jobs: group together API calls under the same job lock

Now that the API offers also _locked() functions, take advantage
of it and give also the caller control to take the lock and call
_locked functions.

This makes sense especially when we have for loops, because it
makes no sense to have:

for(job = job_next(); ...)

where each job_next() takes the lock internally.
Instead we want

JOB_LOCK_GUARD();
for(job = job_next_locked(); ...)

In addition, protect also direct field accesses, by either creating a
new critical section or widening the existing ones.

Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-Id: <20220926093214.506243-12-eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/qemu-img.c b/qemu-img.c
index cab9776f42..e0a30b1f4c 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -912,9 +912,11 @@ static void run_block_job(BlockJob *job, Error **errp)
     int ret = 0;
 
     aio_context_acquire(aio_context);
-    job_ref(&job->job);
+    job_lock();
+    job_ref_locked(&job->job);
     do {
         float progress = 0.0f;
+        job_unlock();
         aio_poll(aio_context, true);
 
         progress_get_snapshot(&job->job.progress, &progress_current,
@@ -923,14 +925,17 @@ static void run_block_job(BlockJob *job, Error **errp)
             progress = (float)progress_current / progress_total * 100.f;
         }
         qemu_progress_print(progress, 0);
-    } while (!job_is_ready(&job->job) && !job_is_completed(&job->job));
+        job_lock();
+    } while (!job_is_ready_locked(&job->job) &&
+             !job_is_completed_locked(&job->job));
 
-    if (!job_is_completed(&job->job)) {
-        ret = job_complete_sync(&job->job, errp);
+    if (!job_is_completed_locked(&job->job)) {
+        ret = job_complete_sync_locked(&job->job, errp);
     } else {
         ret = job->job.ret;
     }
-    job_unref(&job->job);
+    job_unref_locked(&job->job);
+    job_unlock();
     aio_context_release(aio_context);
 
     /* publish completion progress only when success */