6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yu Kuai <yukuai3@xxxxxxxxxx> [ Upstream commit 06a4d0d8c642b5ea654e832b74dca12965356da0 ] 'conf->log' is set with 'reconfig_mutex' grabbed, however, readers are not procted, hence protect it with READ_ONCE/WRITE_ONCE to prevent reading abnormal values. Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> Signed-off-by: Song Liu <song@xxxxxxxxxx> Link: https://lore.kernel.org/r/20231010151958.145896-3-yukuai1@xxxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/md/raid5-cache.c | 47 +++++++++++++++++++++------------------- 1 file changed, 25 insertions(+), 22 deletions(-) diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index eb66d0bfe39d2..4b9585875a669 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -327,8 +327,9 @@ void r5l_wake_reclaim(struct r5l_log *log, sector_t space); void r5c_check_stripe_cache_usage(struct r5conf *conf) { int total_cached; + struct r5l_log *log = READ_ONCE(conf->log); - if (!r5c_is_writeback(conf->log)) + if (!r5c_is_writeback(log)) return; total_cached = atomic_read(&conf->r5c_cached_partial_stripes) + @@ -344,7 +345,7 @@ void r5c_check_stripe_cache_usage(struct r5conf *conf) */ if (total_cached > conf->min_nr_stripes * 1 / 2 || atomic_read(&conf->empty_inactive_list_nr) > 0) - r5l_wake_reclaim(conf->log, 0); + r5l_wake_reclaim(log, 0); } /* @@ -353,7 +354,9 @@ void r5c_check_stripe_cache_usage(struct r5conf *conf) */ void r5c_check_cached_full_stripe(struct r5conf *conf) { - if (!r5c_is_writeback(conf->log)) + struct r5l_log *log = READ_ONCE(conf->log); + + if (!r5c_is_writeback(log)) return; /* @@ -363,7 +366,7 @@ void r5c_check_cached_full_stripe(struct r5conf *conf) if (atomic_read(&conf->r5c_cached_full_stripes) >= min(R5C_FULL_STRIPE_FLUSH_BATCH(conf), conf->chunk_sectors >> RAID5_STRIPE_SHIFT(conf))) - r5l_wake_reclaim(conf->log, 0); + r5l_wake_reclaim(log, 0); } /* @@ -396,7 +399,7 @@ void r5c_check_cached_full_stripe(struct r5conf *conf) */ static sector_t r5c_log_required_to_flush_cache(struct r5conf *conf) { - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); if (!r5c_is_writeback(log)) return 0; @@ -449,7 +452,7 @@ static inline void r5c_update_log_state(struct r5l_log *log) void r5c_make_stripe_write_out(struct stripe_head *sh) { struct r5conf *conf = sh->raid_conf; - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); BUG_ON(!r5c_is_writeback(log)); @@ -491,7 +494,7 @@ static void r5c_handle_parity_cached(struct stripe_head *sh) */ static void r5c_finish_cache_stripe(struct stripe_head *sh) { - struct r5l_log *log = sh->raid_conf->log; + struct r5l_log *log = READ_ONCE(sh->raid_conf->log); if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) { BUG_ON(test_bit(STRIPE_R5C_CACHING, &sh->state)); @@ -692,7 +695,7 @@ static void r5c_disable_writeback_async(struct work_struct *work) /* wait superblock change before suspend */ wait_event(mddev->sb_wait, - conf->log == NULL || + !READ_ONCE(conf->log) || (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) && (locked = mddev_trylock(mddev)))); if (locked) { @@ -1151,7 +1154,7 @@ static void r5l_run_no_space_stripes(struct r5l_log *log) static sector_t r5c_calculate_new_cp(struct r5conf *conf) { struct stripe_head *sh; - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); sector_t new_cp; unsigned long flags; @@ -1159,12 +1162,12 @@ static sector_t r5c_calculate_new_cp(struct r5conf *conf) return log->next_checkpoint; spin_lock_irqsave(&log->stripe_in_journal_lock, flags); - if (list_empty(&conf->log->stripe_in_journal_list)) { + if (list_empty(&log->stripe_in_journal_list)) { /* all stripes flushed */ spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags); return log->next_checkpoint; } - sh = list_first_entry(&conf->log->stripe_in_journal_list, + sh = list_first_entry(&log->stripe_in_journal_list, struct stripe_head, r5c); new_cp = sh->log_start; spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags); @@ -1399,7 +1402,7 @@ void r5c_flush_cache(struct r5conf *conf, int num) struct stripe_head *sh, *next; lockdep_assert_held(&conf->device_lock); - if (!conf->log) + if (!READ_ONCE(conf->log)) return; count = 0; @@ -1420,7 +1423,7 @@ void r5c_flush_cache(struct r5conf *conf, int num) static void r5c_do_reclaim(struct r5conf *conf) { - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); struct stripe_head *sh; int count = 0; unsigned long flags; @@ -1549,7 +1552,7 @@ static void r5l_reclaim_thread(struct md_thread *thread) { struct mddev *mddev = thread->mddev; struct r5conf *conf = mddev->private; - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); if (!log) return; @@ -1589,7 +1592,7 @@ void r5l_quiesce(struct r5l_log *log, int quiesce) bool r5l_log_disk_error(struct r5conf *conf) { - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); /* don't allow write if journal disk is missing */ if (!log) @@ -2633,7 +2636,7 @@ int r5c_try_caching_write(struct r5conf *conf, struct stripe_head_state *s, int disks) { - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); int i; struct r5dev *dev; int to_cache = 0; @@ -2800,7 +2803,7 @@ void r5c_finish_stripe_write_out(struct r5conf *conf, struct stripe_head *sh, struct stripe_head_state *s) { - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); int i; int do_wakeup = 0; sector_t tree_index; @@ -2939,7 +2942,7 @@ int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh) /* check whether this big stripe is in write back cache. */ bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect) { - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); sector_t tree_index; void *slot; @@ -3047,14 +3050,14 @@ int r5l_start(struct r5l_log *log) void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev) { struct r5conf *conf = mddev->private; - struct r5l_log *log = conf->log; + struct r5l_log *log = READ_ONCE(conf->log); if (!log) return; if ((raid5_calc_degraded(conf) > 0 || test_bit(Journal, &rdev->flags)) && - conf->log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK) + log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK) schedule_work(&log->disable_writeback_work); } @@ -3143,7 +3146,7 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) spin_lock_init(&log->stripe_in_journal_lock); atomic_set(&log->stripe_in_journal_count, 0); - conf->log = log; + WRITE_ONCE(conf->log, log); set_bit(MD_HAS_JOURNAL, &conf->mddev->flags); return 0; @@ -3171,7 +3174,7 @@ void r5l_exit_log(struct r5conf *conf) * 'reconfig_mutex' is held by caller, set 'confg->log' to NULL to * ensure disable_writeback_work wakes up and exits. */ - conf->log = NULL; + WRITE_ONCE(conf->log, NULL); wake_up(&conf->mddev->sb_wait); flush_work(&log->disable_writeback_work); -- 2.43.0
