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tcp: do not allocate linear memory for zerocopy skbs

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Zerocopy payload is now always stored in frags, and space for headers
is reversed, so this memory is unused.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Willem de Bruijn 2017-12-22 19:00:20 -05:00 committed by David S. Miller
parent 02583adeff
commit 8ddab50839
1 changed files with 7 additions and 4 deletions
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11
net/ipv4/tcp.c
View file

@ -1104,12 +1104,15 @@ static int linear_payload_sz(bool first_skb)
return 0;
}
static int select_size(const struct sock *sk, bool sg, bool first_skb)
static int select_size(const struct sock *sk, bool sg, bool first_skb, bool zc)
{
const struct tcp_sock *tp = tcp_sk(sk);
int tmp = tp->mss_cache;
if (sg) {
if (zc)
return 0;
if (sk_can_gso(sk)) {
tmp = linear_payload_sz(first_skb);
} else {
@ -1282,6 +1285,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
bool first_skb;
int linear;
new_segment:
/* Allocate new segment. If the interface is SG,
@ -1295,9 +1299,8 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
goto restart;
}
first_skb = tcp_rtx_and_write_queues_empty(sk);
skb = sk_stream_alloc_skb(sk,
select_size(sk, sg, first_skb),
sk->sk_allocation,
linear = select_size(sk, sg, first_skb, zc);
skb = sk_stream_alloc_skb(sk, linear, sk->sk_allocation,
first_skb);
if (!skb)
goto wait_for_memory;