Re: [PATCH v2 1/2] io_uring/zcrx: add single shot recvzc

[Pavel Begunkov <asml.silence@gmail.com>]

On 2/21/25 20:51, David Wei wrote:
> diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
> index f2d326e18e67..74bca4e471bc 100644
> --- a/io_uring/zcrx.c
> +++ b/io_uring/zcrx.c
...
>   static int io_zcrx_tcp_recvmsg(struct io_kiocb *req, struct io_zcrx_ifq *ifq,
>   				struct sock *sk, int flags,
> -				unsigned issue_flags)
> +				unsigned issue_flags, unsigned int *outlen)
>   {
> +	unsigned int len = *outlen;
> +	bool limit = len != UINT_MAX;
>   	struct io_zcrx_args args = {
>   		.req = req,
>   		.ifq = ifq,
>   		.sock = sk->sk_socket,
>   	};
>   	read_descriptor_t rd_desc = {
> -		.count = 1,
> +		.count = len,
>   		.arg.data = &args,
>   	};
>   	int ret;
>   
>   	lock_sock(sk);
>   	ret = tcp_read_sock(sk, &rd_desc, io_zcrx_recv_skb);
> +	if (limit && ret)
> +		*outlen = len - ret;

ret can be negative, the check will pass and the calculations
will turn it into something weird.

-- 
Pavel Begunkov