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>
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 2ce44a7..dd01b58 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -169,7 +169,7 @@
union iwreq_data wrqu;
#endif
- lockdep_assert_held(&rdev->sched_scan_mtx);
+ ASSERT_RTNL();
request = rdev->scan_req;
@@ -230,9 +230,9 @@
rdev = container_of(wk, struct cfg80211_registered_device,
scan_done_wk);
- mutex_lock(&rdev->sched_scan_mtx);
+ rtnl_lock();
___cfg80211_scan_done(rdev, false);
- mutex_unlock(&rdev->sched_scan_mtx);
+ rtnl_unlock();
}
void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted)
@@ -241,6 +241,7 @@
WARN_ON(request != wiphy_to_dev(request->wiphy)->scan_req);
request->aborted = aborted;
+ request->notified = true;
queue_work(cfg80211_wq, &wiphy_to_dev(request->wiphy)->scan_done_wk);
}
EXPORT_SYMBOL(cfg80211_scan_done);
@@ -255,7 +256,7 @@
request = rdev->sched_scan_req;
- mutex_lock(&rdev->sched_scan_mtx);
+ rtnl_lock();
/* we don't have sched_scan_req anymore if the scan is stopping */
if (request) {
@@ -270,7 +271,7 @@
nl80211_send_sched_scan_results(rdev, request->dev);
}
- mutex_unlock(&rdev->sched_scan_mtx);
+ rtnl_unlock();
}
void cfg80211_sched_scan_results(struct wiphy *wiphy)
@@ -289,9 +290,9 @@
trace_cfg80211_sched_scan_stopped(wiphy);
- mutex_lock(&rdev->sched_scan_mtx);
+ rtnl_lock();
__cfg80211_stop_sched_scan(rdev, true);
- mutex_unlock(&rdev->sched_scan_mtx);
+ rtnl_unlock();
}
EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
@@ -300,7 +301,7 @@
{
struct net_device *dev;
- lockdep_assert_held(&rdev->sched_scan_mtx);
+ ASSERT_RTNL();
if (!rdev->sched_scan_req)
return -ENOENT;
@@ -1043,21 +1044,19 @@
static struct cfg80211_registered_device *
cfg80211_get_dev_from_ifindex(struct net *net, int ifindex)
{
- struct cfg80211_registered_device *rdev = ERR_PTR(-ENODEV);
+ struct cfg80211_registered_device *rdev;
struct net_device *dev;
- mutex_lock(&cfg80211_mutex);
+ ASSERT_RTNL();
+
dev = dev_get_by_index(net, ifindex);
if (!dev)
- goto out;
- if (dev->ieee80211_ptr) {
+ return ERR_PTR(-ENODEV);
+ if (dev->ieee80211_ptr)
rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
- mutex_lock(&rdev->mtx);
- } else
+ else
rdev = ERR_PTR(-ENODEV);
dev_put(dev);
- out:
- mutex_unlock(&cfg80211_mutex);
return rdev;
}
@@ -1083,7 +1082,6 @@
if (IS_ERR(rdev))
return PTR_ERR(rdev);
- mutex_lock(&rdev->sched_scan_mtx);
if (rdev->scan_req) {
err = -EBUSY;
goto out;
@@ -1190,9 +1188,7 @@
dev_hold(dev);
}
out:
- mutex_unlock(&rdev->sched_scan_mtx);
kfree(creq);
- cfg80211_unlock_rdev(rdev);
return err;
}
EXPORT_SYMBOL_GPL(cfg80211_wext_siwscan);
@@ -1491,10 +1487,8 @@
if (IS_ERR(rdev))
return PTR_ERR(rdev);
- if (rdev->scan_req) {
- res = -EAGAIN;
- goto out;
- }
+ if (rdev->scan_req)
+ return -EAGAIN;
res = ieee80211_scan_results(rdev, info, extra, data->length);
data->length = 0;
@@ -1503,8 +1497,6 @@
res = 0;
}
- out:
- cfg80211_unlock_rdev(rdev);
return res;
}
EXPORT_SYMBOL_GPL(cfg80211_wext_giwscan);