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Commit 42065460 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm delay: use per-bio data instead of a mempool and slab cache 



Starting with commit c0820cf5 ("dm: introduce per_bio_data"),
device mapper has the capability to pre-allocate a target-specific
structure with the bio.

This patch changes dm-delay to use this facility instead of a slab cache
and mempool.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 57a2f238

drivers/md/dm-delay.c

+7 −28
Original line number Diff line number Diff line
@@ -24,7 +24,6 @@ struct delay_c { 
	struct work_struct flush_expired_bios;

	struct list_head delayed_bios;

	atomic_t may_delay;

	mempool_t *delayed_pool;



	struct dm_dev *dev_read;

	sector_t start_read;
@@ -40,14 +39,11 @@ struct delay_c { 
struct dm_delay_info {

	struct delay_c *context;

	struct list_head list;

	struct bio *bio;

	unsigned long expires;

};



static DEFINE_MUTEX(delayed_bios_lock);



static struct kmem_cache *delayed_cache;



static void handle_delayed_timer(unsigned long data)

{

	struct delay_c *dc = (struct delay_c *)data;
@@ -87,13 +83,14 @@ static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all) 
	mutex_lock(&delayed_bios_lock);

	list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {

		if (flush_all || time_after_eq(jiffies, delayed->expires)) {

			struct bio *bio = dm_bio_from_per_bio_data(delayed,

						sizeof(struct dm_delay_info));

			list_del(&delayed->list);

			bio_list_add(&flush_bios, delayed->bio);

			if ((bio_data_dir(delayed->bio) == WRITE))

			bio_list_add(&flush_bios, bio);

			if ((bio_data_dir(bio) == WRITE))

				delayed->context->writes--;

			else

				delayed->context->reads--;

			mempool_free(delayed, dc->delayed_pool);

			continue;

		}
@@ -185,12 +182,6 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv) 
	}



out:

	dc->delayed_pool = mempool_create_slab_pool(128, delayed_cache);

	if (!dc->delayed_pool) {

		DMERR("Couldn't create delayed bio pool.");

		goto bad_dev_write;

	}



	dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);

	if (!dc->kdelayd_wq) {

		DMERR("Couldn't start kdelayd");
@@ -206,12 +197,11 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv) 


	ti->num_flush_bios = 1;

	ti->num_discard_bios = 1;

	ti->per_bio_data_size = sizeof(struct dm_delay_info);

	ti->private = dc;

	return 0;



bad_queue:

	mempool_destroy(dc->delayed_pool);

bad_dev_write:

	if (dc->dev_write)

		dm_put_device(ti, dc->dev_write);

bad_dev_read:
@@ -232,7 +222,6 @@ static void delay_dtr(struct dm_target *ti) 
	if (dc->dev_write)

		dm_put_device(ti, dc->dev_write);



	mempool_destroy(dc->delayed_pool);

	kfree(dc);

}
@@ -244,10 +233,9 @@ static int delay_bio(struct delay_c *dc, int delay, struct bio *bio) 
	if (!delay || !atomic_read(&dc->may_delay))

		return 1;



	delayed = mempool_alloc(dc->delayed_pool, GFP_NOIO);

	delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));



	delayed->context = dc;

	delayed->bio = bio;

	delayed->expires = expires = jiffies + (delay * HZ / 1000);



	mutex_lock(&delayed_bios_lock);
@@ -356,13 +344,7 @@ static struct target_type delay_target = { 


static int __init dm_delay_init(void)

{

	int r = -ENOMEM;



	delayed_cache = KMEM_CACHE(dm_delay_info, 0);

	if (!delayed_cache) {

		DMERR("Couldn't create delayed bio cache.");

		goto bad_memcache;

	}

	int r;



	r = dm_register_target(&delay_target);

	if (r < 0) {
@@ -373,15 +355,12 @@ static int __init dm_delay_init(void) 
	return 0;



bad_register:

	kmem_cache_destroy(delayed_cache);

bad_memcache:

	return r;

}



static void __exit dm_delay_exit(void)

{

	dm_unregister_target(&delay_target);

	kmem_cache_destroy(delayed_cache);

}



/* Module hooks */