blockjob: return status from block_job_set_speed()

Better to return status together with setting errp. It allows to avoid
error propagation in the caller.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20210202124956.63146-8-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

blockjob.c

@@ -258,18 +258,18 @@ static bool job_timer_pending(Job *job)
     return timer_pending(&job->sleep_timer);
 }
 
-void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
+bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 {
     const BlockJobDriver *drv = block_job_driver(job);
     int64_t old_speed = job->speed;
 
-    if (job_apply_verb(&job->job, JOB_VERB_SET_SPEED, errp)) {
-        return;
+    if (job_apply_verb(&job->job, JOB_VERB_SET_SPEED, errp) < 0) {
+        return false;
     }
     if (speed < 0) {
         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "speed",
                    "a non-negative value");
-        return;
+        return false;
     }
 
     ratelimit_set_speed(&job->limit, speed, BLOCK_JOB_SLICE_TIME);
@@ -281,11 +281,13 @@ void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
     }
 
     if (speed && speed <= old_speed) {
-        return;
+        return true;
     }
 
     /* kick only if a timer is pending */
     job_enter_cond(&job->job, job_timer_pending);
+
+    return true;
 }
 
 int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n)
@@ -458,12 +460,8 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
 
     /* Only set speed when necessary to avoid NotSupported error */
     if (speed != 0) {
-        Error *local_err = NULL;
-
-        block_job_set_speed(job, speed, &local_err);
-        if (local_err) {
+        if (!block_job_set_speed(job, speed, errp)) {
             job_early_fail(&job->job);
-            error_propagate(errp, local_err);
             return NULL;
         }
     }

include/block/blockjob.h

@@ -139,7 +139,7 @@ bool block_job_has_bdrv(BlockJob *job, BlockDriverState *bs);
  * Set a rate-limiting parameter for the job; the actual meaning may
  * vary depending on the job type.
  */
-void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
+bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
 
 /**
  * block_job_query: