[CCID3]: Reorganise timeval handling
Introducing functions to add to or subtract from a timeval variable
and renaming now_delta to timeval_new_delta that calls do_gettimeofday
and then timeval_delta, that should be used when there are several
deltas made relative to the current time or setting variables to it,
so as to avoid calling do_gettimeofday excessively.
I'm leaving these "timeval_" prefixed funcions internal to DCCP for a
while till we're sure there are no subtle bugs in it.
It also is more correct as it checks if the number of usecs added to
or subtracted from a tv_usec field is more than 2 seconds.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 225c530..60e3a5f 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -156,26 +156,6 @@
hctx->ccid3hctx_state = state;
}
-static void timeval_sub(struct timeval large, struct timeval small,
- struct timeval *result)
-{
- result->tv_sec = large.tv_sec-small.tv_sec;
- if (large.tv_usec < small.tv_usec) {
- (result->tv_sec)--;
- result->tv_usec = USEC_PER_SEC +
- large.tv_usec - small.tv_usec;
- } else
- result->tv_usec = large.tv_usec-small.tv_usec;
-}
-
-static inline void timeval_fix(struct timeval *tv)
-{
- if (tv->tv_usec >= USEC_PER_SEC) {
- tv->tv_sec++;
- tv->tv_usec -= USEC_PER_SEC;
- }
-}
-
#define CALCX_ARRSIZE 500
#define CALCX_SPLIT 50000
@@ -816,18 +796,22 @@
2 * hctx->ccid3hctx_x_recv),
(hctx->ccid3hctx_s /
TFRC_MAX_BACK_OFF_TIME));
- } else if (now_delta(hctx->ccid3hctx_t_ld) >= hctx->ccid3hctx_rtt) {
- u32 rtt = hctx->ccid3hctx_rtt;
- if (rtt < 10) {
- rtt = 10;
- } /* avoid divide by zero below */
-
- hctx->ccid3hctx_x = max_t(u32, min_t(u32, 2 * hctx->ccid3hctx_x_recv,
- 2 * hctx->ccid3hctx_x),
- ((hctx->ccid3hctx_s * 100000) /
- (rtt / 10)));
- /* Using 100000 and 10 to avoid 32 bit overflow for jumbo frames */
- do_gettimeofday(&hctx->ccid3hctx_t_ld);
+ } else {
+ struct timeval now;
+
+ do_gettimeofday(&now);
+ if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >=
+ hctx->ccid3hctx_rtt) {
+ /* Avoid divide by zero below */
+ const u32 rtt = max_t(u32, hctx->ccid3hctx_rtt, 10);
+
+ hctx->ccid3hctx_x = max_t(u32, min_t(u32, 2 * hctx->ccid3hctx_x_recv,
+ 2 * hctx->ccid3hctx_x),
+ ((hctx->ccid3hctx_s * 100000) /
+ (rtt / 10)));
+ /* Using 100000 and 10 to avoid 32 bit overflow for jumbo frames */
+ hctx->ccid3hctx_t_ld = now;
+ }
}
if (hctx->ccid3hctx_x == 0) {
@@ -999,14 +983,15 @@
/* Set nominal send time for initial packet */
hctx->ccid3hctx_t_nom = now;
- (hctx->ccid3hctx_t_nom).tv_usec += hctx->ccid3hctx_t_ipi;
- timeval_fix(&(hctx->ccid3hctx_t_nom));
+ timeval_add_usecs(&hctx->ccid3hctx_t_nom,
+ hctx->ccid3hctx_t_ipi);
ccid3_calc_new_delta(hctx);
rc = 0;
break;
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
- delay = now_delta(hctx->ccid3hctx_t_nom) - hctx->ccid3hctx_delta;
+ delay = (timeval_delta(&now, &hctx->ccid3hctx_t_nom) -
+ hctx->ccid3hctx_delta);
ccid3_pr_debug("send_packet delay=%ld\n", delay);
delay /= -1000;
/* divide by -1000 is to convert to ms and get sign right */
@@ -1068,7 +1053,7 @@
* Algorithm in "8.1. Window Counter Valuer" in
* draft-ietf-dccp-ccid3-11.txt
*/
- quarter_rtt = now_delta(hctx->ccid3hctx_t_last_win_count) /
+ quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count) /
(hctx->ccid3hctx_rtt / 4);
if (quarter_rtt > 0) {
hctx->ccid3hctx_t_last_win_count = now;
@@ -1102,8 +1087,8 @@
hctx->ccid3hctx_t_nom = now;
ccid3_calc_new_t_ipi(hctx);
ccid3_calc_new_delta(hctx);
- (hctx->ccid3hctx_t_nom).tv_usec += hctx->ccid3hctx_t_ipi;
- timeval_fix(&(hctx->ccid3hctx_t_nom));
+ timeval_add_usecs(&hctx->ccid3hctx_t_nom,
+ hctx->ccid3hctx_t_ipi);
}
break;
default:
@@ -1167,7 +1152,7 @@
}
/* Update RTT */
- r_sample = now_delta(packet->dccphtx_tstamp);
+ r_sample = timeval_now_delta(&packet->dccphtx_tstamp);
/* FIXME: */
// r_sample -= usecs_to_jiffies(t_elapsed * 10);
@@ -1224,15 +1209,11 @@
ccid3_hc_tx_update_x(sk);
/* Update next send time */
- if (hctx->ccid3hctx_t_ipi > (hctx->ccid3hctx_t_nom).tv_usec) {
- hctx->ccid3hctx_t_nom.tv_usec += USEC_PER_SEC;
- (hctx->ccid3hctx_t_nom).tv_sec--;
- }
- /* FIXME - if no feedback then t_ipi can go > 1 second */
- (hctx->ccid3hctx_t_nom).tv_usec -= hctx->ccid3hctx_t_ipi;
+ timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
+ hctx->ccid3hctx_t_ipi);
ccid3_calc_new_t_ipi(hctx);
- (hctx->ccid3hctx_t_nom).tv_usec += hctx->ccid3hctx_t_ipi;
- timeval_fix(&(hctx->ccid3hctx_t_nom));
+ timeval_add_usecs(&hctx->ccid3hctx_t_nom,
+ hctx->ccid3hctx_t_ipi);
ccid3_calc_new_delta(hctx);
/* remove all packets older than the one acked from history */
@@ -1559,20 +1540,24 @@
struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_rx_sock *hcrx = dp->dccps_hc_rx_ccid_private;
struct dccp_rx_hist_entry *packet;
+ struct timeval now;
ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
+ do_gettimeofday(&now);
+
switch (hcrx->ccid3hcrx_state) {
case TFRC_RSTATE_NO_DATA:
hcrx->ccid3hcrx_x_recv = 0;
break;
case TFRC_RSTATE_DATA: {
- u32 delta = now_delta(hcrx->ccid3hcrx_tstamp_last_feedback);
+ const u32 delta = timeval_delta(&now,
+ &hcrx->ccid3hcrx_tstamp_last_feedback);
- if (delta == 0)
- delta = 1; /* to prevent divide by zero */
hcrx->ccid3hcrx_x_recv = (hcrx->ccid3hcrx_bytes_recv *
- USEC_PER_SEC) / delta;
+ USEC_PER_SEC);
+ if (likely(delta > 1))
+ hcrx->ccid3hcrx_x_recv /= delta;
}
break;
default:
@@ -1590,13 +1575,14 @@
return;
}
- do_gettimeofday(&(hcrx->ccid3hcrx_tstamp_last_feedback));
+ hcrx->ccid3hcrx_tstamp_last_feedback = now;
hcrx->ccid3hcrx_last_counter = packet->dccphrx_ccval;
hcrx->ccid3hcrx_seqno_last_counter = packet->dccphrx_seqno;
hcrx->ccid3hcrx_bytes_recv = 0;
/* Convert to multiples of 10us */
- hcrx->ccid3hcrx_elapsed_time = now_delta(packet->dccphrx_tstamp) / 10;
+ hcrx->ccid3hcrx_elapsed_time =
+ timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
if (hcrx->ccid3hcrx_p == 0)
hcrx->ccid3hcrx_pinv = ~0;
else
@@ -1676,7 +1662,7 @@
struct ccid3_hc_rx_sock *hcrx = dp->dccps_hc_rx_ccid_private;
struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
u32 rtt, delta, x_recv, fval, p, tmp2;
- struct timeval tstamp = { 0 }, tmp_tv;
+ struct timeval tstamp = { 0, };
int interval = 0;
int win_count = 0;
int step = 0;
@@ -1718,18 +1704,16 @@
interval = 1;
}
found:
- timeval_sub(tstamp,tail->dccphrx_tstamp,&tmp_tv);
- rtt = (tmp_tv.tv_sec * USEC_PER_SEC + tmp_tv.tv_usec) * 4 / interval;
+ rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
dccp_role(sk), sk, rtt);
if (rtt == 0)
rtt = 1;
- delta = now_delta(hcrx->ccid3hcrx_tstamp_last_feedback);
- if (delta == 0)
- delta = 1;
-
- x_recv = (hcrx->ccid3hcrx_bytes_recv * USEC_PER_SEC) / delta;
+ delta = timeval_now_delta(&hcrx->ccid3hcrx_tstamp_last_feedback);
+ x_recv = hcrx->ccid3hcrx_bytes_recv * USEC_PER_SEC;
+ if (likely(delta > 1))
+ x_recv /= delta;
tmp1 = (u64)x_recv * (u64)rtt;
do_div(tmp1,10000000);
@@ -1926,7 +1910,6 @@
const struct dccp_options_received *opt_recv;
struct dccp_rx_hist_entry *packet;
struct timeval now;
- u32 now_usecs;
u8 win_count;
u32 p_prev;
int ins;
@@ -1948,8 +1931,7 @@
break;
p_prev = hcrx->ccid3hcrx_rtt;
do_gettimeofday(&now);
- now_usecs = now.tv_sec * USEC_PER_SEC + now.tv_usec;
- hcrx->ccid3hcrx_rtt = now_usecs -
+ hcrx->ccid3hcrx_rtt = timeval_usecs(&now) -
(opt_recv->dccpor_timestamp_echo -
opt_recv->dccpor_elapsed_time) * 10;
if (p_prev != hcrx->ccid3hcrx_rtt)
@@ -1994,15 +1976,16 @@
case TFRC_RSTATE_DATA:
hcrx->ccid3hcrx_bytes_recv += skb->len -
dccp_hdr(skb)->dccph_doff * 4;
- if (ins == 0) {
- if (now_delta(hcrx->ccid3hcrx_tstamp_last_ack) >=
- hcrx->ccid3hcrx_rtt) {
- do_gettimeofday(&hcrx->ccid3hcrx_tstamp_last_ack);
- ccid3_hc_rx_send_feedback(sk);
- }
- return;
+ if (ins != 0)
+ break;
+
+ do_gettimeofday(&now);
+ if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
+ hcrx->ccid3hcrx_rtt) {
+ hcrx->ccid3hcrx_tstamp_last_ack = now;
+ ccid3_hc_rx_send_feedback(sk);
}
- break;
+ return;
default:
printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
__FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state);
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 6ba2150..5cd9e79 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -429,17 +429,53 @@
extern void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap,
struct sock *sk, u64 ackno);
+static inline suseconds_t timeval_usecs(const struct timeval *tv)
+{
+ return tv->tv_sec * USEC_PER_SEC + tv->tv_usec;
+}
+
+static inline suseconds_t timeval_delta(const struct timeval *large,
+ const struct timeval *small)
+{
+ time_t secs = large->tv_sec - small->tv_sec;
+ suseconds_t usecs = large->tv_usec - small->tv_usec;
+
+ if (usecs < 0) {
+ secs--;
+ usecs += USEC_PER_SEC;
+ }
+ return secs * USEC_PER_SEC + usecs;
+}
+
+static inline void timeval_add_usecs(struct timeval *tv,
+ const suseconds_t usecs)
+{
+ tv->tv_usec += usecs;
+ while (tv->tv_usec >= USEC_PER_SEC) {
+ tv->tv_sec++;
+ tv->tv_usec -= USEC_PER_SEC;
+ }
+}
+
+static inline void timeval_sub_usecs(struct timeval *tv,
+ const suseconds_t usecs)
+{
+ tv->tv_usec -= usecs;
+ while (tv->tv_usec < 0) {
+ tv->tv_sec--;
+ tv->tv_usec += USEC_PER_SEC;
+ }
+}
+
/*
* Returns the difference in usecs between timeval
* passed in and current time
*/
-static inline u32 now_delta(struct timeval tv)
+static inline suseconds_t timeval_now_delta(const struct timeval *tv)
{
struct timeval now;
-
do_gettimeofday(&now);
- return (now.tv_sec - tv.tv_sec) * USEC_PER_SEC +
- (now.tv_usec - tv.tv_usec);
+ return timeval_delta(&now, tv);
}
#ifdef CONFIG_IP_DCCP_DEBUG
diff --git a/net/dccp/options.c b/net/dccp/options.c
index eabcc8f..382c589 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -359,7 +359,7 @@
#endif
struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
int len = ap->dccpap_buf_vector_len + 2;
- const u32 elapsed_time = now_delta(ap->dccpap_time) / 10;
+ const u32 elapsed_time = timeval_now_delta(&ap->dccpap_time) / 10;
unsigned char *to, *from;
if (elapsed_time != 0)
@@ -451,7 +451,8 @@
"CLIENT TX opt: " : "server TX opt: ";
#endif
u32 tstamp_echo;
- const u32 elapsed_time = now_delta(dp->dccps_timestamp_time) / 10;
+ const u32 elapsed_time =
+ timeval_now_delta(&dp->dccps_timestamp_time) / 10;
const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
const int len = 6 + elapsed_time_len;
unsigned char *to;
