From: Sebastian Andrzej Siewior Date: Mon, 7 May 2018 17:42:52 +0200 Subject: [PATCH] md: raid5: use refcount_t for reference counting instead atomic_t Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.16/older/patches-4.16.8-rt3.tar.xz refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Most changes are 1:1 replacements except for BUG_ON(atomic_inc_return(&sh->count) != 1); which has been turned into refcount_inc(&sh->count); BUG_ON(refcount_read(&sh->count) != 1); Suggested-by: Peter Zijlstra Signed-off-by: Sebastian Andrzej Siewior --- drivers/md/raid5-cache.c | 8 ++--- drivers/md/raid5-ppl.c | 2 - drivers/md/raid5.c | 67 +++++++++++++++++++++++------------------------ drivers/md/raid5.h | 4 +- 4 files changed, 41 insertions(+), 40 deletions(-) --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -1049,7 +1049,7 @@ int r5l_write_stripe(struct r5l_log *log * don't delay. */ clear_bit(STRIPE_DELAYED, &sh->state); - atomic_inc(&sh->count); + refcount_inc(&sh->count); mutex_lock(&log->io_mutex); /* meta + data */ @@ -1388,7 +1388,7 @@ static void r5c_flush_stripe(struct r5co lockdep_assert_held(&conf->device_lock); list_del_init(&sh->lru); - atomic_inc(&sh->count); + refcount_inc(&sh->count); set_bit(STRIPE_HANDLE, &sh->state); atomic_inc(&conf->active_stripes); @@ -1491,7 +1491,7 @@ static void r5c_do_reclaim(struct r5conf */ if (!list_empty(&sh->lru) && !test_bit(STRIPE_HANDLE, &sh->state) && - atomic_read(&sh->count) == 0) { + refcount_read(&sh->count) == 0) { r5c_flush_stripe(conf, sh); if (count++ >= R5C_RECLAIM_STRIPE_GROUP) break; @@ -2912,7 +2912,7 @@ int r5c_cache_data(struct r5l_log *log, * don't delay. */ clear_bit(STRIPE_DELAYED, &sh->state); - atomic_inc(&sh->count); + refcount_inc(&sh->count); mutex_lock(&log->io_mutex); /* meta + data */ --- a/drivers/md/raid5-ppl.c +++ b/drivers/md/raid5-ppl.c @@ -388,7 +388,7 @@ int ppl_write_stripe(struct r5conf *conf set_bit(STRIPE_LOG_TRAPPED, &sh->state); clear_bit(STRIPE_DELAYED, &sh->state); - atomic_inc(&sh->count); + refcount_inc(&sh->count); if (ppl_log_stripe(log, sh)) { spin_lock_irq(&ppl_conf->no_mem_stripes_lock); --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -306,7 +306,7 @@ static void do_release_stripe(struct r5c static void __release_stripe(struct r5conf *conf, struct stripe_head *sh, struct list_head *temp_inactive_list) { - if (atomic_dec_and_test(&sh->count)) + if (refcount_dec_and_test(&sh->count)) do_release_stripe(conf, sh, temp_inactive_list); } @@ -398,7 +398,7 @@ void raid5_release_stripe(struct stripe_ /* Avoid release_list until the last reference. */ - if (atomic_add_unless(&sh->count, -1, 1)) + if (refcount_dec_not_one(&sh->count)) return; if (unlikely(!conf->mddev->thread) || @@ -411,7 +411,7 @@ void raid5_release_stripe(struct stripe_ slow_path: local_irq_save(flags); /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */ - if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) { + if (refcount_dec_and_lock(&sh->count, &conf->device_lock)) { INIT_LIST_HEAD(&list); hash = sh->hash_lock_index; do_release_stripe(conf, sh, &list); @@ -501,7 +501,7 @@ static void init_stripe(struct stripe_he struct r5conf *conf = sh->raid_conf; int i, seq; - BUG_ON(atomic_read(&sh->count) != 0); + BUG_ON(refcount_read(&sh->count) != 0); BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); BUG_ON(stripe_operations_active(sh)); BUG_ON(sh->batch_head); @@ -678,11 +678,11 @@ raid5_get_active_stripe(struct r5conf *c &conf->cache_state); } else { init_stripe(sh, sector, previous); - atomic_inc(&sh->count); + refcount_inc(&sh->count); } - } else if (!atomic_inc_not_zero(&sh->count)) { + } else if (!refcount_inc_not_zero(&sh->count)) { spin_lock(&conf->device_lock); - if (!atomic_read(&sh->count)) { + if (!refcount_read(&sh->count)) { if (!test_bit(STRIPE_HANDLE, &sh->state)) atomic_inc(&conf->active_stripes); BUG_ON(list_empty(&sh->lru) && @@ -698,7 +698,7 @@ raid5_get_active_stripe(struct r5conf *c sh->group = NULL; } } - atomic_inc(&sh->count); + refcount_inc(&sh->count); spin_unlock(&conf->device_lock); } } while (sh == NULL); @@ -760,9 +760,9 @@ static void stripe_add_to_batch_list(str hash = stripe_hash_locks_hash(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)) { + if (head && !refcount_inc_not_zero(&head->count)) { spin_lock(&conf->device_lock); - if (!atomic_read(&head->count)) { + if (!refcount_read(&head->count)) { if (!test_bit(STRIPE_HANDLE, &head->state)) atomic_inc(&conf->active_stripes); BUG_ON(list_empty(&head->lru) && @@ -778,7 +778,7 @@ static void stripe_add_to_batch_list(str head->group = NULL; } } - atomic_inc(&head->count); + refcount_inc(&head->count); spin_unlock(&conf->device_lock); } spin_unlock_irq(conf->hash_locks + hash); @@ -847,7 +847,7 @@ static void stripe_add_to_batch_list(str sh->batch_head->bm_seq = seq; } - atomic_inc(&sh->count); + refcount_inc(&sh->count); unlock_out: unlock_two_stripes(head, sh); out: @@ -1110,9 +1110,9 @@ static void ops_run_io(struct stripe_hea pr_debug("%s: for %llu schedule op %d on disc %d\n", __func__, (unsigned long long)sh->sector, bi->bi_opf, i); - atomic_inc(&sh->count); + refcount_inc(&sh->count); if (sh != head_sh) - atomic_inc(&head_sh->count); + refcount_inc(&head_sh->count); if (use_new_offset(conf, sh)) bi->bi_iter.bi_sector = (sh->sector + rdev->new_data_offset); @@ -1174,9 +1174,9 @@ static void ops_run_io(struct stripe_hea "replacement disc %d\n", __func__, (unsigned long long)sh->sector, rbi->bi_opf, i); - atomic_inc(&sh->count); + refcount_inc(&sh->count); if (sh != head_sh) - atomic_inc(&head_sh->count); + refcount_inc(&head_sh->count); if (use_new_offset(conf, sh)) rbi->bi_iter.bi_sector = (sh->sector + rrdev->new_data_offset); @@ -1354,7 +1354,7 @@ static void ops_run_biofill(struct strip } } - atomic_inc(&sh->count); + refcount_inc(&sh->count); init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL); async_trigger_callback(&submit); } @@ -1432,7 +1432,7 @@ ops_run_compute5(struct stripe_head *sh, if (i != target) xor_srcs[count++] = sh->dev[i].page; - atomic_inc(&sh->count); + refcount_inc(&sh->count); init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL, ops_complete_compute, sh, to_addr_conv(sh, percpu, 0)); @@ -1521,7 +1521,7 @@ ops_run_compute6_1(struct stripe_head *s BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags)); dest = tgt->page; - atomic_inc(&sh->count); + refcount_inc(&sh->count); if (target == qd_idx) { count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL); @@ -1596,7 +1596,7 @@ ops_run_compute6_2(struct stripe_head *s pr_debug("%s: stripe: %llu faila: %d failb: %d\n", __func__, (unsigned long long)sh->sector, faila, failb); - atomic_inc(&sh->count); + refcount_inc(&sh->count); if (failb == syndrome_disks+1) { /* Q disk is one of the missing disks */ @@ -1867,7 +1867,7 @@ ops_run_reconstruct5(struct stripe_head break; } if (i >= sh->disks) { - atomic_inc(&sh->count); + refcount_inc(&sh->count); set_bit(R5_Discard, &sh->dev[pd_idx].flags); ops_complete_reconstruct(sh); return; @@ -1908,7 +1908,7 @@ ops_run_reconstruct5(struct stripe_head flags = ASYNC_TX_ACK | (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST); - atomic_inc(&head_sh->count); + refcount_inc(&head_sh->count); init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh, to_addr_conv(sh, percpu, j)); } else { @@ -1950,7 +1950,7 @@ ops_run_reconstruct6(struct stripe_head break; } if (i >= sh->disks) { - atomic_inc(&sh->count); + refcount_inc(&sh->count); set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags); set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags); ops_complete_reconstruct(sh); @@ -1974,7 +1974,7 @@ ops_run_reconstruct6(struct stripe_head struct stripe_head, batch_list) == head_sh; if (last_stripe) { - atomic_inc(&head_sh->count); + refcount_inc(&head_sh->count); init_async_submit(&submit, txflags, tx, ops_complete_reconstruct, head_sh, to_addr_conv(sh, percpu, j)); } else @@ -2031,7 +2031,7 @@ static void ops_run_check_p(struct strip tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &sh->ops.zero_sum_result, &submit); - atomic_inc(&sh->count); + refcount_inc(&sh->count); init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL); tx = async_trigger_callback(&submit); } @@ -2050,7 +2050,7 @@ static void ops_run_check_pq(struct stri if (!checkp) srcs[count] = NULL; - atomic_inc(&sh->count); + refcount_inc(&sh->count); init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check, sh, to_addr_conv(sh, percpu, 0)); async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE, @@ -2150,7 +2150,7 @@ static struct stripe_head *alloc_stripe( INIT_LIST_HEAD(&sh->lru); INIT_LIST_HEAD(&sh->r5c); INIT_LIST_HEAD(&sh->log_list); - atomic_set(&sh->count, 1); + refcount_set(&sh->count, 1); sh->raid_conf = conf; sh->log_start = MaxSector; for (i = 0; i < disks; i++) { @@ -2451,7 +2451,7 @@ static int drop_one_stripe(struct r5conf spin_unlock_irq(conf->hash_locks + hash); if (!sh) return 0; - BUG_ON(atomic_read(&sh->count)); + BUG_ON(refcount_read(&sh->count)); shrink_buffers(sh); free_stripe(conf->slab_cache, sh); atomic_dec(&conf->active_stripes); @@ -2483,7 +2483,7 @@ static void raid5_end_read_request(struc break; pr_debug("end_read_request %llu/%d, count: %d, error %d.\n", - (unsigned long long)sh->sector, i, atomic_read(&sh->count), + (unsigned long long)sh->sector, i, refcount_read(&sh->count), bi->bi_status); if (i == disks) { bio_reset(bi); @@ -2620,7 +2620,7 @@ static void raid5_end_write_request(stru } } pr_debug("end_write_request %llu/%d, count %d, error: %d.\n", - (unsigned long long)sh->sector, i, atomic_read(&sh->count), + (unsigned long long)sh->sector, i, refcount_read(&sh->count), bi->bi_status); if (i == disks) { bio_reset(bi); @@ -4687,7 +4687,7 @@ static void handle_stripe(struct stripe_ pr_debug("handling stripe %llu, state=%#lx cnt=%d, " "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n", (unsigned long long)sh->sector, sh->state, - atomic_read(&sh->count), sh->pd_idx, sh->qd_idx, + refcount_read(&sh->count), sh->pd_idx, sh->qd_idx, sh->check_state, sh->reconstruct_state); analyse_stripe(sh, &s); @@ -5062,7 +5062,7 @@ static void activate_bit_delay(struct r5 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); int hash; list_del_init(&sh->lru); - atomic_inc(&sh->count); + refcount_inc(&sh->count); hash = sh->hash_lock_index; __release_stripe(conf, sh, &temp_inactive_list[hash]); } @@ -5387,7 +5387,8 @@ static struct stripe_head *__get_priorit sh->group = NULL; } list_del_init(&sh->lru); - BUG_ON(atomic_inc_return(&sh->count) != 1); + refcount_inc(&sh->count); + BUG_ON(refcount_read(&sh->count) != 1); return sh; } --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -4,7 +4,7 @@ #include #include - +#include /* * * Each stripe contains one buffer per device. Each buffer can be in @@ -208,7 +208,7 @@ struct stripe_head { short ddf_layout;/* use DDF ordering to calculate Q */ short hash_lock_index; unsigned long state; /* state flags */ - atomic_t count; /* nr of active thread/requests */ + refcount_t count; /* nr of active thread/requests */ int bm_seq; /* sequence number for bitmap flushes */ int disks; /* disks in stripe */ int overwrite_disks; /* total overwrite disks in stripe,