From fbf934068f6b93a8c4ddda293fc02b4eb3747323 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 9 Jun 2023 20:42:44 +0000 Subject: tcp: let tcp_send_syn_data() build headless packets tcp_send_syn_data() is the last component in TCP transmit path to put payload in skb->head. Switch it to use page frags, so that we can remove dead code later. This allows to put more payload than previous implementation. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/tcp.h | 1 + net/ipv4/tcp.c | 2 +- net/ipv4/tcp_output.c | 31 +++++++++++++++++++------------ 3 files changed, 21 insertions(+), 13 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 49611af31bb7..f718ed258f07 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -333,6 +333,7 @@ int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset, size_t size, int flags); int tcp_send_mss(struct sock *sk, int *size_goal, int flags); +int tcp_wmem_schedule(struct sock *sk, int copy); void tcp_push(struct sock *sk, int flags, int mss_now, int nonagle, int size_goal); void tcp_release_cb(struct sock *sk); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 09f03221a6f1..da7f156d9fad 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -957,7 +957,7 @@ static int tcp_downgrade_zcopy_pure(struct sock *sk, struct sk_buff *skb) } -static int tcp_wmem_schedule(struct sock *sk, int copy) +int tcp_wmem_schedule(struct sock *sk, int copy) { int left; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index f8ce77ce7c3e..d03966337359 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3802,8 +3802,9 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn) struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct tcp_fastopen_request *fo = tp->fastopen_req; - int space, err = 0; + struct page_frag *pfrag = sk_page_frag(sk); struct sk_buff *syn_data; + int space, err = 0; tp->rx_opt.mss_clamp = tp->advmss; /* If MSS is not cached */ if (!tcp_fastopen_cookie_check(sk, &tp->rx_opt.mss_clamp, &fo->cookie)) @@ -3822,25 +3823,31 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn) space = min_t(size_t, space, fo->size); - /* limit to order-0 allocations */ - space = min_t(size_t, space, SKB_MAX_HEAD(MAX_TCP_HEADER)); - - syn_data = tcp_stream_alloc_skb(sk, space, sk->sk_allocation, false); + if (space && + !skb_page_frag_refill(min_t(size_t, space, PAGE_SIZE), + pfrag, sk->sk_allocation)) + goto fallback; + syn_data = tcp_stream_alloc_skb(sk, 0, sk->sk_allocation, false); if (!syn_data) goto fallback; memcpy(syn_data->cb, syn->cb, sizeof(syn->cb)); if (space) { - int copied = copy_from_iter(skb_put(syn_data, space), space, - &fo->data->msg_iter); - if (unlikely(!copied)) { + space = min_t(size_t, space, pfrag->size - pfrag->offset); + space = tcp_wmem_schedule(sk, space); + } + if (space) { + space = copy_page_from_iter(pfrag->page, pfrag->offset, + space, &fo->data->msg_iter); + if (unlikely(!space)) { tcp_skb_tsorted_anchor_cleanup(syn_data); kfree_skb(syn_data); goto fallback; } - if (copied != space) { - skb_trim(syn_data, copied); - space = copied; - } + skb_fill_page_desc(syn_data, 0, pfrag->page, + pfrag->offset, space); + page_ref_inc(pfrag->page); + pfrag->offset += space; + skb_len_add(syn_data, space); skb_zcopy_set(syn_data, fo->uarg, NULL); } /* No more data pending in inet_wait_for_connect() */ -- cgit v1.2.3-58-ga151