[PATCH] io_uring/net: fix a multishot termination case for recv

[Jens Axboe <axboe@kernel.dk>]

If the recv returns zero, or an error, then it doesn't matter if more
data has already been received for this buffer. A condition like that
should terminate the multishot receive. Rather than pass in the
collected return value, pass in whether to terminate or keep the recv
going separately.

Link: https://github.com/axboe/liburing/issues/1246
Cc: stable@vger.kernel.org
Fixes: b3fdea6ecb55 ("io_uring: multishot recv")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

---

diff --git a/io_uring/net.c b/io_uring/net.c
index f10f5a22d66a..18507658a921 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1133,6 +1133,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags)
 	int ret, min_ret = 0;
 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
 	size_t len = sr->len;
+	bool mshot_finished;
 
 	if (!(req->flags & REQ_F_POLLED) &&
 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
@@ -1187,6 +1188,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags)
 		req_set_fail(req);
 	}
 
+	mshot_finished = ret <= 0;
 	if (ret > 0)
 		ret += sr->done_io;
 	else if (sr->done_io)
@@ -1194,7 +1196,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags)
 	else
 		io_kbuf_recycle(req, issue_flags);
 
-	if (!io_recv_finish(req, &ret, kmsg, ret <= 0, issue_flags))
+	if (!io_recv_finish(req, &ret, kmsg, mshot_finished, issue_flags))
 		goto retry_multishot;
 
 	return ret;

-- 
Jens Axboe