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ath6kl: Fix lockdep warning

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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>
This commit is contained in:
Vasanthakumar Thiagarajan 2011-11-01 16:38:50 +05:30 committed by Kalle Valo
parent b4b2a0b116
commit 11f6e40d9f
5 changed files with 20 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/net/wireless/ath/ath6kl/cfg80211.c
View File

@ -1320,9 +1320,9 @@ static int ath6kl_cfg80211_del_iface(struct wiphy *wiphy,
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 @@ struct net_device *ath6kl_interface_add(struct ath6kl *ar, char *name,
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;

8
drivers/net/wireless/ath/ath6kl/init.c
View File

@ -1685,17 +1685,17 @@ void ath6kl_stop_txrx(struct ath6kl *ar)
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_del(&vif->list);
spin_unlock(&ar->list_lock);
spin_unlock_bh(&ar->list_lock);
ath6kl_cleanup_vif(vif, test_bit(WMI_READY, &ar->flag));
rtnl_lock();
ath6kl_deinit_if_data(vif);
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);

6
drivers/net/wireless/ath/ath6kl/main.c
View File

@ -1046,15 +1046,15 @@ struct ath6kl_vif *ath6kl_vif_first(struct ath6kl *ar)
{
struct ath6kl_vif *vif;
spin_lock(&ar->list_lock);
spin_lock_bh(&ar->list_lock);
if (list_empty(&ar->vif_list)) {
spin_unlock(&ar->list_lock);
spin_unlock_bh(&ar->list_lock);
return NULL;
}
vif = list_first_entry(&ar->vif_list, struct ath6kl_vif, list);
spin_unlock(&ar->list_lock);
spin_unlock_bh(&ar->list_lock);
return vif;
}

14
drivers/net/wireless/ath/ath6kl/txrx.c
View File

@ -470,10 +470,10 @@ enum htc_send_full_action ath6kl_tx_queue_full(struct htc_target *target,
stop_adhoc_netq:
/* FIXME: Locking */
spin_lock(&ar->list_lock);
spin_lock_bh(&ar->list_lock);
list_for_each_entry(vif, &ar->vif_list, list) {
if (vif->nw_type == ADHOC_NETWORK) {
spin_unlock(&ar->list_lock);
spin_unlock_bh(&ar->list_lock);
spin_lock_bh(&vif->if_lock);
set_bit(NETQ_STOPPED, &vif->flags);
@ -483,7 +483,7 @@ stop_adhoc_netq:
return action;
}
}
spin_unlock(&ar->list_lock);
spin_unlock_bh(&ar->list_lock);
return action;
}
@ -637,16 +637,16 @@ void ath6kl_tx_complete(void *context, struct list_head *packet_queue)
__skb_queue_purge(&skb_queue);
/* FIXME: Locking */
spin_lock(&ar->list_lock);
spin_lock_bh(&ar->list_lock);
list_for_each_entry(vif, &ar->vif_list, list) {
if (test_bit(CONNECTED, &vif->flags) &&
!flushing[vif->fw_vif_idx]) {
spin_unlock(&ar->list_lock);
spin_unlock_bh(&ar->list_lock);
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)
wake_up(&ar->event_wq);

4
drivers/net/wireless/ath/ath6kl/wmi.c
View File

@ -89,14 +89,14 @@ struct ath6kl_vif *ath6kl_get_vif_by_index(struct ath6kl *ar, u8 if_idx)
return NULL;
/* FIXME: Locking */
spin_lock(&ar->list_lock);
spin_lock_bh(&ar->list_lock);
list_for_each_entry(vif, &ar->vif_list, list) {
if (vif->fw_vif_idx == if_idx) {
found = vif;
break;
}
}
spin_unlock(&ar->list_lock);
spin_unlock_bh(&ar->list_lock);
return found;
}