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Commit 24b8d343 authored by Gerrit Renker's avatar Gerrit Renker
Browse files

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: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
parent 8b67ad12

net/dccp/ccids/ccid3.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

net/dccp/ccids/lib/packet_history.c

+30 −22
Original line number Diff line number Diff line
@@ -352,39 +352,47 @@ 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)

void tfrc_rx_hist_purge(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) {

	for (i = 0; i <= TFRC_NDUPACK; ++i)

		if (h->ring[i] != NULL) {

			kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);

			h->ring[i] = NULL;

		}

	return -ENOBUFS;

}

EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc);

EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);



void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)

static int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)

{

	int i;



	for (i = 0; i <= TFRC_NDUPACK; ++i)

		if (h->ring[i] != NULL) {

			kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);

			h->ring[i] = NULL;

	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;

		}

	}

EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);

	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

net/dccp/ccids/lib/packet_history.h

+1 −1
Original line number Diff line number Diff line
@@ -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_ */