block: move poll code to blk-mq

The poll code is blk-mq specific, let's move it to blk-mq.c. This
is a prep patch for improving the polling code.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

block/blk-core.c

@@ -3312,52 +3312,6 @@ void blk_finish_plug(struct blk_plug *plug)
 }
 EXPORT_SYMBOL(blk_finish_plug);
 
-bool blk_poll(struct request_queue *q, blk_qc_t cookie)
-{
-	struct blk_plug *plug;
-	long state;
-	unsigned int queue_num;
-	struct blk_mq_hw_ctx *hctx;
-
-	if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) ||
-	    !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
-		return false;
-
-	queue_num = blk_qc_t_to_queue_num(cookie);
-	hctx = q->queue_hw_ctx[queue_num];
-	hctx->poll_considered++;
-
-	plug = current->plug;
-	if (plug)
-		blk_flush_plug_list(plug, false);
-
-	state = current->state;
-	while (!need_resched()) {
-		int ret;
-
-		hctx->poll_invoked++;
-
-		ret = q->mq_ops->poll(hctx, blk_qc_t_to_tag(cookie));
-		if (ret > 0) {
-			hctx->poll_success++;
-			set_current_state(TASK_RUNNING);
-			return true;
-		}
-
-		if (signal_pending_state(state, current))
-			set_current_state(TASK_RUNNING);
-
-		if (current->state == TASK_RUNNING)
-			return true;
-		if (ret < 0)
-			break;
-		cpu_relax();
-	}
-
-	return false;
-}
-EXPORT_SYMBOL_GPL(blk_poll);
-
 #ifdef CONFIG_PM
 /**
  * blk_pm_runtime_init - Block layer runtime PM initialization routine

block/blk-mq.c

@@ -2461,6 +2461,60 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
 }
 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
 
+static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq)
+{
+	struct request_queue *q = hctx->queue;
+	long state;
+
+	hctx->poll_considered++;
+
+	state = current->state;
+	while (!need_resched()) {
+		int ret;
+
+		hctx->poll_invoked++;
+
+		ret = q->mq_ops->poll(hctx, rq->tag);
+		if (ret > 0) {
+			hctx->poll_success++;
+			set_current_state(TASK_RUNNING);
+			return true;
+		}
+
+		if (signal_pending_state(state, current))
+			set_current_state(TASK_RUNNING);
+
+		if (current->state == TASK_RUNNING)
+			return true;
+		if (ret < 0)
+			break;
+		cpu_relax();
+	}
+
+	return false;
+}
+
+bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
+{
+	struct blk_mq_hw_ctx *hctx;
+	struct blk_plug *plug;
+	struct request *rq;
+
+	if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) ||
+	    !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
+		return false;
+
+	plug = current->plug;
+	if (plug)
+		blk_flush_plug_list(plug, false);
+
+	hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
+	rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie));
+
+	return __blk_mq_poll(hctx, rq);
+}
+EXPORT_SYMBOL_GPL(blk_mq_poll);
+
 void blk_mq_disable_hotplug(void)
 {
 	mutex_lock(&all_q_mutex);

drivers/nvme/target/io-cmd.c

@@ -96,7 +96,7 @@ static void nvmet_execute_rw(struct nvmet_req *req)
 
 	cookie = submit_bio(bio);
 
-	blk_poll(bdev_get_queue(req->ns->bdev), cookie);
+	blk_mq_poll(bdev_get_queue(req->ns->bdev), cookie);
 }
 
 static void nvmet_execute_flush(struct nvmet_req *req)

fs/direct-io.c

@@ -457,7 +457,7 @@ static struct bio *dio_await_one(struct dio *dio)
 		dio->waiter = current;
 		spin_unlock_irqrestore(&dio->bio_lock, flags);
 		if (!(dio->iocb->ki_flags & IOCB_HIPRI) ||
-		    !blk_poll(bdev_get_queue(dio->bio_bdev), dio->bio_cookie))
+		    !blk_mq_poll(bdev_get_queue(dio->bio_bdev), dio->bio_cookie))
 			io_schedule();
 		/* wake up sets us TASK_RUNNING */
 		spin_lock_irqsave(&dio->bio_lock, flags);

include/linux/blkdev.h

@@ -952,7 +952,7 @@ extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 				  struct request *, int, rq_end_io_fn *);
 
-bool blk_poll(struct request_queue *q, blk_qc_t cookie);
+bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie);
 
 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 {