[RFC 19/24] blockjob: add set_speed to BlockJobDriver

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

We are going to use async block-copy call in backup, so we'll need to
passthrough setting backup speed to block-copy call.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 include/block/blockjob_int.h | 2 ++
 blockjob.c                   | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
index e2824a36a8..6633d83da2 100644
--- a/include/block/blockjob_int.h
+++ b/include/block/blockjob_int.h
@@ -52,6 +52,8 @@ struct BlockJobDriver {
      * besides job->blk to the new AioContext.
      */
     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
+
+    void (*set_speed)(BlockJob *job, int64_t speed);
 };
 
 /**
diff --git a/blockjob.c b/blockjob.c
index c6e20e2fcd..3b827d420d 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -255,6 +255,7 @@ static bool job_timer_pending(Job *job)
 
 void 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)) {
@@ -268,6 +269,11 @@ void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
     ratelimit_set_speed(&job->limit, speed, BLOCK_JOB_SLICE_TIME);
 
     job->speed = speed;
+
+    if (drv->set_speed) {
+        drv->set_speed(job, speed);
+    }
+
     if (speed && speed <= old_speed) {
         return;
     }
-- 
2.21.0