jobs: remove ret argument to job_completed; privatize it

Jobs are now expected to return their retcode on the stack, from the
.run callback, so we can remove that argument.

job_cancel does not need to set -ECANCELED because job_completed will
update the return code itself if the job was canceled.

While we're here, make job_completed static to job.c and remove it from
job.h; move the documentation of return code to the .run() callback and
to the job->ret property, accordingly.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20180830015734.19765-9-jsnow@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

include/qemu/job.h

@@ -124,7 +124,11 @@ typedef struct Job {
     /** Estimated progress_current value at the completion of the job */
     int64_t progress_total;
 
-    /** ret code passed to job_completed. */
+    /**
+     * Return code from @run and/or @prepare callback(s).
+     * Not final until the job has reached the CONCLUDED status.
+     * 0 on success, -errno on failure.
+     */
     int ret;
 
     /**
@@ -172,7 +176,16 @@ struct JobDriver {
     /** Enum describing the operation */
     JobType job_type;
 
-    /** Mandatory: Entrypoint for the Coroutine. */
+    /**
+     * Mandatory: Entrypoint for the Coroutine.
+     *
+     * This callback will be invoked when moving from CREATED to RUNNING.
+     *
+     * If this callback returns nonzero, the job transaction it is part of is
+     * aborted. If it returns zero, the job moves into the WAITING state. If it
+     * is the last job to complete in its transaction, all jobs in the
+     * transaction move from WAITING to PENDING.
+     */
     int coroutine_fn (*run)(Job *job, Error **errp);
 
     /**
@@ -496,17 +509,6 @@ void job_early_fail(Job *job);
 /** Moves the @job from RUNNING to READY */
 void job_transition_to_ready(Job *job);
 
-/**
- * @job: The job being completed.
- * @ret: The status code.
- *
- * Marks @job as completed. If @ret is non-zero, the job transaction it is part
- * of is aborted. If @ret is zero, the job moves into the WAITING state. If it
- * is the last job to complete in its transaction, all jobs in the transaction
- * move from WAITING to PENDING.
- */
-void job_completed(Job *job, int ret);
-
 /** Asynchronously complete the specified @job. */
 void job_complete(Job *job, Error **errp);
 

job.c

@@ -535,6 +535,8 @@ void job_drain(Job *job)
     }
 }
 
+static void job_completed(Job *job);
+
 static void job_exit(void *opaque)
 {
     Job *job = (Job *)opaque;
@@ -545,7 +547,7 @@ static void job_exit(void *opaque)
         job->driver->exit(job);
         aio_context_release(aio_context);
     }
-    job_completed(job, job->ret);
+    job_completed(job);
 }
 
 /**
@@ -883,13 +885,12 @@ static void job_completed_txn_success(Job *job)
     }
 }
 
-void job_completed(Job *job, int ret)
+static void job_completed(Job *job)
 {
     assert(job && job->txn && !job_is_completed(job));
 
-    job->ret = ret;
     job_update_rc(job);
-    trace_job_completed(job, ret, job->ret);
+    trace_job_completed(job, job->ret);
     if (job->ret) {
         job_completed_txn_abort(job);
     } else {
@@ -905,7 +906,7 @@ void job_cancel(Job *job, bool force)
     }
     job_cancel_async(job, force);
     if (!job_started(job)) {
-        job_completed(job, -ECANCELED);
+        job_completed(job);
     } else if (job->deferred_to_main_loop) {
         job_completed_txn_abort(job);
     } else {

trace-events

@@ -107,7 +107,7 @@ gdbstub_err_checksum_incorrect(uint8_t expected, uint8_t got) "got command packe
 # job.c
 job_state_transition(void *job,  int ret, const char *legal, const char *s0, const char *s1) "job %p (ret: %d) attempting %s transition (%s-->%s)"
 job_apply_verb(void *job, const char *state, const char *verb, const char *legal) "job %p in state %s; applying verb %s (%s)"
-job_completed(void *job, int ret, int jret) "job %p ret %d corrected ret %d"
+job_completed(void *job, int ret) "job %p ret %d"
 
 # job-qmp.c
 qmp_job_cancel(void *job) "job %p"