Re: Linux 6.2.4

From: Greg Kroah-Hartman
Date: Sat Mar 11 2023 - 05:13:09 EST


diff --git a/Makefile b/Makefile
index eef164b4172a..83cbbc3adbb1 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
VERSION = 6
PATCHLEVEL = 2
-SUBLEVEL = 3
+SUBLEVEL = 4
EXTRAVERSION =
NAME = Hurr durr I'ma ninja sloth

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 45881f8c7913..9ac1efb053e0 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -118,32 +118,14 @@ 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);
@@ -176,6 +158,8 @@ static void __blkg_release(struct rcu_head *rcu)

/* release the blkcg and parent blkg refs this blkg has been holding */
css_put(&blkg->blkcg->css);
+ if (blkg->parent)
+ blkg_put(blkg->parent);
blkg_free(blkg);
}

@@ -474,14 +458,9 @@ 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];
@@ -493,6 +472,7 @@ 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);

/*
@@ -1293,7 +1273,6 @@ 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)
@@ -1531,7 +1510,6 @@ 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);
@@ -1550,7 +1528,6 @@ 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 10ee92db680c..43d4e073b111 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -484,7 +484,6 @@ 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;