Re: [PATCH] io_uring/net: clear msg_controllen on partial sendmsg retry

[Stefan Metzmacher <metze@samba.org>]

Hi Jens,

> If we have cmsg attached AND we transferred partial data at least, clear
> msg_controllen on retry so we don't attempt to send that again.
> 
> Cc: stable@vger.kernel.org # 5.10+
> Fixes: cac9e4418f4c ("io_uring/net: save msghdr->msg_control for retries")
> Reported-by: Stefan Metzmacher <metze@samba.org>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> 
> ---
> 
> diff --git a/io_uring/net.c b/io_uring/net.c
> index 51b0f7fbb4f5..fe1c478c7dec 100644
> --- a/io_uring/net.c
> +++ b/io_uring/net.c
> @@ -326,6 +326,7 @@ int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
>   		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
>   			return io_setup_async_msg(req, kmsg, issue_flags);
>   		if (ret > 0 && io_net_retry(sock, flags)) {
> +			kmsg->msg.msg_controllen = 0;
>   			sr->done_io += ret;
>   			req->flags |= REQ_F_PARTIAL_IO;
>   			return io_setup_async_msg(req, kmsg, issue_flags);
> 

Should we also set 'kmsg->msg.msg_control' to NULL?

metze