From 1baa1126e0f6d366187f740144947b6cf619b4f2 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Thu, 16 Jun 2022 13:19:35 -0600 Subject: [PATCH] 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: Logan Gunthorpe Reviewed-by: Christoph Hellwig Acked-by: Guoqing Jiang Signed-off-by: Song Liu Signed-off-by: Jens Axboe --- drivers/md/raid5.c | 131 ++++++++++++++++++++++----------------------- 1 file changed, 64 insertions(+), 67 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index ae2c1ec8bc20..47b6ff2a7b16 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -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); @@ -726,57 +768,34 @@ 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) { - 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 (noblock && sh == NULL) - break; + sh = find_get_stripe(conf, sector, conf->generation - previous, + hash); + if (sh) + break; - r5c_check_stripe_cache_usage(conf); - if (!sh) { - set_bit(R5_INACTIVE_BLOCKED, - &conf->cache_state); - r5l_wake_reclaim(conf->log, 0); - wait_event_lock_irq( - conf->wait_for_stripe, + 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 (noblock && !sh) + break; + + r5c_check_stripe_cache_usage(conf); + if (!sh) { + set_bit(R5_INACTIVE_BLOCKED, &conf->cache_state); + r5l_wake_reclaim(conf->log, 0); + 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); - } 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; - } - } + clear_bit(R5_INACTIVE_BLOCKED, &conf->cache_state); + } else { + init_stripe(sh, sector, previous); atomic_inc(&sh->count); - spin_unlock(&conf->device_lock); } } while (sh == NULL); @@ -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)