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cfg80211: fix locking and lockdep complaints 

To call cfg80211_get_chan_state() we need to lock
the wdev, so we need to lock the wdev_iter mutex
in cfg80211_can_use_iftype_chan(). This needs to
use nested locking for lockdep.

Also, cfg80211_get_chan_state() doesn't actually
use the rdev, so remove that completely including
the lock assertion that isn't needed.

Reported-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2012-07-10 19:39:02 +02:00
parent 2a9e6c5887
commit 8e95ea49c9
3 changed files with 12 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
net/wireless/chan.c
View File

@ -103,15 +103,13 @@ int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
}
void
cfg80211_get_chan_state(struct cfg80211_registered_device *rdev,
struct wireless_dev *wdev,
cfg80211_get_chan_state(struct wireless_dev *wdev,
struct ieee80211_channel **chan,
enum cfg80211_chan_mode *chanmode)
{
*chan = NULL;
*chanmode = CHAN_MODE_UNDEFINED;
ASSERT_RDEV_LOCK(rdev);
ASSERT_WDEV_LOCK(wdev);
if (!netif_running(wdev->netdev))

3
net/wireless/core.h
View File

@ -463,8 +463,7 @@ cfg80211_can_use_chan(struct cfg80211_registered_device *rdev,
}
void
cfg80211_get_chan_state(struct cfg80211_registered_device *rdev,
struct wireless_dev *wdev,
cfg80211_get_chan_state(struct wireless_dev *wdev,
struct ieee80211_channel **chan,
enum cfg80211_chan_mode *chanmode);

11
net/wireless/util.c
View File

@ -1059,7 +1059,16 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
if (rdev->wiphy.software_iftypes & BIT(wdev_iter->iftype))
continue;
cfg80211_get_chan_state(rdev, wdev_iter, &ch, &chmode);
/*
* We may be holding the "wdev" mutex, but now need to lock
* wdev_iter. This is OK because once we get here wdev_iter
* is not wdev (tested above), but we need to use the nested
* locking for lockdep.
*/
mutex_lock_nested(&wdev_iter->mtx, 1);
__acquire(wdev_iter->mtx);
cfg80211_get_chan_state(wdev_iter, &ch, &chmode);
wdev_unlock(wdev_iter);
switch (chmode) {
case CHAN_MODE_UNDEFINED: