mac80211: fix deadlock with multiple interfaces

The locking around ieee80211_recalc_smps is
buggy -- it cannot acquire another interface's
mutex while the iflist mutex is held because
another code path could be holding the iface
mutex and trying to acquire the iflist mutex.

But the locking is also unnecessary, we only
check "ifmgd->associated" as a bool, and don't
use the pointer (in check_mgd_smps).

Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 55d79db985fc..08509e212841 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1297,8 +1297,7 @@ u32 ieee80211_sta_get_rates(struct ieee80211_local *local,
                             enum ieee80211_band band);
 int __ieee80211_request_smps(struct ieee80211_sub_if_data *sdata,
                              enum ieee80211_smps_mode smps_mode);
-void ieee80211_recalc_smps(struct ieee80211_local *local,
-                           struct ieee80211_sub_if_data *forsdata);
+void ieee80211_recalc_smps(struct ieee80211_local *local);
 
 size_t ieee80211_ie_split(const u8 *ies, size_t ielen,
                           const u8 *ids, int n_ids, size_t offset);