[TFRC]: Remove previous loss intervals implementation

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/ccids/lib/loss_interval.c

@@ -14,15 +14,6 @@
 #include <net/sock.h>
 #include "tfrc.h"
 
-#define DCCP_LI_HIST_IVAL_F_LENGTH  8
-
-struct dccp_li_hist_entry {
-	struct list_head dccplih_node;
-	u64		 dccplih_seqno:48,
-			 dccplih_win_count:4;
-	u32		 dccplih_interval;
-};
-
 static struct kmem_cache  *tfrc_lh_slab  __read_mostly;
 /* Loss Interval weights from [RFC 3448, 5.4], scaled by 10 */
 static const int tfrc_lh_weights[NINTERVAL] = { 10, 10, 10, 10, 8, 6, 4, 2 };
@@ -71,77 +62,6 @@ void tfrc_lh_cleanup(struct tfrc_loss_hist *lh)
 }
 EXPORT_SYMBOL_GPL(tfrc_lh_cleanup);
 
-static struct kmem_cache *dccp_li_cachep __read_mostly;
-
-static inline struct dccp_li_hist_entry *dccp_li_hist_entry_new(const gfp_t prio)
-{
-	return kmem_cache_alloc(dccp_li_cachep, prio);
-}
-
-static inline void dccp_li_hist_entry_delete(struct dccp_li_hist_entry *entry)
-{
-	if (entry != NULL)
-		kmem_cache_free(dccp_li_cachep, entry);
-}
-
-void dccp_li_hist_purge(struct list_head *list)
-{
-	struct dccp_li_hist_entry *entry, *next;
-
-	list_for_each_entry_safe(entry, next, list, dccplih_node) {
-		list_del_init(&entry->dccplih_node);
-		kmem_cache_free(dccp_li_cachep, entry);
-	}
-}
-
-EXPORT_SYMBOL_GPL(dccp_li_hist_purge);
-
-/* Weights used to calculate loss event rate */
-/*
- * These are integers as per section 8 of RFC3448. We can then divide by 4 *
- * when we use it.
- */
-static const int dccp_li_hist_w[DCCP_LI_HIST_IVAL_F_LENGTH] = {
-	4, 4, 4, 4, 3, 2, 1, 1,
-};
-
-u32 dccp_li_hist_calc_i_mean(struct list_head *list)
-{
-	struct dccp_li_hist_entry *li_entry, *li_next;
-	int i = 0;
-	u32 i_tot;
-	u32 i_tot0 = 0;
-	u32 i_tot1 = 0;
-	u32 w_tot  = 0;
-
-	list_for_each_entry_safe(li_entry, li_next, list, dccplih_node) {
-		if (li_entry->dccplih_interval != ~0U) {
-			i_tot0 += li_entry->dccplih_interval * dccp_li_hist_w[i];
-			w_tot  += dccp_li_hist_w[i];
-			if (i != 0)
-				i_tot1 += li_entry->dccplih_interval * dccp_li_hist_w[i - 1];
-		}
-
-
-		if (++i > DCCP_LI_HIST_IVAL_F_LENGTH)
-			break;
-	}
-
-	if (i != DCCP_LI_HIST_IVAL_F_LENGTH)
-		return 0;
-
-	i_tot = max(i_tot0, i_tot1);
-
-	if (!w_tot) {
-		DCCP_WARN("w_tot = 0\n");
-		return 1;
-	}
-
-	return i_tot / w_tot;
-}
-
-EXPORT_SYMBOL_GPL(dccp_li_hist_calc_i_mean);
-
 static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh)
 {
 	u32 i_i, i_tot0 = 0, i_tot1 = 0, w_tot = 0;
@@ -201,192 +121,6 @@ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
 }
 EXPORT_SYMBOL_GPL(tfrc_lh_update_i_mean);
 
-static int dccp_li_hist_interval_new(struct list_head *list,
-				     const u64 seq_loss, const u8 win_loss)
-{
-	struct dccp_li_hist_entry *entry;
-	int i;
-
-	for (i = 0; i < DCCP_LI_HIST_IVAL_F_LENGTH; i++) {
-		entry = dccp_li_hist_entry_new(GFP_ATOMIC);
-		if (entry == NULL) {
-			dccp_li_hist_purge(list);
-			DCCP_BUG("loss interval list entry is NULL");
-			return 0;
-		}
-		entry->dccplih_interval = ~0;
-		list_add(&entry->dccplih_node, list);
-	}
-
-	entry->dccplih_seqno     = seq_loss;
-	entry->dccplih_win_count = win_loss;
-	return 1;
-}
-
-/* calculate first loss interval
- *
- * returns estimated loss interval in usecs */
-static u32 dccp_li_calc_first_li(struct sock *sk,
-				 struct list_head *hist_list,
-				 ktime_t last_feedback,
-				 u16 s, u32 bytes_recv,
-				 u32 previous_x_recv)
-{
-/*
- * FIXME:
- * Will be rewritten in the upcoming new loss intervals code.
- * Has to be commented ou because it relies on the old rx history
- * data structures
- */
-#if 0
-	struct tfrc_rx_hist_entry *entry, *next, *tail = NULL;
-	u32 x_recv, p;
-	suseconds_t rtt, delta;
-	ktime_t tstamp = ktime_set(0, 0);
-	int interval = 0;
-	int win_count = 0;
-	int step = 0;
-	u64 fval;
-
-	list_for_each_entry_safe(entry, next, hist_list, tfrchrx_node) {
-		if (tfrc_rx_hist_entry_data_packet(entry)) {
-			tail = entry;
-
-			switch (step) {
-			case 0:
-				tstamp	  = entry->tfrchrx_tstamp;
-				win_count = entry->tfrchrx_ccval;
-				step = 1;
-				break;
-			case 1:
-				interval = win_count - entry->tfrchrx_ccval;
-				if (interval < 0)
-					interval += TFRC_WIN_COUNT_LIMIT;
-				if (interval > 4)
-					goto found;
-				break;
-			}
-		}
-	}
-
-	if (unlikely(step == 0)) {
-		DCCP_WARN("%s(%p), packet history has no data packets!\n",
-			  dccp_role(sk), sk);
-		return ~0;
-	}
-
-	if (unlikely(interval == 0)) {
-		DCCP_WARN("%s(%p), Could not find a win_count interval > 0. "
-			  "Defaulting to 1\n", dccp_role(sk), sk);
-		interval = 1;
-	}
-found:
-	if (!tail) {
-		DCCP_CRIT("tail is null\n");
-		return ~0;
-	}
-
-	delta = ktime_us_delta(tstamp, tail->tfrchrx_tstamp);
-	DCCP_BUG_ON(delta < 0);
-
-	rtt = delta * 4 / interval;
-	dccp_pr_debug("%s(%p), approximated RTT to %dus\n",
-		      dccp_role(sk), sk, (int)rtt);
-
-	/*
-	 * Determine the length of the first loss interval via inverse lookup.
-	 * Assume that X_recv can be computed by the throughput equation
-	 *		    s
-	 *	X_recv = --------
-	 *		 R * fval
-	 * Find some p such that f(p) = fval; return 1/p [RFC 3448, 6.3.1].
-	 */
-	if (rtt == 0) {			/* would result in divide-by-zero */
-		DCCP_WARN("RTT==0\n");
-		return ~0;
-	}
-
-	delta = ktime_us_delta(ktime_get_real(), last_feedback);
-	DCCP_BUG_ON(delta <= 0);
-
-	x_recv = scaled_div32(bytes_recv, delta);
-	if (x_recv == 0) {		/* would also trigger divide-by-zero */
-		DCCP_WARN("X_recv==0\n");
-		if (previous_x_recv == 0) {
-			DCCP_BUG("stored value of X_recv is zero");
-			return ~0;
-		}
-		x_recv = previous_x_recv;
-	}
-
-	fval = scaled_div(s, rtt);
-	fval = scaled_div32(fval, x_recv);
-	p = tfrc_calc_x_reverse_lookup(fval);
-
-	dccp_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
-		      "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
-
-	if (p != 0)
-		return 1000000 / p;
-#endif
-	return ~0;
-}
-
-void dccp_li_update_li(struct sock *sk,
-		       struct list_head *li_hist_list,
-		       struct list_head *hist_list,
-		       ktime_t last_feedback, u16 s, u32 bytes_recv,
-		       u32 previous_x_recv, u64 seq_loss, u8 win_loss)
-{
-	struct dccp_li_hist_entry *head;
-	u64 seq_temp;
-
-	if (list_empty(li_hist_list)) {
-		if (!dccp_li_hist_interval_new(li_hist_list, seq_loss,
-					       win_loss))
-			return;
-
-		head = list_entry(li_hist_list->next, struct dccp_li_hist_entry,
-				  dccplih_node);
-		head->dccplih_interval = dccp_li_calc_first_li(sk, hist_list,
-							       last_feedback,
-							       s, bytes_recv,
-							       previous_x_recv);
-	} else {
-		struct dccp_li_hist_entry *entry;
-		struct list_head *tail;
-
-		head = list_entry(li_hist_list->next, struct dccp_li_hist_entry,
-				  dccplih_node);
-		/* FIXME win count check removed as was wrong */
-		/* should make this check with receive history */
-		/* and compare there as per section 10.2 of RFC4342 */
-
-		/* new loss event detected */
-		/* calculate last interval length */
-		seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss);
-		entry = dccp_li_hist_entry_new(GFP_ATOMIC);
-
-		if (entry == NULL) {
-			DCCP_BUG("out of memory - can not allocate entry");
-			return;
-		}
-
-		list_add(&entry->dccplih_node, li_hist_list);
-
-		tail = li_hist_list->prev;
-		list_del(tail);
-		kmem_cache_free(dccp_li_cachep, tail);
-
-		/* Create the newest interval */
-		entry->dccplih_seqno = seq_loss;
-		entry->dccplih_interval = seq_temp;
-		entry->dccplih_win_count = win_loss;
-	}
-}
-
-EXPORT_SYMBOL_GPL(dccp_li_update_li);
-
 /* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */
 static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,
 				     struct tfrc_rx_hist_entry *new_loss)

net/dccp/ccids/lib/loss_interval.h

@@ -65,19 +65,11 @@ static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
 	return min(lh->counter, (u8)LIH_SIZE);
 }
 
-extern void dccp_li_hist_purge(struct list_head *list);
 struct tfrc_rx_hist;
+
 extern int  tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
 				 u32 (*first_li)(struct sock *), struct sock *);
 extern u8   tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
 extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
 
-extern u32 dccp_li_hist_calc_i_mean(struct list_head *list);
-
-extern void dccp_li_update_li(struct sock *sk,
-			      struct list_head *li_hist_list,
-			      struct list_head *hist_list,
-			      ktime_t last_feedback, u16 s,
-			      u32 bytes_recv, u32 previous_x_recv,
-			      u64 seq_loss, u8 win_loss);
 #endif /* _DCCP_LI_HIST_ */