[PATCH 1/2] io_uring/net: let io_recv_buf_select return the length of the buffer region

[Gabriel Krisman Bertazi <krisman@suse.de>]

In preparation to using this field as an upper limit to truncation,
return the size of the allocated region.

Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption")
Cc: stable@vger.kernel.org
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
 io_uring/net.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/io_uring/net.c b/io_uring/net.c
index fbe719d86c46..647156c9331a 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1108,6 +1108,7 @@ static int io_recv_buf_select(struct io_kiocb *req, struct io_async_msghdr *kmsg
 			      struct io_br_sel *sel, unsigned int issue_flags)
 {
 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
+	size_t len;
 	int ret;
 
 	/*
@@ -1153,13 +1154,14 @@ static int io_recv_buf_select(struct io_kiocb *req, struct io_async_msghdr *kmsg
 		/* special case 1 vec, can be a fast path */
 		if (ret == 1) {
 			sr->buf = arg.iovs[0].iov_base;
-			sr->len = arg.iovs[0].iov_len;
+			len = sr->len = arg.iovs[0].iov_len;
 			goto map_ubuf;
 		}
 		iov_iter_init(&kmsg->msg.msg_iter, ITER_DEST, arg.iovs, ret,
-				arg.out_len);
+			      arg.out_len);
+		len = arg.out_len;
 	} else {
-		size_t len = sel->val;
+		len = sel->val;
 
 		*sel = io_buffer_select(req, &len, sr->buf_group, issue_flags);
 		if (!sel->addr)
@@ -1173,7 +1175,7 @@ static int io_recv_buf_select(struct io_kiocb *req, struct io_async_msghdr *kmsg
 			return ret;
 	}
 
-	return 0;
+	return len;
 }
 
 int io_recv(struct io_kiocb *req, unsigned int issue_flags)
-- 
2.55.0