io_uring: only initialize io_kiocb rsrc_nodes when needed

Add the empty node initializing to the preinit part of the io_kiocb
allocation, and reset them if they have been used.

Signed-off-by: Jens Axboe <[email protected]>

Author: axboe

io_uring/io_uring.c

@@ -947,6 +947,8 @@ void io_req_defer_failed(struct io_kiocb *req, s32 res)
 static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
 {
 	req->ctx = ctx;
+	req->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
+	req->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
 	req->link = NULL;
 	req->async_data = NULL;
 	/* not necessary, but safer to zero */
@@ -2032,8 +2034,6 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 	req->flags = (__force io_req_flags_t) sqe_flags;
 	req->cqe.user_data = READ_ONCE(sqe->user_data);
 	req->file = NULL;
-	req->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
-	req->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
 	req->task = current;
 	req->cancel_seq_set = false;
 

io_uring/rsrc.h

@@ -81,8 +81,14 @@ static inline void io_put_rsrc_node(struct io_rsrc_node *node)
 
 static inline void io_req_put_rsrc_nodes(struct io_kiocb *req)
 {
-	io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_FILE]);
-	io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_BUFFER]);
+	if (req->rsrc_nodes[IORING_RSRC_FILE] != rsrc_empty_node) {
+		io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_FILE]);
+		req->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
+	}
+	if (req->rsrc_nodes[IORING_RSRC_BUFFER] != rsrc_empty_node) {
+		io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_BUFFER]);
+		req->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
+	}
 }
 
 static inline void io_req_assign_rsrc_node(struct io_kiocb *req,