On Fri, 11 Dec 2020 10:44:19 -0800 Arjun Roy wrote:
> From: Arjun Roy <arjun...@google.com>
>
> tcp_recvmsg() uses the CMSG mechanism to receive control information
> like packet receive timestamps. This patch adds CMSG fields to
> struct tcp_zerocopy_receive, and provides receive timestamps
> if available to the user.
>
> Signed-off-by: Arjun Roy <arjun...@google.com>
> Signed-off-by: Eric Dumazet <eduma...@google.com>
> Signed-off-by: Soheil Hassas Yeganeh <soh...@google.com>
> struct scm_timestamping_internal *tss,
> int *cmsg_flags);
> static int receive_fallback_to_copy(struct sock *sk,
> - struct tcp_zerocopy_receive *zc, int inq)
> + struct tcp_zerocopy_receive *zc, int inq,
> + struct scm_timestamping_internal *tss)
> {
> unsigned long copy_address = (unsigned long)zc->copybuf_address;
> - struct scm_timestamping_internal tss_unused;
> - int err, cmsg_flags_unused;
> + int err;
> struct msghdr msg = {};
> struct iovec iov;
>
rev xmas tree
> @@ -1913,17 +1927,24 @@ static int tcp_zerocopy_handle_leftover_data(struct
> tcp_zerocopy_receive *zc,
> struct sock *sk,
> struct sk_buff *skb,
> u32 *seq,
> - s32 copybuf_len)
> + s32 copybuf_len,
> + struct scm_timestamping_internal
> + *tss)
I appreciate the attempt to make the code fit 80 chars, but this
particular wrapping does more harm than good.
> @@ -4116,6 +4138,30 @@ static int do_tcp_getsockopt(struct sock *sk, int
> level,
> default:
> goto zerocopy_rcv_out;
> }
> +zerocopy_rcv_cmsg:
> + if (zc.msg_flags & TCP_CMSG_TS) {
> + unsigned long msg_control_addr;
> + struct msghdr cmsg_dummy;
> +
> + msg_control_addr = (unsigned long)zc.msg_control;
> + cmsg_dummy.msg_control = (void *)msg_control_addr;
> + cmsg_dummy.msg_controllen =
> + (__kernel_size_t)zc.msg_controllen;
> + cmsg_dummy.msg_flags = in_compat_syscall()
> + ? MSG_CMSG_COMPAT : 0;
> + zc.msg_flags = 0;
> + if (zc.msg_control == msg_control_addr &&
> + zc.msg_controllen == cmsg_dummy.msg_controllen) {
> + tcp_recv_timestamp(&cmsg_dummy, sk, &tss);
> + zc.msg_control = (__u64)
> + ((uintptr_t)cmsg_dummy.msg_control);
> + zc.msg_controllen =
> + (__u64)cmsg_dummy.msg_controllen;
> + zc.msg_flags = (__u32)cmsg_dummy.msg_flags;
This is indented by 4 levels. Time to create a helper?
Do we really need to cast each of these assignments explicitly?
