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dccp tfrc: Receiver history initialisation routine 

This patch 
 1) separates history allocation and initialisation, to facilitate early
    loss detection (implemented by a subsequent patch);

 2) removes duplication by using the existing tfrc_rx_hist_purge() if the
    allocation fails. This is now possible, since the initialisation routine
 3) zeroes out the entire history before using it. 

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This commit is contained in:
Gerrit Renker 2008-09-04 07:30:19 +02:00
parent 8b67ad12b0
commit 24b8d34321
3 changed files with 32 additions and 24 deletions
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2
net/dccp/ccids/ccid3.c
View File

@ -766,7 +766,7 @@ static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
hcrx->state = TFRC_RSTATE_NO_DATA;
tfrc_lh_init(&hcrx->li_hist);
return tfrc_rx_hist_alloc(&hcrx->hist);
return tfrc_rx_hist_init(&hcrx->hist, sk);
}
static void ccid3_hc_rx_exit(struct sock *sk)

52
net/dccp/ccids/lib/packet_history.c
View File

@ -352,28 +352,6 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
}
EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss);
int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
{
int i;
for (i = 0; i <= TFRC_NDUPACK; i++) {
h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC);
if (h->ring[i] == NULL)
goto out_free;
}
h->loss_count = h->loss_start = 0;
return 0;
out_free:
while (i-- != 0) {
kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
h->ring[i] = NULL;
}
return -ENOBUFS;
}
EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc);
void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
{
int i;
@ -386,6 +364,36 @@ void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
}
EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);
static int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
{
int i;
memset(h, 0, sizeof(*h));
for (i = 0; i <= TFRC_NDUPACK; i++) {
h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC);
if (h->ring[i] == NULL) {
tfrc_rx_hist_purge(h);
return -ENOBUFS;
}
}
return 0;
}
int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk)
{
if (tfrc_rx_hist_alloc(h))
return -ENOBUFS;
/*
* Initialise first entry with GSR to start loss detection as early as
* possible. Code using this must not use any other fields. The entry
* will be overwritten once the CCID updates its received packets.
*/
tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno = dccp_sk(sk)->dccps_gsr;
return 0;
}
EXPORT_SYMBOL_GPL(tfrc_rx_hist_init);
/**
* tfrc_rx_hist_rtt_last_s - reference entry to compute RTT samples against
*/

2
net/dccp/ccids/lib/packet_history.h
View File

@ -153,7 +153,7 @@ extern int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
struct sock *sk);
extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h,
const struct sk_buff *skb);
extern int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h);
extern int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk);
extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
#endif /* _DCCP_PKT_HIST_ */