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>

1 files changed, 44 insertions, 44 deletions

diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index 37f0c2b94ae7..9efeb1f07025 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -79,7 +79,7 @@ void mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
  *
  * @sta: mes peer link to restart
  *
- * Locking: this function must be called holding sta->plink_lock
+ * Locking: this function must be called holding sta->lock
  */
 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
 {
@@ -105,7 +105,7 @@ static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
         if (!sta)
                 return NULL;
 
-        sta->flags |= WLAN_STA_AUTHORIZED;
+        sta->flags = WLAN_STA_AUTHORIZED;
         sta->supp_rates[local->hw.conf.channel->band] = rates;
 
         return sta;
@@ -118,7 +118,7 @@ static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
  *
  * All mesh paths with this peer as next hop will be flushed
  *
- * Locking: the caller must hold sta->plink_lock
+ * Locking: the caller must hold sta->lock
  */
 static void __mesh_plink_deactivate(struct sta_info *sta)
 {
@@ -139,9 +139,9 @@ static void __mesh_plink_deactivate(struct sta_info *sta)
  */
 void mesh_plink_deactivate(struct sta_info *sta)
 {
-        spin_lock_bh(&sta->plink_lock);
+        spin_lock_bh(&sta->lock);
         __mesh_plink_deactivate(sta);
-        spin_unlock_bh(&sta->plink_lock);
+        spin_unlock_bh(&sta->lock);
 }
 
 static int mesh_plink_frame_tx(struct net_device *dev,
@@ -270,10 +270,10 @@ static void mesh_plink_timer(unsigned long data)
          */
         sta = (struct sta_info *) data;
 
-        spin_lock_bh(&sta->plink_lock);
+        spin_lock_bh(&sta->lock);
         if (sta->ignore_plink_timer) {
                 sta->ignore_plink_timer = false;
-                spin_unlock_bh(&sta->plink_lock);
+                spin_unlock_bh(&sta->lock);
                 return;
         }
         mpl_dbg("Mesh plink timer for %s fired on state %d\n",
@@ -298,7 +298,7 @@ static void mesh_plink_timer(unsigned long data)
                                              rand % sta->plink_timeout;
                         ++sta->plink_retries;
                         mod_plink_timer(sta, sta->plink_timeout);
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_OPEN, sta->addr, llid,
                                             0, 0);
                         break;
@@ -311,7 +311,7 @@ static void mesh_plink_timer(unsigned long data)
                         reason = cpu_to_le16(MESH_CONFIRM_TIMEOUT);
                 sta->plink_state = PLINK_HOLDING;
                 mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
-                spin_unlock_bh(&sta->plink_lock);
+                spin_unlock_bh(&sta->lock);
                 mesh_plink_frame_tx(dev, PLINK_CLOSE, sta->addr, llid, plid,
                                     reason);
                 break;
@@ -319,10 +319,10 @@ static void mesh_plink_timer(unsigned long data)
                 /* holding timer */
                 del_timer(&sta->plink_timer);
                 mesh_plink_fsm_restart(sta);
-                spin_unlock_bh(&sta->plink_lock);
+                spin_unlock_bh(&sta->lock);
                 break;
         default:
-                spin_unlock_bh(&sta->plink_lock);
+                spin_unlock_bh(&sta->lock);
                 break;
         }
 }
@@ -344,16 +344,16 @@ int mesh_plink_open(struct sta_info *sta)
         DECLARE_MAC_BUF(mac);
 #endif
 
-        spin_lock_bh(&sta->plink_lock);
+        spin_lock_bh(&sta->lock);
         get_random_bytes(&llid, 2);
         sta->llid = llid;
         if (sta->plink_state != PLINK_LISTEN) {
-                spin_unlock_bh(&sta->plink_lock);
+                spin_unlock_bh(&sta->lock);
                 return -EBUSY;
         }
         sta->plink_state = PLINK_OPN_SNT;
         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
-        spin_unlock_bh(&sta->plink_lock);
+        spin_unlock_bh(&sta->lock);
         mpl_dbg("Mesh plink: starting establishment with %s\n",
                 print_mac(mac, sta->addr));
 
@@ -367,10 +367,10 @@ void mesh_plink_block(struct sta_info *sta)
         DECLARE_MAC_BUF(mac);
 #endif
 
-        spin_lock_bh(&sta->plink_lock);
+        spin_lock_bh(&sta->lock);
         __mesh_plink_deactivate(sta);
         sta->plink_state = PLINK_BLOCKED;
-        spin_unlock_bh(&sta->plink_lock);
+        spin_unlock_bh(&sta->lock);
 }
 
 int mesh_plink_close(struct sta_info *sta)
@@ -383,14 +383,14 @@ int mesh_plink_close(struct sta_info *sta)
 
         mpl_dbg("Mesh plink: closing link with %s\n",
                         print_mac(mac, sta->addr));
-        spin_lock_bh(&sta->plink_lock);
+        spin_lock_bh(&sta->lock);
         sta->reason = cpu_to_le16(MESH_LINK_CANCELLED);
         reason = sta->reason;
 
         if (sta->plink_state == PLINK_LISTEN ||
             sta->plink_state == PLINK_BLOCKED) {
                 mesh_plink_fsm_restart(sta);
-                spin_unlock_bh(&sta->plink_lock);
+                spin_unlock_bh(&sta->lock);
                 return 0;
         } else if (sta->plink_state == PLINK_ESTAB) {
                 __mesh_plink_deactivate(sta);
@@ -402,7 +402,7 @@ int mesh_plink_close(struct sta_info *sta)
         sta->plink_state = PLINK_HOLDING;
         llid = sta->llid;
         plid = sta->plid;
-        spin_unlock_bh(&sta->plink_lock);
+        spin_unlock_bh(&sta->lock);
         mesh_plink_frame_tx(sta->sdata->dev, PLINK_CLOSE, sta->addr, llid,
                             plid, reason);
         return 0;
@@ -490,7 +490,7 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         /* avoid warning */
                         break;
                 }
-                spin_lock_bh(&sta->plink_lock);
+                spin_lock_bh(&sta->lock);
         } else if (!sta) {
                 /* ftype == PLINK_OPEN */
                 u64 rates;
@@ -512,9 +512,9 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         return;
                 }
                 event = OPN_ACPT;
-                spin_lock_bh(&sta->plink_lock);
+                spin_lock_bh(&sta->lock);
         } else {
-                spin_lock_bh(&sta->plink_lock);
+                spin_lock_bh(&sta->lock);
                 switch (ftype) {
                 case PLINK_OPEN:
                         if (!mesh_plink_free_count(sdata) ||
@@ -551,7 +551,7 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         break;
                 default:
                         mpl_dbg("Mesh plink: unknown frame subtype\n");
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         rcu_read_unlock();
                         return;
                 }
@@ -568,7 +568,7 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                 switch (event) {
                 case CLS_ACPT:
                         mesh_plink_fsm_restart(sta);
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         break;
                 case OPN_ACPT:
                         sta->plink_state = PLINK_OPN_RCVD;
@@ -576,14 +576,14 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         get_random_bytes(&llid, 2);
                         sta->llid = llid;
                         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_OPEN, sta->addr, llid,
                                             0, 0);
                         mesh_plink_frame_tx(dev, PLINK_CONFIRM, sta->addr,
                                             llid, plid, 0);
                         break;
                 default:
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         break;
                 }
                 break;
@@ -603,7 +603,7 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                                 sta->ignore_plink_timer = true;
 
                         llid = sta->llid;
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_CLOSE, sta->addr, llid,
                                             plid, reason);
                         break;
@@ -612,7 +612,7 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         sta->plink_state = PLINK_OPN_RCVD;
                         sta->plid = plid;
                         llid = sta->llid;
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_CONFIRM, sta->addr, llid,
                                             plid, 0);
                         break;
@@ -622,10 +622,10 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                                              dot11MeshConfirmTimeout(sdata)))
                                 sta->ignore_plink_timer = true;
 
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         break;
                 default:
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         break;
                 }
                 break;
@@ -645,13 +645,13 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                                 sta->ignore_plink_timer = true;
 
                         llid = sta->llid;
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_CLOSE, sta->addr, llid,
                                             plid, reason);
                         break;
                 case OPN_ACPT:
                         llid = sta->llid;
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_CONFIRM, sta->addr, llid,
                                             plid, 0);
                         break;
@@ -659,12 +659,12 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         del_timer(&sta->plink_timer);
                         sta->plink_state = PLINK_ESTAB;
                         mesh_plink_inc_estab_count(sdata);
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mpl_dbg("Mesh plink with %s ESTABLISHED\n",
                                         print_mac(mac, sta->addr));
                         break;
                 default:
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         break;
                 }
                 break;
@@ -684,7 +684,7 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                                 sta->ignore_plink_timer = true;
 
                         llid = sta->llid;
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_CLOSE, sta->addr, llid,
                                             plid, reason);
                         break;
@@ -692,14 +692,14 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         del_timer(&sta->plink_timer);
                         sta->plink_state = PLINK_ESTAB;
                         mesh_plink_inc_estab_count(sdata);
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mpl_dbg("Mesh plink with %s ESTABLISHED\n",
                                         print_mac(mac, sta->addr));
                         mesh_plink_frame_tx(dev, PLINK_CONFIRM, sta->addr, llid,
                                             plid, 0);
                         break;
                 default:
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         break;
                 }
                 break;
@@ -713,18 +713,18 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         sta->plink_state = PLINK_HOLDING;
                         llid = sta->llid;
                         mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_CLOSE, sta->addr, llid,
                                             plid, reason);
                         break;
                 case OPN_ACPT:
                         llid = sta->llid;
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_CONFIRM, sta->addr, llid,
                                             plid, 0);
                         break;
                 default:
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         break;
                 }
                 break;
@@ -734,7 +734,7 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                         if (del_timer(&sta->plink_timer))
                                 sta->ignore_plink_timer = 1;
                         mesh_plink_fsm_restart(sta);
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         break;
                 case OPN_ACPT:
                 case CNF_ACPT:
@@ -742,19 +742,19 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
                 case CNF_RJCT:
                         llid = sta->llid;
                         reason = sta->reason;
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                         mesh_plink_frame_tx(dev, PLINK_CLOSE, sta->addr, llid,
                                             plid, reason);
                         break;
                 default:
-                        spin_unlock_bh(&sta->plink_lock);
+                        spin_unlock_bh(&sta->lock);
                 }
                 break;
         default:
                 /* should not get here, PLINK_BLOCKED is dealt with at the
                  * beggining of the function
                  */
-                spin_unlock_bh(&sta->plink_lock);
+                spin_unlock_bh(&sta->lock);
                 break;
         }