[CCID3]: Sending time: update to ktime_t and bug-fix
This updates the computation of t_nom and t_last_win_count to use the newer
gettimeofday interface.
The second point of this patch is to fix a bug in the send time processing:
ccid3_hc_tx_send_packet currently returns 0 when the time difference
between current time and t_nom is less than 1000 microseconds.
In this case the packet is sent immediately; but, unlike other packets
that can be emitted on first attempt, it will not have its window
counter updated and its options set as required. This is a bug.
Fix: Require the time difference to be at least 1000 microseconds. The
algorithm then converges: time differences > 1000 microseconds trigger the
timer in dccp_write_xmit; after timer expiry this function is tried again;
when the time difference is less than 1000, the packet will have its options
added and window counter updated as required.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
net/dccp/ccids/ccid3.c | 30 ++++++++++++------------------
net/dccp/ccids/ccid3.h | 4 ++--
2 files changed, 14 insertions(+), 20 deletions(-)
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -108,10 +108,10 @@ struct ccid3_hc_tx_sock {
enum ccid3_hc_tx_states ccid3hctx_state:8;
u8 ccid3hctx_last_win_count;
u8 ccid3hctx_idle;
- struct timeval ccid3hctx_t_last_win_count;
+ ktime_t ccid3hctx_t_last_win_count;
struct timer_list ccid3hctx_no_feedback_timer;
struct timeval ccid3hctx_t_ld;
- struct timeval ccid3hctx_t_nom;
+ ktime_t ccid3hctx_t_nom;
u32 ccid3hctx_delta;
struct list_head ccid3hctx_hist;
struct ccid3_options_received ccid3hctx_options_received;
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -194,25 +194,20 @@ static inline void ccid3_hc_tx_update_s(
* The algorithm is not applicable if RTT < 4 microseconds.
*/
static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
- struct timeval *now)
+ ktime_t now)
{
- suseconds_t delta;
u32 quarter_rtts;
if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */
return;
- delta = timeval_delta(now, &hctx->ccid3hctx_t_last_win_count);
- DCCP_BUG_ON(delta < 0);
-
- quarter_rtts = (u32)delta / (hctx->ccid3hctx_rtt / 4);
+ quarter_rtts = ktime_delta(now, hctx->ccid3hctx_t_last_win_count);
+ quarter_rtts /= (hctx->ccid3hctx_rtt / 4);
if (quarter_rtts > 0) {
- hctx->ccid3hctx_t_last_win_count = *now;
+ hctx->ccid3hctx_t_last_win_count = now;
hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5);
hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
-
- ccid3_pr_debug("now at %#X\n", hctx->ccid3hctx_last_win_count);
}
}
@@ -312,8 +307,8 @@ static int ccid3_hc_tx_send_packet(struc
{
struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
- struct timeval now;
- suseconds_t delay;
+ ktime_t now = ktime_get_real();
+ s64 delay;
BUG_ON(hctx == NULL);
@@ -325,8 +320,6 @@ static int ccid3_hc_tx_send_packet(struc
if (unlikely(skb->len == 0))
return -EBADMSG;
- dccp_timestamp(sk, &now);
-
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_SENT:
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
@@ -361,7 +354,7 @@ static int ccid3_hc_tx_send_packet(struc
break;
case TFRC_SSTATE_NO_FBACK:
case TFRC_SSTATE_FBACK:
- delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
+ delay = ktime_delta(hctx->ccid3hctx_t_nom, now);
ccid3_pr_debug("delay=%ld\n", (long)delay);
/*
* Scheduling of packet transmissions [RFC 3448, 4.6]
@@ -371,10 +364,10 @@ static int ccid3_hc_tx_send_packet(struc
* else
* // send the packet in (t_nom - t_now) milliseconds.
*/
- if (delay - (suseconds_t)hctx->ccid3hctx_delta >= 0)
- return delay / 1000L;
+ if (delay - (s64)hctx->ccid3hctx_delta >= 1000)
+ return (u32)delay / 1000L;
- ccid3_hc_tx_update_win_count(hctx, &now);
+ ccid3_hc_tx_update_win_count(hctx, now);
break;
case TFRC_SSTATE_TERM:
DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
@@ -387,7 +380,8 @@ static int ccid3_hc_tx_send_packet(struc
hctx->ccid3hctx_idle = 0;
/* set the nominal send time for the next following packet */
- timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
+ hctx->ccid3hctx_t_nom = ktime_add_ns(hctx->ccid3hctx_t_nom,
+ hctx->ccid3hctx_t_ipi * 1000);
return 0;
}
-
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