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Commit eca7ee6d authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm: distinquish old .request_fn (dm-old) vs dm-mq request-based DM 



Rename various methods to have either a "dm_old" or "dm_mq" prefix.
Improve code comments to assist with understanding the duality of code
that handles both "dm_old" and "dm_mq" cases.

It is no much easier to quickly look at the code and _know_ that a given
method is either 1) "dm_old" only 2) "dm_mq" only 3) common to both.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent c5248f79

drivers/md/dm-mpath.c

+5 −1
Original line number Diff line number Diff line
@@ -426,7 +426,11 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, 
		clone->rq_disk = bdev->bd_disk;

		clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;

	} else {

		/* blk-mq request-based interface */

		/*

		 * blk-mq request-based interface; used by both:

		 * .request_fn stacked on blk-mq path(s) and

		 * blk-mq stacked on blk-mq path(s).

		 */

		*__clone = blk_get_request(bdev_get_queue(bdev),

					   rq_data_dir(rq), GFP_ATOMIC);

		if (IS_ERR(*__clone)) {

drivers/md/dm.c

+53 −49
Original line number Diff line number Diff line
@@ -333,7 +333,7 @@ static int __init local_init(void) 
	if (!_rq_tio_cache)

		goto out_free_io_cache;



	_rq_cache = kmem_cache_create("dm_clone_request", sizeof(struct request),

	_rq_cache = kmem_cache_create("dm_old_clone_request", sizeof(struct request),

				      __alignof__(struct request), 0, NULL);

	if (!_rq_cache)

		goto out_free_rq_tio_cache;
@@ -652,24 +652,24 @@ static void free_tio(struct mapped_device *md, struct dm_target_io *tio) 
	bio_put(&tio->clone);

}



static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,

static struct dm_rq_target_io *alloc_old_rq_tio(struct mapped_device *md,

						gfp_t gfp_mask)

{

	return mempool_alloc(md->io_pool, gfp_mask);

}



static void free_rq_tio(struct dm_rq_target_io *tio)

static void free_old_rq_tio(struct dm_rq_target_io *tio)

{

	mempool_free(tio, tio->md->io_pool);

}



static struct request *alloc_clone_request(struct mapped_device *md,

static struct request *alloc_old_clone_request(struct mapped_device *md,

					       gfp_t gfp_mask)

{

	return mempool_alloc(md->rq_pool, gfp_mask);

}



static void free_clone_request(struct mapped_device *md, struct request *rq)

static void free_old_clone_request(struct mapped_device *md, struct request *rq)

{

	mempool_free(rq, md->rq_pool);

}
@@ -1140,10 +1140,10 @@ static void free_rq_clone(struct request *clone) 
		tio->ti->type->release_clone_rq(clone);

	else if (!md->queue->mq_ops)

		/* request_fn queue stacked on request_fn queue(s) */

		free_clone_request(md, clone);

		free_old_clone_request(md, clone);



	if (!md->queue->mq_ops)

		free_rq_tio(tio);

		free_old_rq_tio(tio);

}



/*
@@ -1193,13 +1193,13 @@ static void dm_unprep_request(struct request *rq) 
	if (clone)

		free_rq_clone(clone);

	else if (!tio->md->queue->mq_ops)

		free_rq_tio(tio);

		free_old_rq_tio(tio);

}



/*

 * Requeue the original request of a clone.

 */

static void old_requeue_request(struct request *rq)

static void dm_old_requeue_request(struct request *rq)

{

	struct request_queue *q = rq->q;

	unsigned long flags;
@@ -1231,14 +1231,14 @@ static void dm_requeue_original_request(struct mapped_device *md, 


	rq_end_stats(md, rq);

	if (!rq->q->mq_ops)

		old_requeue_request(rq);

		dm_old_requeue_request(rq);

	else

		dm_mq_requeue_request(rq);



	rq_completed(md, rw, false);

}



static void old_stop_queue(struct request_queue *q)

static void dm_old_stop_queue(struct request_queue *q)

{

	unsigned long flags;
@@ -1252,15 +1252,15 @@ static void old_stop_queue(struct request_queue *q) 
	spin_unlock_irqrestore(q->queue_lock, flags);

}



static void stop_queue(struct request_queue *q)

static void dm_stop_queue(struct request_queue *q)

{

	if (!q->mq_ops)

		old_stop_queue(q);

		dm_old_stop_queue(q);

	else

		blk_mq_stop_hw_queues(q);

}



static void old_start_queue(struct request_queue *q)

static void dm_old_start_queue(struct request_queue *q)

{

	unsigned long flags;
@@ -1270,10 +1270,10 @@ static void old_start_queue(struct request_queue *q) 
	spin_unlock_irqrestore(q->queue_lock, flags);

}



static void start_queue(struct request_queue *q)

static void dm_start_queue(struct request_queue *q)

{

	if (!q->mq_ops)

		old_start_queue(q);

		dm_old_start_queue(q);

	else {

		blk_mq_start_stopped_hw_queues(q, true);

		blk_mq_kick_requeue_list(q);
@@ -1328,7 +1328,7 @@ static void dm_softirq_done(struct request *rq) 
		if (!rq->q->mq_ops) {

			blk_end_request_all(rq, tio->error);

			rq_completed(tio->md, rw, false);

			free_rq_tio(tio);

			free_old_rq_tio(tio);

		} else {

			blk_mq_end_request(rq, tio->error);

			rq_completed(tio->md, rw, false);
@@ -1370,7 +1370,7 @@ static void dm_kill_unmapped_request(struct request *rq, int error) 
}



/*

 * Called with the clone's queue lock held (for non-blk-mq)

 * Called with the clone's queue lock held (in the case of .request_fn)

 */

static void end_clone_request(struct request *clone, int error)

{
@@ -1857,7 +1857,7 @@ static int setup_clone(struct request *clone, struct request *rq, 
	return 0;

}



static struct request *clone_rq(struct request *rq, struct mapped_device *md,

static struct request *clone_old_rq(struct request *rq, struct mapped_device *md,

				    struct dm_rq_target_io *tio, gfp_t gfp_mask)

{

	/*
@@ -1865,14 +1865,14 @@ static struct request *clone_rq(struct request *rq, struct mapped_device *md, 
	 */

	struct request *clone;



	clone = alloc_clone_request(md, gfp_mask);

	clone = alloc_old_clone_request(md, gfp_mask);

	if (!clone)

		return NULL;



	blk_rq_init(NULL, clone);

	if (setup_clone(clone, rq, tio, gfp_mask)) {

		/* -ENOMEM */

		free_clone_request(md, clone);

		free_old_clone_request(md, clone);

		return NULL;

	}
@@ -1894,24 +1894,29 @@ static void init_tio(struct dm_rq_target_io *tio, struct request *rq, 
		init_kthread_work(&tio->work, map_tio_request);

}



static struct dm_rq_target_io *prep_tio(struct request *rq,

					struct mapped_device *md, gfp_t gfp_mask)

static struct dm_rq_target_io *dm_old_prep_tio(struct request *rq,

					       struct mapped_device *md,

					       gfp_t gfp_mask)

{

	struct dm_rq_target_io *tio;

	int srcu_idx;

	struct dm_table *table;



	tio = alloc_rq_tio(md, gfp_mask);

	tio = alloc_old_rq_tio(md, gfp_mask);

	if (!tio)

		return NULL;



	init_tio(tio, rq, md);



	table = dm_get_live_table(md, &srcu_idx);

	/*

	 * Must clone a request if this .request_fn DM device

	 * is stacked on .request_fn device(s).

	 */

	if (!dm_table_mq_request_based(table)) {

		if (!clone_rq(rq, md, tio, gfp_mask)) {

		if (!clone_old_rq(rq, md, tio, gfp_mask)) {

			dm_put_live_table(md, srcu_idx);

			free_rq_tio(tio);

			free_old_rq_tio(tio);

			return NULL;

		}

	}
@@ -1923,7 +1928,7 @@ static struct dm_rq_target_io *prep_tio(struct request *rq, 
/*

 * Called with the queue lock held.

 */

static int dm_prep_fn(struct request_queue *q, struct request *rq)

static int dm_old_prep_fn(struct request_queue *q, struct request *rq)

{

	struct mapped_device *md = q->queuedata;

	struct dm_rq_target_io *tio;
@@ -1933,7 +1938,7 @@ static int dm_prep_fn(struct request_queue *q, struct request *rq) 
		return BLKPREP_KILL;

	}



	tio = prep_tio(rq, md, GFP_ATOMIC);

	tio = dm_old_prep_tio(rq, md, GFP_ATOMIC);

	if (!tio)

		return BLKPREP_DEFER;
@@ -2236,7 +2241,7 @@ static void dm_init_md_queue(struct mapped_device *md) 
	md->queue->backing_dev_info.congested_data = md;

}



static void dm_init_old_md_queue(struct mapped_device *md)

static void dm_init_normal_md_queue(struct mapped_device *md)

{

	md->use_blk_mq = false;

	dm_init_md_queue(md);
@@ -2503,7 +2508,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t, 
	 * because request-based dm may be run just after the setting.

	 */

	if (dm_table_request_based(t)) {

		stop_queue(q);

		dm_stop_queue(q);

		/*

		 * Leverage the fact that request-based DM targets are

		 * immutable singletons and establish md->immutable_target
@@ -2600,7 +2605,7 @@ struct queue_limits *dm_get_queue_limits(struct mapped_device *md) 
}

EXPORT_SYMBOL_GPL(dm_get_queue_limits);



static void init_rq_based_worker_thread(struct mapped_device *md)

static void dm_old_init_rq_based_worker_thread(struct mapped_device *md)

{

	/* Initialize the request-based DM worker thread */

	init_kthread_worker(&md->kworker);
@@ -2609,9 +2614,9 @@ static void init_rq_based_worker_thread(struct mapped_device *md) 
}



/*

 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).

 * Fully initialize a .request_fn request-based queue.

 */

static int dm_init_request_based_queue(struct mapped_device *md)

static int dm_old_init_request_queue(struct mapped_device *md)

{

	struct request_queue *q = NULL;
@@ -2624,11 +2629,11 @@ static int dm_init_request_based_queue(struct mapped_device *md) 
	md->seq_rq_merge_deadline_usecs = 0;



	md->queue = q;

	dm_init_old_md_queue(md);

	dm_init_normal_md_queue(md);

	blk_queue_softirq_done(md->queue, dm_softirq_done);

	blk_queue_prep_rq(md->queue, dm_prep_fn);

	blk_queue_prep_rq(md->queue, dm_old_prep_fn);



	init_rq_based_worker_thread(md);

	dm_old_init_rq_based_worker_thread(md);



	elv_register_queue(md->queue);
@@ -2699,9 +2704,8 @@ static struct blk_mq_ops dm_mq_ops = { 
	.init_request = dm_mq_init_request,

};



static int dm_init_request_based_blk_mq_queue(struct mapped_device *md)

static int dm_mq_init_request_queue(struct mapped_device *md)

{

	unsigned md_type = dm_get_md_type(md);

	struct request_queue *q;

	int err;
@@ -2766,21 +2770,21 @@ int dm_setup_md_queue(struct mapped_device *md) 


	switch (md_type) {

	case DM_TYPE_REQUEST_BASED:

		r = dm_init_request_based_queue(md);

		r = dm_old_init_request_queue(md);

		if (r) {

			DMWARN("Cannot initialize queue for request-based mapped device");

			DMERR("Cannot initialize queue for request-based mapped device");

			return r;

		}

		break;

	case DM_TYPE_MQ_REQUEST_BASED:

		r = dm_init_request_based_blk_mq_queue(md);

		r = dm_mq_init_request_queue(md);

		if (r) {

			DMWARN("Cannot initialize queue for request-based blk-mq mapped device");

			DMERR("Cannot initialize queue for request-based dm-mq mapped device");

			return r;

		}

		break;

	case DM_TYPE_BIO_BASED:

		dm_init_old_md_queue(md);

		dm_init_normal_md_queue(md);

		blk_queue_make_request(md->queue, dm_make_request);

		/*

		 * DM handles splitting bios as needed.  Free the bio_split bioset
@@ -3123,7 +3127,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, 
	 * dm defers requests to md->wq from md->queue.

	 */

	if (dm_request_based(md)) {

		stop_queue(md->queue);

		dm_stop_queue(md->queue);

		if (md->kworker_task)

			flush_kthread_worker(&md->kworker);

	}
@@ -3147,7 +3151,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, 
		dm_queue_flush(md);



		if (dm_request_based(md))

			start_queue(md->queue);

			dm_start_queue(md->queue);



		unlock_fs(md);

		dm_table_presuspend_undo_targets(map);
@@ -3226,7 +3230,7 @@ static int __dm_resume(struct mapped_device *md, struct dm_table *map) 
	 * Request-based dm is queueing the deferred I/Os in its request_queue.

	 */

	if (dm_request_based(md))

		start_queue(md->queue);

		dm_start_queue(md->queue);



	unlock_fs(md);