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SubjectRE: [PATCH] drivers, md: convert stripe_head.count from atomic_t to refcount_t
Date
Just a ping on this updated patch. Did you find any new issues or could you please apply it?

Best Regards,
Elena.

> 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.
>
> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: David Windsor <dwindsor@gmail.com>
> ---
> drivers/md/raid5-cache.c | 8 +++---
> drivers/md/raid5.c | 68 +++++++++++++++++++++++++-----------------------
> drivers/md/raid5.h | 3 ++-
> 3 files changed, 41 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
> index 3f307be..6c05e12 100644
> --- a/drivers/md/raid5-cache.c
> +++ b/drivers/md/raid5-cache.c
> @@ -979,7 +979,7 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head
> *sh)
> * don't delay.
> */
> clear_bit(STRIPE_DELAYED, &sh->state);
> - atomic_inc(&sh->count);
> + refcount_inc(&sh->count);
>
> mutex_lock(&log->io_mutex);
> /* meta + data */
> @@ -1321,7 +1321,7 @@ static void r5c_flush_stripe(struct r5conf *conf, struct
> stripe_head *sh)
> assert_spin_locked(&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);
> @@ -1424,7 +1424,7 @@ static void r5c_do_reclaim(struct r5conf *conf)
> */
> 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;
> @@ -2650,7 +2650,7 @@ r5c_cache_data(struct r5l_log *log, struct stripe_head
> *sh,
> * don't delay.
> */
> clear_bit(STRIPE_DELAYED, &sh->state);
> - atomic_inc(&sh->count);
> + refcount_inc(&sh->count);
>
> mutex_lock(&log->io_mutex);
> /* meta + data */
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 2ce23b0..7e3913a 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -296,7 +296,7 @@ static void do_release_stripe(struct r5conf *conf, struct
> stripe_head *sh,
> 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);
> }
>
> @@ -388,7 +388,7 @@ void raid5_release_stripe(struct stripe_head *sh)
>
> /* 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) ||
> @@ -401,7 +401,7 @@ void raid5_release_stripe(struct stripe_head *sh)
> 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);
> @@ -491,7 +491,7 @@ static void init_stripe(struct stripe_head *sh, sector_t
> sector, int previous)
> 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);
> @@ -668,11 +668,11 @@ raid5_get_active_stripe(struct r5conf *conf, sector_t
> sector,
> &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) &&
> @@ -688,7 +688,7 @@ raid5_get_active_stripe(struct r5conf *conf, sector_t
> sector,
> sh-
> >group = NULL;
> }
> }
> - atomic_inc(&sh->count);
> + refcount_inc(&sh->count);
> spin_unlock(&conf->device_lock);
> }
> } while (sh == NULL);
> @@ -752,9 +752,9 @@ static void stripe_add_to_batch_list(struct r5conf *conf,
> struct stripe_head *sh
> 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) &&
> @@ -770,7 +770,7 @@ static void stripe_add_to_batch_list(struct r5conf *conf,
> struct stripe_head *sh
> head->group = NULL;
> }
> }
> - atomic_inc(&head->count);
> + refcount_inc(&head->count);
> spin_unlock(&conf->device_lock);
> }
> spin_unlock_irq(conf->hash_locks + hash);
> @@ -833,7 +833,7 @@ static void stripe_add_to_batch_list(struct r5conf *conf,
> struct stripe_head *sh
> sh->batch_head->bm_seq = seq;
> }
>
> - atomic_inc(&sh->count);
> + refcount_inc(&sh->count);
> unlock_out:
> unlock_two_stripes(head, sh);
> out:
> @@ -1036,9 +1036,9 @@ static void ops_run_io(struct stripe_head *sh, struct
> stripe_head_state *s)
> 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);
> @@ -1097,9 +1097,9 @@ static void ops_run_io(struct stripe_head *sh, struct
> stripe_head_state *s)
> "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);
> @@ -1275,7 +1275,7 @@ static void ops_run_biofill(struct stripe_head *sh)
> }
> }
>
> - 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);
> }
> @@ -1353,7 +1353,7 @@ ops_run_compute5(struct stripe_head *sh, struct
> raid5_percpu *percpu)
> 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));
> @@ -1441,7 +1441,7 @@ ops_run_compute6_1(struct stripe_head *sh, struct
> raid5_percpu *percpu)
> 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);
> @@ -1516,7 +1516,7 @@ ops_run_compute6_2(struct stripe_head *sh, struct
> raid5_percpu *percpu)
> 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 */
> @@ -1784,7 +1784,7 @@ ops_run_reconstruct5(struct stripe_head *sh, struct
> raid5_percpu *percpu,
> 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;
> @@ -1825,7 +1825,7 @@ ops_run_reconstruct5(struct stripe_head *sh, struct
> raid5_percpu *percpu,
> 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 {
> @@ -1867,7 +1867,7 @@ ops_run_reconstruct6(struct stripe_head *sh, struct
> raid5_percpu *percpu,
> 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);
> @@ -1891,7 +1891,7 @@ ops_run_reconstruct6(struct stripe_head *sh, struct
> raid5_percpu *percpu,
> 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
> @@ -1948,7 +1948,7 @@ static void ops_run_check_p(struct stripe_head *sh,
> struct raid5_percpu *percpu)
> 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);
> }
> @@ -1967,7 +1967,7 @@ static void ops_run_check_pq(struct stripe_head *sh,
> struct raid5_percpu *percpu
> 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,
> @@ -2057,7 +2057,7 @@ static struct stripe_head *alloc_stripe(struct
> kmem_cache *sc, gfp_t gfp,
> 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->log_start = MaxSector;
> for (i = 0; i < disks; i++) {
> struct r5dev *dev = &sh->dev[i];
> @@ -2354,7 +2354,7 @@ static int drop_one_stripe(struct r5conf *conf)
> 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);
> kmem_cache_free(conf->slab_cache, sh);
> atomic_dec(&conf->active_stripes);
> @@ -2386,7 +2386,7 @@ static void raid5_end_read_request(struct bio * bi)
> 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_error);
> if (i == disks) {
> bio_reset(bi);
> @@ -2523,7 +2523,7 @@ static void raid5_end_write_request(struct bio *bi)
> }
> }
> 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_error);
> if (i == disks) {
> bio_reset(bi);
> @@ -4545,7 +4545,7 @@ static void handle_stripe(struct stripe_head *sh)
> 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);
> @@ -4924,7 +4924,7 @@ static void activate_bit_delay(struct r5conf *conf,
> 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]);
> }
> @@ -5240,7 +5240,9 @@ static struct stripe_head *__get_priority_stripe(struct
> r5conf *conf, int group)
> sh->group = NULL;
> }
> list_del_init(&sh->lru);
> - BUG_ON(atomic_inc_return(&sh->count) != 1);
> + BUG_ON(refcount_read(&sh->count) != 0);
> + refcount_set(&sh->count, 1);
> +
> return sh;
> }
>
> diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
> index 4bb27b9..a1ed351 100644
> --- a/drivers/md/raid5.h
> +++ b/drivers/md/raid5.h
> @@ -3,6 +3,7 @@
>
> #include <linux/raid/xor.h>
> #include <linux/dmaengine.h>
> +#include <linux/refcount.h>
>
> /*
> *
> @@ -207,7 +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,
> --
> 2.7.4

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