ath6kl: Fix lockdep warning
The following is the lockdep warning which detects possible
deadlock condition with the way ar->lock and ar->list_lock
are being used.
(&(&ar->lock)->rlock){+.-...}, at: [<ffffffffa0492d13>] ath6kl_indicate_tx_activity+0x83/0x110 [ath6kl]
but this lock took another, SOFTIRQ-unsafe lock in the past:
(&(&ar->list_lock)->rlock){+.+...}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&(&ar->list_lock)->rlock);
local_irq_disable();
lock(&(&ar->lock)->rlock);
lock(&(&ar->list_lock)->rlock);
<Interrupt>
lock(&(&ar->lock)->rlock);
*** DEADLOCK ***
softirqs have to be disabled when acquiring ar->list_lock to avoid
the above deadlock condition. When the above warning printed the
interface is still up and running without issue.
Reported-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath6kl/cfg80211.c b/drivers/net/wireless/ath/ath6kl/cfg80211.c
index 5dab4f2..4a880b4 100644
--- a/drivers/net/wireless/ath/ath6kl/cfg80211.c
+++ b/drivers/net/wireless/ath/ath6kl/cfg80211.c
@@ -1320,9 +1320,9 @@
struct ath6kl *ar = wiphy_priv(wiphy);
struct ath6kl_vif *vif = netdev_priv(ndev);
- spin_lock(&ar->list_lock);
+ spin_lock_bh(&ar->list_lock);
list_del(&vif->list);
- spin_unlock(&ar->list_lock);
+ spin_unlock_bh(&ar->list_lock);
ath6kl_cleanup_vif(vif, test_bit(WMI_READY, &ar->flag));
@@ -2437,9 +2437,9 @@
if (type == NL80211_IFTYPE_ADHOC)
ar->ibss_if_active = true;
- spin_lock(&ar->list_lock);
+ spin_lock_bh(&ar->list_lock);
list_add_tail(&vif->list, &ar->vif_list);
- spin_unlock(&ar->list_lock);
+ spin_unlock_bh(&ar->list_lock);
return ndev;