From c492db370c17c428a0a58d3673294d4e99634b7d Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 6 Dec 2012 16:29:25 +0100 Subject: [PATCH] regulatory: use RCU to protect last_request This will allow making freq_reg_info() lock-free. Acked-by: Luis R. Rodriguez Signed-off-by: Johannes Berg --- include/net/regulatory.h | 2 + net/wireless/reg.c | 199 +++++++++++++++++++++------------------ 2 files changed, 111 insertions(+), 90 deletions(-) diff --git a/include/net/regulatory.h b/include/net/regulatory.h index 96b0f07cb85b..f17ed590d64a 100644 --- a/include/net/regulatory.h +++ b/include/net/regulatory.h @@ -36,6 +36,7 @@ enum environment_cap { /** * struct regulatory_request - used to keep track of regulatory requests * + * @rcu_head: RCU head struct used to free the request * @wiphy_idx: this is set if this request's initiator is * %REGDOM_SET_BY_COUNTRY_IE or %REGDOM_SET_BY_DRIVER. This * can be used by the wireless core to deal with conflicts @@ -73,6 +74,7 @@ enum environment_cap { * @list: used to insert into the reg_requests_list linked list */ struct regulatory_request { + struct rcu_head rcu_head; int wiphy_idx; enum nl80211_reg_initiator initiator; enum nl80211_user_reg_hint_type user_reg_hint_type; diff --git a/net/wireless/reg.c b/net/wireless/reg.c index 9b64b201cdf1..2a7c3adf902f 100644 --- a/net/wireless/reg.c +++ b/net/wireless/reg.c @@ -82,7 +82,8 @@ static struct regulatory_request core_request_world = { }; /* Receipt of information from last regulatory request */ -static struct regulatory_request *last_request = &core_request_world; +static struct regulatory_request __rcu *last_request = + (void __rcu *)&core_request_world; /* To trigger userspace events */ static struct platform_device *reg_pdev; @@ -102,7 +103,7 @@ const struct ieee80211_regdomain __rcu *cfg80211_regdomain; * Protects static reg.c components: * - cfg80211_regdomain (if not used with RCU) * - cfg80211_world_regdom - * - last_request + * - last_request (if not used with RCU) * - reg_num_devs_support_basehint */ static DEFINE_MUTEX(reg_mutex); @@ -137,6 +138,12 @@ static void rcu_free_regdom(const struct ieee80211_regdomain *r) kfree_rcu((struct ieee80211_regdomain *)r, rcu_head); } +static struct regulatory_request *get_last_request(void) +{ + return rcu_dereference_protected(last_request, + lockdep_is_held(®_mutex)); +} + /* Used to queue up regulatory hints */ static LIST_HEAD(reg_requests_list); static spinlock_t reg_requests_lock; @@ -206,6 +213,7 @@ static void reset_regdomains(bool full_reset, const struct ieee80211_regdomain *new_regdom) { const struct ieee80211_regdomain *r; + struct regulatory_request *lr; assert_reg_lock(); @@ -228,9 +236,10 @@ static void reset_regdomains(bool full_reset, if (!full_reset) return; - if (last_request != &core_request_world) - kfree(last_request); - last_request = &core_request_world; + lr = get_last_request(); + if (lr != &core_request_world && lr) + kfree_rcu(lr, rcu_head); + rcu_assign_pointer(last_request, &core_request_world); } /* @@ -239,9 +248,11 @@ static void reset_regdomains(bool full_reset, */ static void update_world_regdomain(const struct ieee80211_regdomain *rd) { - WARN_ON(!last_request); + struct regulatory_request *lr; - assert_reg_lock(); + lr = get_last_request(); + + WARN_ON(!lr); reset_regdomains(false, rd); @@ -448,15 +459,12 @@ static int call_crda(const char *alpha2) static bool reg_is_valid_request(const char *alpha2) { - assert_reg_lock(); + struct regulatory_request *lr = get_last_request(); - if (!last_request) + if (!lr || lr->processed) return false; - if (last_request->processed) - return false; - - return alpha2_equal(last_request->alpha2, alpha2); + return alpha2_equal(lr->alpha2, alpha2); } /* Sanity check on a regulatory rule */ @@ -746,15 +754,14 @@ int freq_reg_info(struct wiphy *wiphy, u32 center_freq, const struct ieee80211_reg_rule **reg_rule) { const struct ieee80211_regdomain *regd; - - assert_reg_lock(); + struct regulatory_request *lr = get_last_request(); /* * Follow the driver's regulatory domain, if present, unless a country * IE has been processed or a user wants to help complaince further */ - if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE && - last_request->initiator != NL80211_REGDOM_SET_BY_USER && + if (lr->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE && + lr->initiator != NL80211_REGDOM_SET_BY_USER && wiphy->regd) regd = get_wiphy_regdom(wiphy); else @@ -828,8 +835,9 @@ static void handle_channel(struct wiphy *wiphy, const struct ieee80211_power_rule *power_rule = NULL; const struct ieee80211_freq_range *freq_range = NULL; struct wiphy *request_wiphy = NULL; + struct regulatory_request *lr = get_last_request(); - request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx); + request_wiphy = wiphy_idx_to_wiphy(lr->wiphy_idx); flags = chan->orig_flags; @@ -862,7 +870,7 @@ static void handle_channel(struct wiphy *wiphy, if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(40)) bw_flags = IEEE80211_CHAN_NO_HT40; - if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER && + if (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER && request_wiphy && request_wiphy == wiphy && request_wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY) { /* @@ -927,7 +935,7 @@ bool reg_last_request_cell_base(void) bool val; mutex_lock(®_mutex); - val = reg_request_cell_base(last_request); + val = reg_request_cell_base(get_last_request()); mutex_unlock(®_mutex); return val; @@ -938,10 +946,12 @@ bool reg_last_request_cell_base(void) static enum reg_request_treatment reg_ignore_cell_hint(struct regulatory_request *pending_request) { + struct regulatory_request *lr = get_last_request(); + if (!reg_num_devs_support_basehint) return REG_REQ_IGNORE; - if (reg_request_cell_base(last_request) && + if (reg_request_cell_base(lr) && !regdom_changes(pending_request->alpha2)) return REG_REQ_ALREADY_SET; @@ -969,7 +979,9 @@ static bool reg_dev_ignore_cell_hint(struct wiphy *wiphy) static bool ignore_reg_update(struct wiphy *wiphy, enum nl80211_reg_initiator initiator) { - if (!last_request) { + struct regulatory_request *lr = get_last_request(); + + if (!lr) { REG_DBG_PRINT("Ignoring regulatory request %s since last_request is not set\n", reg_initiator_name(initiator)); return true; @@ -988,13 +1000,13 @@ static bool ignore_reg_update(struct wiphy *wiphy, */ if (wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY && !wiphy->regd && initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE && - !is_world_regdom(last_request->alpha2)) { + !is_world_regdom(lr->alpha2)) { REG_DBG_PRINT("Ignoring regulatory request %s since the driver requires its own regulatory domain to be set first\n", reg_initiator_name(initiator)); return true; } - if (reg_request_cell_base(last_request)) + if (reg_request_cell_base(lr)) return reg_dev_ignore_cell_hint(wiphy); return false; @@ -1080,12 +1092,12 @@ static bool reg_is_world_roaming(struct wiphy *wiphy) { const struct ieee80211_regdomain *cr = get_cfg80211_regdom(); const struct ieee80211_regdomain *wr = get_wiphy_regdom(wiphy); + struct regulatory_request *lr = get_last_request(); if (is_world_regdom(cr->alpha2) || (wr && is_world_regdom(wr->alpha2))) return true; - if (last_request && - last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE && + if (lr && lr->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE && wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY) return true; @@ -1184,13 +1196,12 @@ static void wiphy_update_regulatory(struct wiphy *wiphy, enum nl80211_reg_initiator initiator) { enum ieee80211_band band; - - assert_reg_lock(); + struct regulatory_request *lr = get_last_request(); if (ignore_reg_update(wiphy, initiator)) return; - last_request->dfs_region = get_cfg80211_regdom()->dfs_region; + lr->dfs_region = get_cfg80211_regdom()->dfs_region; for (band = 0; band < IEEE80211_NUM_BANDS; band++) handle_band(wiphy, initiator, wiphy->bands[band]); @@ -1199,7 +1210,7 @@ static void wiphy_update_regulatory(struct wiphy *wiphy, reg_process_ht_flags(wiphy); if (wiphy->reg_notifier) - wiphy->reg_notifier(wiphy, last_request); + wiphy->reg_notifier(wiphy, lr); } static void update_all_wiphy_regulatory(enum nl80211_reg_initiator initiator) @@ -1220,7 +1231,7 @@ static void update_all_wiphy_regulatory(enum nl80211_reg_initiator initiator) if (initiator == NL80211_REGDOM_SET_BY_CORE && wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY && wiphy->reg_notifier) - wiphy->reg_notifier(wiphy, last_request); + wiphy->reg_notifier(wiphy, get_last_request()); } } @@ -1300,28 +1311,28 @@ get_reg_request_treatment(struct wiphy *wiphy, struct regulatory_request *pending_request) { struct wiphy *last_wiphy = NULL; + struct regulatory_request *lr = get_last_request(); /* All initial requests are respected */ - if (!last_request) + if (!lr) return REG_REQ_OK; switch (pending_request->initiator) { case NL80211_REGDOM_SET_BY_CORE: return REG_REQ_OK; case NL80211_REGDOM_SET_BY_COUNTRY_IE: - if (reg_request_cell_base(last_request)) { + if (reg_request_cell_base(lr)) { /* Trust a Cell base station over the AP's country IE */ if (regdom_changes(pending_request->alpha2)) return REG_REQ_IGNORE; return REG_REQ_ALREADY_SET; } - last_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx); + last_wiphy = wiphy_idx_to_wiphy(lr->wiphy_idx); if (unlikely(!is_an_alpha2(pending_request->alpha2))) return -EINVAL; - if (last_request->initiator == - NL80211_REGDOM_SET_BY_COUNTRY_IE) { + if (lr->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE) { if (last_wiphy != wiphy) { /* * Two cards with two APs claiming different @@ -1343,7 +1354,7 @@ get_reg_request_treatment(struct wiphy *wiphy, } return 0; case NL80211_REGDOM_SET_BY_DRIVER: - if (last_request->initiator == NL80211_REGDOM_SET_BY_CORE) { + if (lr->initiator == NL80211_REGDOM_SET_BY_CORE) { if (regdom_changes(pending_request->alpha2)) return REG_REQ_OK; return REG_REQ_ALREADY_SET; @@ -1354,7 +1365,7 @@ get_reg_request_treatment(struct wiphy *wiphy, * back in or if you add a new device for which the previously * loaded card also agrees on the regulatory domain. */ - if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER && + if (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER && !regdom_changes(pending_request->alpha2)) return REG_REQ_ALREADY_SET; @@ -1363,26 +1374,26 @@ get_reg_request_treatment(struct wiphy *wiphy, if (reg_request_cell_base(pending_request)) return reg_ignore_cell_hint(pending_request); - if (reg_request_cell_base(last_request)) + if (reg_request_cell_base(lr)) return REG_REQ_IGNORE; - if (last_request->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE) + if (lr->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE) return REG_REQ_INTERSECT; /* * If the user knows better the user should set the regdom * to their country before the IE is picked up */ - if (last_request->initiator == NL80211_REGDOM_SET_BY_USER && - last_request->intersect) + if (lr->initiator == NL80211_REGDOM_SET_BY_USER && + lr->intersect) return REG_REQ_IGNORE; /* * Process user requests only after previous user/driver/core * requests have been processed */ - if ((last_request->initiator == NL80211_REGDOM_SET_BY_CORE || - last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER || - last_request->initiator == NL80211_REGDOM_SET_BY_USER) && - regdom_changes(last_request->alpha2)) + if ((lr->initiator == NL80211_REGDOM_SET_BY_CORE || + lr->initiator == NL80211_REGDOM_SET_BY_DRIVER || + lr->initiator == NL80211_REGDOM_SET_BY_USER) && + regdom_changes(lr->alpha2)) return REG_REQ_IGNORE; if (!regdom_changes(pending_request->alpha2)) @@ -1397,15 +1408,16 @@ get_reg_request_treatment(struct wiphy *wiphy, static void reg_set_request_processed(void) { bool need_more_processing = false; + struct regulatory_request *lr = get_last_request(); - last_request->processed = true; + lr->processed = true; spin_lock(®_requests_lock); if (!list_empty(®_requests_list)) need_more_processing = true; spin_unlock(®_requests_lock); - if (last_request->initiator == NL80211_REGDOM_SET_BY_USER) + if (lr->initiator == NL80211_REGDOM_SET_BY_USER) cancel_delayed_work(®_timeout); if (need_more_processing) @@ -1432,6 +1444,7 @@ __regulatory_hint(struct wiphy *wiphy, const struct ieee80211_regdomain *regd; bool intersect = false; enum reg_request_treatment treatment; + struct regulatory_request *lr; treatment = get_reg_request_treatment(wiphy, pending_request); @@ -1472,18 +1485,20 @@ __regulatory_hint(struct wiphy *wiphy, } new_request: - if (last_request != &core_request_world) - kfree(last_request); + lr = get_last_request(); + if (lr != &core_request_world && lr) + kfree_rcu(lr, rcu_head); - last_request = pending_request; - last_request->intersect = intersect; - last_request->processed = false; + pending_request->intersect = intersect; + pending_request->processed = false; + rcu_assign_pointer(last_request, pending_request); + lr = pending_request; pending_request = NULL; - if (last_request->initiator == NL80211_REGDOM_SET_BY_USER) { - user_alpha2[0] = last_request->alpha2[0]; - user_alpha2[1] = last_request->alpha2[1]; + if (lr->initiator == NL80211_REGDOM_SET_BY_USER) { + user_alpha2[0] = lr->alpha2[0]; + user_alpha2[1] = lr->alpha2[1]; } /* When r == REG_REQ_INTERSECT we do need to call CRDA */ @@ -1494,13 +1509,13 @@ new_request: * inform userspace we have processed the request */ if (treatment == REG_REQ_ALREADY_SET) { - nl80211_send_reg_change_event(last_request); + nl80211_send_reg_change_event(lr); reg_set_request_processed(); } return treatment; } - if (call_crda(last_request->alpha2)) + if (call_crda(lr->alpha2)) return REG_REQ_IGNORE; return REG_REQ_OK; } @@ -1543,13 +1558,14 @@ static void reg_process_hint(struct regulatory_request *reg_request, */ static void reg_process_pending_hints(void) { - struct regulatory_request *reg_request; + struct regulatory_request *reg_request, *lr; mutex_lock(&cfg80211_mutex); mutex_lock(®_mutex); + lr = get_last_request(); /* When last_request->processed becomes true this will be rescheduled */ - if (last_request && !last_request->processed) { + if (lr && !lr->processed) { REG_DBG_PRINT("Pending regulatory request, waiting for it to be processed...\n"); goto out; } @@ -1702,11 +1718,12 @@ void regulatory_hint_11d(struct wiphy *wiphy, enum ieee80211_band band, { char alpha2[2]; enum environment_cap env = ENVIRON_ANY; - struct regulatory_request *request; + struct regulatory_request *request, *lr; mutex_lock(®_mutex); + lr = get_last_request(); - if (unlikely(!last_request)) + if (unlikely(!lr)) goto out; /* IE len must be evenly divisible by 2 */ @@ -1729,8 +1746,8 @@ void regulatory_hint_11d(struct wiphy *wiphy, enum ieee80211_band band, * We leave conflict resolution to the workqueue, where can hold * cfg80211_mutex. */ - if (last_request->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE && - last_request->wiphy_idx != WIPHY_IDX_INVALID) + if (lr->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE && + lr->wiphy_idx != WIPHY_IDX_INVALID) goto out; request = kzalloc(sizeof(struct regulatory_request), GFP_KERNEL); @@ -2021,13 +2038,12 @@ static void print_dfs_region(u8 dfs_region) static void print_regdomain(const struct ieee80211_regdomain *rd) { + struct regulatory_request *lr = get_last_request(); if (is_intersected_alpha2(rd->alpha2)) { - if (last_request->initiator == - NL80211_REGDOM_SET_BY_COUNTRY_IE) { + if (lr->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE) { struct cfg80211_registered_device *rdev; - rdev = cfg80211_rdev_by_wiphy_idx( - last_request->wiphy_idx); + rdev = cfg80211_rdev_by_wiphy_idx(lr->wiphy_idx); if (rdev) { pr_info("Current regulatory domain updated by AP to: %c%c\n", rdev->country_ie_alpha2[0], @@ -2042,7 +2058,7 @@ static void print_regdomain(const struct ieee80211_regdomain *rd) if (is_unknown_alpha2(rd->alpha2)) pr_info("Regulatory domain changed to driver built-in settings (unknown country)\n"); else { - if (reg_request_cell_base(last_request)) + if (reg_request_cell_base(lr)) pr_info("Regulatory domain changed to country: %c%c by Cell Station\n", rd->alpha2[0], rd->alpha2[1]); else @@ -2067,11 +2083,10 @@ static int __set_regdom(const struct ieee80211_regdomain *rd) const struct ieee80211_regdomain *regd; const struct ieee80211_regdomain *intersected_rd = NULL; struct wiphy *request_wiphy; + struct regulatory_request *lr = get_last_request(); /* Some basic sanity checks first */ - assert_reg_lock(); - if (!reg_is_valid_request(rd->alpha2)) return -EINVAL; @@ -2089,7 +2104,7 @@ static int __set_regdom(const struct ieee80211_regdomain *rd) * rd is non static (it means CRDA was present and was used last) * and the pending request came in from a country IE */ - if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) { + if (lr->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) { /* * If someone else asked us to change the rd lets only bother * checking if the alpha2 changes if CRDA was already called @@ -2111,16 +2126,16 @@ static int __set_regdom(const struct ieee80211_regdomain *rd) return -EINVAL; } - request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx); + request_wiphy = wiphy_idx_to_wiphy(lr->wiphy_idx); if (!request_wiphy && - (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER || - last_request->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE)) { + (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER || + lr->initiator == NL80211_REGDOM_SET_BY_COUNTRY_IE)) { schedule_delayed_work(®_timeout, 0); return -ENODEV; } - if (!last_request->intersect) { - if (last_request->initiator != NL80211_REGDOM_SET_BY_DRIVER) { + if (!lr->intersect) { + if (lr->initiator != NL80211_REGDOM_SET_BY_DRIVER) { reset_regdomains(false, rd); return 0; } @@ -2148,7 +2163,7 @@ static int __set_regdom(const struct ieee80211_regdomain *rd) /* Intersection requires a bit more work */ - if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) { + if (lr->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) { intersected_rd = regdom_intersect(rd, get_cfg80211_regdom()); if (!intersected_rd) return -EINVAL; @@ -2158,7 +2173,7 @@ static int __set_regdom(const struct ieee80211_regdomain *rd) * However if a driver requested this specific regulatory * domain we keep it for its private use */ - if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER) + if (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER) rcu_assign_pointer(request_wiphy->regd, rd); else kfree(rd); @@ -2181,9 +2196,11 @@ static int __set_regdom(const struct ieee80211_regdomain *rd) */ int set_regdom(const struct ieee80211_regdomain *rd) { + struct regulatory_request *lr; int r; mutex_lock(®_mutex); + lr = get_last_request(); /* Note that this doesn't update the wiphys, this is done below */ r = __set_regdom(rd); @@ -2196,18 +2213,17 @@ int set_regdom(const struct ieee80211_regdomain *rd) } /* This would make this whole thing pointless */ - if (WARN_ON(!last_request->intersect && - rd != get_cfg80211_regdom())) { + if (WARN_ON(!lr->intersect && rd != get_cfg80211_regdom())) { r = -EINVAL; goto out; } /* update all wiphys now with the new established regulatory domain */ - update_all_wiphy_regulatory(last_request->initiator); + update_all_wiphy_regulatory(lr->initiator); print_regdomain(get_cfg80211_regdom()); - nl80211_send_reg_change_event(last_request); + nl80211_send_reg_change_event(lr); reg_set_request_processed(); @@ -2220,10 +2236,11 @@ int set_regdom(const struct ieee80211_regdomain *rd) #ifdef CONFIG_HOTPLUG int reg_device_uevent(struct device *dev, struct kobj_uevent_env *env) { - if (last_request && !last_request->processed) { + struct regulatory_request *lr = get_last_request(); + + if (lr && !lr->processed) { if (add_uevent_var(env, "COUNTRY=%c%c", - last_request->alpha2[0], - last_request->alpha2[1])) + lr->alpha2[0], lr->alpha2[1])) return -ENOMEM; } @@ -2252,8 +2269,10 @@ void wiphy_regulatory_register(struct wiphy *wiphy) void wiphy_regulatory_deregister(struct wiphy *wiphy) { struct wiphy *request_wiphy = NULL; + struct regulatory_request *lr; mutex_lock(®_mutex); + lr = get_last_request(); if (!reg_dev_ignore_cell_hint(wiphy)) reg_num_devs_support_basehint--; @@ -2261,14 +2280,14 @@ void wiphy_regulatory_deregister(struct wiphy *wiphy) rcu_free_regdom(get_wiphy_regdom(wiphy)); rcu_assign_pointer(wiphy->regd, NULL); - if (last_request) - request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx); + if (lr) + request_wiphy = wiphy_idx_to_wiphy(lr->wiphy_idx); if (!request_wiphy || request_wiphy != wiphy) goto out; - last_request->wiphy_idx = WIPHY_IDX_INVALID; - last_request->country_ie_env = ENVIRON_ANY; + lr->wiphy_idx = WIPHY_IDX_INVALID; + lr->country_ie_env = ENVIRON_ANY; out: mutex_unlock(®_mutex); }