mac80211: proper STA info locking
As discussed earlier, we can unify locking in struct sta_info
and use just a single spinlock protecting all members of the
structure that need protection. Many don't, but one of the
especially bad ones is the 'flags' member that can currently
be clobbered when RX and TX is being processed on different
CPUs at the same time.
Because having four spinlocks for different, mostly exclusive
parts of a single structure is overkill, this patch also kills
the ampdu and mesh plink spinlocks and uses just a single one
for everything. Because none of the spinlocks are nested, this
is safe.
It remains to be seen whether or not we should make the sta
flags use atomic bit operations instead, for now though this
is a safe thing and using atomic operations instead will be
very simple using the new static inline functions this patch
introduces for accessing sta->flags.
Since spin_lock_bh() is used with this lock, there shouldn't
be any contention even if aggregation is enabled at around the
same time as both requires frame transmission/reception which
is in a bh context.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Tomas Winkler <tomasw@gmail.com>
Cc: Ron Rindjunsky <ron.rindjunsky@intel.com>
Cc: Luis Carlos Cobo <luisca@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 55e7611..f277407 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -346,6 +346,7 @@
goto err_del_interface;
}
+ /* no locking required since STA is not live yet */
sta->flags |= WLAN_STA_AUTHORIZED;
res = sta_info_insert(sta);
@@ -588,7 +589,7 @@
return -ENOENT;
}
- spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_lock_bh(&sta->lock);
/* we have tried too many times, receiver does not want A-MPDU */
if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
@@ -691,7 +692,7 @@
spin_unlock_bh(&local->mdev->queue_lock);
ret = -EBUSY;
start_ba_exit:
- spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_unlock_bh(&sta->lock);
rcu_read_unlock();
return ret;
}
@@ -719,7 +720,7 @@
/* check if the TID is in aggregation */
state = &sta->ampdu_mlme.tid_state_tx[tid];
- spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_lock_bh(&sta->lock);
if (*state != HT_AGG_STATE_OPERATIONAL) {
ret = -ENOENT;
@@ -749,7 +750,7 @@
}
stop_BA_exit:
- spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_unlock_bh(&sta->lock);
rcu_read_unlock();
return ret;
}
@@ -778,12 +779,12 @@
}
state = &sta->ampdu_mlme.tid_state_tx[tid];
- spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_lock_bh(&sta->lock);
if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
*state);
- spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_unlock_bh(&sta->lock);
rcu_read_unlock();
return;
}
@@ -796,7 +797,7 @@
printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
ieee80211_wake_queue(hw, sta->tid_to_tx_q[tid]);
}
- spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_unlock_bh(&sta->lock);
rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
@@ -830,10 +831,10 @@
}
state = &sta->ampdu_mlme.tid_state_tx[tid];
- spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_lock_bh(&sta->lock);
if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
- spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_unlock_bh(&sta->lock);
rcu_read_unlock();
return;
}
@@ -860,7 +861,7 @@
sta->ampdu_mlme.addba_req_num[tid] = 0;
kfree(sta->ampdu_mlme.tid_tx[tid]);
sta->ampdu_mlme.tid_tx[tid] = NULL;
- spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+ spin_unlock_bh(&sta->lock);
rcu_read_unlock();
}
@@ -1315,7 +1316,7 @@
* packet. If the STA went to power save mode, this will happen
* happen when it wakes up for the next time.
*/
- sta->flags |= WLAN_STA_CLEAR_PS_FILT;
+ set_sta_flags(sta, WLAN_STA_CLEAR_PS_FILT);
/*
* This code races in the following way:
@@ -1347,7 +1348,7 @@
* can be unknown, for example with different interrupt status
* bits.
*/
- if (sta->flags & WLAN_STA_PS &&
+ if (test_sta_flags(sta, WLAN_STA_PS) &&
skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
ieee80211_remove_tx_extra(local, sta->key, skb,
&status->control);
@@ -1355,7 +1356,7 @@
return;
}
- if (!(sta->flags & WLAN_STA_PS) &&
+ if (!test_sta_flags(sta, WLAN_STA_PS) &&
!(status->control.flags & IEEE80211_TXCTL_REQUEUE)) {
/* Software retry the packet once */
status->control.flags |= IEEE80211_TXCTL_REQUEUE;
@@ -1370,7 +1371,7 @@
"queue_len=%d PS=%d @%lu\n",
wiphy_name(local->hw.wiphy),
skb_queue_len(&sta->tx_filtered),
- !!(sta->flags & WLAN_STA_PS), jiffies);
+ !!test_sta_flags(sta, WLAN_STA_PS), jiffies);
dev_kfree_skb(skb);
}
@@ -1399,7 +1400,7 @@
struct sta_info *sta;
sta = sta_info_get(local, hdr->addr1);
if (sta) {
- if (sta->flags & WLAN_STA_PS) {
+ if (test_sta_flags(sta, WLAN_STA_PS)) {
/*
* The STA is in power save mode, so assume
* that this TX packet failed because of that.