blk-mq: Move more error handling into blk_mq_submit_bio()

The error handling code in blk_mq_get_new_requests() cannot be understood
without knowing that this function is only called by blk_mq_submit_bio().
Hence move the code for handling blk_mq_get_new_requests() failures into
blk_mq_submit_bio().

Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20241218212246.1073149-3-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: bvanassche

block/blk-mq.c

@@ -2984,12 +2984,9 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q,
 	}
 
 	rq = __blk_mq_alloc_requests(&data);
-	if (rq)
-		return rq;
-	rq_qos_cleanup(q, bio);
-	if (bio->bi_opf & REQ_NOWAIT)
-		bio_wouldblock_error(bio);
-	return NULL;
+	if (unlikely(!rq))
+		rq_qos_cleanup(q, bio);
+	return rq;
 }
 
 /*
@@ -3129,8 +3126,11 @@ void blk_mq_submit_bio(struct bio *bio)
 		blk_mq_use_cached_rq(rq, plug, bio);
 	} else {
 		rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
-		if (unlikely(!rq))
+		if (unlikely(!rq)) {
+			if (bio->bi_opf & REQ_NOWAIT)
+				bio_wouldblock_error(bio);
 			goto queue_exit;
+		}
 	}
 
 	trace_block_getrq(bio);