Re: [RFC PATCH v2 1/9] vsock: use sk_rcvlowat to set POLLIN/POLLRDNORM

[Stefano Garzarella]

On Mon, Jul 25, 2022 at 07:56:59AM +0000, Arseniy Krasnov wrote:
> Both bits indicate, that next data read call won't be blocked, but when
> sk_rcvlowat is not 1, these bits will be set by poll anyway, thus when
> user tries to dequeue data,it will wait until sk_rcvlowat bytes of data
> will be available.

The patch LGTM, but I suggest you to rewrite the title and commit of the 
message to better explain what this patch does (pass sock_rcvlowat to 
notify_poll_in as target) and then explain why as you already did (to 
set POLLIN/POLLRDNORM only when target is reached).

Thanks,
Stefano

> Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
> ---
> net/vmw_vsock/af_vsock.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> index f04abf662ec6..63a13fa2686a 100644
> --- a/net/vmw_vsock/af_vsock.c
> +++ b/net/vmw_vsock/af_vsock.c
> @@ -1066,8 +1066,9 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
> 		if (transport && transport->stream_is_active(vsk) &&
> 		    !(sk->sk_shutdown & RCV_SHUTDOWN)) {
> 			bool data_ready_now = false;
> +			int target = sock_rcvlowat(sk, 0, INT_MAX);
> 			int ret = transport->notify_poll_in(
> -					vsk, 1, &data_ready_now);
> +					vsk, target, &data_ready_now);
> 			if (ret < 0) {
> 				mask |= EPOLLERR;
> 			} else {
> --
> 2.25.1