[PATCH] mempool helpers used by device mapper

include/linux/mempool.h

@@ -27,4 +27,11 @@ extern void mempool_destroy(mempool_t *pool);
 extern void * mempool_alloc(mempool_t *pool, int gfp_mask);
 extern void mempool_free(void *element, mempool_t *pool);
 
+/*
+ * A mempool_alloc_t and mempool_free_t that get the memory from
+ * a slab that is passed in through pool_data.
+ */
+void *mempool_alloc_slab(int gfp_mask, void *pool_data);
+void mempool_free_slab(void *element, void *pool_data);
+
 #endif /* _LINUX_MEMPOOL_H */

mm/mempool.c

@@ -259,8 +259,25 @@ void mempool_free(void *element, mempool_t *pool)
 	pool->free(element, pool->pool_data);
 }
 
+/*
+ * A commonly used alloc and free fn.
+ */
+void *mempool_alloc_slab(int gfp_mask, void *pool_data)
+{
+	kmem_cache_t *mem = (kmem_cache_t *) pool_data;
+	return kmem_cache_alloc(mem, gfp_mask);
+}
+
+void mempool_free_slab(void *element, void *pool_data)
+{
+	kmem_cache_t *mem = (kmem_cache_t *) pool_data;
+	kmem_cache_free(mem, element);
+}
+
 EXPORT_SYMBOL(mempool_create);
 EXPORT_SYMBOL(mempool_resize);
 EXPORT_SYMBOL(mempool_destroy);
 EXPORT_SYMBOL(mempool_alloc);
 EXPORT_SYMBOL(mempool_free);
+EXPORT_SYMBOL(mempool_alloc_slab);
+EXPORT_SYMBOL(mempool_free_slab);