slub: Remove userspace notifier for cache add/remove

I came across some unnecessary uevents once again which reminded me
this.  The patch seems to be lost in the leaves of the original
discussion [1], so resending.

[1] https://lore.kernel.org/r/alpine.DEB.2.21.2001281813130.745@www.lameter.com

Kmem caches are internal kernel structures so it is strange that
userspace notifiers would be needed.  And I am not aware of any use of
these notifiers.  These notifiers may just exist because in the initial
slub release the sysfs code was copied from another subsystem.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Koutný <mkoutny@suse.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200423115721.19821-1-mkoutny@suse.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/slub.c b/mm/slub.c
index 6972c27..2ae5580 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5715,19 +5715,6 @@ static struct kobj_type slab_ktype = {
        .release = kmem_cache_release,
 };
 
-static int uevent_filter(struct kset *kset, struct kobject *kobj)
-{
-       struct kobj_type *ktype = get_ktype(kobj);
-
-       if (ktype == &slab_ktype)
-               return 1;
-       return 0;
-}
-
-static const struct kset_uevent_ops slab_uevent_ops = {
-       .filter = uevent_filter,
-};
-
 static struct kset *slab_kset;
 
 static inline struct kset *cache_kset(struct kmem_cache *s)
@@ -5795,7 +5782,6 @@ static void sysfs_slab_remove_workfn(struct work_struct *work)
 #ifdef CONFIG_MEMCG
        kset_unregister(s->memcg_kset);
 #endif
-       kobject_uevent(&s->kobj, KOBJ_REMOVE);
 out:
        kobject_put(&s->kobj);
 }
@@ -5853,7 +5839,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
        }
 #endif
 
-       kobject_uevent(&s->kobj, KOBJ_ADD);
        if (!unmergeable) {
                /* Setup first alias */
                sysfs_slab_alias(s, s->name);
@@ -5934,7 +5919,7 @@ static int __init slab_sysfs_init(void)
 
        mutex_lock(&slab_mutex);
 
-       slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
+       slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
        if (!slab_kset) {
                mutex_unlock(&slab_mutex);
                pr_err("Cannot register slab subsystem.\n");