[CCID3]: Perform history operations only after packet has been sent
This migrates all packet history operations into the routine
ccid3_hc_tx_packet_sent, thereby removing synchronization problems
that occur when, as before, the operations are spread over multiple
routines.
The following minor simplifications are also applied:
* several simplifications now follow from this change - several tests
are now no longer required
* removal of one unnecessary variable (dp)
Justification:
--------------
Currently packet history operations span two different routines,
one of which is likely to pass through several iterations of sleeping
and awakening.
The first routine, ccid3_hc_tx_send_packet, allocates an entry and
sets a few fields. The remaining fields are filled in when the second
routine (which is not within a sleeping context), ccid3_hc_tx_packet_sent,
is called. This has several strong drawbacks:
* it is not necessary to split history operations - all fields can be
filled in by the second routine
* the first routine is called multiple times, until a packet can be sent,
and sleeps meanwhile - this causes a lot of difficulties with regard to
keeping the list consistent
* since both routines do not have a producer-consumer like synchronization,
it is very difficult to maintain data across calls to these routines
* the fact that the routines are called in different contexts (sleeping, not
sleeping) adds further problems
Signed-off-by: Gerrit Renker <[EMAIL PROTECTED]>
---
net/dccp/ccids/ccid3.c | 38 +++++++++-----------------------------
1 file changed, 9 insertions(+), 29 deletions(-)
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -296,7 +296,6 @@ 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 dccp_tx_hist_entry *new_packet;
struct timeval now;
suseconds_t delay;
@@ -310,21 +309,6 @@ static int ccid3_hc_tx_send_packet(struc
if (unlikely(skb->len == 0))
return -EBADMSG;
- /* See if last packet allocated was not sent */
- new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
- if (new_packet == NULL || new_packet->dccphtx_sent) {
- new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
- SLAB_ATOMIC);
-
- if (unlikely(new_packet == NULL)) {
- DCCP_WARN("%s, sk=%p, not enough mem to add to history,"
- "send refused\n", dccp_role(sk), sk);
- return -ENOBUFS;
- }
-
- dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
- }
-
dccp_timestamp(sk, &now);
switch (hctx->ccid3hctx_state) {
@@ -380,31 +364,27 @@ static int ccid3_hc_tx_send_packet(struc
static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, unsigned int
len)
{
- const struct dccp_sock *dp = dccp_sk(sk);
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
struct timeval now;
struct dccp_tx_hist_entry *packet;
BUG_ON(hctx == NULL);
- dccp_timestamp(sk, &now);
-
ccid3_hc_tx_update_s(hctx, len);
- packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
+ packet = dccp_tx_hist_entry_new(ccid3_tx_hist, SLAB_ATOMIC);
if (unlikely(packet == NULL)) {
- DCCP_WARN("packet doesn't exist in history!\n");
- return;
- }
- if (unlikely(packet->dccphtx_sent)) {
- DCCP_WARN("no unsent packet in history!\n");
+ DCCP_CRIT("packet history - out of memory!");
return;
}
+ dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
+
+ dccp_timestamp(sk, &now);
packet->dccphtx_tstamp = now;
- packet->dccphtx_seqno = dp->dccps_gss;
- hctx->ccid3hctx_idle = 0;
- packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
- packet->dccphtx_sent = 1;
+ packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
+ packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
+ packet->dccphtx_sent = 1;
+ hctx->ccid3hctx_idle = 0;
}
static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
-
To unsubscribe from this list: send the line "unsubscribe dccp" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
