Return-path: Received: from he.sipsolutions.net ([78.46.109.217]:56792 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754096Ab0FAIS5 (ORCPT ); Tue, 1 Jun 2010 04:18:57 -0400 Subject: [PATCH] mac80211: simplify key locking From: Johannes Berg To: John Linville Cc: linux-wireless Content-Type: text/plain; charset="UTF-8" Date: Tue, 01 Jun 2010 10:19:19 +0200 Message-ID: <1275380359.3621.17.camel@jlt3.sipsolutions.net> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Johannes Berg 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 --- net/mac80211/cfg.c | 18 +- net/mac80211/ieee80211_i.h | 4 net/mac80211/iface.c | 5 net/mac80211/key.c | 288 ++++++++++----------------------------------- net/mac80211/key.h | 22 --- net/mac80211/main.c | 2 net/mac80211/sta_info.c | 8 - 7 files changed, 80 insertions(+), 267 deletions(-) --- wireless-testing.orig/net/mac80211/cfg.c 2010-05-31 20:51:37.000000000 +0200 +++ wireless-testing/net/mac80211/cfg.c 2010-06-01 10:07:00.000000000 +0200 @@ -120,6 +120,9 @@ static int ieee80211_add_key(struct wiph 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 wiph 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 wiph 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 wiph 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 wiph 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 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; } --- wireless-testing.orig/net/mac80211/ieee80211_i.h 2010-05-31 21:20:18.000000000 +0200 +++ wireless-testing/net/mac80211/ieee80211_i.h 2010-06-01 09:51:50.000000000 +0200 @@ -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 */ --- wireless-testing.orig/net/mac80211/key.c 2010-05-31 15:48:26.000000000 +0200 +++ wireless-testing/net/mac80211/key.c 2010-06-01 10:15:41.000000000 +0200 @@ -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) -{ - 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) +static void assert_key_lock(struct ieee80211_local *local) { - 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_acce 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_acce 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_acc 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_acc 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_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 { 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_allo } 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_allo 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 } } - 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 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 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); + mutex_unlock(&local->key_mtx); } -/* - * 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) +void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata) { 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(); -} - -void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata) -{ ASSERT_RTNL(); if (WARN_ON(!ieee80211_sdata_running(sdata))) return; - ieee80211_todo_for_each_key(sdata, KEY_FLAG_TODO_HWACCEL_ADD); -} - -void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata) -{ - ASSERT_RTNL(); - - ieee80211_todo_for_each_key(sdata, KEY_FLAG_TODO_HWACCEL_REMOVE); -} - -static void __ieee80211_key_destroy(struct ieee80211_key *key) -{ - if (!key) - return; + mutex_lock(&sdata->local->key_mtx); - 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); + list_for_each_entry(key, &sdata->key_list, list) + ieee80211_key_enable_hw_accel(key); - kfree(key); + mutex_unlock(&sdata->local->key_mtx); } -static void __ieee80211_key_todo(void) +void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata) { 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; - } + ASSERT_RTNL(); - WARN_ON(!work_done); + mutex_lock(&sdata->local->key_mtx); - spin_lock_bh(&todo_lock); - } - spin_unlock_bh(&todo_lock); -} + list_for_each_entry(key, &sdata->key_list, list) + ieee80211_key_disable_hw_accel(key); -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); } --- wireless-testing.orig/net/mac80211/main.c 2010-05-31 21:20:16.000000000 +0200 +++ wireless-testing/net/mac80211/main.c 2010-06-01 09:51:50.000000000 +0200 @@ -396,7 +396,7 @@ struct ieee80211_hw *ieee80211_alloc_hw( 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); --- wireless-testing.orig/net/mac80211/key.h 2010-05-31 15:48:26.000000000 +0200 +++ wireless-testing/net/mac80211/key.h 2010-06-01 09:51:50.000000000 +0200 @@ -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 ieee8021 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 */ --- wireless-testing.orig/net/mac80211/sta_info.c 2010-05-31 21:20:15.000000000 +0200 +++ wireless-testing/net/mac80211/sta_info.c 2010-06-01 10:15:45.000000000 +0200 @@ -648,14 +648,6 @@ static int __must_check __sta_info_destr 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); } --- wireless-testing.orig/net/mac80211/iface.c 2010-06-01 09:51:49.000000000 +0200 +++ wireless-testing/net/mac80211/iface.c 2010-06-01 09:51:50.000000000 +0200 @@ -268,7 +268,6 @@ static int ieee80211_open(struct net_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_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); }