From b5dae1cd0d8368b4338430ff93403df67f0b8bcc Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sat, 11 Mar 2023 10:34:32 +0100 Subject: [PATCH] Revert "blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()" This reverts commit 81c1188905f88b77743d1fdeeedfc8cb7b67787d which is commit f1c006f1c6850c14040f8337753a63119bba39b9 upstream. It is reported to cause problems, as only 2 of the 3 patch series were applied to the stable branches. Reported-by: Mike Cloaked Reported-by: Eric Biggers Cc: Yu Kuai Cc: Tejun Heo Cc: Christoph Hellwig Cc: Jens Axboe Cc: Sasha Levin Link: https://bugzilla.kernel.org/show_bug.cgi?id=217174 Link: https://lore.kernel.org/r/ZAuPkCn49urWBN5P@sol.localdomain Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- block/blk-cgroup.c | 35 ++++++----------------------------- include/linux/blkdev.h | 1 - 2 files changed, 6 insertions(+), 30 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index f8b21be..8d1b775 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -87,32 +87,16 @@ static void blkg_free_workfn(struct work_struct *work) { struct blkcg_gq *blkg = container_of(work, struct blkcg_gq, free_work); - struct request_queue *q = blkg->q; int i; - /* - * pd_free_fn() can also be called from blkcg_deactivate_policy(), - * in order to make sure pd_free_fn() is called in order, the deletion - * of the list blkg->q_node is delayed to here from blkg_destroy(), and - * blkcg_mutex is used to synchronize blkg_free_workfn() and - * blkcg_deactivate_policy(). - */ - if (q) - mutex_lock(&q->blkcg_mutex); - for (i = 0; i < BLKCG_MAX_POLS; i++) if (blkg->pd[i]) blkcg_policy[i]->pd_free_fn(blkg->pd[i]); if (blkg->parent) blkg_put(blkg->parent); - - if (q) { - list_del_init(&blkg->q_node); - mutex_unlock(&q->blkcg_mutex); - blk_put_queue(q); - } - + if (blkg->q) + blk_put_queue(blkg->q); free_percpu(blkg->iostat_cpu); percpu_ref_exit(&blkg->refcnt); kfree(blkg); @@ -441,14 +425,9 @@ static void blkg_destroy(struct blkcg_gq *blkg) lockdep_assert_held(&blkg->q->queue_lock); lockdep_assert_held(&blkcg->lock); - /* - * blkg stays on the queue list until blkg_free_workfn(), see details in - * blkg_free_workfn(), hence this function can be called from - * blkcg_destroy_blkgs() first and again from blkg_destroy_all() before - * blkg_free_workfn(). - */ - if (hlist_unhashed(&blkg->blkcg_node)) - return; + /* Something wrong if we are trying to remove same group twice */ + WARN_ON_ONCE(list_empty(&blkg->q_node)); + WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node)); for (i = 0; i < BLKCG_MAX_POLS; i++) { struct blkcg_policy *pol = blkcg_policy[i]; @@ -460,6 +439,7 @@ static void blkg_destroy(struct blkcg_gq *blkg) blkg->online = false; radix_tree_delete(&blkcg->blkg_tree, blkg->q->id); + list_del_init(&blkg->q_node); hlist_del_init_rcu(&blkg->blkcg_node); /* @@ -1246,7 +1226,6 @@ int blkcg_init_disk(struct gendisk *disk) int ret; INIT_LIST_HEAD(&q->blkg_list); - mutex_init(&q->blkcg_mutex); new_blkg = blkg_alloc(&blkcg_root, disk, GFP_KERNEL); if (!new_blkg) @@ -1484,7 +1463,6 @@ void blkcg_deactivate_policy(struct request_queue *q, if (queue_is_mq(q)) blk_mq_freeze_queue(q); - mutex_lock(&q->blkcg_mutex); spin_lock_irq(&q->queue_lock); __clear_bit(pol->plid, q->blkcg_pols); @@ -1503,7 +1481,6 @@ void blkcg_deactivate_policy(struct request_queue *q, } spin_unlock_irq(&q->queue_lock); - mutex_unlock(&q->blkcg_mutex); if (queue_is_mq(q)) blk_mq_unfreeze_queue(q); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1680b6e..891f8cb 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -487,7 +487,6 @@ struct request_queue { DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS); struct blkcg_gq *root_blkg; struct list_head blkg_list; - struct mutex blkcg_mutex; #endif struct queue_limits limits; -- 2.7.4