[SLAB] Introduce kmem_cache_name

This is for use with slab users that pass a dynamically allocated slab name in
kmem_cache_create, so that before destroying the slab one can retrieve the name
and free its memory.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/slab.h

@@ -64,6 +64,7 @@ extern int kmem_cache_shrink(kmem_cache_t *);
 extern void *kmem_cache_alloc(kmem_cache_t *, unsigned int __nocast);
 extern void kmem_cache_free(kmem_cache_t *, void *);
 extern unsigned int kmem_cache_size(kmem_cache_t *);
+extern const char *kmem_cache_name(kmem_cache_t *);
 extern kmem_cache_t *kmem_find_general_cachep(size_t size, int gfpflags);
 
 /* Size description struct for general caches. */

mm/slab.c

@@ -2620,6 +2620,12 @@ unsigned int kmem_cache_size(kmem_cache_t *cachep)
 }
 EXPORT_SYMBOL(kmem_cache_size);
 
+const char *kmem_cache_name(kmem_cache_t *cachep)
+{
+	return cachep->name;
+}
+EXPORT_SYMBOL_GPL(kmem_cache_name);
+
 struct ccupdate_struct {
 	kmem_cache_t *cachep;
 	struct array_cache *new[NR_CPUS];