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regulatory: use RCU to protect global and wiphy regdomains

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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
2012-12-06 15:47:38 +01:00
parent 379b82f4c9
commit 458f4f9e96
5 changed files with 88 additions and 66 deletions
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35
net/wireless/nl80211.c
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@@ -3787,12 +3787,8 @@ static int nl80211_req_set_reg(struct sk_buff *skb, struct genl_info *info)
* window between nl80211_init() and regulatory_init(), if that is
* even possible.
*/
mutex_lock(&cfg80211_mutex);
if (unlikely(!cfg80211_regdomain)) {
mutex_unlock(&cfg80211_mutex);
if (unlikely(!rcu_access_pointer(cfg80211_regdomain)))
return -EINPROGRESS;
}
mutex_unlock(&cfg80211_mutex);
if (!info->attrs[NL80211_ATTR_REG_ALPHA2])
return -EINVAL;
@@ -4152,6 +4148,7 @@ static int nl80211_update_mesh_config(struct sk_buff *skb,
static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
{
const struct ieee80211_regdomain *regdom;
struct sk_buff *msg;
void *hdr = NULL;
struct nlattr *nl_reg_rules;
@@ -4174,35 +4171,36 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
if (!hdr)
goto put_failure;
if (nla_put_string(msg, NL80211_ATTR_REG_ALPHA2,
cfg80211_regdomain->alpha2) ||
(cfg80211_regdomain->dfs_region &&
nla_put_u8(msg, NL80211_ATTR_DFS_REGION,
cfg80211_regdomain->dfs_region)))
goto nla_put_failure;
if (reg_last_request_cell_base() &&
nla_put_u32(msg, NL80211_ATTR_USER_REG_HINT_TYPE,
NL80211_USER_REG_HINT_CELL_BASE))
goto nla_put_failure;
rcu_read_lock();
regdom = rcu_dereference(cfg80211_regdomain);
if (nla_put_string(msg, NL80211_ATTR_REG_ALPHA2, regdom->alpha2) ||
(regdom->dfs_region &&
nla_put_u8(msg, NL80211_ATTR_DFS_REGION, regdom->dfs_region)))
goto nla_put_failure_rcu;
nl_reg_rules = nla_nest_start(msg, NL80211_ATTR_REG_RULES);
if (!nl_reg_rules)
goto nla_put_failure;
goto nla_put_failure_rcu;
for (i = 0; i < cfg80211_regdomain->n_reg_rules; i++) {
for (i = 0; i < regdom->n_reg_rules; i++) {
struct nlattr *nl_reg_rule;
const struct ieee80211_reg_rule *reg_rule;
const struct ieee80211_freq_range *freq_range;
const struct ieee80211_power_rule *power_rule;
reg_rule = &cfg80211_regdomain->reg_rules[i];
reg_rule = &regdom->reg_rules[i];
freq_range = &reg_rule->freq_range;
power_rule = &reg_rule->power_rule;
nl_reg_rule = nla_nest_start(msg, i);
if (!nl_reg_rule)
goto nla_put_failure;
goto nla_put_failure_rcu;
if (nla_put_u32(msg, NL80211_ATTR_REG_RULE_FLAGS,
reg_rule->flags) ||
@@ -4216,10 +4214,11 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
power_rule->max_antenna_gain) ||
nla_put_u32(msg, NL80211_ATTR_POWER_RULE_MAX_EIRP,
power_rule->max_eirp))
goto nla_put_failure;
goto nla_put_failure_rcu;
nla_nest_end(msg, nl_reg_rule);
}
rcu_read_unlock();
nla_nest_end(msg, nl_reg_rules);
@@ -4227,6 +4226,8 @@ static int nl80211_get_reg(struct sk_buff *skb, struct genl_info *info)
err = genlmsg_reply(msg, info);
goto out;
nla_put_failure_rcu:
rcu_read_unlock();
nla_put_failure:
genlmsg_cancel(msg, hdr);
put_failure: