mac80211: proper IBSS locking
IBSS has never had locking, instead relying on some
memory barriers etc. That's hard to get right, and
I think we had it wrong too until the previous patch.
Since this is not performance sensitive, it doesn't
make sense to have the maintenance overhead of that,
so add proper locking.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 090e344..c691780 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -43,6 +43,8 @@
{
u16 auth_alg, auth_transaction, status_code;
+ lockdep_assert_held(&sdata->u.ibss.mtx);
+
if (len < 24 + 6)
return;
@@ -78,6 +80,8 @@
u32 bss_change;
u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
+ lockdep_assert_held(&ifibss->mtx);
+
/* Reset own TSF to allow time synchronization work. */
drv_reset_tsf(local);
@@ -205,6 +209,8 @@
int i, j;
u16 beacon_int = cbss->beacon_interval;
+ lockdep_assert_held(&sdata->u.ibss.mtx);
+
if (beacon_int < 10)
beacon_int = 10;
@@ -449,6 +455,8 @@
int active = 0;
struct sta_info *sta;
+ lockdep_assert_held(&sdata->u.ibss.mtx);
+
rcu_read_lock();
list_for_each_entry_rcu(sta, &local->sta_list, list) {
@@ -473,6 +481,8 @@
{
struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+ lockdep_assert_held(&ifibss->mtx);
+
mod_timer(&ifibss->timer,
round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
@@ -505,6 +515,8 @@
u16 capability;
int i;
+ lockdep_assert_held(&ifibss->mtx);
+
if (ifibss->fixed_bssid) {
memcpy(bssid, ifibss->bssid, ETH_ALEN);
} else {
@@ -549,6 +561,8 @@
int active_ibss;
u16 capability;
+ lockdep_assert_held(&ifibss->mtx);
+
active_ibss = ieee80211_sta_active_ibss(sdata);
#ifdef CONFIG_MAC80211_IBSS_DEBUG
printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
@@ -637,6 +651,8 @@
struct ieee80211_mgmt *resp;
u8 *pos, *end;
+ lockdep_assert_held(&ifibss->mtx);
+
if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
len < 24 + 2 || !ifibss->presp)
return;
@@ -740,6 +756,8 @@
mgmt = (struct ieee80211_mgmt *) skb->data;
fc = le16_to_cpu(mgmt->frame_control);
+ mutex_lock(&sdata->u.ibss.mtx);
+
switch (fc & IEEE80211_FCTL_STYPE) {
case IEEE80211_STYPE_PROBE_REQ:
ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
@@ -756,14 +774,23 @@
ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
break;
}
+
+ mutex_unlock(&sdata->u.ibss.mtx);
}
void ieee80211_ibss_work(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
- if (!test_and_clear_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request))
- return;
+ mutex_lock(&ifibss->mtx);
+
+ /*
+ * Work could be scheduled after scan or similar
+ * when we aren't even joined (or trying) with a
+ * network.
+ */
+ if (!ifibss->ssid_len)
+ goto out;
switch (ifibss->state) {
case IEEE80211_IBSS_MLME_SEARCH:
@@ -776,15 +803,9 @@
WARN_ON(1);
break;
}
-}
-static void ieee80211_queue_ibss_work(struct ieee80211_sub_if_data *sdata)
-{
- struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
- struct ieee80211_local *local = sdata->local;
-
- set_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request);
- ieee80211_queue_work(&local->hw, &sdata->work);
+ out:
+ mutex_unlock(&ifibss->mtx);
}
static void ieee80211_ibss_timer(unsigned long data)
@@ -799,7 +820,7 @@
return;
}
- ieee80211_queue_ibss_work(sdata);
+ ieee80211_queue_work(&local->hw, &sdata->work);
}
#ifdef CONFIG_PM
@@ -828,6 +849,7 @@
setup_timer(&ifibss->timer, ieee80211_ibss_timer,
(unsigned long) sdata);
+ mutex_init(&ifibss->mtx);
}
/* scan finished notification */
@@ -841,10 +863,8 @@
continue;
if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
continue;
- if (!sdata->u.ibss.ssid_len)
- continue;
sdata->u.ibss.last_scan_completed = jiffies;
- ieee80211_queue_ibss_work(sdata);
+ ieee80211_queue_work(&local->hw, &sdata->work);
}
mutex_unlock(&local->iflist_mtx);
}
@@ -854,6 +874,17 @@
{
struct sk_buff *skb;
+ skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
+ 36 /* bitrates */ +
+ 34 /* SSID */ +
+ 3 /* DS params */ +
+ 4 /* IBSS params */ +
+ params->ie_len);
+ if (!skb)
+ return -ENOMEM;
+
+ mutex_lock(&sdata->u.ibss.mtx);
+
if (params->bssid) {
memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
sdata->u.ibss.fixed_bssid = true;
@@ -882,35 +913,19 @@
sdata->u.ibss.ie_len = params->ie_len;
}
- skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
- 36 /* bitrates */ +
- 34 /* SSID */ +
- 3 /* DS params */ +
- 4 /* IBSS params */ +
- params->ie_len);
- if (!skb)
- return -ENOMEM;
-
sdata->u.ibss.skb = skb;
sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
sdata->u.ibss.ibss_join_req = jiffies;
memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);
-
- /*
- * The ssid_len setting below is used to see whether
- * we are active, and we need all other settings
- * before that may get visible.
- */
- mb();
-
sdata->u.ibss.ssid_len = params->ssid_len;
ieee80211_recalc_idle(sdata->local);
- set_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
ieee80211_queue_work(&sdata->local->hw, &sdata->work);
+ mutex_unlock(&sdata->u.ibss.mtx);
+
return 0;
}
@@ -921,7 +936,9 @@
struct ieee80211_local *local = sdata->local;
struct cfg80211_bss *cbss;
u16 capability;
- int active_ibss = 0;
+ int active_ibss;
+
+ mutex_lock(&sdata->u.ibss.mtx);
active_ibss = ieee80211_sta_active_ibss(sdata);
@@ -959,19 +976,9 @@
memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
sdata->u.ibss.ssid_len = 0;
- /*
- * ssid_len indicates active or not, so needs to be visible to
- * everybody, especially ieee80211_ibss_notify_scan_completed,
- * so it won't restart the timer after we remove it here.
- */
- mb();
-
del_timer_sync(&sdata->u.ibss.timer);
- clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
- /*
- * Since the REQ_RUN bit is clear, the work won't do
- * anything if it runs after this.
- */
+
+ mutex_unlock(&sdata->u.ibss.mtx);
ieee80211_recalc_idle(sdata->local);
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f9251d5..c6b5c2d 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -377,14 +377,11 @@
int last_cqm_event_signal;
};
-enum ieee80211_ibss_request {
- IEEE80211_IBSS_REQ_RUN = 0,
-};
-
struct ieee80211_if_ibss {
struct timer_list timer;
- unsigned long request;
+ struct mutex mtx;
+
unsigned long last_scan_completed;
u32 basic_rates;
