[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 <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 234 insertions, 139 deletions

diff --git a/net/dccp/ccids/Makefile b/net/dccp/ccids/Makefile
index 1c720131c5db..323b68f3b607 100644
--- a/net/dccp/ccids/Makefile
+++ b/net/dccp/ccids/Makefile
@@ -1,3 +1,3 @@
 obj-$(CONFIG_IP_DCCP_CCID3) += dccp_ccid3.o
 
-dccp_ccid3-y := ccid3.o
+dccp_ccid3-y := ccid3.o lib/loss_interval.o
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index cfd11234d8f9..7468928b83c6 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -38,6 +38,7 @@
 #include "../ccid.h"
 #include "../dccp.h"
 #include "../packet_history.h"
+#include "lib/loss_interval.h"
 #include "ccid3.h"
 
 /*
@@ -62,30 +63,7 @@ static int ccid3_debug;
 
 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)
 {
@@ -1414,7 +1392,7 @@ trim_history:
          */
         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) {
@@ -1555,15 +1533,6 @@ static void ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
                            &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
@@ -1672,41 +1641,17 @@ static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
 {
         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;
-
-                        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);
-                        }
+        if (seq_loss != DCCP_MAX_SEQNO + 1 &&
+            list_empty(&hcrx->ccid3hcrx_li_hist)) {
+                struct dccp_li_hist_entry *li_tail;
 
-                        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 */
 }
@@ -1746,12 +1691,11 @@ static void ccid3_hc_rx_detect_loss(struct sock *sk)
         }
 
         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 "
@@ -1799,48 +1743,6 @@ 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)
 {
         struct dccp_sock *dp = dccp_sk(sk);
@@ -1939,9 +1841,9 @@ 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);
@@ -1971,7 +1873,7 @@ static int ccid3_hc_rx_init(struct sock *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
@@ -1996,7 +1898,7 @@ static void ccid3_hc_rx_exit(struct sock *sk)
         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;
@@ -2063,11 +1965,8 @@ static __init int ccid3_module_init(void)
         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);
@@ -2077,8 +1976,8 @@ out:
         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;
@@ -2110,9 +2009,9 @@ static __exit void ccid3_module_exit(void)
                 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);
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
index f8965700bbe9..f68d0b4e31e9 100644
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
@@ -59,8 +59,6 @@
 
 #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
 
@@ -119,13 +117,6 @@ struct ccid3_hc_tx_sock {
         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,
@@ -136,7 +127,7 @@ struct ccid3_hc_rx_sock {
         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;
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
new file mode 100644
index 000000000000..4c01a54143ad
--- /dev/null
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -0,0 +1,144 @@
+/*
+ *  net/dccp/ccids/lib/loss_interval.c
+ *
+ *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  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);
diff --git a/net/dccp/ccids/lib/loss_interval.h b/net/dccp/ccids/lib/loss_interval.h
new file mode 100644
index 000000000000..13ad47ba1420
--- /dev/null
+++ b/net/dccp/ccids/lib/loss_interval.h
@@ -0,0 +1,61 @@
+#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 <iam4@cs.waikato.ac.nz>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  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_ */