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Commit 11f6e40d authored by Vasanthakumar Thiagarajan's avatar Vasanthakumar Thiagarajan Committed by Kalle Valo
Browse files

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: default avatarKalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: default avatarVasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Signed-off-by: default avatarKalle Valo <kvalo@qca.qualcomm.com>
parent b4b2a0b1

drivers/net/wireless/ath/ath6kl/cfg80211.c

+4 −4
Original line number Original line Diff line number Diff line
@@ -1320,9 +1320,9 @@ static int ath6kl_cfg80211_del_iface(struct wiphy *wiphy, 
	struct ath6kl *ar = wiphy_priv(wiphy);

	struct ath6kl *ar = wiphy_priv(wiphy);

	struct ath6kl_vif *vif = netdev_priv(ndev);

	struct ath6kl_vif *vif = netdev_priv(ndev);





	spin_lock(&ar->list_lock);

	spin_lock_bh(&ar->list_lock);

	list_del(&vif->list);

	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));

	ath6kl_cleanup_vif(vif, test_bit(WMI_READY, &ar->flag));
@@ -2437,9 +2437,9 @@ struct net_device *ath6kl_interface_add(struct ath6kl *ar, char *name, 
	if (type == NL80211_IFTYPE_ADHOC)

	if (type == NL80211_IFTYPE_ADHOC)

		ar->ibss_if_active = true;

		ar->ibss_if_active = true;





	spin_lock(&ar->list_lock);

	spin_lock_bh(&ar->list_lock);

	list_add_tail(&vif->list, &ar->vif_list);

	list_add_tail(&vif->list, &ar->vif_list);

	spin_unlock(&ar->list_lock);

	spin_unlock_bh(&ar->list_lock);





	return ndev;

	return ndev;

drivers/net/wireless/ath/ath6kl/init.c

+4 −4
Original line number Original line Diff line number Diff line
@@ -1685,17 +1685,17 @@ void ath6kl_stop_txrx(struct ath6kl *ar) 
		return;

		return;

	}

	}





	spin_lock(&ar->list_lock);

	spin_lock_bh(&ar->list_lock);

	list_for_each_entry_safe(vif, tmp_vif, &ar->vif_list, list) {

	list_for_each_entry_safe(vif, tmp_vif, &ar->vif_list, list) {

		list_del(&vif->list);

		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));

		ath6kl_cleanup_vif(vif, test_bit(WMI_READY, &ar->flag));

		rtnl_lock();

		rtnl_lock();

		ath6kl_deinit_if_data(vif);

		ath6kl_deinit_if_data(vif);

		rtnl_unlock();

		rtnl_unlock();

		spin_lock(&ar->list_lock);

		spin_lock_bh(&ar->list_lock);

	}

	}

	spin_unlock(&ar->list_lock);

	spin_unlock_bh(&ar->list_lock);





	clear_bit(WMI_READY, &ar->flag);

	clear_bit(WMI_READY, &ar->flag);

drivers/net/wireless/ath/ath6kl/main.c

+3 −3
Original line number Original line Diff line number Diff line
@@ -1046,15 +1046,15 @@ struct ath6kl_vif *ath6kl_vif_first(struct ath6kl *ar) 
{

{

	struct ath6kl_vif *vif;

	struct ath6kl_vif *vif;





	spin_lock(&ar->list_lock);

	spin_lock_bh(&ar->list_lock);

	if (list_empty(&ar->vif_list)) {

	if (list_empty(&ar->vif_list)) {

		spin_unlock(&ar->list_lock);

		spin_unlock_bh(&ar->list_lock);

		return NULL;

		return NULL;

	}

	}





	vif = list_first_entry(&ar->vif_list, struct ath6kl_vif, list);

	vif = list_first_entry(&ar->vif_list, struct ath6kl_vif, list);





	spin_unlock(&ar->list_lock);

	spin_unlock_bh(&ar->list_lock);





	return vif;

	return vif;

}

}

drivers/net/wireless/ath/ath6kl/txrx.c

+7 −7
Original line number Original line Diff line number Diff line
@@ -470,10 +470,10 @@ enum htc_send_full_action ath6kl_tx_queue_full(struct htc_target *target, 




stop_adhoc_netq:

stop_adhoc_netq:

	/* FIXME: Locking */

	/* FIXME: Locking */

	spin_lock(&ar->list_lock);

	spin_lock_bh(&ar->list_lock);

	list_for_each_entry(vif, &ar->vif_list, list) {

	list_for_each_entry(vif, &ar->vif_list, list) {

		if (vif->nw_type == ADHOC_NETWORK) {

		if (vif->nw_type == ADHOC_NETWORK) {

			spin_unlock(&ar->list_lock);

			spin_unlock_bh(&ar->list_lock);





			spin_lock_bh(&vif->if_lock);

			spin_lock_bh(&vif->if_lock);

			set_bit(NETQ_STOPPED, &vif->flags);

			set_bit(NETQ_STOPPED, &vif->flags);
@@ -483,7 +483,7 @@ enum htc_send_full_action ath6kl_tx_queue_full(struct htc_target *target, 
			return action;

			return action;

		}

		}

	}

	}

	spin_unlock(&ar->list_lock);

	spin_unlock_bh(&ar->list_lock);





	return action;

	return action;

}

}
@@ -637,16 +637,16 @@ void ath6kl_tx_complete(void *context, struct list_head *packet_queue) 
	__skb_queue_purge(&skb_queue);

	__skb_queue_purge(&skb_queue);





	/* FIXME: Locking */

	/* FIXME: Locking */

	spin_lock(&ar->list_lock);

	spin_lock_bh(&ar->list_lock);

	list_for_each_entry(vif, &ar->vif_list, list) {

	list_for_each_entry(vif, &ar->vif_list, list) {

		if (test_bit(CONNECTED, &vif->flags) &&

		if (test_bit(CONNECTED, &vif->flags) &&

		    !flushing[vif->fw_vif_idx]) {

		    !flushing[vif->fw_vif_idx]) {

			spin_unlock(&ar->list_lock);

			spin_unlock_bh(&ar->list_lock);

			netif_wake_queue(vif->ndev);

			netif_wake_queue(vif->ndev);

			spin_lock(&ar->list_lock);

			spin_lock_bh(&ar->list_lock);

		}

		}

	}

	}

	spin_unlock(&ar->list_lock);

	spin_unlock_bh(&ar->list_lock);





	if (wake_event)

	if (wake_event)

		wake_up(&ar->event_wq);

		wake_up(&ar->event_wq);

drivers/net/wireless/ath/ath6kl/wmi.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -89,14 +89,14 @@ struct ath6kl_vif *ath6kl_get_vif_by_index(struct ath6kl *ar, u8 if_idx) 
		return NULL;

		return NULL;





	/* FIXME: Locking */

	/* FIXME: Locking */

	spin_lock(&ar->list_lock);

	spin_lock_bh(&ar->list_lock);

	list_for_each_entry(vif, &ar->vif_list, list) {

	list_for_each_entry(vif, &ar->vif_list, list) {

		if (vif->fw_vif_idx == if_idx) {

		if (vif->fw_vif_idx == if_idx) {

			found = vif;

			found = vif;

			break;

			break;

		}

		}

	}

	}

	spin_unlock(&ar->list_lock);

	spin_unlock_bh(&ar->list_lock);





	return found;

	return found;

}

}