+++ /dev/null
-From 4f081c633e99e0f6dc7fee60fe37d7788b74e1e2 Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Wed, 18 Dec 2024 18:16:14 +0800
-Subject: block: Revert "block: Fix potential deadlock while freezing queue and
- acquiring sysfs_lock"
-
-From: Ming Lei <ming.lei@redhat.com>
-
-[ Upstream commit 224749be6c23efe7fb8a030854f4fc5d1dd813b3 ]
-
-This reverts commit be26ba96421ab0a8fa2055ccf7db7832a13c44d2.
-
-Commit be26ba96421a ("block: Fix potential deadlock while freezing queue and
-acquiring sysfs_loc") actually reverts commit 22465bbac53c ("blk-mq: move cpuhp
-callback registering out of q->sysfs_lock"), and causes the original resctrl
-lockdep warning.
-
-So revert it and we need to fix the issue in another way.
-
-Cc: Nilay Shroff <nilay@linux.ibm.com>
-Fixes: be26ba96421a ("block: Fix potential deadlock while freezing queue and acquiring sysfs_loc")
-Signed-off-by: Ming Lei <ming.lei@redhat.com>
-Link: https://lore.kernel.org/r/20241218101617.3275704-2-ming.lei@redhat.com
-Signed-off-by: Jens Axboe <axboe@kernel.dk>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- block/blk-mq-sysfs.c | 16 ++++++++++------
- block/blk-mq.c | 29 +++++++++++------------------
- block/blk-sysfs.c | 4 ++--
- 3 files changed, 23 insertions(+), 26 deletions(-)
-
-diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
-index cd5ea6eaa76b..156e9bb07abf 100644
---- a/block/blk-mq-sysfs.c
-+++ b/block/blk-mq-sysfs.c
-@@ -275,13 +275,15 @@ void blk_mq_sysfs_unregister_hctxs(struct request_queue *q)
- struct blk_mq_hw_ctx *hctx;
- unsigned long i;
-
-- lockdep_assert_held(&q->sysfs_dir_lock);
--
-+ mutex_lock(&q->sysfs_dir_lock);
- if (!q->mq_sysfs_init_done)
-- return;
-+ goto unlock;
-
- queue_for_each_hw_ctx(q, hctx, i)
- blk_mq_unregister_hctx(hctx);
-+
-+unlock:
-+ mutex_unlock(&q->sysfs_dir_lock);
- }
-
- int blk_mq_sysfs_register_hctxs(struct request_queue *q)
-@@ -290,10 +292,9 @@ int blk_mq_sysfs_register_hctxs(struct request_queue *q)
- unsigned long i;
- int ret = 0;
-
-- lockdep_assert_held(&q->sysfs_dir_lock);
--
-+ mutex_lock(&q->sysfs_dir_lock);
- if (!q->mq_sysfs_init_done)
-- return ret;
-+ goto unlock;
-
- queue_for_each_hw_ctx(q, hctx, i) {
- ret = blk_mq_register_hctx(hctx);
-@@ -301,5 +302,8 @@ int blk_mq_sysfs_register_hctxs(struct request_queue *q)
- break;
- }
-
-+unlock:
-+ mutex_unlock(&q->sysfs_dir_lock);
-+
- return ret;
- }
-diff --git a/block/blk-mq.c b/block/blk-mq.c
-index cc1b32023838..1030875a3e95 100644
---- a/block/blk-mq.c
-+++ b/block/blk-mq.c
-@@ -4462,8 +4462,7 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
- unsigned long i, j;
-
- /* protect against switching io scheduler */
-- lockdep_assert_held(&q->sysfs_lock);
--
-+ mutex_lock(&q->sysfs_lock);
- for (i = 0; i < set->nr_hw_queues; i++) {
- int old_node;
- int node = blk_mq_get_hctx_node(set, i);
-@@ -4496,6 +4495,7 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
-
- xa_for_each_start(&q->hctx_table, j, hctx, j)
- blk_mq_exit_hctx(q, set, hctx, j);
-+ mutex_unlock(&q->sysfs_lock);
-
- /* unregister cpuhp callbacks for exited hctxs */
- blk_mq_remove_hw_queues_cpuhp(q);
-@@ -4527,14 +4527,10 @@ int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
-
- xa_init(&q->hctx_table);
-
-- mutex_lock(&q->sysfs_lock);
--
- blk_mq_realloc_hw_ctxs(set, q);
- if (!q->nr_hw_queues)
- goto err_hctxs;
-
-- mutex_unlock(&q->sysfs_lock);
--
- INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
- blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
-
-@@ -4553,7 +4549,6 @@ int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
- return 0;
-
- err_hctxs:
-- mutex_unlock(&q->sysfs_lock);
- blk_mq_release(q);
- err_exit:
- q->mq_ops = NULL;
-@@ -4934,12 +4929,12 @@ static bool blk_mq_elv_switch_none(struct list_head *head,
- return false;
-
- /* q->elevator needs protection from ->sysfs_lock */
-- lockdep_assert_held(&q->sysfs_lock);
-+ mutex_lock(&q->sysfs_lock);
-
- /* the check has to be done with holding sysfs_lock */
- if (!q->elevator) {
- kfree(qe);
-- goto out;
-+ goto unlock;
- }
-
- INIT_LIST_HEAD(&qe->node);
-@@ -4949,7 +4944,9 @@ static bool blk_mq_elv_switch_none(struct list_head *head,
- __elevator_get(qe->type);
- list_add(&qe->node, head);
- elevator_disable(q);
--out:
-+unlock:
-+ mutex_unlock(&q->sysfs_lock);
-+
- return true;
- }
-
-@@ -4978,9 +4975,11 @@ static void blk_mq_elv_switch_back(struct list_head *head,
- list_del(&qe->node);
- kfree(qe);
-
-+ mutex_lock(&q->sysfs_lock);
- elevator_switch(q, t);
- /* drop the reference acquired in blk_mq_elv_switch_none */
- elevator_put(t);
-+ mutex_unlock(&q->sysfs_lock);
- }
-
- static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
-@@ -5000,11 +4999,8 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
- if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
- return;
-
-- list_for_each_entry(q, &set->tag_list, tag_set_list) {
-- mutex_lock(&q->sysfs_dir_lock);
-- mutex_lock(&q->sysfs_lock);
-+ list_for_each_entry(q, &set->tag_list, tag_set_list)
- blk_mq_freeze_queue(q);
-- }
- /*
- * Switch IO scheduler to 'none', cleaning up the data associated
- * with the previous scheduler. We will switch back once we are done
-@@ -5060,11 +5056,8 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
- list_for_each_entry(q, &set->tag_list, tag_set_list)
- blk_mq_elv_switch_back(&head, q);
-
-- list_for_each_entry(q, &set->tag_list, tag_set_list) {
-+ list_for_each_entry(q, &set->tag_list, tag_set_list)
- blk_mq_unfreeze_queue(q);
-- mutex_unlock(&q->sysfs_lock);
-- mutex_unlock(&q->sysfs_dir_lock);
-- }
-
- /* Free the excess tags when nr_hw_queues shrink. */
- for (i = set->nr_hw_queues; i < prev_nr_hw_queues; i++)
-diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
-index 42c2cb97d778..207577145c54 100644
---- a/block/blk-sysfs.c
-+++ b/block/blk-sysfs.c
-@@ -690,11 +690,11 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
- return res;
- }
-
-- mutex_lock(&q->sysfs_lock);
- blk_mq_freeze_queue(q);
-+ mutex_lock(&q->sysfs_lock);
- res = entry->store(disk, page, length);
-- blk_mq_unfreeze_queue(q);
- mutex_unlock(&q->sysfs_lock);
-+ blk_mq_unfreeze_queue(q);
- return res;
- }
-
---
-2.39.5
-
projects / thirdparty / kernel / stable-queue.git / commitdiff
