ath9k_htc: Queue WMI events

Use a queue to handle WMI events and schedule a tasklet
to process the events. This fixes the race between the
WMI event ISR and the SWBA tasklet when the arrival of
WMI events in quick succession could overwrite the SWBA
data before the tasklet from a previous iteration could
have been scheduled. Also, drain the WMI queue properly.

Signed-off-by: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 63 insertions, 34 deletions

diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c
index a39552b3077b..45784754dbc2 100644
--- a/drivers/net/wireless/ath/ath9k/wmi.c
+++ b/drivers/net/wireless/ath/ath9k/wmi.c
@@ -104,9 +104,12 @@ struct wmi *ath9k_init_wmi(struct ath9k_htc_priv *priv)
 
         wmi->drv_priv = priv;
         wmi->stopped = false;
+        skb_queue_head_init(&wmi->wmi_event_queue);
         mutex_init(&wmi->op_mutex);
         mutex_init(&wmi->multi_write_mutex);
         init_completion(&wmi->cmd_wait);
+        tasklet_init(&wmi->wmi_event_tasklet, ath9k_wmi_event_tasklet,
+                     (unsigned long)wmi);
 
         return wmi;
 }
@@ -122,11 +125,64 @@ void ath9k_deinit_wmi(struct ath9k_htc_priv *priv)
         kfree(priv->wmi);
 }
 
-void ath9k_swba_tasklet(unsigned long data)
+void ath9k_wmi_event_drain(struct ath9k_htc_priv *priv)
 {
-        struct ath9k_htc_priv *priv = (struct ath9k_htc_priv *)data;
+        unsigned long flags;
 
-        ath9k_htc_swba(priv);
+        tasklet_kill(&priv->wmi->wmi_event_tasklet);
+        spin_lock_irqsave(&priv->wmi->wmi_lock, flags);
+        __skb_queue_purge(&priv->wmi->wmi_event_queue);
+        spin_unlock_irqrestore(&priv->wmi->wmi_lock, flags);
+}
+
+void ath9k_wmi_event_tasklet(unsigned long data)
+{
+        struct wmi *wmi = (struct wmi *)data;
+        struct ath9k_htc_priv *priv = wmi->drv_priv;
+        struct wmi_cmd_hdr *hdr;
+        void *wmi_event;
+        struct wmi_event_swba *swba;
+        struct sk_buff *skb = NULL;
+        unsigned long flags;
+        u16 cmd_id;
+#ifdef CONFIG_ATH9K_HTC_DEBUGFS
+        __be32 txrate;
+#endif
+
+        do {
+                spin_lock_irqsave(&wmi->wmi_lock, flags);
+                skb = __skb_dequeue(&wmi->wmi_event_queue);
+                if (!skb) {
+                        spin_unlock_irqrestore(&wmi->wmi_lock, flags);
+                        return;
+                }
+                spin_unlock_irqrestore(&wmi->wmi_lock, flags);
+
+                hdr = (struct wmi_cmd_hdr *) skb->data;
+                cmd_id = be16_to_cpu(hdr->command_id);
+                wmi_event = skb_pull(skb, sizeof(struct wmi_cmd_hdr));
+
+                switch (cmd_id) {
+                case WMI_SWBA_EVENTID:
+                        swba = (struct wmi_event_swba *) wmi_event;
+                        ath9k_htc_swba(priv, swba);
+                        break;
+                case WMI_FATAL_EVENTID:
+                        ieee80211_queue_work(wmi->drv_priv->hw,
+                                             &wmi->drv_priv->fatal_work);
+                        break;
+                case WMI_TXRATE_EVENTID:
+#ifdef CONFIG_ATH9K_HTC_DEBUGFS
+                        txrate = ((struct wmi_event_txrate *)wmi_event)->txrate;
+                        wmi->drv_priv->debug.txrate = be32_to_cpu(txrate);
+#endif
+                        break;
+                default:
+                        break;
+                }
+
+                kfree_skb(skb);
+        } while (1);
 }
 
 void ath9k_fatal_work(struct work_struct *work)
@@ -155,11 +211,6 @@ static void ath9k_wmi_ctrl_rx(void *priv, struct sk_buff *skb,
         struct wmi *wmi = (struct wmi *) priv;
         struct wmi_cmd_hdr *hdr;
         u16 cmd_id;
-        void *wmi_event;
-        struct wmi_event_swba *swba;
-#ifdef CONFIG_ATH9K_HTC_DEBUGFS
-        __be32 txrate;
-#endif
 
         if (unlikely(wmi->stopped))
                 goto free_skb;
@@ -168,32 +219,10 @@ static void ath9k_wmi_ctrl_rx(void *priv, struct sk_buff *skb,
         cmd_id = be16_to_cpu(hdr->command_id);
 
         if (cmd_id & 0x1000) {
-                wmi_event = skb_pull(skb, sizeof(struct wmi_cmd_hdr));
-                switch (cmd_id) {
-                case WMI_SWBA_EVENTID:
-                        swba = (struct wmi_event_swba *) wmi_event;
-
-                        spin_lock(&wmi->wmi_lock);
-                        wmi->tsf = be64_to_cpu(swba->tsf);
-                        wmi->beacon_pending = swba->beacon_pending;
-                        spin_unlock(&wmi->wmi_lock);
-
-                        tasklet_schedule(&wmi->drv_priv->swba_tasklet);
-                        break;
-                case WMI_FATAL_EVENTID:
-                        ieee80211_queue_work(wmi->drv_priv->hw,
-                                             &wmi->drv_priv->fatal_work);
-                        break;
-                case WMI_TXRATE_EVENTID:
-#ifdef CONFIG_ATH9K_HTC_DEBUGFS
-                        txrate = ((struct wmi_event_txrate *)wmi_event)->txrate;
-                        wmi->drv_priv->debug.txrate = be32_to_cpu(txrate);
-#endif
-                        break;
-                default:
-                        break;
-                }
-                kfree_skb(skb);
+                spin_lock(&wmi->wmi_lock);
+                __skb_queue_tail(&wmi->wmi_event_queue, skb);
+                spin_unlock(&wmi->wmi_lock);
+                tasklet_schedule(&wmi->wmi_event_tasklet);
                 return;
         }