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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: [PATCH v3 09/16] jobs: remove aiocontext locks since the functions are under BQL
Date: Wed,  5 Jan 2022 09:02:01 -0500	[thread overview]
Message-ID: <20220105140208.365608-10-eesposit@redhat.com> (raw)
In-Reply-To: <20220105140208.365608-1-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 11fd651bde..ee35aff13a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3707,15 +3707,11 @@ 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 de4120a1d4..f6f9840436 100644
--- a/job-qmp.c
+++ b/job-qmp.c
@@ -173,15 +173,11 @@ JobInfoList *qmp_query_jobs(Error **errp)
 
     for (job = job_next_locked(NULL); job; job = job_next_locked(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;
-- 
2.31.1



  parent reply	other threads:[~2022-01-05 15:07 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-05 14:01 [PATCH v3 00/16] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
2022-01-05 14:01 ` [PATCH v3 01/16] job.c: make job_mutex and job_lock/unlock() public Emanuele Giuseppe Esposito
2022-01-19  9:56   ` Paolo Bonzini
2022-01-19 11:13     ` Paolo Bonzini
2022-01-05 14:01 ` [PATCH v3 02/16] job.h: categorize fields in struct Job Emanuele Giuseppe Esposito
2022-01-19  9:57   ` Paolo Bonzini
2022-01-05 14:01 ` [PATCH v3 03/16] job.h: define locked functions Emanuele Giuseppe Esposito
2022-01-19 10:44   ` Paolo Bonzini
2022-01-21 15:25     ` Emanuele Giuseppe Esposito
2022-01-21 16:04       ` Vladimir Sementsov-Ogievskiy
2022-01-24 14:26         ` Paolo Bonzini
2022-01-26 15:58           ` Emanuele Giuseppe Esposito
2022-01-05 14:01 ` [PATCH v3 04/16] job.h: define unlocked functions Emanuele Giuseppe Esposito
2022-01-05 14:01 ` [PATCH v3 05/16] block/mirror.c: use of job helpers in drivers to avoid TOC/TOU Emanuele Giuseppe Esposito
2022-01-19 11:06   ` Paolo Bonzini
2022-01-05 14:01 ` [PATCH v3 06/16] job.c: make job_event_* functions static Emanuele Giuseppe Esposito
2022-01-05 14:01 ` [PATCH v3 07/16] job.c: move inner aiocontext lock in callbacks Emanuele Giuseppe Esposito
2022-01-05 14:02 ` [PATCH v3 08/16] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED Emanuele Giuseppe Esposito
2022-01-05 14:02 ` Emanuele Giuseppe Esposito [this message]
2022-01-19 11:09   ` [PATCH v3 09/16] jobs: remove aiocontext locks since the functions are under BQL Paolo Bonzini
2022-01-26 16:18     ` Emanuele Giuseppe Esposito
2022-01-05 14:02 ` [PATCH v3 10/16] jobs: protect jobs with job_lock/unlock Emanuele Giuseppe Esposito
2022-01-19 10:50   ` Paolo Bonzini
2022-01-05 14:02 ` [PATCH v3 11/16] jobs: document all static functions and add _locked() suffix Emanuele Giuseppe Esposito
2022-01-05 14:02 ` [PATCH v3 12/16] jobs: use job locks and helpers also in the unit tests Emanuele Giuseppe Esposito
2022-01-05 14:02 ` [PATCH v3 13/16] jobs: add job lock in find_* functions Emanuele Giuseppe Esposito
2022-01-05 14:02 ` [PATCH v3 14/16] job.c: use job_get_aio_context() Emanuele Giuseppe Esposito
2022-01-19 10:31   ` Paolo Bonzini
2022-01-21 12:33     ` Emanuele Giuseppe Esposito
2022-01-21 17:43       ` Emanuele Giuseppe Esposito
2022-01-21 15:18     ` Emanuele Giuseppe Esposito
2022-01-24 14:22       ` Paolo Bonzini
2022-01-26 15:58         ` Emanuele Giuseppe Esposito
2022-01-05 14:02 ` [PATCH v3 15/16] job.c: enable job lock/unlock and remove Aiocontext locks Emanuele Giuseppe Esposito
2022-01-19 10:35   ` Paolo Bonzini
2022-01-05 14:02 ` [PATCH v3 16/16] block_job_query: remove atomic read Emanuele Giuseppe Esposito
2022-01-19 10:34   ` Paolo Bonzini
2022-01-19 11:15 ` [PATCH v3 00/16] job: replace AioContext lock with job_mutex Paolo Bonzini

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