[PATCH] ath10k: fix kernel panic while shutting down AP

[Rajkumar Manoharan]

The commit "ath10k: workaround fw beaconing bug" is freeing
DMA-coherent memory in irq context which is hitting BUG ON
in ARM platforms. Fix this by moving dma_free out of spin
lock.

kernel BUG at mm/vmalloc.c:1512!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
CPU: 0 PID: 722 Comm: hostapd Not tainted 3.14.0 #3
task: dd58b840 ti: da6a6000 task.ti: da6a6000
PC is at vunmap+0x24/0x34
LR is at __arm_dma_free.isra.21+0x12c/0x190
[<c02a97d0>] (vunmap) from [<c021f81c>] (__arm_dma_free.isra.21+0x12c/0x190)
[<c021f81c>] (__arm_dma_free.isra.21) from [<bf3b2440>]
			(ath10k_mac_vif_beacon_free+0xf4/0x100 [ath10k_core])
[<bf3b2440>] (ath10k_mac_vif_beacon_free [ath10k_core]) from [<bf3b2490>]
			(ath10k_remove_interface+0x44/0x1ec [ath10k_core])
[<bf3b2490>] (ath10k_remove_interface [ath10k_core]) from [<bf3352e4>]
			(ieee80211_add_virtual_monitor+0x9d8/0x9f0 [mac80211])
[<bf3352e4>] (ieee80211_add_virtual_monitor [mac80211]) from [<bf33530c>]
			(ieee80211_stop+0x10/0x18 [mac80211])
[<bf33530c>] (ieee80211_stop [mac80211]) from [<c040d144>]
			(__dev_close_many+0x9c/0xcc)

Cc: Michal Kazior <michal.kazior at tieto.com>
Signed-off-by: Rajkumar Manoharan <rmanohar at qti.qualcomm.com>
---
 drivers/net/wireless/ath/ath10k/mac.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index bf8333c..dd4f56a 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -498,21 +498,6 @@ void ath10k_mac_vif_beacon_free(struct ath10k_vif *arvif)
 	arvif->beacon_sent = false;
 }
 
-static void ath10k_mac_vif_beacon_cleanup(struct ath10k_vif *arvif)
-{
-	struct ath10k *ar = arvif->ar;
-
-	lockdep_assert_held(&ar->data_lock);
-
-	ath10k_mac_vif_beacon_free(arvif);
-
-	if (arvif->beacon_buf) {
-		dma_free_coherent(ar->dev, IEEE80211_MAX_FRAME_LEN,
-				  arvif->beacon_buf, arvif->beacon_paddr);
-		arvif->beacon_buf = NULL;
-	}
-}
-
 static inline int ath10k_vdev_setup_sync(struct ath10k *ar)
 {
 	int ret;
@@ -2404,8 +2389,15 @@ void ath10k_halt(struct ath10k *ar)
 
 	spin_lock_bh(&ar->data_lock);
 	list_for_each_entry(arvif, &ar->arvifs, list)
-		ath10k_mac_vif_beacon_cleanup(arvif);
+		ath10k_mac_vif_beacon_free(arvif);
 	spin_unlock_bh(&ar->data_lock);
+	list_for_each_entry(arvif, &ar->arvifs, list) {
+		if (!arvif->beacon_buf)
+			continue;
+		dma_free_coherent(ar->dev, IEEE80211_MAX_FRAME_LEN,
+				  arvif->beacon_buf, arvif->beacon_paddr);
+		arvif->beacon_buf = NULL;
+	}
 }
 
 static int ath10k_get_antenna(struct ieee80211_hw *hw, u32 *tx_ant, u32 *rx_ant)
@@ -2988,9 +2980,15 @@ static void ath10k_remove_interface(struct ieee80211_hw *hw,
 	cancel_work_sync(&arvif->wep_key_work);
 
 	spin_lock_bh(&ar->data_lock);
-	ath10k_mac_vif_beacon_cleanup(arvif);
+	ath10k_mac_vif_beacon_free(arvif);
 	spin_unlock_bh(&ar->data_lock);
 
+	if (arvif->beacon_buf) {
+		dma_free_coherent(ar->dev, IEEE80211_MAX_FRAME_LEN,
+				  arvif->beacon_buf, arvif->beacon_paddr);
+		arvif->beacon_buf = NULL;
+	}
+
 	ret = ath10k_spectral_vif_stop(arvif);
 	if (ret)
 		ath10k_warn(ar, "failed to stop spectral for vdev %i: %d\n",
-- 
2.1.2