mempool: add @gfp_mask to mempool_create_node()

mempool_create_node() currently assumes %GFP_KERNEL.  Its only user,
blk_init_free_list(), is about to be updated to use other allocation
flags - add @gfp_mask argument to the function.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/mempool.h b/include/linux/mempool.h
index 7c08052..39ed62a 100644
--- a/include/linux/mempool.h
+++ b/include/linux/mempool.h
@@ -26,7 +26,8 @@
 extern mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
 			mempool_free_t *free_fn, void *pool_data);
 extern mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
-			mempool_free_t *free_fn, void *pool_data, int nid);
+			mempool_free_t *free_fn, void *pool_data,
+			gfp_t gfp_mask, int nid);
 
 extern int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask);
 extern void mempool_destroy(mempool_t *pool);