ath10k: fix bug reported by lockdep

ath10k_tx_wep_key_work() acquires conf_mutex, so
cancelling it when conf_mutex is already taken
in ath10k_remove_interface() is incorrect, so
move it outside the lock.

Snippet from the lockdep report:

kernel: ======================================================
kernel: [ INFO: possible circular locking dependency detected ]
kernel: 3.18.0-rc5-wl-debug #34 Tainted: G           O
kernel: -------------------------------------------------------
kernel: hostapd/451 is trying to acquire lock:
kernel:  ((&arvif->wep_key_work)){+.+...}, at: [<ffffffff810872d5>] flush_work+0x5/0x290
kernel: but task is already holding lock:
kernel:  (&ar->conf_mutex){+.+.+.}, at: [<ffffffffa0b99f00>] ath10k_remove_interface+0x40/0x290 [ath10k_core]
kernel: which lock already depends on the new lock.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index d5aaaa0b9e152e050e5e21e39144de385d6f08a9..982bd48227e5da624e71688662735e240ea0f6dd 100644 (file)
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -3101,10 +3101,10 @@ static void ath10k_remove_interface(struct ieee80211_hw *hw,
        struct ath10k_vif *arvif = ath10k_vif_to_arvif(vif);
        int ret;
 
-       mutex_lock(&ar->conf_mutex);
-
        cancel_work_sync(&arvif->wep_key_work);
 
+       mutex_lock(&ar->conf_mutex);
+
        spin_lock_bh(&ar->data_lock);
        ath10k_mac_vif_beacon_cleanup(arvif);
        spin_unlock_bh(&ar->data_lock);