forked from Minki/linux
cfg80211: decouple regulatory variables from cfg80211_mutex
We change regulatory code to be protected by its own regulatory mutex and alleviate cfg80211_mutex to only be used to protect cfg80211_rdev_list, the registered device list. By doing this we will be able to work on regulatory core components without having to have hog up the cfg80211_mutex. An example here is we no longer need to use the cfg80211_mutex during driver specific wiphy_apply_custom_regulatory(). We also no longer need it for the the country IE regulatory hint; by doing so we end up curing this new lockdep warning: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.31-rc4-wl #12 ------------------------------------------------------- phy1/1709 is trying to acquire lock: (cfg80211_mutex){+.+.+.}, at: [<ffffffffa00af852>] regulatory_hint_11d+0x32/0x3f0 [cfg80211] but task is already holding lock: (&ifmgd->mtx){+.+.+.}, at: [<ffffffffa0144228>] ieee80211_sta_work+0x108/0x10f0 [mac80211] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&ifmgd->mtx){+.+.+.}: [<ffffffff810857b6>] __lock_acquire+0xd76/0x12b0 [<ffffffff81085dd3>] lock_acquire+0xe3/0x120 [<ffffffff814eeae4>] mutex_lock_nested+0x44/0x350 [<ffffffffa0141bb8>] ieee80211_mgd_auth+0x108/0x1f0 [mac80211] [<ffffffffa0148563>] ieee80211_auth+0x13/0x20 [mac80211] [<ffffffffa00bc3a1>] __cfg80211_mlme_auth+0x1b1/0x2a0 [cfg80211] [<ffffffffa00bc516>] cfg80211_mlme_auth+0x86/0xc0 [cfg80211] [<ffffffffa00b368d>] nl80211_authenticate+0x21d/0x230 [cfg80211] [<ffffffff81416ba6>] genl_rcv_msg+0x1b6/0x1f0 [<ffffffff81415c39>] netlink_rcv_skb+0x89/0xb0 [<ffffffff814169d9>] genl_rcv+0x29/0x40 [<ffffffff8141591d>] netlink_unicast+0x29d/0x2b0 [<ffffffff81416514>] netlink_sendmsg+0x214/0x300 [<ffffffff813e4407>] sock_sendmsg+0x107/0x130 [<ffffffff813e45b9>] sys_sendmsg+0x189/0x320 [<ffffffff81011f82>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff -> #2 (&wdev->mtx){+.+.+.}: [<ffffffff810857b6>] __lock_acquire+0xd76/0x12b0 [<ffffffff81085dd3>] lock_acquire+0xe3/0x120 [<ffffffff814eeae4>] mutex_lock_nested+0x44/0x350 [<ffffffffa00ab304>] cfg80211_netdev_notifier_call+0x1a4/0x390 [cfg80211] [<ffffffff814f3dff>] notifier_call_chain+0x3f/0x80 [<ffffffff81075a91>] raw_notifier_call_chain+0x11/0x20 [<ffffffff813f665a>] dev_open+0x10a/0x120 [<ffffffff813f59bd>] dev_change_flags+0x9d/0x1e0 [<ffffffff8144eb6e>] devinet_ioctl+0x6fe/0x760 [<ffffffff81450204>] inet_ioctl+0x94/0xc0 [<ffffffff813e25fa>] sock_ioctl+0x6a/0x290 [<ffffffff8111e911>] vfs_ioctl+0x31/0xa0 [<ffffffff8111ea9a>] do_vfs_ioctl+0x8a/0x5c0 [<ffffffff8111f069>] sys_ioctl+0x99/0xa0 [<ffffffff81011f82>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff -> #1 (&rdev->mtx){+.+.+.}: [<ffffffff810857b6>] __lock_acquire+0xd76/0x12b0 [<ffffffff81085dd3>] lock_acquire+0xe3/0x120 [<ffffffff814eeae4>] mutex_lock_nested+0x44/0x350 [<ffffffffa00ac4d0>] cfg80211_get_dev_from_ifindex+0x60/0x90 [cfg80211] [<ffffffffa00b21ff>] get_rdev_dev_by_info_ifindex+0x6f/0xa0 [cfg80211] [<ffffffffa00b51eb>] nl80211_set_interface+0x3b/0x260 [cfg80211] [<ffffffff81416ba6>] genl_rcv_msg+0x1b6/0x1f0 [<ffffffff81415c39>] netlink_rcv_skb+0x89/0xb0 [<ffffffff814169d9>] genl_rcv+0x29/0x40 [<ffffffff8141591d>] netlink_unicast+0x29d/0x2b0 [<ffffffff81416514>] netlink_sendmsg+0x214/0x300 [<ffffffff813e4407>] sock_sendmsg+0x107/0x130 [<ffffffff813e45b9>] sys_sendmsg+0x189/0x320 [<ffffffff81011f82>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff other info that might help us debug this: 3 locks held by phy1/1709: #0: ((wiphy_name(local->hw.wiphy))){+.+.+.}, at: [<ffffffff8106b45d>] worker_thread+0x19d/0x340 #1: (&ifmgd->work){+.+.+.}, at: [<ffffffff8106b45d>] worker_thread+0x19d/0x340 #2: (&ifmgd->mtx){+.+.+.}, at: [<ffffffffa0144228>] ieee80211_sta_work+0x108/0x10f0 [mac80211] Reported-by: Reinette Chatre <reinette.chatre@intel.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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abc7381bcc
@ -34,9 +34,7 @@ MODULE_DESCRIPTION("wireless configuration support");
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LIST_HEAD(cfg80211_rdev_list);
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/*
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* This is used to protect the cfg80211_rdev_list, cfg80211_regdomain,
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* country_ie_regdomain, the reg_beacon_list and the the last regulatory
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* request receipt (last_request).
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* This is used to protect the cfg80211_rdev_list
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*/
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DEFINE_MUTEX(cfg80211_mutex);
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@ -62,6 +62,16 @@ const struct ieee80211_regdomain *cfg80211_regdomain;
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*/
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static const struct ieee80211_regdomain *country_ie_regdomain;
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/*
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* Protects static reg.c components:
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* - cfg80211_world_regdom
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* - cfg80211_regdom
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* - country_ie_regdomain
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* - last_request
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*/
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DEFINE_MUTEX(reg_mutex);
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#define assert_reg_lock() WARN_ON(!mutex_is_locked(®_mutex))
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/* Used to queue up regulatory hints */
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static LIST_HEAD(reg_requests_list);
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static spinlock_t reg_requests_lock;
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@ -1293,7 +1303,7 @@ static void handle_channel_custom(struct wiphy *wiphy,
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struct ieee80211_supported_band *sband;
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struct ieee80211_channel *chan;
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assert_cfg80211_lock();
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assert_reg_lock();
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sband = wiphy->bands[band];
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BUG_ON(chan_idx >= sband->n_channels);
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@ -1342,14 +1352,14 @@ void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
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enum ieee80211_band band;
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unsigned int bands_set = 0;
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mutex_lock(&cfg80211_mutex);
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mutex_lock(®_mutex);
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for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
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if (!wiphy->bands[band])
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continue;
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handle_band_custom(wiphy, band, regd);
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bands_set++;
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}
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mutex_unlock(&cfg80211_mutex);
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mutex_unlock(®_mutex);
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/*
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* no point in calling this if it won't have any effect
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@ -1495,7 +1505,7 @@ static int ignore_request(struct wiphy *wiphy,
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* Returns zero if all went fine, %-EALREADY if a regulatory domain had
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* already been set or other standard error codes.
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*
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* Caller must hold &cfg80211_mutex
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* Caller must hold &cfg80211_mutex and ®_mutex
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*/
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static int __regulatory_hint(struct wiphy *wiphy,
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struct regulatory_request *pending_request)
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@ -1570,6 +1580,7 @@ static void reg_process_hint(struct regulatory_request *reg_request)
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BUG_ON(!reg_request->alpha2);
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mutex_lock(&cfg80211_mutex);
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mutex_lock(®_mutex);
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if (wiphy_idx_valid(reg_request->wiphy_idx))
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wiphy = wiphy_idx_to_wiphy(reg_request->wiphy_idx);
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@ -1585,6 +1596,7 @@ static void reg_process_hint(struct regulatory_request *reg_request)
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if (r == -EALREADY && wiphy && wiphy->strict_regulatory)
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wiphy_update_regulatory(wiphy, reg_request->initiator);
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out:
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mutex_unlock(®_mutex);
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mutex_unlock(&cfg80211_mutex);
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}
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@ -1613,6 +1625,10 @@ static void reg_process_pending_beacon_hints(void)
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struct cfg80211_registered_device *rdev;
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struct reg_beacon *pending_beacon, *tmp;
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/*
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* No need to hold the reg_mutex here as we just touch wiphys
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* and do not read or access regulatory variables.
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*/
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mutex_lock(&cfg80211_mutex);
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/* This goes through the _pending_ beacon list */
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@ -1734,12 +1750,13 @@ int regulatory_hint(struct wiphy *wiphy, const char *alpha2)
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}
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EXPORT_SYMBOL(regulatory_hint);
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/* Caller must hold reg_mutex */
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static bool reg_same_country_ie_hint(struct wiphy *wiphy,
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u32 country_ie_checksum)
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{
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struct wiphy *request_wiphy;
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assert_cfg80211_lock();
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assert_reg_lock();
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if (unlikely(last_request->initiator !=
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NL80211_REGDOM_SET_BY_COUNTRY_IE))
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@ -1776,7 +1793,7 @@ void regulatory_hint_11d(struct wiphy *wiphy,
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enum environment_cap env = ENVIRON_ANY;
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struct regulatory_request *request;
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mutex_lock(&cfg80211_mutex);
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mutex_lock(®_mutex);
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if (unlikely(!last_request))
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goto out;
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@ -1850,7 +1867,7 @@ void regulatory_hint_11d(struct wiphy *wiphy,
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request->country_ie_checksum = checksum;
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request->country_ie_env = env;
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mutex_unlock(&cfg80211_mutex);
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mutex_unlock(®_mutex);
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queue_regulatory_request(request);
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@ -1859,7 +1876,7 @@ void regulatory_hint_11d(struct wiphy *wiphy,
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free_rd_out:
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kfree(rd);
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out:
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mutex_unlock(&cfg80211_mutex);
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mutex_unlock(®_mutex);
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}
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EXPORT_SYMBOL(regulatory_hint_11d);
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@ -2192,10 +2209,13 @@ int set_regdom(const struct ieee80211_regdomain *rd)
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assert_cfg80211_lock();
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mutex_lock(®_mutex);
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/* Note that this doesn't update the wiphys, this is done below */
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r = __set_regdom(rd);
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if (r) {
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kfree(rd);
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mutex_unlock(®_mutex);
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return r;
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}
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@ -2210,6 +2230,8 @@ int set_regdom(const struct ieee80211_regdomain *rd)
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nl80211_send_reg_change_event(last_request);
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mutex_unlock(®_mutex);
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return r;
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}
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@ -2220,16 +2242,20 @@ void reg_device_remove(struct wiphy *wiphy)
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assert_cfg80211_lock();
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mutex_lock(®_mutex);
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kfree(wiphy->regd);
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if (last_request)
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request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);
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if (!request_wiphy || request_wiphy != wiphy)
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return;
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goto out;
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last_request->wiphy_idx = WIPHY_IDX_STALE;
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last_request->country_ie_env = ENVIRON_ANY;
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out:
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mutex_unlock(®_mutex);
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}
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int regulatory_init(void)
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@ -2290,6 +2316,7 @@ void regulatory_exit(void)
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cancel_work_sync(®_work);
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mutex_lock(&cfg80211_mutex);
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mutex_lock(®_mutex);
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reset_regdomains();
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@ -2328,5 +2355,6 @@ void regulatory_exit(void)
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}
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spin_unlock(®_requests_lock);
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mutex_unlock(®_mutex);
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mutex_unlock(&cfg80211_mutex);
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}
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