mm/slab_common.c: remove test if cache name is accessible

Since commit db265eca77 ("mm/sl[aou]b: Move duping of slab name to
slab_common.c"), the kernel always duplicates the slab cache name when
creating a slab cache, so the test if the slab name is accessible is
useless.

Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1803231133310.22626@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slab_common.c

@@ -84,31 +84,12 @@ EXPORT_SYMBOL(kmem_cache_size);
 #ifdef CONFIG_DEBUG_VM
 static int kmem_cache_sanity_check(const char *name, unsigned int size)
 {
-	struct kmem_cache *s = NULL;
-
 	if (!name || in_interrupt() || size < sizeof(void *) ||
 		size > KMALLOC_MAX_SIZE) {
 		pr_err("kmem_cache_create(%s) integrity check failed\n", name);
 		return -EINVAL;
 	}
 
-	list_for_each_entry(s, &slab_caches, list) {
-		char tmp;
-		int res;
-
-		/*
-		 * This happens when the module gets unloaded and doesn't
-		 * destroy its slab cache and no-one else reuses the vmalloc
-		 * area of the module.  Print a warning.
-		 */
-		res = probe_kernel_address(s->name, tmp);
-		if (res) {
-			pr_err("Slab cache with size %u has lost its name\n",
-			       s->object_size);
-			continue;
-		}
-	}
-
 	WARN_ON(strchr(name, ' '));	/* It confuses parsers */
 	return 0;
 }