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tcp: do not block bh during prequeue processing

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AFAIK, nothing in current TCP stack absolutely wants BH
being disabled once socket is owned by a thread running in
process context.

As mentioned in my prior patch ("tcp: give prequeue mode some care"),
processing a batch of packets might take time, better not block BH
at all.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2016-04-29 14:16:48 -07:00 committed by David S. Miller
parent c10d9310ed
commit fb3477c0f4
2 changed files with 2 additions and 32 deletions
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4
net/ipv4/tcp.c
View File

@ -1449,12 +1449,8 @@ static void tcp_prequeue_process(struct sock *sk)
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPREQUEUED);
/* RX process wants to run with disabled BHs, though it is not
* necessary */
local_bh_disable();
while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
sk_backlog_rcv(sk, skb);
local_bh_enable();
/* Clear memory counter. */
tp->ucopy.memory = 0;

30
net/ipv4/tcp_input.c
View File

@ -4611,14 +4611,12 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
__set_current_state(TASK_RUNNING);
local_bh_enable();
if (!skb_copy_datagram_msg(skb, 0, tp->ucopy.msg, chunk)) {
tp->ucopy.len -= chunk;
tp->copied_seq += chunk;
eaten = (chunk == skb->len);
tcp_rcv_space_adjust(sk);
}
local_bh_disable();
}
if (eaten <= 0) {
@ -5134,7 +5132,6 @@ static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen)
int chunk = skb->len - hlen;
int err;
local_bh_enable();
if (skb_csum_unnecessary(skb))
err = skb_copy_datagram_msg(skb, hlen, tp->ucopy.msg, chunk);
else
@ -5146,32 +5143,9 @@ static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen)
tcp_rcv_space_adjust(sk);
}
local_bh_disable();
return err;
}
static __sum16 __tcp_checksum_complete_user(struct sock *sk,
struct sk_buff *skb)
{
__sum16 result;
if (sock_owned_by_user(sk)) {
local_bh_enable();
result = __tcp_checksum_complete(skb);
local_bh_disable();
} else {
result = __tcp_checksum_complete(skb);
}
return result;
}
static inline bool tcp_checksum_complete_user(struct sock *sk,
struct sk_buff *skb)
{
return !skb_csum_unnecessary(skb) &&
__tcp_checksum_complete_user(sk, skb);
}
/* Does PAWS and seqno based validation of an incoming segment, flags will
* play significant role here.
*/
@ -5386,7 +5360,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
}
}
if (!eaten) {
if (tcp_checksum_complete_user(sk, skb))
if (tcp_checksum_complete(skb))
goto csum_error;
if ((int)skb->truesize > sk->sk_forward_alloc)
@ -5430,7 +5404,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
}
slow_path:
if (len < (th->doff << 2) || tcp_checksum_complete_user(sk, skb))
if (len < (th->doff << 2) || tcp_checksum_complete(skb))
goto csum_error;
if (!th->ack && !th->rst && !th->syn)