mac80211: unify scan and work mutexes

Having both scan and work mutexes is not just
a bit too fine grained, it also creates issues
when there's code that needs both since they
then need to be acquired in the right order,
which can be hard to do.

Therefore, use just a single mutex for both.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 15 insertions, 20 deletions

diff --git a/net/mac80211/work.c b/net/mac80211/work.c
index 81d4ad64184a..b98af64f5862 100644
--- a/net/mac80211/work.c
+++ b/net/mac80211/work.c
@@ -43,7 +43,7 @@ enum work_action {
 /* utils */
 static inline void ASSERT_WORK_MTX(struct ieee80211_local *local)
 {
-        WARN_ON(!mutex_is_locked(&local->work_mtx));
+        lockdep_assert_held(&local->mtx);
 }
 
 /*
@@ -757,7 +757,7 @@ static void ieee80211_work_rx_queued_mgmt(struct ieee80211_local *local,
         mgmt = (struct ieee80211_mgmt *) skb->data;
         fc = le16_to_cpu(mgmt->frame_control);
 
-        mutex_lock(&local->work_mtx);
+        mutex_lock(&local->mtx);
 
         list_for_each_entry(wk, &local->work_list, list) {
                 const u8 *bssid = NULL;
@@ -833,7 +833,7 @@ static void ieee80211_work_rx_queued_mgmt(struct ieee80211_local *local,
                 WARN(1, "unexpected: %d", rma);
         }
 
-        mutex_unlock(&local->work_mtx);
+        mutex_unlock(&local->mtx);
 
         if (rma != WORK_ACT_DONE)
                 goto out;
@@ -845,9 +845,9 @@ static void ieee80211_work_rx_queued_mgmt(struct ieee80211_local *local,
         case WORK_DONE_REQUEUE:
                 synchronize_rcu();
                 wk->started = false; /* restart */
-                mutex_lock(&local->work_mtx);
+                mutex_lock(&local->mtx);
                 list_add_tail(&wk->list, &local->work_list);
-                mutex_unlock(&local->work_mtx);
+                mutex_unlock(&local->mtx);
         }
 
  out:
@@ -890,7 +890,7 @@ static void ieee80211_work_work(struct work_struct *work)
 
         ieee80211_recalc_idle(local);
 
-        mutex_lock(&local->work_mtx);
+        mutex_lock(&local->mtx);
 
         list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
                 bool started = wk->started;
@@ -995,17 +995,13 @@ static void ieee80211_work_work(struct work_struct *work)
                 run_again(local, jiffies + HZ/2);
         }
 
-        mutex_lock(&local->scan_mtx);
-
         if (list_empty(&local->work_list) && local->scan_req &&
             !local->scanning)
                 ieee80211_queue_delayed_work(&local->hw,
                                              &local->scan_work,
                                              round_jiffies_relative(0));
 
-        mutex_unlock(&local->scan_mtx);
-
-        mutex_unlock(&local->work_mtx);
+        mutex_unlock(&local->mtx);
 
         ieee80211_recalc_idle(local);
 
@@ -1035,16 +1031,15 @@ void ieee80211_add_work(struct ieee80211_work *wk)
         wk->started = false;
 
         local = wk->sdata->local;
-        mutex_lock(&local->work_mtx);
+        mutex_lock(&local->mtx);
         list_add_tail(&wk->list, &local->work_list);
-        mutex_unlock(&local->work_mtx);
+        mutex_unlock(&local->mtx);
 
         ieee80211_queue_work(&local->hw, &local->work_work);
 }
 
 void ieee80211_work_init(struct ieee80211_local *local)
 {
-        mutex_init(&local->work_mtx);
         INIT_LIST_HEAD(&local->work_list);
         setup_timer(&local->work_timer, ieee80211_work_timer,
                     (unsigned long)local);
@@ -1057,7 +1052,7 @@ void ieee80211_work_purge(struct ieee80211_sub_if_data *sdata)
         struct ieee80211_local *local = sdata->local;
         struct ieee80211_work *wk;
 
-        mutex_lock(&local->work_mtx);
+        mutex_lock(&local->mtx);
         list_for_each_entry(wk, &local->work_list, list) {
                 if (wk->sdata != sdata)
                         continue;
@@ -1065,19 +1060,19 @@ void ieee80211_work_purge(struct ieee80211_sub_if_data *sdata)
                 wk->started = true;
                 wk->timeout = jiffies;
         }
-        mutex_unlock(&local->work_mtx);
+        mutex_unlock(&local->mtx);
 
         /* run cleanups etc. */
         ieee80211_work_work(&local->work_work);
 
-        mutex_lock(&local->work_mtx);
+        mutex_lock(&local->mtx);
         list_for_each_entry(wk, &local->work_list, list) {
                 if (wk->sdata != sdata)
                         continue;
                 WARN_ON(1);
                 break;
         }
-        mutex_unlock(&local->work_mtx);
+        mutex_unlock(&local->mtx);
 }
 
 ieee80211_rx_result ieee80211_work_rx_mgmt(struct ieee80211_sub_if_data *sdata,
@@ -1163,7 +1158,7 @@ int ieee80211_wk_cancel_remain_on_channel(struct ieee80211_sub_if_data *sdata,
         struct ieee80211_work *wk, *tmp;
         bool found = false;
 
-        mutex_lock(&local->work_mtx);
+        mutex_lock(&local->mtx);
         list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
                 if ((unsigned long) wk == cookie) {
                         wk->timeout = jiffies;
@@ -1171,7 +1166,7 @@ int ieee80211_wk_cancel_remain_on_channel(struct ieee80211_sub_if_data *sdata,
                         break;
                 }
         }
-        mutex_unlock(&local->work_mtx);
+        mutex_unlock(&local->mtx);
 
         if (!found)
                 return -ENOENT;