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authorDavid Howells <dhowells@redhat.com>2016-09-22 02:29:31 +0300
committerDavid Howells <dhowells@redhat.com>2016-09-22 10:21:24 +0300
commit50235c4b5a2fb9a9690f02cd1dea6ca047d7f79e (patch)
tree3dc5a178820b16d5eaef0484fe7751cb4f71375e /net/rxrpc/call_event.c
parent77f2efcbdd7133466060198e02c6e8a170c3cd14 (diff)
downloadlinux-50235c4b5a2fb9a9690f02cd1dea6ca047d7f79e.tar.xz
rxrpc: Obtain RTT data by requesting ACKs on DATA packets
In addition to sending a PING ACK to gain RTT data, we can set the RXRPC_REQUEST_ACK flag on a DATA packet and get a REQUESTED-ACK ACK. The ACK packet contains the serial number of the packet it is in response to, so we can look through the Tx buffer for a matching DATA packet. This requires that the data packets be stamped with the time of transmission as a ktime rather than having the resend_at time in jiffies. This further requires the resend code to do the resend determination in ktimes and convert to jiffies to set the timer. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'net/rxrpc/call_event.c')
-rw-r--r--net/rxrpc/call_event.c19
1 files changed, 9 insertions, 10 deletions
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 34ad967f2d81..adb2ec61e21f 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -142,12 +142,14 @@ static void rxrpc_resend(struct rxrpc_call *call)
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
rxrpc_seq_t cursor, seq, top;
- unsigned long resend_at, now;
+ ktime_t now = ktime_get_real(), max_age, oldest, resend_at;
int ix;
u8 annotation, anno_type;
_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
+ max_age = ktime_sub_ms(now, rxrpc_resend_timeout);
+
spin_lock_bh(&call->lock);
cursor = call->tx_hard_ack;
@@ -160,8 +162,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
* the packets in the Tx buffer we're going to resend and what the new
* resend timeout will be.
*/
- now = jiffies;
- resend_at = now + rxrpc_resend_timeout;
+ oldest = now;
for (seq = cursor + 1; before_eq(seq, top); seq++) {
ix = seq & RXRPC_RXTX_BUFF_MASK;
annotation = call->rxtx_annotations[ix];
@@ -175,9 +176,9 @@ static void rxrpc_resend(struct rxrpc_call *call)
sp = rxrpc_skb(skb);
if (anno_type == RXRPC_TX_ANNO_UNACK) {
- if (time_after(sp->resend_at, now)) {
- if (time_before(sp->resend_at, resend_at))
- resend_at = sp->resend_at;
+ if (ktime_after(skb->tstamp, max_age)) {
+ if (ktime_before(skb->tstamp, oldest))
+ oldest = skb->tstamp;
continue;
}
}
@@ -186,7 +187,8 @@ static void rxrpc_resend(struct rxrpc_call *call)
call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
}
- call->resend_at = resend_at;
+ resend_at = ktime_sub(ktime_add_ns(oldest, rxrpc_resend_timeout), now);
+ call->resend_at = jiffies + nsecs_to_jiffies(ktime_to_ns(resend_at));
/* Now go through the Tx window and perform the retransmissions. We
* have to drop the lock for each send. If an ACK comes in whilst the
@@ -205,15 +207,12 @@ static void rxrpc_resend(struct rxrpc_call *call)
spin_unlock_bh(&call->lock);
if (rxrpc_send_data_packet(call, skb) < 0) {
- call->resend_at = now + 2;
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
return;
}
if (rxrpc_is_client_call(call))
rxrpc_expose_client_call(call);
- sp = rxrpc_skb(skb);
- sp->resend_at = now + rxrpc_resend_timeout;
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
spin_lock_bh(&call->lock);