[PATCH RFC 4/6] mm, slab: simplify kmem_cache_release()

From: Vlastimil Babka
Date: Mon Jul 15 2024 - 16:29:59 EST


kfence_shutdown_cache() is now called always just before
kmem_cache_release() so move it there.

Also replace two variants of the functions by using
__is_defined(SLAB_SUPPORTS_SYSFS).

Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
---
mm/slab_common.c | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 2eef5ad37fa7..57962e1a5a86 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -486,7 +486,6 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags,
}
EXPORT_SYMBOL(kmem_buckets_create);

-#ifdef SLAB_SUPPORTS_SYSFS
/*
* For a given kmem_cache, kmem_cache_destroy() should only be called
* once or there will be a use-after-free problem. The actual deletion
@@ -495,18 +494,12 @@ EXPORT_SYMBOL(kmem_buckets_create);
*/
static void kmem_cache_release(struct kmem_cache *s)
{
- if (slab_state >= FULL) {
+ kfence_shutdown_cache(s);
+ if (__is_defined(SLAB_SUPPORTS_SYSFS) && slab_state >= FULL)
sysfs_slab_release(s);
- } else {
+ else
slab_kmem_cache_release(s);
- }
-}
-#else
-static void kmem_cache_release(struct kmem_cache *s)
-{
- slab_kmem_cache_release(s);
}
-#endif

static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
{
@@ -531,10 +524,8 @@ 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)
@@ -591,7 +582,6 @@ void kmem_cache_destroy(struct kmem_cache *s)
schedule_work(&slab_caches_to_rcu_destroy_work);
mutex_unlock(&slab_mutex);
} else {
- kfence_shutdown_cache(s);
kmem_cache_release(s);
}
}

--
2.45.2