forked from mirrors/linux
tcp: Add receive timestamp support for receive zerocopy.
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 <arjunroy@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Arjun Roy
Jakub Kicinski
parent
925bba24e6
commit
7eeba1706e
2 changed files with 88 additions and 32 deletions
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@ -354,5 +354,9 @@ struct tcp_zerocopy_receive {
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__u64 copybuf_address; /* in: copybuf address (small reads) */
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__s32 copybuf_len; /* in/out: copybuf bytes avail/used or error */
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__u32 flags; /* in: flags */
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__u64 msg_control; /* ancillary data */
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__u64 msg_controllen;
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__u32 msg_flags;
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/* __u32 hole; Next we must add >1 u32 otherwise length checks fail. */
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};
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#endif /* _UAPI_LINUX_TCP_H */
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110
net/ipv4/tcp.c
110
net/ipv4/tcp.c
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@ -1745,6 +1745,20 @@ int tcp_set_rcvlowat(struct sock *sk, int val)
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}
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EXPORT_SYMBOL(tcp_set_rcvlowat);
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static void tcp_update_recv_tstamps(struct sk_buff *skb,
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struct scm_timestamping_internal *tss)
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{
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if (skb->tstamp)
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tss->ts[0] = ktime_to_timespec64(skb->tstamp);
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else
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tss->ts[0] = (struct timespec64) {0};
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if (skb_hwtstamps(skb)->hwtstamp)
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tss->ts[2] = ktime_to_timespec64(skb_hwtstamps(skb)->hwtstamp);
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else
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tss->ts[2] = (struct timespec64) {0};
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}
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#ifdef CONFIG_MMU
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static const struct vm_operations_struct tcp_vm_ops = {
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};
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@ -1848,13 +1862,13 @@ static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len,
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struct scm_timestamping_internal *tss,
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int *cmsg_flags);
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static int receive_fallback_to_copy(struct sock *sk,
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struct tcp_zerocopy_receive *zc, int inq)
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struct tcp_zerocopy_receive *zc, int inq,
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struct scm_timestamping_internal *tss)
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{
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unsigned long copy_address = (unsigned long)zc->copybuf_address;
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struct scm_timestamping_internal tss_unused;
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int err, cmsg_flags_unused;
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struct msghdr msg = {};
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struct iovec iov;
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int err;
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zc->length = 0;
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zc->recv_skip_hint = 0;
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@ -1868,7 +1882,7 @@ static int receive_fallback_to_copy(struct sock *sk,
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return err;
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err = tcp_recvmsg_locked(sk, &msg, inq, /*nonblock=*/1, /*flags=*/0,
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&tss_unused, &cmsg_flags_unused);
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tss, &zc->msg_flags);
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if (err < 0)
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return err;
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@ -1909,21 +1923,27 @@ static int tcp_copy_straggler_data(struct tcp_zerocopy_receive *zc,
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return (__s32)copylen;
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}
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static int tcp_zerocopy_handle_leftover_data(struct tcp_zerocopy_receive *zc,
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static int tcp_zc_handle_leftover(struct tcp_zerocopy_receive *zc,
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struct sock *sk,
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struct sk_buff *skb,
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u32 *seq,
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s32 copybuf_len)
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s32 copybuf_len,
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struct scm_timestamping_internal *tss)
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{
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u32 offset, copylen = min_t(u32, copybuf_len, zc->recv_skip_hint);
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if (!copylen)
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return 0;
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/* skb is null if inq < PAGE_SIZE. */
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if (skb)
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if (skb) {
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offset = *seq - TCP_SKB_CB(skb)->seq;
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else
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} else {
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skb = tcp_recv_skb(sk, *seq, &offset);
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if (TCP_SKB_CB(skb)->has_rxtstamp) {
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tcp_update_recv_tstamps(skb, tss);
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zc->msg_flags |= TCP_CMSG_TS;
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}
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}
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zc->copybuf_len = tcp_copy_straggler_data(zc, skb, copylen, &offset,
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seq);
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@ -2010,9 +2030,37 @@ static int tcp_zerocopy_vm_insert_batch(struct vm_area_struct *vma,
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err);
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}
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static void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
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struct scm_timestamping_internal *tss);
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static void tcp_zc_finalize_rx_tstamp(struct sock *sk,
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struct tcp_zerocopy_receive *zc,
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struct scm_timestamping_internal *tss)
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{
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unsigned long msg_control_addr;
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struct msghdr cmsg_dummy;
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msg_control_addr = (unsigned long)zc->msg_control;
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cmsg_dummy.msg_control = (void *)msg_control_addr;
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cmsg_dummy.msg_controllen =
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(__kernel_size_t)zc->msg_controllen;
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cmsg_dummy.msg_flags = in_compat_syscall()
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? MSG_CMSG_COMPAT : 0;
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zc->msg_flags = 0;
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if (zc->msg_control == msg_control_addr &&
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zc->msg_controllen == cmsg_dummy.msg_controllen) {
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tcp_recv_timestamp(&cmsg_dummy, sk, tss);
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zc->msg_control = (__u64)
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((uintptr_t)cmsg_dummy.msg_control);
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zc->msg_controllen =
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(__u64)cmsg_dummy.msg_controllen;
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zc->msg_flags = (__u32)cmsg_dummy.msg_flags;
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}
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}
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#define TCP_ZEROCOPY_PAGE_BATCH_SIZE 32
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static int tcp_zerocopy_receive(struct sock *sk,
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struct tcp_zerocopy_receive *zc)
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struct tcp_zerocopy_receive *zc,
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struct scm_timestamping_internal *tss)
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{
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u32 length = 0, offset, vma_len, avail_len, copylen = 0;
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unsigned long address = (unsigned long)zc->address;
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@ -2029,6 +2077,7 @@ static int tcp_zerocopy_receive(struct sock *sk,
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int ret;
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zc->copybuf_len = 0;
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zc->msg_flags = 0;
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if (address & (PAGE_SIZE - 1) || address != zc->address)
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return -EINVAL;
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@ -2039,7 +2088,7 @@ static int tcp_zerocopy_receive(struct sock *sk,
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sock_rps_record_flow(sk);
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if (inq && inq <= copybuf_len)
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return receive_fallback_to_copy(sk, zc, inq);
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return receive_fallback_to_copy(sk, zc, inq, tss);
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if (inq < PAGE_SIZE) {
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zc->length = 0;
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@ -2084,6 +2133,11 @@ static int tcp_zerocopy_receive(struct sock *sk,
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} else {
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skb = tcp_recv_skb(sk, seq, &offset);
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}
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if (TCP_SKB_CB(skb)->has_rxtstamp) {
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tcp_update_recv_tstamps(skb, tss);
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zc->msg_flags |= TCP_CMSG_TS;
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}
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zc->recv_skip_hint = skb->len - offset;
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frags = skb_advance_to_frag(skb, offset, &offset_frag);
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if (!frags || offset_frag)
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@ -2126,8 +2180,7 @@ static int tcp_zerocopy_receive(struct sock *sk,
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mmap_read_unlock(current->mm);
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/* Try to copy straggler data. */
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if (!ret)
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copylen = tcp_zerocopy_handle_leftover_data(zc, sk, skb, &seq,
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copybuf_len);
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copylen = tcp_zc_handle_leftover(zc, sk, skb, &seq, copybuf_len, tss);
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if (length + copylen) {
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WRITE_ONCE(tp->copied_seq, seq);
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@ -2148,20 +2201,6 @@ static int tcp_zerocopy_receive(struct sock *sk,
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}
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#endif
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static void tcp_update_recv_tstamps(struct sk_buff *skb,
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struct scm_timestamping_internal *tss)
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{
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if (skb->tstamp)
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tss->ts[0] = ktime_to_timespec64(skb->tstamp);
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else
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tss->ts[0] = (struct timespec64) {0};
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if (skb_hwtstamps(skb)->hwtstamp)
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tss->ts[2] = ktime_to_timespec64(skb_hwtstamps(skb)->hwtstamp);
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else
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tss->ts[2] = (struct timespec64) {0};
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}
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/* Similar to __sock_recv_timestamp, but does not require an skb */
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static void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
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struct scm_timestamping_internal *tss)
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@ -4105,6 +4144,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
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}
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#ifdef CONFIG_MMU
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case TCP_ZEROCOPY_RECEIVE: {
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struct scm_timestamping_internal tss;
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struct tcp_zerocopy_receive zc = {};
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int err;
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@ -4120,11 +4160,18 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
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if (copy_from_user(&zc, optval, len))
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return -EFAULT;
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lock_sock(sk);
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err = tcp_zerocopy_receive(sk, &zc);
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err = tcp_zerocopy_receive(sk, &zc, &tss);
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release_sock(sk);
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if (len >= offsetofend(struct tcp_zerocopy_receive, err))
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goto zerocopy_rcv_sk_err;
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if (len >= offsetofend(struct tcp_zerocopy_receive, msg_flags))
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goto zerocopy_rcv_cmsg;
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switch (len) {
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case offsetofend(struct tcp_zerocopy_receive, msg_flags):
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goto zerocopy_rcv_cmsg;
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case offsetofend(struct tcp_zerocopy_receive, msg_controllen):
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case offsetofend(struct tcp_zerocopy_receive, msg_control):
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case offsetofend(struct tcp_zerocopy_receive, flags):
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case offsetofend(struct tcp_zerocopy_receive, copybuf_len):
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case offsetofend(struct tcp_zerocopy_receive, copybuf_address):
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case offsetofend(struct tcp_zerocopy_receive, err):
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goto zerocopy_rcv_sk_err;
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case offsetofend(struct tcp_zerocopy_receive, inq):
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@ -4133,6 +4180,11 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
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default:
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goto zerocopy_rcv_out;
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}
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zerocopy_rcv_cmsg:
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if (zc.msg_flags & TCP_CMSG_TS)
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tcp_zc_finalize_rx_tstamp(sk, &zc, &tss);
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else
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zc.msg_flags = 0;
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zerocopy_rcv_sk_err:
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if (!err)
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zc.err = sock_error(sk);
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