regulatory: use RCU to protect global and wiphy regdomains
To simplify the locking and not require cfg80211_mutex (which nl80211 uses to access the global regdomain) and also to make it possible for drivers to access their wiphy->regd safely, use RCU to protect these pointers. Acked-by: Luis R. Rodriguez <mcgrof@do-not-panic.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg
parent
379b82f4c9
commit
458f4f9e96
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@ -2369,7 +2369,7 @@ struct wiphy {
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/* fields below are read-only, assigned by cfg80211 */
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const struct ieee80211_regdomain *regd;
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const struct ieee80211_regdomain __rcu *regd;
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/* the item in /sys/class/ieee80211/ points to this,
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* you need use set_wiphy_dev() (see below) */
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@ -18,6 +18,7 @@
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <linux/rcupdate.h>
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/**
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* enum environment_cap - Environment parsed from country IE
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@ -101,6 +102,7 @@ struct ieee80211_reg_rule {
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};
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struct ieee80211_regdomain {
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struct rcu_head rcu_head;
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u32 n_reg_rules;
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char alpha2[2];
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u8 dfs_region;
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@ -3787,12 +3787,8 @@ static int nl80211_req_set_reg(struct sk_buff *skb, struct genl_info *info)
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* window between nl80211_init() and regulatory_init(), if that is
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* even possible.
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*/
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mutex_lock(&cfg80211_mutex);
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if (unlikely(!cfg80211_regdomain)) {
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mutex_unlock(&cfg80211_mutex);
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if (unlikely(!rcu_access_pointer(cfg80211_regdomain)))
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return -EINPROGRESS;
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}
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mutex_unlock(&cfg80211_mutex);
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if (!info->attrs[NL80211_ATTR_REG_ALPHA2])
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return -EINVAL;
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@ -4152,6 +4148,7 @@ static int nl80211_update_mesh_config(struct sk_buff *skb,
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static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
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{
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const struct ieee80211_regdomain *regdom;
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struct sk_buff *msg;
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void *hdr = NULL;
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struct nlattr *nl_reg_rules;
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@ -4174,35 +4171,36 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
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if (!hdr)
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goto put_failure;
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if (nla_put_string(msg, NL80211_ATTR_REG_ALPHA2,
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cfg80211_regdomain->alpha2) ||
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(cfg80211_regdomain->dfs_region &&
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nla_put_u8(msg, NL80211_ATTR_DFS_REGION,
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cfg80211_regdomain->dfs_region)))
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goto nla_put_failure;
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if (reg_last_request_cell_base() &&
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nla_put_u32(msg, NL80211_ATTR_USER_REG_HINT_TYPE,
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NL80211_USER_REG_HINT_CELL_BASE))
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goto nla_put_failure;
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rcu_read_lock();
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regdom = rcu_dereference(cfg80211_regdomain);
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if (nla_put_string(msg, NL80211_ATTR_REG_ALPHA2, regdom->alpha2) ||
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(regdom->dfs_region &&
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nla_put_u8(msg, NL80211_ATTR_DFS_REGION, regdom->dfs_region)))
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goto nla_put_failure_rcu;
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nl_reg_rules = nla_nest_start(msg, NL80211_ATTR_REG_RULES);
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if (!nl_reg_rules)
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goto nla_put_failure;
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goto nla_put_failure_rcu;
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for (i = 0; i < cfg80211_regdomain->n_reg_rules; i++) {
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for (i = 0; i < regdom->n_reg_rules; i++) {
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struct nlattr *nl_reg_rule;
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const struct ieee80211_reg_rule *reg_rule;
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const struct ieee80211_freq_range *freq_range;
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const struct ieee80211_power_rule *power_rule;
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reg_rule = &cfg80211_regdomain->reg_rules[i];
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reg_rule = ®dom->reg_rules[i];
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freq_range = ®_rule->freq_range;
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power_rule = ®_rule->power_rule;
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nl_reg_rule = nla_nest_start(msg, i);
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if (!nl_reg_rule)
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goto nla_put_failure;
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goto nla_put_failure_rcu;
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if (nla_put_u32(msg, NL80211_ATTR_REG_RULE_FLAGS,
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reg_rule->flags) ||
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@ -4216,10 +4214,11 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
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power_rule->max_antenna_gain) ||
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nla_put_u32(msg, NL80211_ATTR_POWER_RULE_MAX_EIRP,
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power_rule->max_eirp))
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goto nla_put_failure;
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goto nla_put_failure_rcu;
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nla_nest_end(msg, nl_reg_rule);
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}
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rcu_read_unlock();
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nla_nest_end(msg, nl_reg_rules);
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@ -4227,6 +4226,8 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
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err = genlmsg_reply(msg, info);
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goto out;
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nla_put_failure_rcu:
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rcu_read_unlock();
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nla_put_failure:
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genlmsg_cancel(msg, hdr);
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put_failure:
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@ -95,15 +95,15 @@ static struct device_type reg_device_type = {
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* Central wireless core regulatory domains, we only need two,
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* the current one and a world regulatory domain in case we have no
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* information to give us an alpha2.
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* Protected by the cfg80211_mutex.
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*/
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const struct ieee80211_regdomain *cfg80211_regdomain;
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const struct ieee80211_regdomain __rcu *cfg80211_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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* - last_request
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* - reg_num_devs_support_basehint
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* - cfg80211_regdomain (if not used with RCU)
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* - cfg80211_world_regdom
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* - last_request
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* - reg_num_devs_support_basehint
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*/
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static DEFINE_MUTEX(reg_mutex);
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@ -118,6 +118,25 @@ static inline void assert_reg_lock(void)
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lockdep_assert_held(®_mutex);
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}
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static const struct ieee80211_regdomain *get_cfg80211_regdom(void)
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{
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return rcu_dereference_protected(cfg80211_regdomain,
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lockdep_is_held(®_mutex));
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}
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static const struct ieee80211_regdomain *get_wiphy_regdom(struct wiphy *wiphy)
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{
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return rcu_dereference_protected(wiphy->regd,
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lockdep_is_held(®_mutex));
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}
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static void rcu_free_regdom(const struct ieee80211_regdomain *r)
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{
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if (!r)
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return;
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kfree_rcu((struct ieee80211_regdomain *)r, rcu_head);
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}
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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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@ -186,22 +205,25 @@ MODULE_PARM_DESC(ieee80211_regdom, "IEEE 802.11 regulatory domain code");
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static void reset_regdomains(bool full_reset,
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const struct ieee80211_regdomain *new_regdom)
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{
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assert_cfg80211_lock();
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const struct ieee80211_regdomain *r;
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assert_reg_lock();
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r = get_cfg80211_regdom();
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/* avoid freeing static information or freeing something twice */
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if (cfg80211_regdomain == cfg80211_world_regdom)
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cfg80211_regdomain = NULL;
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if (r == cfg80211_world_regdom)
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r = NULL;
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if (cfg80211_world_regdom == &world_regdom)
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cfg80211_world_regdom = NULL;
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if (cfg80211_regdomain == &world_regdom)
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cfg80211_regdomain = NULL;
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if (r == &world_regdom)
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r = NULL;
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kfree(cfg80211_regdomain);
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kfree(cfg80211_world_regdom);
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rcu_free_regdom(r);
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rcu_free_regdom(cfg80211_world_regdom);
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cfg80211_world_regdom = &world_regdom;
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cfg80211_regdomain = new_regdom;
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rcu_assign_pointer(cfg80211_regdomain, new_regdom);
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if (!full_reset)
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return;
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@ -219,7 +241,6 @@ static void update_world_regdomain(const struct ieee80211_regdomain *rd)
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{
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WARN_ON(!last_request);
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assert_cfg80211_lock();
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assert_reg_lock();
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reset_regdomains(false, rd);
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@ -280,11 +301,11 @@ static bool alpha2_equal(const char *alpha2_x, const char *alpha2_y)
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static bool regdom_changes(const char *alpha2)
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{
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assert_cfg80211_lock();
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const struct ieee80211_regdomain *r = get_cfg80211_regdom();
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if (!cfg80211_regdomain)
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if (!r)
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return true;
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return !alpha2_equal(cfg80211_regdomain->alpha2, alpha2);
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return !alpha2_equal(r->alpha2, alpha2);
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}
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/*
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@ -727,7 +748,6 @@ int freq_reg_info(struct wiphy *wiphy, u32 center_freq,
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const struct ieee80211_regdomain *regd;
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assert_reg_lock();
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assert_cfg80211_lock();
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/*
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* Follow the driver's regulatory domain, if present, unless a country
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@ -736,9 +756,9 @@ int freq_reg_info(struct wiphy *wiphy, u32 center_freq,
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if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&
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last_request->initiator != NL80211_REGDOM_SET_BY_USER &&
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wiphy->regd)
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regd = wiphy->regd;
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regd = get_wiphy_regdom(wiphy);
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else
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regd = cfg80211_regdomain;
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regd = get_cfg80211_regdom();
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return freq_reg_info_regd(wiphy, center_freq, reg_rule, regd);
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}
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@ -809,8 +829,6 @@ static void handle_channel(struct wiphy *wiphy,
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const struct ieee80211_freq_range *freq_range = NULL;
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struct wiphy *request_wiphy = NULL;
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assert_cfg80211_lock();
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request_wiphy = wiphy_idx_to_wiphy(last_request->wiphy_idx);
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flags = chan->orig_flags;
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@ -1060,15 +1078,17 @@ static void wiphy_update_beacon_reg(struct wiphy *wiphy)
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static bool reg_is_world_roaming(struct wiphy *wiphy)
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{
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assert_cfg80211_lock();
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const struct ieee80211_regdomain *cr = get_cfg80211_regdom();
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const struct ieee80211_regdomain *wr = get_wiphy_regdom(wiphy);
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if (is_world_regdom(cfg80211_regdomain->alpha2) ||
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(wiphy->regd && is_world_regdom(wiphy->regd->alpha2)))
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if (is_world_regdom(cr->alpha2) || (wr && is_world_regdom(wr->alpha2)))
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return true;
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if (last_request &&
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last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE &&
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wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY)
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return true;
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return false;
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}
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@ -1165,13 +1185,12 @@ static void wiphy_update_regulatory(struct wiphy *wiphy,
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{
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enum ieee80211_band band;
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assert_cfg80211_lock();
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assert_reg_lock();
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if (ignore_reg_update(wiphy, initiator))
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return;
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last_request->dfs_region = cfg80211_regdomain->dfs_region;
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last_request->dfs_region = get_cfg80211_regdom()->dfs_region;
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for (band = 0; band < IEEE80211_NUM_BANDS; band++)
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handle_band(wiphy, initiator, wiphy->bands[band]);
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@ -1188,6 +1207,8 @@ static void update_all_wiphy_regulatory(enum nl80211_reg_initiator initiator)
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struct cfg80211_registered_device *rdev;
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struct wiphy *wiphy;
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assert_cfg80211_lock();
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list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
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wiphy = &rdev->wiphy;
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wiphy_update_regulatory(wiphy, initiator);
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@ -1402,7 +1423,7 @@ static void reg_set_request_processed(void)
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*
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* Returns one of the different reg request treatment values.
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*
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* Caller must hold &cfg80211_mutex and ®_mutex
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* Caller must hold ®_mutex
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*/
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static enum reg_request_treatment
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__regulatory_hint(struct wiphy *wiphy,
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@ -1412,20 +1433,18 @@ __regulatory_hint(struct wiphy *wiphy,
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bool intersect = false;
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enum reg_request_treatment treatment;
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assert_cfg80211_lock();
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treatment = get_reg_request_treatment(wiphy, pending_request);
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switch (treatment) {
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case REG_REQ_INTERSECT:
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if (pending_request->initiator ==
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NL80211_REGDOM_SET_BY_DRIVER) {
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regd = reg_copy_regd(cfg80211_regdomain);
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regd = reg_copy_regd(get_cfg80211_regdom());
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if (IS_ERR(regd)) {
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kfree(pending_request);
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return PTR_ERR(regd);
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}
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wiphy->regd = regd;
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rcu_assign_pointer(wiphy->regd, regd);
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}
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intersect = true;
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break;
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@ -1439,13 +1458,13 @@ __regulatory_hint(struct wiphy *wiphy,
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*/
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if (treatment == REG_REQ_ALREADY_SET &&
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pending_request->initiator == NL80211_REGDOM_SET_BY_DRIVER) {
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regd = reg_copy_regd(cfg80211_regdomain);
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regd = reg_copy_regd(get_cfg80211_regdom());
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if (IS_ERR(regd)) {
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kfree(pending_request);
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return REG_REQ_IGNORE;
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}
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treatment = REG_REQ_ALREADY_SET;
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wiphy->regd = regd;
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rcu_assign_pointer(wiphy->regd, regd);
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goto new_request;
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}
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kfree(pending_request);
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@ -2051,6 +2070,8 @@ static int __set_regdom(const struct ieee80211_regdomain *rd)
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/* Some basic sanity checks first */
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assert_reg_lock();
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if (!reg_is_valid_request(rd->alpha2))
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return -EINVAL;
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@ -2120,7 +2141,7 @@ static int __set_regdom(const struct ieee80211_regdomain *rd)
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if (IS_ERR(regd))
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return PTR_ERR(regd);
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request_wiphy->regd = regd;
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rcu_assign_pointer(request_wiphy->regd, regd);
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reset_regdomains(false, rd);
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return 0;
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}
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@ -2128,7 +2149,7 @@ static int __set_regdom(const struct ieee80211_regdomain *rd)
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/* Intersection requires a bit more work */
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if (last_request->initiator != NL80211_REGDOM_SET_BY_COUNTRY_IE) {
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intersected_rd = regdom_intersect(rd, cfg80211_regdomain);
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intersected_rd = regdom_intersect(rd, get_cfg80211_regdom());
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if (!intersected_rd)
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return -EINVAL;
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@ -2138,7 +2159,7 @@ static int __set_regdom(const struct ieee80211_regdomain *rd)
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* domain we keep it for its private use
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*/
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if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER)
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request_wiphy->regd = rd;
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rcu_assign_pointer(request_wiphy->regd, rd);
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else
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kfree(rd);
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@ -2156,14 +2177,12 @@ static int __set_regdom(const struct ieee80211_regdomain *rd)
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/*
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* Use this call to set the current regulatory domain. Conflicts with
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* multiple drivers can be ironed out later. Caller must've already
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* kmalloc'd the rd structure. Caller must hold cfg80211_mutex
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* kmalloc'd the rd structure.
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*/
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int set_regdom(const struct ieee80211_regdomain *rd)
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{
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int r;
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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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@ -2177,7 +2196,8 @@ int set_regdom(const struct ieee80211_regdomain *rd)
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}
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/* This would make this whole thing pointless */
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if (WARN_ON(!last_request->intersect && rd != cfg80211_regdomain)) {
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if (WARN_ON(!last_request->intersect &&
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rd != get_cfg80211_regdom())) {
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r = -EINVAL;
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goto out;
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}
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@ -2185,7 +2205,7 @@ int set_regdom(const struct ieee80211_regdomain *rd)
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/* update all wiphys now with the new established regulatory domain */
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update_all_wiphy_regulatory(last_request->initiator);
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print_regdomain(cfg80211_regdomain);
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print_regdomain(get_cfg80211_regdom());
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nl80211_send_reg_change_event(last_request);
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@ -2238,7 +2258,8 @@ void wiphy_regulatory_deregister(struct wiphy *wiphy)
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if (!reg_dev_ignore_cell_hint(wiphy))
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reg_num_devs_support_basehint--;
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kfree(wiphy->regd);
|
||||
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);
|
||||
|
|
@ -2273,13 +2294,13 @@ int __init regulatory_init(void)
|
|||
|
||||
reg_regdb_size_check();
|
||||
|
||||
cfg80211_regdomain = cfg80211_world_regdom;
|
||||
rcu_assign_pointer(cfg80211_regdomain, cfg80211_world_regdom);
|
||||
|
||||
user_alpha2[0] = '9';
|
||||
user_alpha2[1] = '7';
|
||||
|
||||
/* We always try to get an update for the static regdomain */
|
||||
err = regulatory_hint_core(cfg80211_regdomain->alpha2);
|
||||
err = regulatory_hint_core(cfg80211_world_regdom->alpha2);
|
||||
if (err) {
|
||||
if (err == -ENOMEM)
|
||||
return err;
|
||||
|
|
@ -2313,10 +2334,8 @@ void regulatory_exit(void)
|
|||
cancel_delayed_work_sync(®_timeout);
|
||||
|
||||
/* Lock to suppress warnings */
|
||||
mutex_lock(&cfg80211_mutex);
|
||||
mutex_lock(®_mutex);
|
||||
reset_regdomains(true, NULL);
|
||||
mutex_unlock(&cfg80211_mutex);
|
||||
mutex_unlock(®_mutex);
|
||||
|
||||
dev_set_uevent_suppress(®_pdev->dev, true);
|
||||
|
|
|
|||
|
|
@ -16,7 +16,7 @@
|
|||
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
||||
*/
|
||||
|
||||
extern const struct ieee80211_regdomain *cfg80211_regdomain;
|
||||
extern const struct ieee80211_regdomain __rcu *cfg80211_regdomain;
|
||||
|
||||
bool is_world_regdom(const char *alpha2);
|
||||
bool reg_supported_dfs_region(u8 dfs_region);
|
||||
|
|
|
|||
Loading…
Reference in New Issue