Commit 1baa1126 authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Jens Axboe
Browse files

md/raid5: Move common stripe get code into new find_get_stripe() helper 



Both uses of find_stripe() require a fairly complicated dance to
increment the reference count. Move this into a common find_get_stripe()
helper.

No functional changes intended.

Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: default avatarSong Liu <song@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8757fef6

drivers/md/raid5.c

+64 −67
Original line number Diff line number Diff line
@@ -624,6 +624,49 @@ static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector, 
	return NULL;

}



static struct stripe_head *find_get_stripe(struct r5conf *conf,

		sector_t sector, short generation, int hash)

{

	int inc_empty_inactive_list_flag;

	struct stripe_head *sh;



	sh = __find_stripe(conf, sector, generation);

	if (!sh)

		return NULL;



	if (atomic_inc_not_zero(&sh->count))

		return sh;



	/*

	 * Slow path. The reference count is zero which means the stripe must

	 * be on a list (sh->lru). Must remove the stripe from the list that

	 * references it with the device_lock held.

	 */



	spin_lock(&conf->device_lock);

	if (!atomic_read(&sh->count)) {

		if (!test_bit(STRIPE_HANDLE, &sh->state))

			atomic_inc(&conf->active_stripes);

		BUG_ON(list_empty(&sh->lru) &&

		       !test_bit(STRIPE_EXPANDING, &sh->state));

		inc_empty_inactive_list_flag = 0;

		if (!list_empty(conf->inactive_list + hash))

			inc_empty_inactive_list_flag = 1;

		list_del_init(&sh->lru);

		if (list_empty(conf->inactive_list + hash) &&

		    inc_empty_inactive_list_flag)

			atomic_inc(&conf->empty_inactive_list_nr);

		if (sh->group) {

			sh->group->stripes_cnt--;

			sh->group = NULL;

		}

	}

	atomic_inc(&sh->count);

	spin_unlock(&conf->device_lock);



	return sh;

}



/*

 * Need to check if array has failed when deciding whether to:

 *  - start an array
@@ -716,7 +759,6 @@ raid5_get_active_stripe(struct r5conf *conf, sector_t sector, 
{

	struct stripe_head *sh;

	int hash = stripe_hash_locks_hash(conf, sector);

	int inc_empty_inactive_list_flag;



	pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
@@ -726,58 +768,35 @@ raid5_get_active_stripe(struct r5conf *conf, sector_t sector, 
		wait_event_lock_irq(conf->wait_for_quiescent,

				    conf->quiesce == 0 || noquiesce,

				    *(conf->hash_locks + hash));

		sh = __find_stripe(conf, sector, conf->generation - previous);

		if (!sh) {

		sh = find_get_stripe(conf, sector, conf->generation - previous,

				     hash);

		if (sh)

			break;



		if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {

			sh = get_free_stripe(conf, hash);

				if (!sh && !test_bit(R5_DID_ALLOC,

						     &conf->cache_state))

					set_bit(R5_ALLOC_MORE,

						&conf->cache_state);

			if (!sh && !test_bit(R5_DID_ALLOC, &conf->cache_state))

				set_bit(R5_ALLOC_MORE, &conf->cache_state);

		}

			if (noblock && sh == NULL)

		if (noblock && !sh)

			break;



		r5c_check_stripe_cache_usage(conf);

		if (!sh) {

				set_bit(R5_INACTIVE_BLOCKED,

					&conf->cache_state);

			set_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);

			r5l_wake_reclaim(conf->log, 0);

				wait_event_lock_irq(

					conf->wait_for_stripe,

			wait_event_lock_irq(conf->wait_for_stripe,

					!list_empty(conf->inactive_list + hash) &&

					(atomic_read(&conf->active_stripes)

					 < (conf->max_nr_stripes * 3 / 4)

					 || !test_bit(R5_INACTIVE_BLOCKED,

						      &conf->cache_state)),

					*(conf->hash_locks + hash));

				clear_bit(R5_INACTIVE_BLOCKED,

					  &conf->cache_state);

			clear_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);

		} else {

			init_stripe(sh, sector, previous);

			atomic_inc(&sh->count);

		}

		} else if (!atomic_inc_not_zero(&sh->count)) {

			spin_lock(&conf->device_lock);

			if (!atomic_read(&sh->count)) {

				if (!test_bit(STRIPE_HANDLE, &sh->state))

					atomic_inc(&conf->active_stripes);

				BUG_ON(list_empty(&sh->lru) &&

				       !test_bit(STRIPE_EXPANDING, &sh->state));

				inc_empty_inactive_list_flag = 0;

				if (!list_empty(conf->inactive_list + hash))

					inc_empty_inactive_list_flag = 1;

				list_del_init(&sh->lru);

				if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)

					atomic_inc(&conf->empty_inactive_list_nr);

				if (sh->group) {

					sh->group->stripes_cnt--;

					sh->group = NULL;

				}

			}

			atomic_inc(&sh->count);

			spin_unlock(&conf->device_lock);

		}

	} while (sh == NULL);



	spin_unlock_irq(conf->hash_locks + hash);
@@ -830,7 +849,6 @@ static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh 
	sector_t head_sector, tmp_sec;

	int hash;

	int dd_idx;

	int inc_empty_inactive_list_flag;



	/* Don't cross chunks, so stripe pd_idx/qd_idx is the same */

	tmp_sec = sh->sector;
@@ -840,28 +858,7 @@ static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh 


	hash = stripe_hash_locks_hash(conf, head_sector);

	spin_lock_irq(conf->hash_locks + hash);

	head = __find_stripe(conf, head_sector, conf->generation);

	if (head && !atomic_inc_not_zero(&head->count)) {

		spin_lock(&conf->device_lock);

		if (!atomic_read(&head->count)) {

			if (!test_bit(STRIPE_HANDLE, &head->state))

				atomic_inc(&conf->active_stripes);

			BUG_ON(list_empty(&head->lru) &&

			       !test_bit(STRIPE_EXPANDING, &head->state));

			inc_empty_inactive_list_flag = 0;

			if (!list_empty(conf->inactive_list + hash))

				inc_empty_inactive_list_flag = 1;

			list_del_init(&head->lru);

			if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)

				atomic_inc(&conf->empty_inactive_list_nr);

			if (head->group) {

				head->group->stripes_cnt--;

				head->group = NULL;

			}

		}

		atomic_inc(&head->count);

		spin_unlock(&conf->device_lock);

	}

	head = find_get_stripe(conf, head_sector, conf->generation, hash);

	spin_unlock_irq(conf->hash_locks + hash);



	if (!head)