From 8e95ea49c94908cb10e698c5637d57f0fbdc796d Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 10 Jul 2012 19:39:02 +0200 Subject: [PATCH] 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 Signed-off-by: Johannes Berg --- net/wireless/chan.c | 4 +--- net/wireless/core.h | 3 +-- net/wireless/util.c | 11 ++++++++++- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/net/wireless/chan.c b/net/wireless/chan.c index 434c56b92c3c..1cc4b7cc7372 100644 --- a/net/wireless/chan.c +++ b/net/wireless/chan.c @@ -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)) diff --git a/net/wireless/core.h b/net/wireless/core.h index eae5a25a1691..bac97da751df 100644 --- a/net/wireless/core.h +++ b/net/wireless/core.h @@ -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); diff --git a/net/wireless/util.c b/net/wireless/util.c index f7a0647bde9a..26f8cd30f712 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -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: -- 2.39.5