RFC PATCH v2 11/14] block_job_query: remove atomic read Emanuele Giuseppe Esposito
2021-12-18 12:07   ` Vladimir Sementsov-Ogievskiy
2021-12-23 11:37     ` Emanuele Giuseppe Esposito
2021-11-04 14:53 ` [RFC PATCH v2 12/14] jobs: use job locks and helpers also in the unit tests Emanuele Giuseppe Esposito
2021-11-04 14:53 ` [RFC PATCH v2 13/14] jobs: add job lock in find_* functions Emanuele Giuseppe Esposito
2021-12-18 12:11   ` Vladimir Sementsov-Ogievskiy
2021-12-18 12:22     ` Vladimir Sementsov-Ogievskiy
2021-11-04 14:53 ` [RFC PATCH v2 14/14] job.c: enable job lock/unlock and remove Aiocontext locks Emanuele Giuseppe Esposito
2021-12-18 12:24   ` Vladimir Sementsov-Ogievskiy
2021-12-23 14:59     ` Emanuele Giuseppe Esposito

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