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tcp: remove TCP_SKB_CB(skb)->when

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After commit 740b0f1841 ("tcp: switch rtt estimations to usec resolution"),
we no longer need to maintain timestamps in two different fields.

TCP_SKB_CB(skb)->when can be removed, as same information sits in skb_mstamp.stamp_jiffies

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2014-09-05 15:33:33 -07:00 committed by David S. Miller
parent 04317dafd1
commit 7faee5c0d5
5 changed files with 31 additions and 36 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
include/net/tcp.h
View file

@ -672,6 +672,12 @@ void tcp_send_window_probe(struct sock *sk);
*/
#define tcp_time_stamp ((__u32)(jiffies))
static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
{
return skb->skb_mstamp.stamp_jiffies;
}
#define tcp_flag_byte(th) (((u_int8_t *)th)[13])
#define TCPHDR_FIN 0x01
@ -698,12 +704,7 @@ struct tcp_skb_cb {
} header; /* For incoming frames */
__u32 seq; /* Starting sequence number */
__u32 end_seq; /* SEQ + FIN + SYN + datalen */
union {
/* used in output path */
__u32 when; /* used to compute rtt's */
/* used in input path */
__u32 tcp_tw_isn; /* isn chosen by tcp_timewait_state_process() */
};
__u8 tcp_flags; /* TCP header flags. (tcp[13]) */
__u8 sacked; /* State flags for SACK/FACK. */

3
net/ipv4/tcp_input.c
View file

@ -2967,7 +2967,8 @@ void tcp_rearm_rto(struct sock *sk)
if (icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
struct sk_buff *skb = tcp_write_queue_head(sk);
const u32 rto_time_stamp = TCP_SKB_CB(skb)->when + rto;
const u32 rto_time_stamp =
tcp_skb_timestamp(skb) + rto;
s32 delta = (s32)(rto_time_stamp - tcp_time_stamp);
/* delta may not be positive if the socket is locked
* when the retrans timer fires and is rescheduled.

5
net/ipv4/tcp_ipv4.c
View file

@ -437,8 +437,9 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
skb = tcp_write_queue_head(sk);
BUG_ON(!skb);
remaining = icsk->icsk_rto - min(icsk->icsk_rto,
tcp_time_stamp - TCP_SKB_CB(skb)->when);
remaining = icsk->icsk_rto -
min(icsk->icsk_rto,
tcp_time_stamp - tcp_skb_timestamp(skb));
if (remaining) {
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,

39
net/ipv4/tcp_output.c
View file

@ -550,7 +550,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
if (likely(sysctl_tcp_timestamps && *md5 == NULL)) {
opts->options |= OPTION_TS;
opts->tsval = TCP_SKB_CB(skb)->when + tp->tsoffset;
opts->tsval = tcp_skb_timestamp(skb) + tp->tsoffset;
opts->tsecr = tp->rx_opt.ts_recent;
remaining -= TCPOLEN_TSTAMP_ALIGNED;
}
@ -618,7 +618,7 @@ static unsigned int tcp_synack_options(struct sock *sk,
}
if (likely(ireq->tstamp_ok)) {
opts->options |= OPTION_TS;
opts->tsval = TCP_SKB_CB(skb)->when;
opts->tsval = tcp_skb_timestamp(skb);
opts->tsecr = req->ts_recent;
remaining -= TCPOLEN_TSTAMP_ALIGNED;
}
@ -647,7 +647,6 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
struct tcp_out_options *opts,
struct tcp_md5sig_key **md5)
{
struct tcp_skb_cb *tcb = skb ? TCP_SKB_CB(skb) : NULL;
struct tcp_sock *tp = tcp_sk(sk);
unsigned int size = 0;
unsigned int eff_sacks;
@ -666,7 +665,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
if (likely(tp->rx_opt.tstamp_ok)) {
opts->options |= OPTION_TS;
opts->tsval = tcb ? tcb->when + tp->tsoffset : 0;
opts->tsval = skb ? tcp_skb_timestamp(skb) + tp->tsoffset : 0;
opts->tsecr = tp->rx_opt.ts_recent;
size += TCPOLEN_TSTAMP_ALIGNED;
}
@ -886,8 +885,6 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
skb = skb_clone(skb, gfp_mask);
if (unlikely(!skb))
return -ENOBUFS;
/* Our usage of tstamp should remain private */
skb->tstamp.tv64 = 0;
}
inet = inet_sk(sk);
@ -975,7 +972,10 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
TCP_ADD_STATS(sock_net(sk), TCP_MIB_OUTSEGS,
tcp_skb_pcount(skb));
/* Our usage of tstamp should remain private */
skb->tstamp.tv64 = 0;
err = icsk->icsk_af_ops->queue_xmit(sk, skb, &inet->cork.fl);
if (likely(err <= 0))
return err;
@ -1149,7 +1149,6 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
/* Looks stupid, but our code really uses when of
* skbs, which it never sent before. --ANK
*/
TCP_SKB_CB(buff)->when = TCP_SKB_CB(skb)->when;
buff->tstamp = skb->tstamp;
tcp_fragment_tstamp(skb, buff);
@ -1874,8 +1873,8 @@ static int tcp_mtu_probe(struct sock *sk)
tcp_init_tso_segs(sk, nskb, nskb->len);
/* We're ready to send. If this fails, the probe will
* be resegmented into mss-sized pieces by tcp_write_xmit(). */
TCP_SKB_CB(nskb)->when = tcp_time_stamp;
* be resegmented into mss-sized pieces by tcp_write_xmit().
*/
if (!tcp_transmit_skb(sk, nskb, 1, GFP_ATOMIC)) {
/* Decrement cwnd here because we are sending
* effectively two packets. */
@ -1935,8 +1934,8 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
BUG_ON(!tso_segs);
if (unlikely(tp->repair) && tp->repair_queue == TCP_SEND_QUEUE) {
/* "when" is used as a start point for the retransmit timer */
TCP_SKB_CB(skb)->when = tcp_time_stamp;
/* "skb_mstamp" is used as a start point for the retransmit timer */
skb_mstamp_get(&skb->skb_mstamp);
goto repair; /* Skip network transmission */
}
@ -2000,8 +1999,6 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
unlikely(tso_fragment(sk, skb, limit, mss_now, gfp)))
break;
TCP_SKB_CB(skb)->when = tcp_time_stamp;
if (unlikely(tcp_transmit_skb(sk, skb, 1, gfp)))
break;
@ -2499,7 +2496,6 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
/* Make a copy, if the first transmission SKB clone we made
* is still in somebody's hands, else make a clone.
*/
TCP_SKB_CB(skb)->when = tcp_time_stamp;
/* make sure skb->data is aligned on arches that require it
* and check if ack-trimming & collapsing extended the headroom
@ -2544,7 +2540,7 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
/* Save stamp of the first retransmit. */
if (!tp->retrans_stamp)
tp->retrans_stamp = TCP_SKB_CB(skb)->when;
tp->retrans_stamp = tcp_skb_timestamp(skb);
/* snd_nxt is stored to detect loss of retransmitted segment,
* see tcp_input.c tcp_sacktag_write_queue().
@ -2752,7 +2748,6 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority)
tcp_init_nondata_skb(skb, tcp_acceptable_seq(sk),
TCPHDR_ACK | TCPHDR_RST);
/* Send it off. */
TCP_SKB_CB(skb)->when = tcp_time_stamp;
if (tcp_transmit_skb(sk, skb, 0, priority))
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTFAILED);
@ -2791,7 +2786,6 @@ int tcp_send_synack(struct sock *sk)
TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_ACK;
TCP_ECN_send_synack(tcp_sk(sk), skb);
}
TCP_SKB_CB(skb)->when = tcp_time_stamp;
return tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
}
@ -2835,10 +2829,10 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
memset(&opts, 0, sizeof(opts));
#ifdef CONFIG_SYN_COOKIES
if (unlikely(req->cookie_ts))
TCP_SKB_CB(skb)->when = cookie_init_timestamp(req);
skb->skb_mstamp.stamp_jiffies = cookie_init_timestamp(req);
else
#endif
TCP_SKB_CB(skb)->when = tcp_time_stamp;
skb_mstamp_get(&skb->skb_mstamp);
tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, &md5,
foc) + sizeof(*th);
@ -3086,7 +3080,7 @@ int tcp_connect(struct sock *sk)
skb_reserve(buff, MAX_TCP_HEADER);
tcp_init_nondata_skb(buff, tp->write_seq++, TCPHDR_SYN);
tp->retrans_stamp = TCP_SKB_CB(buff)->when = tcp_time_stamp;
tp->retrans_stamp = tcp_time_stamp;
tcp_connect_queue_skb(sk, buff);
TCP_ECN_send_syn(sk, buff);
@ -3194,7 +3188,7 @@ void tcp_send_ack(struct sock *sk)
tcp_init_nondata_skb(buff, tcp_acceptable_seq(sk), TCPHDR_ACK);
/* Send it off, this clears delayed acks for us. */
TCP_SKB_CB(buff)->when = tcp_time_stamp;
skb_mstamp_get(&buff->skb_mstamp);
tcp_transmit_skb(sk, buff, 0, sk_gfp_atomic(sk, GFP_ATOMIC));
}
@ -3226,7 +3220,7 @@ static int tcp_xmit_probe_skb(struct sock *sk, int urgent)
* send it.
*/
tcp_init_nondata_skb(skb, tp->snd_una - !urgent, TCPHDR_ACK);
TCP_SKB_CB(skb)->when = tcp_time_stamp;
skb_mstamp_get(&skb->skb_mstamp);
return tcp_transmit_skb(sk, skb, 0, GFP_ATOMIC);
}
@ -3270,7 +3264,6 @@ int tcp_write_wakeup(struct sock *sk)
tcp_set_skb_tso_segs(sk, skb, mss);
TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
TCP_SKB_CB(skb)->when = tcp_time_stamp;
err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
if (!err)
tcp_event_new_data_sent(sk, skb);

5
net/ipv4/tcp_timer.c
View file

@ -135,10 +135,9 @@ static bool retransmits_timed_out(struct sock *sk,
if (!inet_csk(sk)->icsk_retransmits)
return false;
if (unlikely(!tcp_sk(sk)->retrans_stamp))
start_ts = TCP_SKB_CB(tcp_write_queue_head(sk))->when;
else
start_ts = tcp_sk(sk)->retrans_stamp;
if (unlikely(!start_ts))
start_ts = tcp_skb_timestamp(tcp_write_queue_head(sk));
if (likely(timeout == 0)) {
linear_backoff_thresh = ilog2(TCP_RTO_MAX/rto_base);