job: Convert block_job_cancel_async() to Job

block_job_cancel_async() did two things that were still block job
specific:

* Setting job->force. This field makes sense on the Job level, so we can
  just move it. While at it, rename it to job->force_cancel to make its
  purpose more obvious.

* Resetting the I/O status. This can't be moved because generic Jobs
  don't have an I/O status. What the function really implements is a
  user resume, except without entering the coroutine. Consequently, it
  makes sense to call the .user_resume driver callback here which
  already resets the I/O status.

  The old block_job_cancel_async() has two separate if statements that
  check job->iostatus != BLOCK_DEVICE_IO_STATUS_OK and job->user_paused.
  However, the former condition always implies the latter (as is
  asserted in block_job_iostatus_reset()), so changing the explicit call
  of block_job_iostatus_reset() on the former condition with the
  .user_resume callback on the latter condition is equivalent and
  doesn't need to access any BlockJob specific state.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

block/mirror.c

@@ -871,7 +871,7 @@ static void coroutine_fn mirror_run(void *opaque)
         trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
         job_sleep_ns(&s->common.job, delay_ns);
         if (job_is_cancelled(&s->common.job) &&
-            (!s->synced || s->common.force))
+            (!s->synced || s->common.job.force_cancel))
         {
             break;
         }
@@ -884,7 +884,7 @@ immediate_exit:
          * or it was cancelled prematurely so that we do not guarantee that
          * the target is a copy of the source.
          */
-        assert(ret < 0 || ((s->common.force || !s->synced) &&
+        assert(ret < 0 || ((s->common.job.force_cancel || !s->synced) &&
                job_is_cancelled(&s->common.job)));
         assert(need_drain);
         mirror_wait_for_all_io(s);

blockjob.c

@@ -270,19 +270,20 @@ static int block_job_prepare(BlockJob *job)
     return job->job.ret;
 }
 
-static void block_job_cancel_async(BlockJob *job, bool force)
+static void job_cancel_async(Job *job, bool force)
 {
-    if (job->iostatus != BLOCK_DEVICE_IO_STATUS_OK) {
+    if (job->user_paused) {
-        block_job_iostatus_reset(job);
+        /* Do not call job_enter here, the caller will handle it.  */
+        job->user_paused = false;
+        if (job->driver->user_resume) {
+            job->driver->user_resume(job);
+        }
+        assert(job->pause_count > 0);
+        job->pause_count--;
     }
-    if (job->job.user_paused) {
+    job->cancelled = true;
-        /* Do not call block_job_enter here, the caller will handle it.  */
-        job->job.user_paused = false;
-        job->job.pause_count--;
-    }
-    job->job.cancelled = true;
     /* To prevent 'force == false' overriding a previous 'force == true' */
-    job->force |= force;
+    job->force_cancel |= force;
 }
 
 static int block_job_txn_apply(BlockJobTxn *txn, int fn(BlockJob *), bool lock)
@@ -367,7 +368,7 @@ static void block_job_completed_txn_abort(BlockJob *job)
      * on the caller, so leave it. */
     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
         if (other_job != job) {
-            block_job_cancel_async(other_job, false);
+            job_cancel_async(&other_job->job, false);
         }
     }
     while (!QLIST_EMPTY(&txn->jobs)) {
@@ -527,7 +528,7 @@ void block_job_cancel(BlockJob *job, bool force)
         job_do_dismiss(&job->job);
         return;
     }
-    block_job_cancel_async(job, force);
+    job_cancel_async(&job->job, force);
     if (!job_started(&job->job)) {
         block_job_completed(job, -ECANCELED);
     } else if (job->job.deferred_to_main_loop) {

include/block/blockjob.h

@@ -50,12 +50,6 @@ typedef struct BlockJob {
     /** The block device on which the job is operating.  */
     BlockBackend *blk;
 
-    /**
-     * Set to true if the job should abort immediately without waiting
-     * for data to be in sync.
-     */
-    bool force;
-
     /**
      * Set to true when the job is ready to be completed.
      */

include/qemu/job.h

@@ -97,6 +97,12 @@ typedef struct Job {
      */
     bool cancelled;
 
+    /**
+     * Set to true if the job should abort immediately without waiting
+     * for data to be in sync.
+     */
+    bool force_cancel;
+
     /** Set to true when the job has deferred work to the main loop. */
     bool deferred_to_main_loop;