block: add queue_is_mq() helper

Various spots check for q->mq_ops being non-NULL, but provide
a helper to do this instead.

Where the ->mq_ops != NULL check is redundant, remove it.

Since mq == rq-based now that legacy is gone, get rid of the
queue_is_rq_based() and just use queue_is_mq() everywhere.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-cgroup.c

@@ -1324,7 +1324,7 @@ int blkcg_activate_policy(struct request_queue *q,
 	if (blkcg_policy_enabled(q, pol))
 		return 0;
 
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_freeze_queue(q);
 pd_prealloc:
 	if (!pd_prealloc) {
@@ -1363,7 +1363,7 @@ int blkcg_activate_policy(struct request_queue *q,
 
 	spin_unlock_irq(&q->queue_lock);
 out_bypass_end:
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_unfreeze_queue(q);
 	if (pd_prealloc)
 		pol->pd_free_fn(pd_prealloc);
@@ -1387,7 +1387,7 @@ void blkcg_deactivate_policy(struct request_queue *q,
 	if (!blkcg_policy_enabled(q, pol))
 		return;
 
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_freeze_queue(q);
 
 	spin_lock_irq(&q->queue_lock);
@@ -1405,7 +1405,7 @@ void blkcg_deactivate_policy(struct request_queue *q,
 
 	spin_unlock_irq(&q->queue_lock);
 
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_unfreeze_queue(q);
 }
 EXPORT_SYMBOL_GPL(blkcg_deactivate_policy);

block/blk-core.c

@@ -232,7 +232,7 @@ void blk_sync_queue(struct request_queue *q)
 	del_timer_sync(&q->timeout);
 	cancel_work_sync(&q->timeout_work);
 
-	if (q->mq_ops) {
+	if (queue_is_mq(q)) {
 		struct blk_mq_hw_ctx *hctx;
 		int i;
 
@@ -281,7 +281,7 @@ void blk_set_queue_dying(struct request_queue *q)
 	 */
 	blk_freeze_queue_start(q);
 
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_wake_waiters(q);
 
 	/* Make blk_queue_enter() reexamine the DYING flag. */
@@ -356,7 +356,7 @@ void blk_cleanup_queue(struct request_queue *q)
 	 * blk_freeze_queue() should be enough for cases of passthrough
 	 * request.
 	 */
-	if (q->mq_ops && blk_queue_init_done(q))
+	if (queue_is_mq(q) && blk_queue_init_done(q))
 		blk_mq_quiesce_queue(q);
 
 	/* for synchronous bio-based driver finish in-flight integrity i/o */
@@ -374,7 +374,7 @@ void blk_cleanup_queue(struct request_queue *q)
 
 	blk_exit_queue(q);
 
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_free_queue(q);
 
 	percpu_ref_exit(&q->q_usage_counter);
@@ -982,7 +982,7 @@ generic_make_request_checks(struct bio *bio)
 	 * For a REQ_NOWAIT based request, return -EOPNOTSUPP
 	 * if queue is not a request based queue.
 	 */
-	if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_rq_based(q))
+	if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q))
 		goto not_supported;
 
 	if (should_fail_bio(bio))
@@ -1657,7 +1657,7 @@ EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
  */
 int blk_lld_busy(struct request_queue *q)
 {
-	if (q->mq_ops && q->mq_ops->busy)
+	if (queue_is_mq(q) && q->mq_ops->busy)
 		return q->mq_ops->busy(q);
 
 	return 0;

block/blk-flush.c

@@ -273,8 +273,7 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
 	 * assigned to empty flushes, and we deadlock if we are expecting
 	 * other requests to make progress. Don't defer for that case.
 	 */
-	if (!list_empty(&fq->flush_data_in_flight) &&
+	if (!list_empty(&fq->flush_data_in_flight) && q->elevator &&
-	    !(q->mq_ops && q->elevator) &&
 	    time_before(jiffies,
 			fq->flush_pending_since + FLUSH_PENDING_TIMEOUT))
 		return;

block/blk-mq.c

@@ -150,7 +150,7 @@ void blk_freeze_queue_start(struct request_queue *q)
 	freeze_depth = atomic_inc_return(&q->mq_freeze_depth);
 	if (freeze_depth == 1) {
 		percpu_ref_kill(&q->q_usage_counter);
-		if (q->mq_ops)
+		if (queue_is_mq(q))
 			blk_mq_run_hw_queues(q, false);
 	}
 }

block/blk-sysfs.c

@@ -68,7 +68,7 @@ queue_requests_store(struct request_queue *q, const char *page, size_t count)
 	unsigned long nr;
 	int ret, err;
 
-	if (!q->mq_ops)
+	if (!queue_is_mq(q))
 		return -EINVAL;
 
 	ret = queue_var_store(&nr, page, count);
@@ -835,12 +835,12 @@ static void __blk_release_queue(struct work_struct *work)
 
 	blk_queue_free_zone_bitmaps(q);
 
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_release(q);
 
 	blk_trace_shutdown(q);
 
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_debugfs_unregister(q);
 
 	bioset_exit(&q->bio_split);
@@ -914,7 +914,7 @@ int blk_register_queue(struct gendisk *disk)
 		goto unlock;
 	}
 
-	if (q->mq_ops) {
+	if (queue_is_mq(q)) {
 		__blk_mq_register_dev(dev, q);
 		blk_mq_debugfs_register(q);
 	}
@@ -925,7 +925,7 @@ int blk_register_queue(struct gendisk *disk)
 
 	blk_throtl_register_queue(q);
 
-	if ((q->mq_ops && q->elevator)) {
+	if (q->elevator) {
 		ret = elv_register_queue(q);
 		if (ret) {
 			mutex_unlock(&q->sysfs_lock);
@@ -974,7 +974,7 @@ void blk_unregister_queue(struct gendisk *disk)
 	 * Remove the sysfs attributes before unregistering the queue data
 	 * structures that can be modified through sysfs.
 	 */
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		blk_mq_unregister_dev(disk_to_dev(disk), q);
 	mutex_unlock(&q->sysfs_lock);
 
@@ -983,7 +983,7 @@ void blk_unregister_queue(struct gendisk *disk)
 	blk_trace_remove_sysfs(disk_to_dev(disk));
 
 	mutex_lock(&q->sysfs_lock);
-	if (q->mq_ops && q->elevator)
+	if (q->elevator)
 		elv_unregister_queue(q);
 	mutex_unlock(&q->sysfs_lock);
 

block/blk-throttle.c

@@ -2456,7 +2456,7 @@ void blk_throtl_register_queue(struct request_queue *q)
 	td->throtl_slice = DFL_THROTL_SLICE_HD;
 #endif
 
-	td->track_bio_latency = !queue_is_rq_based(q);
+	td->track_bio_latency = !queue_is_mq(q);
 	if (!td->track_bio_latency)
 		blk_stat_enable_accounting(q);
 }

block/blk-wbt.c

@@ -701,7 +701,7 @@ void wbt_enable_default(struct request_queue *q)
 	if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
 		return;
 
-	if (q->mq_ops && IS_ENABLED(CONFIG_BLK_WBT_MQ))
+	if (queue_is_mq(q) && IS_ENABLED(CONFIG_BLK_WBT_MQ))
 		wbt_init(q);
 }
 EXPORT_SYMBOL_GPL(wbt_enable_default);

block/blk-zoned.c

@@ -421,7 +421,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
 	 * BIO based queues do not use a scheduler so only q->nr_zones
 	 * needs to be updated so that the sysfs exposed value is correct.
 	 */
-	if (!queue_is_rq_based(q)) {
+	if (!queue_is_mq(q)) {
 		q->nr_zones = nr_zones;
 		return 0;
 	}

block/bsg.c

@@ -471,7 +471,7 @@ int bsg_register_queue(struct request_queue *q, struct device *parent,
 	/*
 	 * we need a proper transport to send commands, not a stacked device
 	 */
-	if (!queue_is_rq_based(q))
+	if (!queue_is_mq(q))
 		return 0;
 
 	bcd = &q->bsg_dev;

block/elevator.c

@@ -667,7 +667,7 @@ static int __elevator_change(struct request_queue *q, const char *name)
 	/*
 	 * Special case for mq, turn off scheduling
 	 */
-	if (q->mq_ops && !strncmp(name, "none", 4))
+	if (!strncmp(name, "none", 4))
 		return elevator_switch(q, NULL);
 
 	strlcpy(elevator_name, name, sizeof(elevator_name));
@@ -685,8 +685,7 @@ static int __elevator_change(struct request_queue *q, const char *name)
 
 static inline bool elv_support_iosched(struct request_queue *q)
 {
-	if (q->mq_ops && q->tag_set && (q->tag_set->flags &
+	if (q->tag_set && (q->tag_set->flags & BLK_MQ_F_NO_SCHED))
-				BLK_MQ_F_NO_SCHED))
 		return false;
 	return true;
 }
@@ -696,7 +695,7 @@ ssize_t elv_iosched_store(struct request_queue *q, const char *name,
 {
 	int ret;
 
-	if (!q->mq_ops || !elv_support_iosched(q))
+	if (!queue_is_mq(q) || !elv_support_iosched(q))
 		return count;
 
 	ret = __elevator_change(q, name);
@@ -713,7 +712,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name)
 	struct elevator_type *__e;
 	int len = 0;
 
-	if (!queue_is_rq_based(q))
+	if (!queue_is_mq(q))
 		return sprintf(name, "none\n");
 
 	if (!q->elevator)
@@ -732,7 +731,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name)
 	}
 	spin_unlock(&elv_list_lock);
 
-	if (q->mq_ops && q->elevator)
+	if (q->elevator)
 		len += sprintf(name+len, "none");
 
 	len += sprintf(len+name, "\n");

block/genhd.c

@@ -47,7 +47,7 @@ static void disk_release_events(struct gendisk *disk);
 
 void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
 {
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		return;
 
 	atomic_inc(&part->in_flight[rw]);
@@ -57,7 +57,7 @@ void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
 
 void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
 {
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		return;
 
 	atomic_dec(&part->in_flight[rw]);
@@ -68,7 +68,7 @@ void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
 void part_in_flight(struct request_queue *q, struct hd_struct *part,
 		    unsigned int inflight[2])
 {
-	if (q->mq_ops) {
+	if (queue_is_mq(q)) {
 		blk_mq_in_flight(q, part, inflight);
 		return;
 	}
@@ -85,7 +85,7 @@ void part_in_flight(struct request_queue *q, struct hd_struct *part,
 void part_in_flight_rw(struct request_queue *q, struct hd_struct *part,
 		       unsigned int inflight[2])
 {
-	if (q->mq_ops) {
+	if (queue_is_mq(q)) {
 		blk_mq_in_flight_rw(q, part, inflight);
 		return;
 	}

drivers/md/dm-rq.c

@@ -43,7 +43,7 @@ static unsigned dm_get_blk_mq_queue_depth(void)
 
 int dm_request_based(struct mapped_device *md)
 {
-	return queue_is_rq_based(md->queue);
+	return queue_is_mq(md->queue);
 }
 
 void dm_start_queue(struct request_queue *q)

drivers/md/dm-table.c

@@ -919,12 +919,12 @@ static int device_is_rq_based(struct dm_target *ti, struct dm_dev *dev,
 	struct request_queue *q = bdev_get_queue(dev->bdev);
 	struct verify_rq_based_data *v = data;
 
-	if (q->mq_ops)
+	if (queue_is_mq(q))
 		v->mq_count++;
 	else
 		v->sq_count++;
 
-	return queue_is_rq_based(q);
+	return queue_is_mq(q);
 }
 
 static int dm_table_determine_type(struct dm_table *t)

include/linux/blkdev.h

@@ -656,11 +656,7 @@ static inline bool blk_account_rq(struct request *rq)
 
 #define rq_data_dir(rq)		(op_is_write(req_op(rq)) ? WRITE : READ)
 
-/*
+static inline bool queue_is_mq(struct request_queue *q)
- * Driver can handle struct request, if it either has an old style
- * request_fn defined, or is blk-mq based.
- */
-static inline bool queue_is_rq_based(struct request_queue *q)
 {
 	return q->mq_ops;
 }