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authorEric Dumazet <edumazet@google.com>2023-06-09 20:42:44 +0000
committerDavid S. Miller <davem@davemloft.net>2023-06-12 11:38:54 +0100
commitfbf934068f6b93a8c4ddda293fc02b4eb3747323 (patch)
tree8fb243da4c08b49f63f920471d3c826a2fe1ebca
parentf2f069da4c40dcf136db731c9fece17c3bbf7cdc (diff)
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 <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/tcp.h1
-rw-r--r--net/ipv4/tcp.c2
-rw-r--r--net/ipv4/tcp_output.c31
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() */