cfg80211: vastly simplify locking

Virtually all code paths in cfg80211 already (need to) hold
the RTNL. As such, there's little point in having another
four mutexes for various parts of the code, they just cause
lock ordering issues (and much of the time, the RTNL and a
few of the others need thus be held.)

Simplify all this by getting rid of the extra four mutexes
and just use the RTNL throughout. Only a few code changes
were needed to do this and we can get rid of a work struct
for bonus points.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 0 insertions, 11 deletions

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 0962f107f57f..501724257af5 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -808,12 +808,8 @@ void cfg80211_process_rdev_events(struct cfg80211_registered_device *rdev)
         ASSERT_RTNL();
         ASSERT_RDEV_LOCK(rdev);
 
-        mutex_lock(&rdev->devlist_mtx);
-
         list_for_each_entry(wdev, &rdev->wdev_list, list)
                 cfg80211_process_wdev_events(wdev);
-
-        mutex_unlock(&rdev->devlist_mtx);
 }
 
 int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
@@ -845,10 +841,8 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
                 return -EBUSY;
 
         if (ntype != otype && netif_running(dev)) {
-                mutex_lock(&rdev->devlist_mtx);
                 err = cfg80211_can_change_interface(rdev, dev->ieee80211_ptr,
                                                     ntype);
-                mutex_unlock(&rdev->devlist_mtx);
                 if (err)
                         return err;
 
@@ -1210,8 +1204,6 @@ int cfg80211_validate_beacon_int(struct cfg80211_registered_device *rdev,
         if (!beacon_int)
                 return -EINVAL;
 
-        mutex_lock(&rdev->devlist_mtx);
-
         list_for_each_entry(wdev, &rdev->wdev_list, list) {
                 if (!wdev->beacon_interval)
                         continue;
@@ -1221,8 +1213,6 @@ int cfg80211_validate_beacon_int(struct cfg80211_registered_device *rdev,
                 }
         }
 
-        mutex_unlock(&rdev->devlist_mtx);
-
         return res;
 }
 
@@ -1246,7 +1236,6 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
         int i, j;
 
         ASSERT_RTNL();
-        lockdep_assert_held(&rdev->devlist_mtx);
 
         if (WARN_ON(hweight32(radar_detect) > 1))
                 return -EINVAL;