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linux/net/mac80211/ieee80211_rate.h
Johannes Berg d0709a6518 mac80211: RCU-ify STA info structure access
This makes access to the STA hash table/list use RCU to protect
against freeing of items. However, it's not a true RCU, the
copy step is missing: whenever somebody changes a STA item it
is simply updated. This is an existing race condition that is
now somewhat understandable.

This patch also fixes the race key freeing vs. STA destruction
by making sure that sta_info_destroy() is always called under
RTNL and frees the key.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-03-06 15:30:46 -05:00

205 lines
5.5 KiB
C

/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005, 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.
*/
#ifndef IEEE80211_RATE_H
#define IEEE80211_RATE_H
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <linux/kref.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "sta_info.h"
/* TODO: kdoc */
struct rate_selection {
/* Selected transmission rate */
struct ieee80211_rate *rate;
/* Non-ERP rate to use if mac80211 decides it cannot use an ERP rate */
struct ieee80211_rate *nonerp;
/* probe with this rate, or NULL for no probing */
struct ieee80211_rate *probe;
};
struct rate_control_ops {
struct module *module;
const char *name;
void (*tx_status)(void *priv, struct net_device *dev,
struct sk_buff *skb,
struct ieee80211_tx_status *status);
void (*get_rate)(void *priv, struct net_device *dev,
struct ieee80211_supported_band *band,
struct sk_buff *skb,
struct rate_selection *sel);
void (*rate_init)(void *priv, void *priv_sta,
struct ieee80211_local *local, struct sta_info *sta);
void (*clear)(void *priv);
void *(*alloc)(struct ieee80211_local *local);
void (*free)(void *priv);
void *(*alloc_sta)(void *priv, gfp_t gfp);
void (*free_sta)(void *priv, void *priv_sta);
int (*add_attrs)(void *priv, struct kobject *kobj);
void (*remove_attrs)(void *priv, struct kobject *kobj);
void (*add_sta_debugfs)(void *priv, void *priv_sta,
struct dentry *dir);
void (*remove_sta_debugfs)(void *priv, void *priv_sta);
};
struct rate_control_ref {
struct rate_control_ops *ops;
void *priv;
struct kref kref;
};
int ieee80211_rate_control_register(struct rate_control_ops *ops);
void ieee80211_rate_control_unregister(struct rate_control_ops *ops);
/* Get a reference to the rate control algorithm. If `name' is NULL, get the
* first available algorithm. */
struct rate_control_ref *rate_control_alloc(const char *name,
struct ieee80211_local *local);
void rate_control_get_rate(struct net_device *dev,
struct ieee80211_supported_band *sband,
struct sk_buff *skb,
struct rate_selection *sel);
struct rate_control_ref *rate_control_get(struct rate_control_ref *ref);
void rate_control_put(struct rate_control_ref *ref);
static inline void rate_control_tx_status(struct net_device *dev,
struct sk_buff *skb,
struct ieee80211_tx_status *status)
{
struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
struct rate_control_ref *ref = local->rate_ctrl;
ref->ops->tx_status(ref->priv, dev, skb, status);
}
static inline void rate_control_rate_init(struct sta_info *sta,
struct ieee80211_local *local)
{
struct rate_control_ref *ref = sta->rate_ctrl;
ref->ops->rate_init(ref->priv, sta->rate_ctrl_priv, local, sta);
}
static inline void rate_control_clear(struct ieee80211_local *local)
{
struct rate_control_ref *ref = local->rate_ctrl;
ref->ops->clear(ref->priv);
}
static inline void *rate_control_alloc_sta(struct rate_control_ref *ref,
gfp_t gfp)
{
return ref->ops->alloc_sta(ref->priv, gfp);
}
static inline void rate_control_free_sta(struct rate_control_ref *ref,
void *priv)
{
ref->ops->free_sta(ref->priv, priv);
}
static inline void rate_control_add_sta_debugfs(struct sta_info *sta)
{
#ifdef CONFIG_MAC80211_DEBUGFS
struct rate_control_ref *ref = sta->rate_ctrl;
if (sta->debugfs.dir && ref->ops->add_sta_debugfs)
ref->ops->add_sta_debugfs(ref->priv, sta->rate_ctrl_priv,
sta->debugfs.dir);
#endif
}
static inline void rate_control_remove_sta_debugfs(struct sta_info *sta)
{
#ifdef CONFIG_MAC80211_DEBUGFS
struct rate_control_ref *ref = sta->rate_ctrl;
if (ref->ops->remove_sta_debugfs)
ref->ops->remove_sta_debugfs(ref->priv, sta->rate_ctrl_priv);
#endif
}
static inline int rate_supported(struct sta_info *sta,
enum ieee80211_band band,
int index)
{
return (sta == NULL || sta->supp_rates[band] & BIT(index));
}
static inline int
rate_lowest_index(struct ieee80211_local *local,
struct ieee80211_supported_band *sband,
struct sta_info *sta)
{
int i;
for (i = 0; i < sband->n_bitrates; i++)
if (rate_supported(sta, sband->band, i))
return i;
/* warn when we cannot find a rate. */
WARN_ON(1);
return 0;
}
static inline struct ieee80211_rate *
rate_lowest(struct ieee80211_local *local,
struct ieee80211_supported_band *sband,
struct sta_info *sta)
{
return &sband->bitrates[rate_lowest_index(local, sband, sta)];
}
/* functions for rate control related to a device */
int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
const char *name);
void rate_control_deinitialize(struct ieee80211_local *local);
/* Rate control algorithms */
#if defined(RC80211_SIMPLE_COMPILE) || \
(defined(CONFIG_MAC80211_RC_SIMPLE) && \
!defined(CONFIG_MAC80211_RC_SIMPLE_MODULE))
extern int rc80211_simple_init(void);
extern void rc80211_simple_exit(void);
#else
static inline int rc80211_simple_init(void)
{
return 0;
}
static inline void rc80211_simple_exit(void)
{
}
#endif
#if defined(RC80211_PID_COMPILE) || \
(defined(CONFIG_MAC80211_RC_PID) && \
!defined(CONFIG_MAC80211_RC_PID_MODULE))
extern int rc80211_pid_init(void);
extern void rc80211_pid_exit(void);
#else
static inline int rc80211_pid_init(void)
{
return 0;
}
static inline void rc80211_pid_exit(void)
{
}
#endif
#endif /* IEEE80211_RATE_H */