linux/net/mac80211/rate.c
Johannes Berg af65cd96dd mac80211: make software rate control optional
Some devices implement the entire rate control in
firmware in some way, like wl1271 or like iwlwifi
which does some things in software but not a lot.
Therefore generic software rate control is rather
useless for them and just adds avoidable overhead
to the transmit path.

It's fairly simple to let drivers indicate that
they do not need rate control, but they need to
fulfil a number of conditions that we encode in
WARN_ONs.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-18 17:09:24 -05:00

331 lines
7.8 KiB
C

/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/rtnetlink.h>
#include "rate.h"
#include "ieee80211_i.h"
#include "debugfs.h"
struct rate_control_alg {
struct list_head list;
struct rate_control_ops *ops;
};
static LIST_HEAD(rate_ctrl_algs);
static DEFINE_MUTEX(rate_ctrl_mutex);
static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
module_param(ieee80211_default_rc_algo, charp, 0644);
MODULE_PARM_DESC(ieee80211_default_rc_algo,
"Default rate control algorithm for mac80211 to use");
int ieee80211_rate_control_register(struct rate_control_ops *ops)
{
struct rate_control_alg *alg;
if (!ops->name)
return -EINVAL;
mutex_lock(&rate_ctrl_mutex);
list_for_each_entry(alg, &rate_ctrl_algs, list) {
if (!strcmp(alg->ops->name, ops->name)) {
/* don't register an algorithm twice */
WARN_ON(1);
mutex_unlock(&rate_ctrl_mutex);
return -EALREADY;
}
}
alg = kzalloc(sizeof(*alg), GFP_KERNEL);
if (alg == NULL) {
mutex_unlock(&rate_ctrl_mutex);
return -ENOMEM;
}
alg->ops = ops;
list_add_tail(&alg->list, &rate_ctrl_algs);
mutex_unlock(&rate_ctrl_mutex);
return 0;
}
EXPORT_SYMBOL(ieee80211_rate_control_register);
void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
{
struct rate_control_alg *alg;
mutex_lock(&rate_ctrl_mutex);
list_for_each_entry(alg, &rate_ctrl_algs, list) {
if (alg->ops == ops) {
list_del(&alg->list);
kfree(alg);
break;
}
}
mutex_unlock(&rate_ctrl_mutex);
}
EXPORT_SYMBOL(ieee80211_rate_control_unregister);
static struct rate_control_ops *
ieee80211_try_rate_control_ops_get(const char *name)
{
struct rate_control_alg *alg;
struct rate_control_ops *ops = NULL;
if (!name)
return NULL;
mutex_lock(&rate_ctrl_mutex);
list_for_each_entry(alg, &rate_ctrl_algs, list) {
if (!strcmp(alg->ops->name, name))
if (try_module_get(alg->ops->module)) {
ops = alg->ops;
break;
}
}
mutex_unlock(&rate_ctrl_mutex);
return ops;
}
/* Get the rate control algorithm. */
static struct rate_control_ops *
ieee80211_rate_control_ops_get(const char *name)
{
struct rate_control_ops *ops;
const char *alg_name;
if (!name)
alg_name = ieee80211_default_rc_algo;
else
alg_name = name;
ops = ieee80211_try_rate_control_ops_get(alg_name);
if (!ops) {
request_module("rc80211_%s", alg_name);
ops = ieee80211_try_rate_control_ops_get(alg_name);
}
if (!ops && name)
/* try default if specific alg requested but not found */
ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
/* try built-in one if specific alg requested but not found */
if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT))
ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
return ops;
}
static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
{
module_put(ops->module);
}
#ifdef CONFIG_MAC80211_DEBUGFS
static ssize_t rcname_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct rate_control_ref *ref = file->private_data;
int len = strlen(ref->ops->name);
return simple_read_from_buffer(userbuf, count, ppos,
ref->ops->name, len);
}
static const struct file_operations rcname_ops = {
.read = rcname_read,
.open = mac80211_open_file_generic,
};
#endif
struct rate_control_ref *rate_control_alloc(const char *name,
struct ieee80211_local *local)
{
struct dentry *debugfsdir = NULL;
struct rate_control_ref *ref;
ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
if (!ref)
goto fail_ref;
kref_init(&ref->kref);
ref->local = local;
ref->ops = ieee80211_rate_control_ops_get(name);
if (!ref->ops)
goto fail_ops;
#ifdef CONFIG_MAC80211_DEBUGFS
debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
local->debugfs.rcdir = debugfsdir;
debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops);
#endif
ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
if (!ref->priv)
goto fail_priv;
return ref;
fail_priv:
ieee80211_rate_control_ops_put(ref->ops);
fail_ops:
kfree(ref);
fail_ref:
return NULL;
}
static void rate_control_release(struct kref *kref)
{
struct rate_control_ref *ctrl_ref;
ctrl_ref = container_of(kref, struct rate_control_ref, kref);
ctrl_ref->ops->free(ctrl_ref->priv);
#ifdef CONFIG_MAC80211_DEBUGFS
debugfs_remove_recursive(ctrl_ref->local->debugfs.rcdir);
ctrl_ref->local->debugfs.rcdir = NULL;
#endif
ieee80211_rate_control_ops_put(ctrl_ref->ops);
kfree(ctrl_ref);
}
static bool rc_no_data_or_no_ack(struct ieee80211_tx_rate_control *txrc)
{
struct sk_buff *skb = txrc->skb;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
__le16 fc;
fc = hdr->frame_control;
return ((info->flags & IEEE80211_TX_CTL_NO_ACK) || !ieee80211_is_data(fc));
}
bool rate_control_send_low(struct ieee80211_sta *sta,
void *priv_sta,
struct ieee80211_tx_rate_control *txrc)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
if (!sta || !priv_sta || rc_no_data_or_no_ack(txrc)) {
info->control.rates[0].idx = rate_lowest_index(txrc->sband, sta);
info->control.rates[0].count =
(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
1 : txrc->hw->max_rate_tries;
return true;
}
return false;
}
EXPORT_SYMBOL(rate_control_send_low);
void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
struct ieee80211_tx_rate_control *txrc)
{
struct rate_control_ref *ref = sdata->local->rate_ctrl;
void *priv_sta = NULL;
struct ieee80211_sta *ista = NULL;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
int i;
if (sta) {
ista = &sta->sta;
priv_sta = sta->rate_ctrl_priv;
}
for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
info->control.rates[i].idx = -1;
info->control.rates[i].flags = 0;
info->control.rates[i].count = 1;
}
if (sta && sdata->force_unicast_rateidx > -1) {
info->control.rates[0].idx = sdata->force_unicast_rateidx;
} else {
ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
info->flags |= IEEE80211_TX_INTFL_RCALGO;
}
/*
* try to enforce the maximum rate the user wanted
*/
if (sdata->max_ratectrl_rateidx > -1)
for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
if (info->control.rates[i].flags & IEEE80211_TX_RC_MCS)
continue;
info->control.rates[i].idx =
min_t(s8, info->control.rates[i].idx,
sdata->max_ratectrl_rateidx);
}
BUG_ON(info->control.rates[0].idx < 0);
}
struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
{
kref_get(&ref->kref);
return ref;
}
void rate_control_put(struct rate_control_ref *ref)
{
kref_put(&ref->kref, rate_control_release);
}
int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
const char *name)
{
struct rate_control_ref *ref, *old;
ASSERT_RTNL();
if (local->open_count)
return -EBUSY;
if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) {
if (WARN_ON(!local->ops->set_rts_threshold))
return -EINVAL;
return 0;
}
ref = rate_control_alloc(name, local);
if (!ref) {
printk(KERN_WARNING "%s: Failed to select rate control "
"algorithm\n", wiphy_name(local->hw.wiphy));
return -ENOENT;
}
old = local->rate_ctrl;
local->rate_ctrl = ref;
if (old) {
rate_control_put(old);
sta_info_flush(local, NULL);
}
printk(KERN_DEBUG "%s: Selected rate control "
"algorithm '%s'\n", wiphy_name(local->hw.wiphy),
ref->ops->name);
return 0;
}
void rate_control_deinitialize(struct ieee80211_local *local)
{
struct rate_control_ref *ref;
ref = local->rate_ctrl;
if (!ref)
return;
local->rate_ctrl = NULL;
rate_control_put(ref);
}