io_uring/rsrc: add & apply io_req_assign_buf_node()

The following pattern becomes more and more:

+       io_req_assign_rsrc_node(&req->buf_node, node);
+       req->flags |= REQ_F_BUF_NODE;

so make it a helper, which is less fragile to use than above code, for
example, the BUF_NODE flag is even missed in current io_uring_cmd_prep().

Signed-off-by: Ming Lei <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: Ming Lei

io_uring/net.c

@@ -1348,8 +1348,7 @@ static int io_send_zc_import(struct io_kiocb *req, unsigned int issue_flags)
 		io_ring_submit_lock(ctx, issue_flags);
 		node = io_rsrc_node_lookup(&ctx->buf_table, sr->buf_index);
 		if (node) {
-			io_req_assign_rsrc_node(&sr->notif->buf_node, node);
-			sr->notif->flags |= REQ_F_BUF_NODE;
+			io_req_assign_buf_node(sr->notif, node);
 			ret = 0;
 		}
 		io_ring_submit_unlock(ctx, issue_flags);

io_uring/nop.c

@@ -67,8 +67,7 @@ int io_nop(struct io_kiocb *req, unsigned int issue_flags)
 		io_ring_submit_lock(ctx, issue_flags);
 		node = io_rsrc_node_lookup(&ctx->buf_table, nop->buffer);
 		if (node) {
-			io_req_assign_rsrc_node(&req->buf_node, node);
-			req->flags |= REQ_F_BUF_NODE;
+			io_req_assign_buf_node(req, node);
 			ret = 0;
 		}
 		io_ring_submit_unlock(ctx, issue_flags);

io_uring/rsrc.h

@@ -111,6 +111,13 @@ static inline void io_req_assign_rsrc_node(struct io_rsrc_node **dst_node,
 	*dst_node = node;
 }
 
+static inline void io_req_assign_buf_node(struct io_kiocb *req,
+					  struct io_rsrc_node *node)
+{
+	io_req_assign_rsrc_node(&req->buf_node, node);
+	req->flags |= REQ_F_BUF_NODE;
+}
+
 int io_files_update(struct io_kiocb *req, unsigned int issue_flags);
 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
 

io_uring/rw.c

@@ -341,8 +341,7 @@ static int io_prep_rw_fixed(struct io_kiocb *req, const struct io_uring_sqe *sqe
 	node = io_rsrc_node_lookup(&ctx->buf_table, req->buf_index);
 	if (!node)
 		return -EFAULT;
-	io_req_assign_rsrc_node(&req->buf_node, node);
-	req->flags |= REQ_F_BUF_NODE;
+	io_req_assign_buf_node(req, node);
 
 	io = req->async_data;
 	ret = io_import_fixed(ddir, &io->iter, node->buf, rw->addr, rw->len);

io_uring/uring_cmd.c

@@ -219,7 +219,7 @@ int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		 * being called. This prevents destruction of the mapped buffer
 		 * we'll need at actual import time.
 		 */
-		io_req_assign_rsrc_node(&req->buf_node, node);
+		io_req_assign_buf_node(req, node);
 	}
 	ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);