ublk_drv: requeue rqs with recovery feature enabled

With recovery feature enabled, in ublk_queue_rq or task work
(in exit_task_work or fallback wq), we requeue rqs instead of
ending(aborting) them. Besides, No matter recovery feature is enabled
or disabled, we schedule monitor_work immediately.

Signed-off-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220923153919.44078-4-ZiyangZhang@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/ublk_drv.c

@@ -655,10 +655,21 @@ static void ubq_complete_io_cmd(struct ublk_io *io, int res)
 
 #define UBLK_REQUEUE_DELAY_MS	3
 
+static inline void __ublk_abort_rq(struct ublk_queue *ubq,
+		struct request *rq)
+{
+	/* We cannot process this rq so just requeue it. */
+	if (ublk_queue_can_use_recovery(ubq))
+		blk_mq_requeue_request(rq, false);
+	else
+		blk_mq_end_request(rq, BLK_STS_IOERR);
+
+	mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0);
+}
+
 static inline void __ublk_rq_task_work(struct request *req)
 {
 	struct ublk_queue *ubq = req->mq_hctx->driver_data;
-	struct ublk_device *ub = ubq->dev;
 	int tag = req->tag;
 	struct ublk_io *io = &ubq->ios[tag];
 	unsigned int mapped_bytes;
@@ -677,8 +688,7 @@ static inline void __ublk_rq_task_work(struct request *req)
 	 * (2) current->flags & PF_EXITING.
 	 */
 	if (unlikely(current != ubq->ubq_daemon || current->flags & PF_EXITING)) {
-		blk_mq_end_request(req, BLK_STS_IOERR);
-		mod_delayed_work(system_wq, &ub->monitor_work, 0);
+		__ublk_abort_rq(ubq, req);
 		return;
 	}
 
@@ -768,8 +778,8 @@ static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	if (unlikely(ubq_daemon_is_dying(ubq))) {
  fail:
-		mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0);
-		return BLK_STS_IOERR;
+		__ublk_abort_rq(ubq, rq);
+		return BLK_STS_OK;
 	}
 
 	if (ublk_can_use_task_work(ubq)) {