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-rw-r--r--net/dccp/ccids/lib/Makefile3
-rw-r--r--net/dccp/ccids/lib/loss_interval.c19
-rw-r--r--net/dccp/ccids/lib/loss_interval.h10
-rw-r--r--net/dccp/ccids/lib/packet_history.c55
-rw-r--r--net/dccp/ccids/lib/packet_history.h48
-rw-r--r--net/dccp/ccids/lib/tfrc.c22
-rw-r--r--net/dccp/ccids/lib/tfrc.h34
-rw-r--r--net/dccp/ccids/lib/tfrc_equation.c42
8 files changed, 98 insertions, 135 deletions
diff --git a/net/dccp/ccids/lib/Makefile b/net/dccp/ccids/lib/Makefile
deleted file mode 100644
index 68c93e3d89d..00000000000
--- a/net/dccp/ccids/lib/Makefile
+++ /dev/null
@@ -1,3 +0,0 @@
-obj-$(CONFIG_IP_DCCP_TFRC_LIB) += dccp_tfrc_lib.o
-
-dccp_tfrc_lib-y := tfrc.o tfrc_equation.o packet_history.o loss_interval.o
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index bcd6ac415bb..57f9fd78c4d 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -1,6 +1,4 @@
/*
- * net/dccp/ccids/lib/loss_interval.c
- *
* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
* Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
* Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
@@ -21,7 +19,7 @@ static const int tfrc_lh_weights[NINTERVAL] = { 10, 10, 10, 10, 8, 6, 4, 2 };
/* implements LIFO semantics on the array */
static inline u8 LIH_INDEX(const u8 ctr)
{
- return (LIH_SIZE - 1 - (ctr % LIH_SIZE));
+ return LIH_SIZE - 1 - (ctr % LIH_SIZE);
}
/* the `counter' index always points at the next entry to be populated */
@@ -60,14 +58,16 @@ void tfrc_lh_cleanup(struct tfrc_loss_hist *lh)
lh->ring[LIH_INDEX(lh->counter)] = NULL;
}
}
-EXPORT_SYMBOL_GPL(tfrc_lh_cleanup);
static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh)
{
u32 i_i, i_tot0 = 0, i_tot1 = 0, w_tot = 0;
int i, k = tfrc_lh_length(lh) - 1; /* k is as in rfc3448bis, 5.4 */
- for (i=0; i <= k; i++) {
+ if (k <= 0)
+ return;
+
+ for (i = 0; i <= k; i++) {
i_i = tfrc_lh_get_interval(lh, i);
if (i < k) {
@@ -78,7 +78,6 @@ static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh)
i_tot1 += i_i * tfrc_lh_weights[i-1];
}
- BUG_ON(w_tot == 0);
lh->i_mean = max(i_tot0, i_tot1) / w_tot;
}
@@ -117,9 +116,8 @@ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
cur->li_length = len;
tfrc_lh_calc_i_mean(lh);
- return (lh->i_mean < old_i_mean);
+ return lh->i_mean < old_i_mean;
}
-EXPORT_SYMBOL_GPL(tfrc_lh_update_i_mean);
/* 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,
@@ -129,11 +127,13 @@ static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,
(cur->li_is_closed || SUB16(new_loss->tfrchrx_ccval, cur->li_ccval) > 4);
}
-/** tfrc_lh_interval_add - Insert new record into the Loss Interval database
+/**
+ * tfrc_lh_interval_add - Insert new record into the Loss Interval database
* @lh: Loss Interval database
* @rh: Receive history containing a fresh loss event
* @calc_first_li: Caller-dependent routine to compute length of first interval
* @sk: Used by @calc_first_li in caller-specific way (subtyping)
+ *
* Updates I_mean and returns 1 if a new interval has in fact been added to @lh.
*/
int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
@@ -167,7 +167,6 @@ int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
}
return 1;
}
-EXPORT_SYMBOL_GPL(tfrc_lh_interval_add);
int __init tfrc_li_init(void)
{
diff --git a/net/dccp/ccids/lib/loss_interval.h b/net/dccp/ccids/lib/loss_interval.h
index 246018a3b26..57f631a86cc 100644
--- a/net/dccp/ccids/lib/loss_interval.h
+++ b/net/dccp/ccids/lib/loss_interval.h
@@ -1,8 +1,6 @@
#ifndef _DCCP_LI_HIST_
#define _DCCP_LI_HIST_
/*
- * net/dccp/ccids/lib/loss_interval.h
- *
* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
* Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
* Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
@@ -67,9 +65,9 @@ static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
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);
+int tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
+ u32 (*first_li)(struct sock *), struct sock *);
+u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
+void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
#endif /* _DCCP_LI_HIST_ */
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 6cc108afdc3..08df7a3acb3 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -1,6 +1,4 @@
/*
- * net/dccp/packet_history.c
- *
* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
* Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
*
@@ -40,18 +38,6 @@
#include "packet_history.h"
#include "../../dccp.h"
-/**
- * tfrc_tx_hist_entry - Simple singly-linked TX history list
- * @next: next oldest entry (LIFO order)
- * @seqno: sequence number of this entry
- * @stamp: send time of packet with sequence number @seqno
- */
-struct tfrc_tx_hist_entry {
- struct tfrc_tx_hist_entry *next;
- u64 seqno;
- ktime_t stamp;
-};
-
/*
* Transmitter History Routines
*/
@@ -73,15 +59,6 @@ void tfrc_tx_packet_history_exit(void)
}
}
-static struct tfrc_tx_hist_entry *
- tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
-{
- while (head != NULL && head->seqno != seqno)
- head = head->next;
-
- return head;
-}
-
int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
{
struct tfrc_tx_hist_entry *entry = kmem_cache_alloc(tfrc_tx_hist_slab, gfp_any());
@@ -94,7 +71,6 @@ int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
*headp = entry;
return 0;
}
-EXPORT_SYMBOL_GPL(tfrc_tx_hist_add);
void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
{
@@ -109,29 +85,9 @@ void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
*headp = NULL;
}
-EXPORT_SYMBOL_GPL(tfrc_tx_hist_purge);
-
-u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno,
- const ktime_t now)
-{
- u32 rtt = 0;
- struct tfrc_tx_hist_entry *packet = tfrc_tx_hist_find_entry(head, seqno);
-
- if (packet != NULL) {
- rtt = ktime_us_delta(now, packet->stamp);
- /*
- * Garbage-collect older (irrelevant) entries:
- */
- tfrc_tx_hist_purge(&packet->next);
- }
-
- return rtt;
-}
-EXPORT_SYMBOL_GPL(tfrc_tx_hist_rtt);
-
/*
- * Receiver History Routines
+ * Receiver History Routines
*/
static struct kmem_cache *tfrc_rx_hist_slab;
@@ -172,7 +128,6 @@ void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
tfrc_rx_hist_entry_from_skb(entry, skb, ndp);
}
-EXPORT_SYMBOL_GPL(tfrc_rx_hist_add_packet);
/* has the packet contained in skb been seen before? */
int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb)
@@ -189,7 +144,6 @@ int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb)
return 0;
}
-EXPORT_SYMBOL_GPL(tfrc_rx_hist_duplicate);
static void tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b)
{
@@ -361,6 +315,7 @@ static void __three_after_loss(struct tfrc_rx_hist *h)
* @ndp: The NDP count belonging to @skb
* @calc_first_li: Caller-dependent computation of first loss interval in @lh
* @sk: Used by @calc_first_li (see tfrc_lh_interval_add)
+ *
* Chooses action according to pending loss, updates LI database when a new
* loss was detected, and does required post-processing. Returns 1 when caller
* should send feedback, 0 otherwise.
@@ -390,7 +345,6 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
}
return is_new_loss;
}
-EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss);
int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
{
@@ -412,7 +366,6 @@ out_free:
}
return -ENOBUFS;
}
-EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc);
void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
{
@@ -424,7 +377,6 @@ void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
h->ring[i] = NULL;
}
}
-EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);
/**
* tfrc_rx_hist_rtt_last_s - reference entry to compute RTT samples against
@@ -436,7 +388,7 @@ static inline struct tfrc_rx_hist_entry *
}
/**
- * tfrc_rx_hist_rtt_prev_s: previously suitable (wrt rtt_last_s) RTT-sampling entry
+ * tfrc_rx_hist_rtt_prev_s - previously suitable (wrt rtt_last_s) RTT-sampling entry
*/
static inline struct tfrc_rx_hist_entry *
tfrc_rx_hist_rtt_prev_s(const struct tfrc_rx_hist *h)
@@ -495,4 +447,3 @@ keep_ref_for_next_time:
return sample;
}
-EXPORT_SYMBOL_GPL(tfrc_rx_hist_sample_rtt);
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index 461cc91cce8..ee362b0b630 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -40,12 +40,28 @@
#include <linux/slab.h>
#include "tfrc.h"
-struct tfrc_tx_hist_entry;
+/**
+ * tfrc_tx_hist_entry - Simple singly-linked TX history list
+ * @next: next oldest entry (LIFO order)
+ * @seqno: sequence number of this entry
+ * @stamp: send time of packet with sequence number @seqno
+ */
+struct tfrc_tx_hist_entry {
+ struct tfrc_tx_hist_entry *next;
+ u64 seqno;
+ ktime_t stamp;
+};
-extern int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
-extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
-extern u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head,
- const u64 seqno, const ktime_t now);
+static inline struct tfrc_tx_hist_entry *
+ tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
+{
+ while (head != NULL && head->seqno != seqno)
+ head = head->next;
+ return head;
+}
+
+int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
+void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
/* Subtraction a-b modulo-16, respects circular wrap-around */
#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
@@ -70,7 +86,6 @@ struct tfrc_rx_hist_entry {
/**
* tfrc_rx_hist - RX history structure for TFRC-based protocols
- *
* @ring: Packet history for RTT sampling and loss detection
* @loss_count: Number of entries in circular history
* @loss_start: Movable index (for loss detection)
@@ -124,20 +139,17 @@ static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
return h->loss_count > 0;
}
-extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
- const struct sk_buff *skb, const u64 ndp);
+void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, const struct sk_buff *skb,
+ const u64 ndp);
-extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
+int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
struct tfrc_loss_hist;
-extern int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
- struct tfrc_loss_hist *lh,
- struct sk_buff *skb, const u64 ndp,
- u32 (*first_li)(struct sock *sk),
- 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 void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
+int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, struct tfrc_loss_hist *lh,
+ struct sk_buff *skb, const u64 ndp,
+ u32 (*first_li)(struct sock *sk), struct sock *sk);
+u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb);
+int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h);
+void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
#endif /* _DCCP_PKT_HIST_ */
diff --git a/net/dccp/ccids/lib/tfrc.c b/net/dccp/ccids/lib/tfrc.c
index 97ecec0a8e7..62b5828acde 100644
--- a/net/dccp/ccids/lib/tfrc.c
+++ b/net/dccp/ccids/lib/tfrc.c
@@ -1,20 +1,19 @@
/*
- * TFRC: main module holding the pieces of the TFRC library together
+ * TFRC library initialisation
*
* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
* Copyright (c) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
*/
-#include <linux/module.h>
#include <linux/moduleparam.h>
#include "tfrc.h"
#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
-int tfrc_debug;
-module_param(tfrc_debug, bool, 0444);
-MODULE_PARM_DESC(tfrc_debug, "Enable debug messages");
+bool tfrc_debug;
+module_param(tfrc_debug, bool, 0644);
+MODULE_PARM_DESC(tfrc_debug, "Enable TFRC debug messages");
#endif
-static int __init tfrc_module_init(void)
+int __init tfrc_lib_init(void)
{
int rc = tfrc_li_init();
@@ -38,18 +37,9 @@ out:
return rc;
}
-static void __exit tfrc_module_exit(void)
+void tfrc_lib_exit(void)
{
tfrc_rx_packet_history_exit();
tfrc_tx_packet_history_exit();
tfrc_li_exit();
}
-
-module_init(tfrc_module_init);
-module_exit(tfrc_module_exit);
-
-MODULE_AUTHOR("Gerrit Renker <gerrit@erg.abdn.ac.uk>, "
- "Ian McDonald <ian.mcdonald@jandi.co.nz>, "
- "Arnaldo Carvalho de Melo <acme@redhat.com>");
-MODULE_DESCRIPTION("DCCP TFRC library");
-MODULE_LICENSE("GPL");
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
index ed9857527ac..40ee7d62b65 100644
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -1,8 +1,6 @@
#ifndef _TFRC_H_
#define _TFRC_H_
/*
- * net/dccp/ccids/lib/tfrc.h
- *
* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
* Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
* Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
@@ -17,12 +15,13 @@
#include <linux/types.h>
#include <linux/math64.h>
#include "../../dccp.h"
-/* internal includes that this module exports: */
+
+/* internal includes that this library exports: */
#include "loss_interval.h"
#include "packet_history.h"
#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
-extern int tfrc_debug;
+extern bool tfrc_debug;
#define tfrc_pr_debug(format, a...) DCCP_PR_DEBUG(tfrc_debug, format, ##a)
#else
#define tfrc_pr_debug(format, a...)
@@ -31,7 +30,7 @@ extern int tfrc_debug;
/* integer-arithmetic divisions of type (a * 1000000)/b */
static inline u64 scaled_div(u64 a, u64 b)
{
- BUG_ON(b==0);
+ BUG_ON(b == 0);
return div64_u64(a * 1000000, b);
}
@@ -56,14 +55,23 @@ static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
return avg ? (weight * avg + (10 - weight) * newval) / 10 : newval;
}
-extern u32 tfrc_calc_x(u16 s, u32 R, u32 p);
-extern u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
+u32 tfrc_calc_x(u16 s, u32 R, u32 p);
+u32 tfrc_calc_x_reverse_lookup(u32 fvalue);
+u32 tfrc_invert_loss_event_rate(u32 loss_event_rate);
+
+int tfrc_tx_packet_history_init(void);
+void tfrc_tx_packet_history_exit(void);
+int tfrc_rx_packet_history_init(void);
+void tfrc_rx_packet_history_exit(void);
-extern int tfrc_tx_packet_history_init(void);
-extern void tfrc_tx_packet_history_exit(void);
-extern int tfrc_rx_packet_history_init(void);
-extern void tfrc_rx_packet_history_exit(void);
+int tfrc_li_init(void);
+void tfrc_li_exit(void);
-extern int tfrc_li_init(void);
-extern void tfrc_li_exit(void);
+#ifdef CONFIG_IP_DCCP_TFRC_LIB
+int tfrc_lib_init(void);
+void tfrc_lib_exit(void);
+#else
+#define tfrc_lib_init() (0)
+#define tfrc_lib_exit()
+#endif
#endif /* _TFRC_H_ */
diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c
index 2f20a29cffe..88ef98285be 100644
--- a/net/dccp/ccids/lib/tfrc_equation.c
+++ b/net/dccp/ccids/lib/tfrc_equation.c
@@ -1,6 +1,4 @@
/*
- * net/dccp/ccids/lib/tfrc_equation.c
- *
* Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
* Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz>
* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
@@ -79,10 +77,10 @@
}
With the given configuration, we have, with M = TFRC_CALC_X_ARRSIZE-1,
- lookup[0][0] = g(1000000/(M+1)) = 1000000 * f(0.2%)
- lookup[M][0] = g(1000000) = 1000000 * f(100%)
- lookup[0][1] = g(TFRC_SMALLEST_P) = 1000000 * f(0.01%)
- lookup[M][1] = g(TFRC_CALC_X_SPLIT) = 1000000 * f(5%)
+ lookup[0][0] = g(1000000/(M+1)) = 1000000 * f(0.2%)
+ lookup[M][0] = g(1000000) = 1000000 * f(100%)
+ lookup[0][1] = g(TFRC_SMALLEST_P) = 1000000 * f(0.01%)
+ lookup[M][1] = g(TFRC_CALC_X_SPLIT) = 1000000 * f(5%)
In summary, the two columns represent f(p) for the following ranges:
* The first column is for 0.002 <= p <= 1.0
@@ -610,11 +608,11 @@ static inline u32 tfrc_binsearch(u32 fval, u8 small)
/**
* tfrc_calc_x - Calculate the send rate as per section 3.1 of RFC3448
+ * @s: packet size in bytes
+ * @R: RTT scaled by 1000000 (i.e., microseconds)
+ * @p: loss ratio estimate scaled by 1000000
*
- * @s: packet size in bytes
- * @R: RTT scaled by 1000000 (i.e., microseconds)
- * @p: loss ratio estimate scaled by 1000000
- * Returns X_calc in bytes per second (not scaled).
+ * Returns X_calc in bytes per second (not scaled).
*/
u32 tfrc_calc_x(u16 s, u32 R, u32 p)
{
@@ -630,17 +628,17 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p)
return ~0U;
}
- if (p <= TFRC_CALC_X_SPLIT) { /* 0.0000 < p <= 0.05 */
+ if (p <= TFRC_CALC_X_SPLIT) { /* 0.0000 < p <= 0.05 */
if (p < TFRC_SMALLEST_P) { /* 0.0000 < p < 0.0001 */
DCCP_WARN("Value of p (%d) below resolution. "
"Substituting %d\n", p, TFRC_SMALLEST_P);
index = 0;
- } else /* 0.0001 <= p <= 0.05 */
+ } else /* 0.0001 <= p <= 0.05 */
index = p/TFRC_SMALLEST_P - 1;
f = tfrc_calc_x_lookup[index][1];
- } else { /* 0.05 < p <= 1.00 */
+ } else { /* 0.05 < p <= 1.00 */
index = p/(1000000/TFRC_CALC_X_ARRSIZE) - 1;
f = tfrc_calc_x_lookup[index][0];
@@ -659,12 +657,10 @@ u32 tfrc_calc_x(u16 s, u32 R, u32 p)
return scaled_div32(result, f);
}
-EXPORT_SYMBOL_GPL(tfrc_calc_x);
-
/**
* tfrc_calc_x_reverse_lookup - try to find p given f(p)
- *
* @fvalue: function value to match, scaled by 1000000
+ *
* Returns closest match for p, also scaled by 1000000
*/
u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
@@ -694,4 +690,16 @@ u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
return (index + 1) * 1000000 / TFRC_CALC_X_ARRSIZE;
}
-EXPORT_SYMBOL_GPL(tfrc_calc_x_reverse_lookup);
+/**
+ * tfrc_invert_loss_event_rate - Compute p so that 10^6 corresponds to 100%
+ * When @loss_event_rate is large, there is a chance that p is truncated to 0.
+ * To avoid re-entering slow-start in that case, we set p = TFRC_SMALLEST_P > 0.
+ */
+u32 tfrc_invert_loss_event_rate(u32 loss_event_rate)
+{
+ if (loss_event_rate == UINT_MAX) /* see RFC 4342, 8.5 */
+ return 0;
+ if (unlikely(loss_event_rate == 0)) /* map 1/0 into 100% */
+ return 1000000;
+ return max_t(u32, scaled_div(1, loss_event_rate), TFRC_SMALLEST_P);
+}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-09 10:34:24 +0000