io_uring/kbuf: flag partial buffer mappings

A previous commit aborted mapping more for a non-incremental ring for
bundle peeking, but depending on where in the process this peeking
happened, it would not necessarily prevent a retry by the user. That can
create gaps in the received/read data.

Add struct buf_sel_arg->partial_map, which can pass this information
back. The networking side can then map that to internal state and use it
to gate retry as well.

Since this necessitates a new flag, change io_sr_msg->retry to a
retry_flags member, and store both the retry and partial map condition
in there.

Cc: stable@vger.kernel.org
Fixes: 26ec15e4b0c1 ("io_uring/kbuf: don't truncate end buffer for multiple buffer peeks")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 1 insertions, 0 deletions

diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index ce95e3af44a9..f2d2cc319faa 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -271,6 +271,7 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg,
 		if (len > arg->max_len) {
 			len = arg->max_len;
 			if (!(bl->flags & IOBL_INC)) {
+				arg->partial_map = 1;
 				if (iov != arg->iovs)
 					break;
 				buf->len = len;