io_uring: split alloc_fixed_file_ref_node

Split alloc_fixed_file_ref_node into resource generic/specific parts,
to be leveraged for fixed buffers.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -7799,7 +7799,7 @@ static void io_rsrc_data_ref_zero(struct percpu_ref *ref)
 		queue_delayed_work(system_wq, &ctx->rsrc_put_work, delay);
 }
 
-static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
+static struct fixed_rsrc_ref_node *alloc_fixed_rsrc_ref_node(
 			struct io_ring_ctx *ctx)
 {
 	struct fixed_rsrc_ref_node *ref_node;
@@ -7815,9 +7815,21 @@ static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
 	}
 	INIT_LIST_HEAD(&ref_node->node);
 	INIT_LIST_HEAD(&ref_node->rsrc_list);
+	ref_node->done = false;
+	return ref_node;
+}
+
+static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
+			struct io_ring_ctx *ctx)
+{
+	struct fixed_rsrc_ref_node *ref_node;
+
+	ref_node = alloc_fixed_rsrc_ref_node(ctx);
+	if (!ref_node)
+		return NULL;
+
 	ref_node->rsrc_data = ctx->file_data;
 	ref_node->rsrc_put = io_ring_file_put;
-	ref_node->done = false;
 	return ref_node;
 }