mac80211: Add scan race fix

SVN-Revision: 25930

diff --git a/package/mac80211/patches/721-mac80211-fix-scan-race.patch b/package/mac80211/patches/721-mac80211-fix-scan-race.patch
new file mode 100644 (file)
index 0000000..efc01b1
--- /dev/null
+++ b/package/mac80211/patches/721-mac80211-fix-scan-race.patch
@@ -0,0 +1,141 @@
+Index: compat-wireless-2011-02-25/net/mac80211/scan.c
+===================================================================
+--- compat-wireless-2011-02-25.orig/net/mac80211/scan.c        2011-03-07 14:43:55.695666042 +0100
++++ compat-wireless-2011-02-25/net/mac80211/scan.c     2011-03-07 14:43:57.594439631 +0100
+@@ -258,10 +258,12 @@ static bool ieee80211_prep_hw_scan(struc
+       return true;
+ }
+ 
+-static bool __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
++static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
+                                      bool was_hw_scan)
+ {
+       struct ieee80211_local *local = hw_to_local(hw);
++      bool on_oper_chan;
++      bool enable_beacons = false;
+ 
+       lockdep_assert_held(&local->mtx);
+ 
+@@ -275,12 +277,12 @@ static bool __ieee80211_scan_completed(s
+               aborted = true;
+ 
+       if (WARN_ON(!local->scan_req))
+-              return false;
++              return;
+ 
+       if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
+               int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
+               if (rc == 0)
+-                      return false;
++                      return;
+       }
+ 
+       kfree(local->hw_scan_req);
+@@ -294,26 +296,13 @@ static bool __ieee80211_scan_completed(s
+       local->scanning = 0;
+       local->scan_channel = NULL;
+ 
+-      return true;
+-}
+-
+-static void __ieee80211_scan_completed_finish(struct ieee80211_hw *hw,
+-                                            bool was_hw_scan)
+-{
+-      struct ieee80211_local *local = hw_to_local(hw);
+-      bool on_oper_chan;
+-      bool enable_beacons = false;
+-
+-      mutex_lock(&local->mtx);
+       on_oper_chan = ieee80211_cfg_on_oper_channel(local);
+ 
+       WARN_ON(local->scanning & (SCAN_SW_SCANNING | SCAN_HW_SCANNING));
+ 
+-      if (was_hw_scan || !on_oper_chan) {
+-              if (WARN_ON(local->scan_channel))
+-                      local->scan_channel = NULL;
++      if (was_hw_scan || !on_oper_chan)
+               ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+-      } else
++      else
+               /* Set power back to normal operating levels. */
+               ieee80211_hw_config(local, 0);
+ 
+@@ -331,7 +320,6 @@ static void __ieee80211_scan_completed_f
+       }
+ 
+       ieee80211_recalc_idle(local);
+-      mutex_unlock(&local->mtx);
+ 
+       ieee80211_mlme_notify_scan_completed(local);
+       ieee80211_ibss_notify_scan_completed(local);
+@@ -686,12 +674,14 @@ void ieee80211_scan_work(struct work_str
+ {
+       struct ieee80211_local *local =
+               container_of(work, struct ieee80211_local, scan_work.work);
+-      struct ieee80211_sub_if_data *sdata = local->scan_sdata;
++      struct ieee80211_sub_if_data *sdata;
+       unsigned long next_delay = 0;
+-      bool aborted, hw_scan, finish;
++      bool aborted, hw_scan;
+ 
+       mutex_lock(&local->mtx);
+ 
++      sdata = local->scan_sdata;
++
+       if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
+               aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
+               goto out_complete;
+@@ -755,17 +745,11 @@ void ieee80211_scan_work(struct work_str
+       } while (next_delay == 0);
+ 
+       ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
+-      mutex_unlock(&local->mtx);
+-      return;
++      goto out;
+ 
+ out_complete:
+       hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
+-      finish = __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
+-      mutex_unlock(&local->mtx);
+-      if (finish)
+-              __ieee80211_scan_completed_finish(&local->hw, hw_scan);
+-      return;
+-
++      __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
+ out:
+       mutex_unlock(&local->mtx);
+ }
+@@ -835,7 +819,6 @@ int ieee80211_request_internal_scan(stru
+ void ieee80211_scan_cancel(struct ieee80211_local *local)
+ {
+       bool abortscan;
+-      bool finish = false;
+ 
+       /*
+        * We are only canceling software scan, or deferred scan that was not
+@@ -855,14 +838,17 @@ void ieee80211_scan_cancel(struct ieee80
+ 
+       mutex_lock(&local->mtx);
+       abortscan = local->scan_req && !test_bit(SCAN_HW_SCANNING, &local->scanning);
+-      if (abortscan)
+-              finish = __ieee80211_scan_completed(&local->hw, true, false);
+-      mutex_unlock(&local->mtx);
+-
+       if (abortscan) {
+-              /* The scan is canceled, but stop work from being pending */
+-              cancel_delayed_work_sync(&local->scan_work);
++              /*
++               * The scan is canceled, but stop work from being pending.
++               *
++               * If the work is currently running, it must be blocked on
++               * the mutex, but we'll set scan_sdata = NULL and it'll
++               * simply exit once it acquires the mutex.
++               */
++              cancel_delayed_work(&local->scan_work);
++              /* and clean up */
++              __ieee80211_scan_completed(&local->hw, true, false);
+       }
+-      if (finish)
+-              __ieee80211_scan_completed_finish(&local->hw, false);
++      mutex_unlock(&local->mtx);
+ }