[PATCH v2 3/7] mm, slab: move kfence_shutdown_cache() outside slab_mutex

Vlastimil Babka
2024-08-07T10:31:42Z

kfence_shutdown_cache() is called under slab_mutex when the cache is
destroyed synchronously, and outside slab_mutex during the delayed
destruction of SLAB_TYPESAFE_BY_RCU caches.

It seems it should always be safe to call it outside of slab_mutex so we
can just move the call to kmem_cache_release(), which is called outside.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/slab_common.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index db61df3b4282..a079b8540334 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -492,6 +492,7 @@ EXPORT_SYMBOL(kmem_buckets_create);
*/
static void kmem_cache_release(struct kmem_cache *s)
{
+ kfence_shutdown_cache(s);
if (__is_defined(SLAB_SUPPORTS_SYSFS) && slab_state >= FULL)
sysfs_slab_release(s);
else
@@ -521,10 +522,8 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)

rcu_barrier();

- list_for_each_entry_safe(s, s2, &to_destroy, list) {
- kfence_shutdown_cache(s);
+ list_for_each_entry_safe(s, s2, &to_destroy, list)
kmem_cache_release(s);
- }
}

void slab_kmem_cache_release(struct kmem_cache *s)
@@ -563,9 +562,6 @@ void kmem_cache_destroy(struct kmem_cache *s)

list_del(&s->list);

- if (!err && !rcu_set)
- kfence_shutdown_cache(s);
-
mutex_unlock(&slab_mutex);
cpus_read_unlock();

--
2.46.0