ip: convert tcp_sendmsg() to iov_iter primitives
patch is actually smaller than it seems to be - most of it is unindenting the inner loop body in tcp_sendmsg() itself... the bit in tcp_input.c is going to get reverted very soon - that's what memcpy_from_msg() will become, but not in this commit; let's keep it reasonably contained... There's one potentially subtle change here: in case of short copy from userland, mainline tcp_send_syn_data() discards the skb it has allocated and falls back to normal path, where we'll send as much as possible after rereading the same data again. This patch trims SYN+data skb instead - that way we don't need to copy from the same place twice. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
parent
cacdc7d2f9
commit
57be5bdad7
@ -1803,27 +1803,25 @@ static inline void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
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}
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static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
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char __user *from, char *to,
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struct iov_iter *from, char *to,
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int copy, int offset)
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{
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if (skb->ip_summed == CHECKSUM_NONE) {
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int err = 0;
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__wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
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if (err)
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return err;
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__wsum csum = 0;
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if (csum_and_copy_from_iter(to, copy, &csum, from) != copy)
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return -EFAULT;
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skb->csum = csum_block_add(skb->csum, csum, offset);
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} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
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if (!access_ok(VERIFY_READ, from, copy) ||
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__copy_from_user_nocache(to, from, copy))
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if (copy_from_iter_nocache(to, copy, from) != copy)
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return -EFAULT;
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} else if (copy_from_user(to, from, copy))
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} else if (copy_from_iter(to, copy, from) != copy)
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return -EFAULT;
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return 0;
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}
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static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
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char __user *from, int copy)
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struct iov_iter *from, int copy)
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{
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int err, offset = skb->len;
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@ -1835,7 +1833,7 @@ static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
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return err;
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}
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static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
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static inline int skb_copy_to_page_nocache(struct sock *sk, struct iov_iter *from,
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struct sk_buff *skb,
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struct page *page,
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int off, int copy)
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@ -1067,11 +1067,10 @@ static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
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int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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size_t size)
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{
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const struct iovec *iov;
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struct tcp_sock *tp = tcp_sk(sk);
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struct sk_buff *skb;
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int iovlen, flags, err, copied = 0;
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int mss_now = 0, size_goal, copied_syn = 0, offset = 0;
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int flags, err, copied = 0;
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int mss_now = 0, size_goal, copied_syn = 0;
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bool sg;
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long timeo;
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@ -1084,7 +1083,6 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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goto out;
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else if (err)
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goto out_err;
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offset = copied_syn;
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}
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timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
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@ -1118,8 +1116,6 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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mss_now = tcp_send_mss(sk, &size_goal, flags);
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/* Ok commence sending. */
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iovlen = msg->msg_iter.nr_segs;
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iov = msg->msg_iter.iov;
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copied = 0;
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err = -EPIPE;
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@ -1128,22 +1124,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
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sg = !!(sk->sk_route_caps & NETIF_F_SG);
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while (--iovlen >= 0) {
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size_t seglen = iov->iov_len;
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unsigned char __user *from = iov->iov_base;
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iov++;
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if (unlikely(offset > 0)) { /* Skip bytes copied in SYN */
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if (offset >= seglen) {
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offset -= seglen;
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continue;
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}
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seglen -= offset;
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from += offset;
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offset = 0;
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}
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while (seglen > 0) {
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while (iov_iter_count(&msg->msg_iter)) {
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int copy = 0;
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int max = size_goal;
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@ -1187,14 +1168,14 @@ new_segment:
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}
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/* Try to append data to the end of skb. */
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if (copy > seglen)
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copy = seglen;
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if (copy > iov_iter_count(&msg->msg_iter))
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copy = iov_iter_count(&msg->msg_iter);
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/* Where to copy to? */
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if (skb_availroom(skb) > 0) {
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/* We have some space in skb head. Superb! */
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copy = min_t(int, copy, skb_availroom(skb));
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err = skb_add_data_nocache(sk, skb, from, copy);
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err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
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if (err)
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goto do_fault;
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} else {
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@ -1219,7 +1200,7 @@ new_segment:
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if (!sk_wmem_schedule(sk, copy))
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goto wait_for_memory;
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err = skb_copy_to_page_nocache(sk, from, skb,
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err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
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pfrag->page,
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pfrag->offset,
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copy);
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@ -1244,9 +1225,8 @@ new_segment:
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TCP_SKB_CB(skb)->end_seq += copy;
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tcp_skb_pcount_set(skb, 0);
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from += copy;
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copied += copy;
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if ((seglen -= copy) == 0 && iovlen == 0) {
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if (!iov_iter_count(&msg->msg_iter)) {
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tcp_tx_timestamp(sk, skb);
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goto out;
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}
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@ -1273,7 +1253,6 @@ wait_for_memory:
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mss_now = tcp_send_mss(sk, &size_goal, flags);
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}
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}
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out:
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if (copied)
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@ -4368,7 +4368,7 @@ int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
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if (tcp_try_rmem_schedule(sk, skb, skb->truesize))
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goto err_free;
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if (memcpy_from_msg(skb_put(skb, size), msg, size))
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if (copy_from_iter(skb_put(skb, size), size, &msg->msg_iter) != size)
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goto err_free;
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TCP_SKB_CB(skb)->seq = tcp_sk(sk)->rcv_nxt;
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@ -3055,7 +3055,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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struct tcp_fastopen_request *fo = tp->fastopen_req;
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int syn_loss = 0, space, err = 0;
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int syn_loss = 0, space, err = 0, copied;
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unsigned long last_syn_loss = 0;
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struct sk_buff *syn_data;
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@ -3093,11 +3093,16 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
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goto fallback;
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syn_data->ip_summed = CHECKSUM_PARTIAL;
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memcpy(syn_data->cb, syn->cb, sizeof(syn->cb));
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if (unlikely(memcpy_fromiovecend(skb_put(syn_data, space),
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fo->data->msg_iter.iov, 0, space))) {
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copied = copy_from_iter(skb_put(syn_data, space), space,
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&fo->data->msg_iter);
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if (unlikely(!copied)) {
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kfree_skb(syn_data);
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goto fallback;
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}
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if (copied != space) {
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skb_trim(syn_data, copied);
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space = copied;
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}
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/* No more data pending in inet_wait_for_connect() */
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if (space == fo->size)
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