Most calls to r5c_is_writeback() have to dereference conf to get the log. The log pointer should be protected by RCU, but isn't. Push the dereference of conf->log into a new r5c_conf_is_writeback() helper to reduce the number of sites that dereference conf->log so this can be improved. No functional changes intended. Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx> --- drivers/md/raid5-cache.c | 7 ++++++- drivers/md/raid5-log.h | 2 +- drivers/md/raid5.c | 16 ++++++++-------- 3 files changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 83c184eddbda..96f51ce9b6c1 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -247,12 +247,17 @@ enum r5l_io_unit_state { IO_UNIT_STRIPE_END = 3, /* stripes data finished writing to raid */ }; -bool r5c_is_writeback(struct r5l_log *log) +static bool r5c_is_writeback(struct r5l_log *log) { return (log != NULL && log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK); } +bool r5c_conf_is_writeback(struct r5conf *conf) +{ + return r5c_is_writeback(conf->log); +} + static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc) { start += inc; diff --git a/drivers/md/raid5-log.h b/drivers/md/raid5-log.h index 270ced4f770f..720e164e4d4d 100644 --- a/drivers/md/raid5-log.h +++ b/drivers/md/raid5-log.h @@ -11,7 +11,7 @@ void r5l_stripe_write_finished(struct stripe_head *sh); int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio); void r5l_quiesce(struct r5l_log *log, int quiesce); bool r5l_log_disk_error(struct r5conf *conf); -bool r5c_is_writeback(struct r5l_log *log); +bool r5c_conf_is_writeback(struct r5conf *conf); int r5c_try_caching_write(struct r5conf *conf, struct stripe_head *sh, struct stripe_head_state *s, int disks); void r5c_finish_stripe_write_out(struct r5conf *conf, struct stripe_head *sh, diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 5d09256d7f81..458d88faf2e9 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -224,7 +224,7 @@ static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh, BUG_ON(!list_empty(&sh->lru)); BUG_ON(atomic_read(&conf->active_stripes)==0); - if (r5c_is_writeback(conf->log)) + if (r5c_conf_is_writeback(conf)) for (i = sh->disks; i--; ) if (test_bit(R5_InJournal, &sh->dev[i].flags)) injournal++; @@ -236,7 +236,7 @@ static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh, * 2. when resync is requested fot the stripe. */ if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) || - (conf->quiesce && r5c_is_writeback(conf->log) && + (conf->quiesce && r5c_conf_is_writeback(conf) && !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) { if (test_bit(STRIPE_R5C_CACHING, &sh->state)) r5c_make_stripe_write_out(sh); @@ -274,7 +274,7 @@ static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh, md_wakeup_thread(conf->mddev->thread); atomic_dec(&conf->active_stripes); if (!test_bit(STRIPE_EXPANDING, &sh->state)) { - if (!r5c_is_writeback(conf->log)) + if (!r5c_conf_is_writeback(conf)) list_add_tail(&sh->lru, temp_inactive_list); else { WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags)); @@ -1786,7 +1786,7 @@ static void ops_complete_prexor(void *stripe_head_ref) pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector); - if (r5c_is_writeback(sh->raid_conf->log)) + if (r5c_conf_is_writeback(sh->raid_conf)) /* * raid5-cache write back uses orig_page during prexor. * After prexor, it is time to free orig_page @@ -1905,9 +1905,9 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx) tx = async_copy_data(1, wbi, &dev->page, dev->offset, dev->sector, tx, sh, - r5c_is_writeback(conf->log)); + r5c_conf_is_writeback(conf)); if (dev->page != dev->orig_page && - !r5c_is_writeback(conf->log)) { + !r5c_conf_is_writeback(conf)) { set_bit(R5_SkipCopy, &dev->flags); clear_bit(R5_UPTODATE, &dev->flags); clear_bit(R5_OVERWRITE, &dev->flags); @@ -5085,7 +5085,7 @@ static void handle_stripe(struct stripe_head *sh) */ if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) { - if (!r5c_is_writeback(conf->log)) { + if (!r5c_conf_is_writeback(conf)) { if (s.to_write) handle_stripe_dirtying(conf, sh, &s, disks); } else { /* write back cache */ @@ -5533,7 +5533,7 @@ static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group) struct stripe_head *sh, *tmp; struct list_head *handle_list = NULL; struct r5worker_group *wg; - bool second_try = !r5c_is_writeback(conf->log) && + bool second_try = !r5c_conf_is_writeback(conf) && !r5l_log_disk_error(conf); bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) || r5l_log_disk_error(conf); -- 2.30.2