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mptcp: cleanup mptcp_subflow_discard_data()

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There is no need to use the tcp_read_sock(), we can
simply drop the skb. Additionally try to look at the
next buffer for in order data.

This both simplifies the code and avoid unneeded indirect
calls.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2020-09-14 10:01:13 +02:00 committed by David S. Miller
parent ab174ad8ef
commit 04e4cd4f7c
2 changed files with 13 additions and 44 deletions
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1
net/mptcp/protocol.h
View file

@ -355,7 +355,6 @@ int mptcp_is_enabled(struct net *net);
void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
struct mptcp_options_received *mp_opt);
bool mptcp_subflow_data_available(struct sock *sk);
int mptcp_subflow_discard_data(struct sock *sk, unsigned int limit);
void __init mptcp_subflow_init(void);
/* called with sk socket lock held */

56
net/mptcp/subflow.c
View file

@ -805,50 +805,22 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
return MAPPING_OK;
}
static int subflow_read_actor(read_descriptor_t *desc,
struct sk_buff *skb,
unsigned int offset, size_t len)
{
size_t copy_len = min(desc->count, len);
desc->count -= copy_len;
pr_debug("flushed %zu bytes, %zu left", copy_len, desc->count);
return copy_len;
}
int mptcp_subflow_discard_data(struct sock *ssk, unsigned int limit)
static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb,
unsigned int limit)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
u32 map_remaining;
size_t delta;
bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
u32 incr;
map_remaining = subflow->map_data_len -
mptcp_subflow_get_map_offset(subflow);
delta = min_t(size_t, limit, map_remaining);
incr = limit >= skb->len ? skb->len + fin : limit;
/* discard mapped data */
pr_debug("discarding %zu bytes, current map len=%d", delta,
map_remaining);
if (delta) {
read_descriptor_t desc = {
.count = delta,
};
int ret;
ret = tcp_read_sock(ssk, &desc, subflow_read_actor);
if (ret < 0) {
ssk->sk_err = -ret;
return ret;
}
if (ret < delta)
return 0;
if (delta == map_remaining) {
subflow->data_avail = 0;
subflow->map_valid = 0;
}
}
return 0;
pr_debug("discarding=%d len=%d seq=%d", incr, skb->len,
subflow->map_subflow_seq);
tcp_sk(ssk)->copied_seq += incr;
if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq))
sk_eat_skb(ssk, skb);
if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len)
subflow->map_valid = 0;
}
static bool subflow_check_data_avail(struct sock *ssk)
@ -923,9 +895,7 @@ static bool subflow_check_data_avail(struct sock *ssk)
/* only accept in-sequence mapping. Old values are spurious
* retransmission
*/
if (mptcp_subflow_discard_data(ssk, old_ack - ack_seq))
goto fatal;
return false;
mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);
}
return true;