Blockjobs: Internalize user_pause logic

BlockJobs will begin hiding their state in preparation for some
refactorings anyway, so let's internalize the user_pause mechanism
instead of leaving it to callers to correctly manage.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 1477584421-1399-6-git-send-email-jsnow@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>

blockdev.c

@@ -3610,7 +3610,7 @@ void qmp_block_job_cancel(const char *device,
         force = false;
     }
 
-    if (job->user_paused && !force) {
+    if (block_job_user_paused(job) && !force) {
         error_setg(errp, "The block job for device '%s' is currently paused",
                    device);
         goto out;
@@ -3627,13 +3627,12 @@ void qmp_block_job_pause(const char *device, Error **errp)
     AioContext *aio_context;
     BlockJob *job = find_block_job(device, &aio_context, errp);
 
-    if (!job || job->user_paused) {
+    if (!job || block_job_user_paused(job)) {
         return;
     }
 
-    job->user_paused = true;
     trace_qmp_block_job_pause(job);
-    block_job_pause(job);
+    block_job_user_pause(job);
     aio_context_release(aio_context);
 }
 
@@ -3642,14 +3641,13 @@ void qmp_block_job_resume(const char *device, Error **errp)
     AioContext *aio_context;
     BlockJob *job = find_block_job(device, &aio_context, errp);
 
-    if (!job || !job->user_paused) {
+    if (!job || !block_job_user_paused(job)) {
         return;
     }
 
-    job->user_paused = false;
     trace_qmp_block_job_resume(job);
     block_job_iostatus_reset(job);
-    block_job_resume(job);
+    block_job_user_resume(job);
     aio_context_release(aio_context);
 }
 

blockjob.c

@@ -373,11 +373,22 @@ void block_job_pause(BlockJob *job)
     job->pause_count++;
 }
 
+void block_job_user_pause(BlockJob *job)
+{
+    job->user_paused = true;
+    block_job_pause(job);
+}
+
 static bool block_job_should_pause(BlockJob *job)
 {
     return job->pause_count > 0;
 }
 
+bool block_job_user_paused(BlockJob *job)
+{
+    return job ? job->user_paused : 0;
+}
+
 void coroutine_fn block_job_pause_point(BlockJob *job)
 {
     if (!block_job_should_pause(job)) {
@@ -414,6 +425,14 @@ void block_job_resume(BlockJob *job)
     block_job_enter(job);
 }
 
+void block_job_user_resume(BlockJob *job)
+{
+    if (job && job->user_paused && job->pause_count > 0) {
+        job->user_paused = false;
+        block_job_resume(job);
+    }
+}
+
 void block_job_enter(BlockJob *job)
 {
     if (job->co && !job->busy) {
@@ -644,8 +663,7 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
     }
     if (action == BLOCK_ERROR_ACTION_STOP) {
         /* make the pause user visible, which will be resumed from QMP. */
-        job->user_paused = true;
+        block_job_user_pause(job);
-        block_job_pause(job);
         block_job_iostatus_set_err(job, error);
     }
     return action;

include/block/blockjob.h

@@ -378,6 +378,23 @@ void coroutine_fn block_job_pause_point(BlockJob *job);
  */
 void block_job_pause(BlockJob *job);
 
+/**
+ * block_job_user_pause:
+ * @job: The job to be paused.
+ *
+ * Asynchronously pause the specified job.
+ * Do not allow a resume until a matching call to block_job_user_resume.
+ */
+void block_job_user_pause(BlockJob *job);
+
+/**
+ * block_job_paused:
+ * @job: The job to query.
+ *
+ * Returns true if the job is user-paused.
+ */
+bool block_job_user_paused(BlockJob *job);
+
 /**
  * block_job_resume:
  * @job: The job to be resumed.
@@ -386,6 +403,15 @@ void block_job_pause(BlockJob *job);
  */
 void block_job_resume(BlockJob *job);
 
+/**
+ * block_job_user_resume:
+ * @job: The job to be resumed.
+ *
+ * Resume the specified job.
+ * Must be paired with a preceding block_job_user_pause.
+ */
+void block_job_user_resume(BlockJob *job);
+
 /**
  * block_job_enter:
  * @job: The job to enter.