[CCID3]: Move the loss interval code to loss_interval.[ch]

And put this into net/dccp/ccids/lib/, where packet_history.[ch] will also be
moved and then we'll have a tfrc_lib.ko module that will be used by
dccp_ccid3.ko and other CCIDs that are variations of TFRC (RFC 3448).

Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/dccp/ccids/Makefile

···
 obj-$(CONFIG_IP_DCCP_CCID3) += dccp_ccid3.o
 
-dccp_ccid3-y := ccid3.o
+dccp_ccid3-y := ccid3.o lib/loss_interval.o

net/dccp/ccids/ccid3.c

···
 #include "../ccid.h"
 #include "../dccp.h"
 #include "../packet_history.h"
+#include "lib/loss_interval.h"
 #include "ccid3.h"
 
 /*
···
 
 static struct dccp_tx_hist *ccid3_tx_hist;
 static struct dccp_rx_hist *ccid3_rx_hist;
-
-static kmem_cache_t *ccid3_loss_interval_hist_slab __read_mostly;
-
-static inline struct ccid3_loss_interval_hist_entry *
-	ccid3_loss_interval_hist_entry_new(const unsigned int __nocast prio)
-{
-	return kmem_cache_alloc(ccid3_loss_interval_hist_slab, prio);
-}
-
-static inline void ccid3_loss_interval_hist_entry_delete(struct ccid3_loss_interval_hist_entry *entry)
-{
-	if (entry != NULL)
-		kmem_cache_free(ccid3_loss_interval_hist_slab, entry);
-}
-
-static void ccid3_loss_interval_history_delete(struct list_head *hist)
-{
-	struct ccid3_loss_interval_hist_entry *entry, *next;
-
-	list_for_each_entry_safe(entry, next, hist, ccid3lih_node) {
-		list_del_init(&entry->ccid3lih_node);
-		kmem_cache_free(ccid3_loss_interval_hist_slab, entry);
-	}
-}
+static struct dccp_li_hist *ccid3_li_hist;
 
 static int ccid3_init(struct sock *sk)
 {
···
 	 */
 	num_later = TFRC_RECV_NUM_LATE_LOSS + 1;
 
-	if (!list_empty(&hcrx->ccid3hcrx_loss_interval_hist)) {
+	if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
 		list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
 					 dccphrx_node) {
 			if (num_later == 0) {
···
 			   &x_recv, sizeof(x_recv));
 }
 
-/* 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 ccid3_hc_rx_w[TFRC_RECV_IVAL_F_LENGTH] = {
-	4, 4, 4, 4, 3, 2, 1, 1,
-};
-
 /*
  * args: fvalue - function value to match
  * returns:  p  closest to that value
···
 {
 	struct dccp_sock *dp = dccp_sk(sk);
 	struct ccid3_hc_rx_sock *hcrx = dp->dccps_hc_rx_ccid_private;
-	struct ccid3_loss_interval_hist_entry *li_entry;
 
-	if (seq_loss != DCCP_MAX_SEQNO + 1) {
-		ccid3_pr_debug("%s, sk=%p, seq_loss=%llu, win_loss=%u, "
-			       "packet loss detected\n",
-			       dccp_role(sk), sk, seq_loss, win_loss);
-		
-		if (list_empty(&hcrx->ccid3hcrx_loss_interval_hist)) {
-			struct ccid3_loss_interval_hist_entry *li_tail = NULL;
-			int i;
+	if (seq_loss != DCCP_MAX_SEQNO + 1 &&
+	    list_empty(&hcrx->ccid3hcrx_li_hist)) {
+		struct dccp_li_hist_entry *li_tail;
 
-			ccid3_pr_debug("%s, sk=%p, first loss event detected, "
-				       "creating history\n",
-				       dccp_role(sk), sk);
-			for (i = 0; i <= TFRC_RECV_IVAL_F_LENGTH; ++i) {
-				li_entry = ccid3_loss_interval_hist_entry_new(SLAB_ATOMIC);
-				if (li_entry == NULL) {
-					ccid3_loss_interval_history_delete(&hcrx->ccid3hcrx_loss_interval_hist);
-					ccid3_pr_debug("%s, sk=%p, not enough "
-						       "mem for creating "
-						       "history\n",
-						       dccp_role(sk), sk);
-					return;
-				}
-				if (li_tail == NULL)
-					li_tail = li_entry;
-				list_add(&li_entry->ccid3lih_node,
-					 &hcrx->ccid3hcrx_loss_interval_hist);
-			}
-
-			li_entry->ccid3lih_seqno     = seq_loss;
-			li_entry->ccid3lih_win_count = win_loss;
-
-			li_tail->ccid3lih_interval   = ccid3_hc_rx_calc_first_li(sk);
-		}
+		li_tail = dccp_li_hist_interval_new(ccid3_li_hist,
+						    &hcrx->ccid3hcrx_li_hist,
+						    seq_loss, win_loss);
+		if (li_tail == NULL)
+			return;
+		li_tail->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
 	}
 	/* FIXME: find end of interval */
 }
···
 	}
 
 	if (a_loss == NULL) {
-		if (list_empty(&hcrx->ccid3hcrx_loss_interval_hist)) {
+		if (list_empty(&hcrx->ccid3hcrx_li_hist)) {
 			/* no loss event have occured yet */
-			ccid3_pr_debug("%s, sk=%p, TODO: find a lost data "
-					"packet by comparing to initial "
-					"seqno\n",
-				       dccp_role(sk), sk);
+			LIMIT_NETDEBUG("%s: TODO: find a lost data packet by "
+				       "comparing to initial seqno\n",
+				       dccp_role(sk));
 			goto out_update_li;
 		} else {
 			pr_info("%s: %s, sk=%p, ERROR! Less than 4 data "
···
 
 out_update_li:
 	ccid3_hc_rx_update_li(sk, seq_loss, win_loss);
-}
-
-static u32 ccid3_hc_rx_calc_i_mean(struct sock *sk)
-{
-	struct dccp_sock *dp = dccp_sk(sk);
-	struct ccid3_hc_rx_sock *hcrx = dp->dccps_hc_rx_ccid_private;
-	struct ccid3_loss_interval_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,
-				 &hcrx->ccid3hcrx_loss_interval_hist,
-				 ccid3lih_node) {
-		if (i < TFRC_RECV_IVAL_F_LENGTH) {
-			i_tot0 += li_entry->ccid3lih_interval * ccid3_hc_rx_w[i];
-			w_tot  += ccid3_hc_rx_w[i];
-		}
-
-		if (i != 0)
-			i_tot1 += li_entry->ccid3lih_interval * ccid3_hc_rx_w[i - 1];
-
-		if (++i > TFRC_RECV_IVAL_F_LENGTH)
-			break;
-	}
-
-	if (i != TFRC_RECV_IVAL_F_LENGTH) {
-		pr_info("%s: %s, sk=%p, ERROR! Missing entry in "
-			"interval history!\n",
-			__FUNCTION__, dccp_role(sk), sk);
-		return 0;
-	}
-
-	i_tot = max(i_tot0, i_tot1);
-
-	/* FIXME: Why do we do this? -Ian McDonald */
-	if (i_tot * 4 < w_tot)
-		i_tot = w_tot * 4;
-
-	return i_tot * 4 / w_tot;
 }
 
 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
···
 	p_prev = hcrx->ccid3hcrx_p;
 	
 	/* Calculate loss event rate */
-	if (!list_empty(&hcrx->ccid3hcrx_loss_interval_hist))
+	if (!list_empty(&hcrx->ccid3hcrx_li_hist))
 		/* Scaling up by 1000000 as fixed decimal */
-		hcrx->ccid3hcrx_p = 1000000 / ccid3_hc_rx_calc_i_mean(sk);
+		hcrx->ccid3hcrx_p = 1000000 / dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
 
 	if (hcrx->ccid3hcrx_p > p_prev) {
 		ccid3_hc_rx_send_feedback(sk);
···
 
 	hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
 	INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
-	INIT_LIST_HEAD(&hcrx->ccid3hcrx_loss_interval_hist);
+	INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
 	/*
 	 * XXX this seems to be paranoid, need to think more about this, for
 	 * now start with something different than zero. -acme
···
 	dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
 
 	/* Empty loss interval history */
-	ccid3_loss_interval_history_delete(&hcrx->ccid3hcrx_loss_interval_hist);
+	dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
 
 	kfree(dp->dccps_hc_rx_ccid_private);
 	dp->dccps_hc_rx_ccid_private = NULL;
···
 	if (ccid3_tx_hist == NULL)
 		goto out_free_rx;
 
-	ccid3_loss_interval_hist_slab = kmem_cache_create("li_hist_ccid3",
-				  sizeof(struct ccid3_loss_interval_hist_entry),
-							  0, SLAB_HWCACHE_ALIGN,
-							  NULL, NULL);
-	if (ccid3_loss_interval_hist_slab == NULL)
+	ccid3_li_hist = dccp_li_hist_new("ccid3");
+	if (ccid3_li_hist == NULL)
 		goto out_free_tx;
 
 	rc = ccid_register(&ccid3);
···
 	return rc;
 
 out_free_loss_interval_history:
-	kmem_cache_destroy(ccid3_loss_interval_hist_slab);
-	ccid3_loss_interval_hist_slab = NULL;
+	dccp_li_hist_delete(ccid3_li_hist);
+	ccid3_li_hist = NULL;
 out_free_tx:
 	dccp_tx_hist_delete(ccid3_tx_hist);
 	ccid3_tx_hist = NULL;
···
 		dccp_rx_hist_delete(ccid3_rx_hist);
 		ccid3_rx_hist = NULL;
 	}
-	if (ccid3_loss_interval_hist_slab != NULL) {
-		kmem_cache_destroy(ccid3_loss_interval_hist_slab);
-		ccid3_loss_interval_hist_slab = NULL;
+	if (ccid3_li_hist != NULL) {
+		dccp_li_hist_delete(ccid3_li_hist);
+		ccid3_li_hist = NULL;
 	}
 }
 module_exit(ccid3_module_exit);

net/dccp/ccids/ccid3.h

···
 
 #define TFRC_SMALLEST_P		   40
 
-#define TFRC_RECV_IVAL_F_LENGTH	    8
-
 /* Number of later packets received before one is considered lost */
 #define TFRC_RECV_NUM_LATE_LOSS	3
 
···
 	struct ccid3_options_received	ccid3hctx_options_received;
 };
 
-struct ccid3_loss_interval_hist_entry {
-	struct list_head	ccid3lih_node;
-	u64			ccid3lih_seqno:48,
-				ccid3lih_win_count:4;
-	u32			ccid3lih_interval;
-};
-
 struct ccid3_hc_rx_sock {
   	u64			ccid3hcrx_seqno_last_counter:48,
 				ccid3hcrx_state:8,
···
   	struct timeval		ccid3hcrx_tstamp_last_feedback;
   	struct timeval		ccid3hcrx_tstamp_last_ack;
 	struct list_head	ccid3hcrx_hist;
-	struct list_head	ccid3hcrx_loss_interval_hist;
+	struct list_head	ccid3hcrx_li_hist;
   	u16			ccid3hcrx_s;
   	u32			ccid3hcrx_pinv;
   	u32			ccid3hcrx_elapsed_time;

net/dccp/ccids/lib/loss_interval.c

···
+/*
+ *  net/dccp/ccids/lib/loss_interval.c
+ *
+ *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005 Ian McDonald <[e-mail]>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <[e-mail]>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+
+#include "loss_interval.h"
+
+struct dccp_li_hist *dccp_li_hist_new(const char *name)
+{
+	struct dccp_li_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);
+	static const char dccp_li_hist_mask[] = "li_hist_%s";
+	char *slab_name;
+
+	if (hist == NULL)
+		goto out;
+
+	slab_name = kmalloc(strlen(name) + sizeof(dccp_li_hist_mask) - 1,
+			    GFP_ATOMIC);
+	if (slab_name == NULL)
+		goto out_free_hist;
+
+	sprintf(slab_name, dccp_li_hist_mask, name);
+	hist->dccplih_slab = kmem_cache_create(slab_name,
+					     sizeof(struct dccp_li_hist_entry),
+					       0, SLAB_HWCACHE_ALIGN,
+					       NULL, NULL);
+	if (hist->dccplih_slab == NULL)
+		goto out_free_slab_name;
+out:
+	return hist;
+out_free_slab_name:
+	kfree(slab_name);
+out_free_hist:
+	kfree(hist);
+	hist = NULL;
+	goto out;
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_new);
+
+void dccp_li_hist_delete(struct dccp_li_hist *hist)
+{
+	const char* name = kmem_cache_name(hist->dccplih_slab);
+
+	kmem_cache_destroy(hist->dccplih_slab);
+	kfree(name);
+	kfree(hist);
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_delete);
+
+void dccp_li_hist_purge(struct dccp_li_hist *hist, 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(hist->dccplih_slab, 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 (i < DCCP_LI_HIST_IVAL_F_LENGTH) {
+			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);
+
+	/* FIXME: Why do we do this? -Ian McDonald */
+	if (i_tot * 4 < w_tot)
+		i_tot = w_tot * 4;
+
+	return i_tot * 4 / w_tot;
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_calc_i_mean);
+
+struct dccp_li_hist_entry *dccp_li_hist_interval_new(struct dccp_li_hist *hist,
+						     struct list_head *list,
+						     const u64 seq_loss,
+						     const u8 win_loss)
+{
+	struct dccp_li_hist_entry *tail = NULL, *entry;
+	int i;
+
+	for (i = 0; i <= DCCP_LI_HIST_IVAL_F_LENGTH; ++i) {
+		entry = dccp_li_hist_entry_new(hist, SLAB_ATOMIC);
+		if (entry == NULL) {
+			dccp_li_hist_purge(hist, list);
+			return NULL;
+		}
+		if (tail == NULL)
+			tail = entry;
+		list_add(&entry->dccplih_node, list);
+	}
+
+	entry->dccplih_seqno     = seq_loss;
+	entry->dccplih_win_count = win_loss;
+	return tail;
+}
+
+EXPORT_SYMBOL_GPL(dccp_li_hist_interval_new);

net/dccp/ccids/lib/loss_interval.h

···
+#ifndef _DCCP_LI_HIST_
+#define _DCCP_LI_HIST_
+/*
+ *  net/dccp/ccids/lib/loss_interval.h
+ *
+ *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005 Ian McDonald <[e-mail]>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <[e-mail]>
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the Free
+ *  Software Foundation; either version 2 of the License, or (at your option)
+ *  any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+
+#define DCCP_LI_HIST_IVAL_F_LENGTH  8
+
+struct dccp_li_hist {
+	kmem_cache_t *dccplih_slab;
+};
+
+extern struct dccp_li_hist *dccp_li_hist_new(const char *name);
+extern void dccp_li_hist_delete(struct dccp_li_hist *hist);
+
+struct dccp_li_hist_entry {
+	struct list_head dccplih_node;
+	u64		 dccplih_seqno:48,
+			 dccplih_win_count:4;
+	u32		 dccplih_interval;
+};
+
+static inline struct dccp_li_hist_entry *
+		dccp_li_hist_entry_new(struct dccp_li_hist *hist,
+				       const unsigned int __nocast prio)
+{
+	return kmem_cache_alloc(hist->dccplih_slab, prio);
+}
+
+static inline void dccp_li_hist_entry_delete(struct dccp_li_hist *hist,
+					     struct dccp_li_hist_entry *entry)
+{
+	if (entry != NULL)
+		kmem_cache_free(hist->dccplih_slab, entry);
+}
+
+extern void dccp_li_hist_purge(struct dccp_li_hist *hist,
+			       struct list_head *list);
+
+extern u32 dccp_li_hist_calc_i_mean(struct list_head *list);
+
+extern struct dccp_li_hist_entry *
+			dccp_li_hist_interval_new(struct dccp_li_hist *hist,
+						  struct list_head *list,
+						  const u64 seq_loss,
+						  const u8 win_loss);
+#endif /* _DCCP_LI_HIST_ */