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mac80211: simplify key locking 

Since I recently made station management able
to sleep, I can now rework key management as
well; since it will no longer need a spinlock
and can also use a mutex instead, a bunch of
code to allow drivers' set_key to sleep while
key management is protected by a spinlock can
now be removed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg 2010-06-01 10:19:19 +02:00 committed by John W. Linville
parent efe4c457a1
commit ad0e2b5a00
7 changed files with 83 additions and 270 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
net/mac80211/cfg.c
View File

@ -120,6 +120,9 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
struct ieee80211_key *key;
int err;
if (!netif_running(dev))
return -ENETDOWN;
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
switch (params->cipher) {
@ -145,7 +148,7 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
if (!key)
return -ENOMEM;
rcu_read_lock();
mutex_lock(&sdata->local->sta_mtx);
if (mac_addr) {
sta = sta_info_get_bss(sdata, mac_addr);
@ -160,7 +163,7 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
err = 0;
out_unlock:
rcu_read_unlock();
mutex_unlock(&sdata->local->sta_mtx);
return err;
}
@ -174,7 +177,7 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
rcu_read_lock();
mutex_lock(&sdata->local->sta_mtx);
if (mac_addr) {
ret = -ENOENT;
@ -202,7 +205,7 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
ret = 0;
out_unlock:
rcu_read_unlock();
mutex_unlock(&sdata->local->sta_mtx);
return ret;
}
@ -305,15 +308,10 @@ static int ieee80211_config_default_key(struct wiphy *wiphy,
struct net_device *dev,
u8 key_idx)
{
struct ieee80211_sub_if_data *sdata;
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
rcu_read_lock();
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
ieee80211_set_default_key(sdata, key_idx);
rcu_read_unlock();
return 0;
}

4
net/mac80211/ieee80211_i.h
View File

@ -746,10 +746,10 @@ struct ieee80211_local {
struct mutex iflist_mtx;
/*
* Key lock, protects sdata's key_list and sta_info's
* Key mutex, protects sdata's key_list and sta_info's
* key pointers (write access, they're RCU.)
*/
spinlock_t key_lock;
struct mutex key_mtx;
/* Scanning and BSS list */

5
net/mac80211/iface.c
View File

@ -268,7 +268,6 @@ static int ieee80211_open(struct net_device *dev)
changed |= ieee80211_reset_erp_info(sdata);
ieee80211_bss_info_change_notify(sdata, changed);
ieee80211_enable_keys(sdata);
if (sdata->vif.type == NL80211_IFTYPE_STATION)
netif_carrier_off(dev);
@ -522,8 +521,8 @@ static int ieee80211_stop(struct net_device *dev)
BSS_CHANGED_BEACON_ENABLED);
}
/* disable all keys for as long as this netdev is down */
ieee80211_disable_keys(sdata);
/* free all remaining keys, there shouldn't be any */
ieee80211_free_keys(sdata);
drv_remove_interface(local, &sdata->vif);
}

294
net/mac80211/key.c
View File

@ -36,80 +36,20 @@
* There is currently no way of knowing this except by looking into
* debugfs.
*
* All key operations are protected internally so you can call them at
* any time.
* All key operations are protected internally.
*
* Within mac80211, key references are, just as STA structure references,
* protected by RCU. Note, however, that some things are unprotected,
* namely the key->sta dereferences within the hardware acceleration
* functions. This means that sta_info_destroy() must flush the key todo
* list.
*
* All the direct key list manipulation functions must not sleep because
* they can operate on STA info structs that are protected by RCU.
* functions. This means that sta_info_destroy() must remove the key
* which waits for an RCU grace period.
*/
static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
/* key mutex: used to synchronise todo runners */
static DEFINE_MUTEX(key_mutex);
static DEFINE_SPINLOCK(todo_lock);
static LIST_HEAD(todo_list);
static void key_todo(struct work_struct *work)
static void assert_key_lock(struct ieee80211_local *local)
{
ieee80211_key_todo();
}
static DECLARE_WORK(todo_work, key_todo);
/**
* add_todo - add todo item for a key
*
* @key: key to add to do item for
* @flag: todo flag(s)
*
* Must be called with IRQs or softirqs disabled.
*/
static void add_todo(struct ieee80211_key *key, u32 flag)
{
if (!key)
return;
spin_lock(&todo_lock);
key->flags |= flag;
/*
* Remove again if already on the list so that we move it to the end.
*/
if (!list_empty(&key->todo))
list_del(&key->todo);
list_add_tail(&key->todo, &todo_list);
schedule_work(&todo_work);
spin_unlock(&todo_lock);
}
/**
* ieee80211_key_lock - lock the mac80211 key operation lock
*
* This locks the (global) mac80211 key operation lock, all
* key operations must be done under this lock.
*/
static void ieee80211_key_lock(void)
{
mutex_lock(&key_mutex);
}
/**
* ieee80211_key_unlock - unlock the mac80211 key operation lock
*/
static void ieee80211_key_unlock(void)
{
mutex_unlock(&key_mutex);
}
static void assert_key_lock(void)
{
WARN_ON(!mutex_is_locked(&key_mutex));
WARN_ON(!mutex_is_locked(&local->key_mtx));
}
static struct ieee80211_sta *get_sta_for_key(struct ieee80211_key *key)
@ -126,12 +66,13 @@ static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
struct ieee80211_sta *sta;
int ret;
assert_key_lock();
might_sleep();
if (!key->local->ops->set_key)
return;
assert_key_lock(key->local);
sta = get_sta_for_key(key);
sdata = key->sdata;
@ -142,11 +83,8 @@ static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
ret = drv_set_key(key->local, SET_KEY, sdata, sta, &key->conf);
if (!ret) {
spin_lock_bh(&todo_lock);
if (!ret)
key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
spin_unlock_bh(&todo_lock);
}
if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
printk(KERN_ERR "mac80211-%s: failed to set key "
@ -161,18 +99,15 @@ static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
struct ieee80211_sta *sta;
int ret;
assert_key_lock();
might_sleep();
if (!key || !key->local->ops->set_key)
return;
spin_lock_bh(&todo_lock);
if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)) {
spin_unlock_bh(&todo_lock);
assert_key_lock(key->local);
if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
return;
}
spin_unlock_bh(&todo_lock);
sta = get_sta_for_key(key);
sdata = key->sdata;
@ -191,9 +126,7 @@ static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
wiphy_name(key->local->hw.wiphy),
key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
spin_lock_bh(&todo_lock);
key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
spin_unlock_bh(&todo_lock);
}
static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
@ -201,22 +134,24 @@ static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
{
struct ieee80211_key *key = NULL;
assert_key_lock(sdata->local);
if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
key = sdata->keys[idx];
rcu_assign_pointer(sdata->default_key, key);
if (key)
add_todo(key, KEY_FLAG_TODO_DEFKEY);
if (key) {
ieee80211_debugfs_key_remove_default(key->sdata);
ieee80211_debugfs_key_add_default(key->sdata);
}
}
void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
{
unsigned long flags;
spin_lock_irqsave(&sdata->local->key_lock, flags);
mutex_lock(&sdata->local->key_mtx);
__ieee80211_set_default_key(sdata, idx);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
mutex_unlock(&sdata->local->key_mtx);
}
static void
@ -224,24 +159,26 @@ __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
{
struct ieee80211_key *key = NULL;
assert_key_lock(sdata->local);
if (idx >= NUM_DEFAULT_KEYS &&
idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
key = sdata->keys[idx];
rcu_assign_pointer(sdata->default_mgmt_key, key);
if (key)
add_todo(key, KEY_FLAG_TODO_DEFMGMTKEY);
if (key) {
ieee80211_debugfs_key_remove_mgmt_default(key->sdata);
ieee80211_debugfs_key_add_mgmt_default(key->sdata);
}
}
void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
int idx)
{
unsigned long flags;
spin_lock_irqsave(&sdata->local->key_lock, flags);
mutex_lock(&sdata->local->key_mtx);
__ieee80211_set_default_mgmt_key(sdata, idx);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
mutex_unlock(&sdata->local->key_mtx);
}
@ -352,7 +289,6 @@ struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
}
memcpy(key->conf.key, key_data, key_len);
INIT_LIST_HEAD(&key->list);
INIT_LIST_HEAD(&key->todo);
if (alg == ALG_CCMP) {
/*
@ -382,12 +318,27 @@ struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
return key;
}
static void __ieee80211_key_destroy(struct ieee80211_key *key)
{
if (!key)
return;
ieee80211_key_disable_hw_accel(key);
if (key->conf.alg == ALG_CCMP)
ieee80211_aes_key_free(key->u.ccmp.tfm);
if (key->conf.alg == ALG_AES_CMAC)
ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
ieee80211_debugfs_key_remove(key);
kfree(key);
}
void ieee80211_key_link(struct ieee80211_key *key,
struct ieee80211_sub_if_data *sdata,
struct sta_info *sta)
{
struct ieee80211_key *old_key;
unsigned long flags;
int idx;
BUG_ON(!sdata);
@ -431,7 +382,7 @@ void ieee80211_key_link(struct ieee80211_key *key,
}
}
spin_lock_irqsave(&sdata->local->key_lock, flags);
mutex_lock(&sdata->local->key_mtx);
if (sta)
old_key = sta->key;
@ -439,15 +390,13 @@ void ieee80211_key_link(struct ieee80211_key *key,
old_key = sdata->keys[idx];
__ieee80211_key_replace(sdata, sta, old_key, key);
__ieee80211_key_destroy(old_key);
/* free old key later */
add_todo(old_key, KEY_FLAG_TODO_DELETE);
ieee80211_debugfs_key_add(key);
add_todo(key, KEY_FLAG_TODO_ADD_DEBUGFS);
if (ieee80211_sdata_running(sdata))
add_todo(key, KEY_FLAG_TODO_HWACCEL_ADD);
ieee80211_key_enable_hw_accel(key);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
mutex_unlock(&sdata->local->key_mtx);
}
static void __ieee80211_key_free(struct ieee80211_key *key)
@ -458,170 +407,65 @@ static void __ieee80211_key_free(struct ieee80211_key *key)
if (key->sdata)
__ieee80211_key_replace(key->sdata, key->sta,
key, NULL);
add_todo(key, KEY_FLAG_TODO_DELETE);
__ieee80211_key_destroy(key);
}
void ieee80211_key_free(struct ieee80211_key *key)
{
unsigned long flags;
struct ieee80211_local *local;
if (!key)
return;
if (!key->sdata) {
/* The key has not been linked yet, simply free it
* and don't Oops */
if (key->conf.alg == ALG_CCMP)
ieee80211_aes_key_free(key->u.ccmp.tfm);
kfree(key);
return;
}
local = key->sdata->local;
spin_lock_irqsave(&key->sdata->local->key_lock, flags);
mutex_lock(&local->key_mtx);
__ieee80211_key_free(key);
spin_unlock_irqrestore(&key->sdata->local->key_lock, flags);
}
/*
* To be safe against concurrent manipulations of the list (which shouldn't
* actually happen) we need to hold the spinlock. But under the spinlock we
* can't actually do much, so we defer processing to the todo list. Then run
* the todo list to be sure the operation and possibly previously pending
* operations are completed.
*/
static void ieee80211_todo_for_each_key(struct ieee80211_sub_if_data *sdata,
u32 todo_flags)
{
struct ieee80211_key *key;
unsigned long flags;
might_sleep();
spin_lock_irqsave(&sdata->local->key_lock, flags);
list_for_each_entry(key, &sdata->key_list, list)
add_todo(key, todo_flags);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
ieee80211_key_todo();
mutex_unlock(&local->key_mtx);
}
void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key;
ASSERT_RTNL();
if (WARN_ON(!ieee80211_sdata_running(sdata)))
return;
ieee80211_todo_for_each_key(sdata, KEY_FLAG_TODO_HWACCEL_ADD);
mutex_lock(&sdata->local->key_mtx);
list_for_each_entry(key, &sdata->key_list, list)
ieee80211_key_enable_hw_accel(key);
mutex_unlock(&sdata->local->key_mtx);
}
void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key;
ASSERT_RTNL();
ieee80211_todo_for_each_key(sdata, KEY_FLAG_TODO_HWACCEL_REMOVE);
}
mutex_lock(&sdata->local->key_mtx);
static void __ieee80211_key_destroy(struct ieee80211_key *key)
{
if (!key)
return;
list_for_each_entry(key, &sdata->key_list, list)
ieee80211_key_disable_hw_accel(key);
ieee80211_key_disable_hw_accel(key);
if (key->conf.alg == ALG_CCMP)
ieee80211_aes_key_free(key->u.ccmp.tfm);
if (key->conf.alg == ALG_AES_CMAC)
ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
ieee80211_debugfs_key_remove(key);
kfree(key);
}
static void __ieee80211_key_todo(void)
{
struct ieee80211_key *key;
bool work_done;
u32 todoflags;
/*
* NB: sta_info_destroy relies on this!
*/
synchronize_rcu();
spin_lock_bh(&todo_lock);
while (!list_empty(&todo_list)) {
key = list_first_entry(&todo_list, struct ieee80211_key, todo);
list_del_init(&key->todo);
todoflags = key->flags & (KEY_FLAG_TODO_ADD_DEBUGFS |
KEY_FLAG_TODO_DEFKEY |
KEY_FLAG_TODO_DEFMGMTKEY |
KEY_FLAG_TODO_HWACCEL_ADD |
KEY_FLAG_TODO_HWACCEL_REMOVE |
KEY_FLAG_TODO_DELETE);
key->flags &= ~todoflags;
spin_unlock_bh(&todo_lock);
work_done = false;
if (todoflags & KEY_FLAG_TODO_ADD_DEBUGFS) {
ieee80211_debugfs_key_add(key);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_DEFKEY) {
ieee80211_debugfs_key_remove_default(key->sdata);
ieee80211_debugfs_key_add_default(key->sdata);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_DEFMGMTKEY) {
ieee80211_debugfs_key_remove_mgmt_default(key->sdata);
ieee80211_debugfs_key_add_mgmt_default(key->sdata);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_HWACCEL_ADD) {
ieee80211_key_enable_hw_accel(key);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_HWACCEL_REMOVE) {
ieee80211_key_disable_hw_accel(key);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_DELETE) {
__ieee80211_key_destroy(key);
work_done = true;
}
WARN_ON(!work_done);
spin_lock_bh(&todo_lock);
}
spin_unlock_bh(&todo_lock);
}
void ieee80211_key_todo(void)
{
ieee80211_key_lock();
__ieee80211_key_todo();
ieee80211_key_unlock();
mutex_unlock(&sdata->local->key_mtx);
}
void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key, *tmp;
unsigned long flags;
ieee80211_key_lock();
mutex_lock(&sdata->local->key_mtx);
ieee80211_debugfs_key_remove_default(sdata);
ieee80211_debugfs_key_remove_mgmt_default(sdata);
spin_lock_irqsave(&sdata->local->key_lock, flags);
list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
__ieee80211_key_free(key);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
__ieee80211_key_todo();
ieee80211_key_unlock();
mutex_unlock(&sdata->local->key_mtx);
}

22
net/mac80211/key.h
View File

@ -38,25 +38,9 @@ struct sta_info;
*
* @KEY_FLAG_UPLOADED_TO_HARDWARE: Indicates that this key is present
* in the hardware for TX crypto hardware acceleration.
* @KEY_FLAG_TODO_DELETE: Key is marked for deletion and will, after an
* RCU grace period, no longer be reachable other than from the
* todo list.
* @KEY_FLAG_TODO_HWACCEL_ADD: Key needs to be added to hardware acceleration.
* @KEY_FLAG_TODO_HWACCEL_REMOVE: Key needs to be removed from hardware
* acceleration.
* @KEY_FLAG_TODO_DEFKEY: Key is default key and debugfs needs to be updated.
* @KEY_FLAG_TODO_ADD_DEBUGFS: Key needs to be added to debugfs.
* @KEY_FLAG_TODO_DEFMGMTKEY: Key is default management key and debugfs needs
* to be updated.
*/
enum ieee80211_internal_key_flags {
KEY_FLAG_UPLOADED_TO_HARDWARE = BIT(0),
KEY_FLAG_TODO_DELETE = BIT(1),
KEY_FLAG_TODO_HWACCEL_ADD = BIT(2),
KEY_FLAG_TODO_HWACCEL_REMOVE = BIT(3),
KEY_FLAG_TODO_DEFKEY = BIT(4),
KEY_FLAG_TODO_ADD_DEBUGFS = BIT(5),
KEY_FLAG_TODO_DEFMGMTKEY = BIT(6),
};
enum ieee80211_internal_tkip_state {
@ -79,10 +63,8 @@ struct ieee80211_key {
/* for sdata list */
struct list_head list;
/* for todo list */
struct list_head todo;
/* protected by todo lock! */
/* protected by key mutex */
unsigned int flags;
union {
@ -155,6 +137,4 @@ void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata);
void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata);
void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata);
void ieee80211_key_todo(void);
#endif /* IEEE80211_KEY_H */

2
net/mac80211/main.c
View File

@ -448,7 +448,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
mutex_init(&local->iflist_mtx);
mutex_init(&local->scan_mtx);
spin_lock_init(&local->key_lock);
mutex_init(&local->key_mtx);
spin_lock_init(&local->filter_lock);
spin_lock_init(&local->queue_stop_reason_lock);

8
net/mac80211/sta_info.c
View File

@ -648,14 +648,6 @@ static int __must_check __sta_info_destroy(struct sta_info *sta)
if (sta->key) {
ieee80211_key_free(sta->key);
/*
* We have only unlinked the key, and actually destroying it
* may mean it is removed from hardware which requires that
* the key->sta pointer is still valid, so flush the key todo
* list here.
*/
ieee80211_key_todo();
WARN_ON(sta->key);
}