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, 2 insertions, 8 deletions

diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
index d80e47194d49..5449c5a6de84 100644
--- a/net/wireless/ibss.c
+++ b/net/wireless/ibss.c
@@ -152,11 +152,11 @@ int cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
         struct wireless_dev *wdev = dev->ieee80211_ptr;
         int err;
 
-        mutex_lock(&rdev->devlist_mtx);
+        ASSERT_RTNL();
+
         wdev_lock(wdev);
         err = __cfg80211_join_ibss(rdev, dev, params, connkeys);
         wdev_unlock(wdev);
-        mutex_unlock(&rdev->devlist_mtx);
 
         return err;
 }
@@ -359,11 +359,9 @@ int cfg80211_ibss_wext_siwfreq(struct net_device *dev,
                 wdev->wext.ibss.channel_fixed = false;
         }
 
-        mutex_lock(&rdev->devlist_mtx);
         wdev_lock(wdev);
         err = cfg80211_ibss_wext_join(rdev, wdev);
         wdev_unlock(wdev);
-        mutex_unlock(&rdev->devlist_mtx);
 
         return err;
 }
@@ -429,11 +427,9 @@ int cfg80211_ibss_wext_siwessid(struct net_device *dev,
         memcpy(wdev->wext.ibss.ssid, ssid, len);
         wdev->wext.ibss.ssid_len = len;
 
-        mutex_lock(&rdev->devlist_mtx);
         wdev_lock(wdev);
         err = cfg80211_ibss_wext_join(rdev, wdev);
         wdev_unlock(wdev);
-        mutex_unlock(&rdev->devlist_mtx);
 
         return err;
 }
@@ -512,11 +508,9 @@ int cfg80211_ibss_wext_siwap(struct net_device *dev,
         } else
                 wdev->wext.ibss.bssid = NULL;
 
-        mutex_lock(&rdev->devlist_mtx);
         wdev_lock(wdev);
         err = cfg80211_ibss_wext_join(rdev, wdev);
         wdev_unlock(wdev);
-        mutex_unlock(&rdev->devlist_mtx);
 
         return err;
 }