[v2,2/4] wl1271: Fix TX starvation

Commit Message

Ido Yariv Oct. 12, 2010, 8:53 a.m. UTC

None

Patch

diff --git a/drivers/net/wireless/wl12xx/wl1271.h b/drivers/net/wireless/wl12xx/wl1271.h
index 8a4cd76..4a034a3 100644
--- a/drivers/net/wireless/wl12xx/wl1271.h
+++ b/drivers/net/wireless/wl12xx/wl1271.h
@@ -351,6 +351,7 @@  struct wl1271 {
 #define WL1271_FLAG_IDLE_REQUESTED    (11)
 #define WL1271_FLAG_PSPOLL_FAILURE    (12)
 #define WL1271_FLAG_STA_STATE_SENT    (13)
+#define WL1271_FLAG_FW_TX_BUSY        (14)
 	unsigned long flags;
 
 	struct wl1271_partition_set part;
diff --git a/drivers/net/wireless/wl12xx/wl1271_main.c b/drivers/net/wireless/wl12xx/wl1271_main.c
index 48a4b99..18aff22 100644
--- a/drivers/net/wireless/wl12xx/wl1271_main.c
+++ b/drivers/net/wireless/wl12xx/wl1271_main.c
@@ -481,9 +481,9 @@  static void wl1271_fw_status(struct wl1271 *wl,
 		total += cnt;
 	}
 
-	/* if more blocks are available now, schedule some tx work */
-	if (total && !skb_queue_empty(&wl->tx_queue))
-		ieee80211_queue_work(wl->hw, &wl->tx_work);
+	/* if more blocks are available now, tx work can be scheduled */
+	if (total)
+		clear_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags);
 
 	/* update the host-chipset time offset */
 	getnstimeofday(&ts);
@@ -537,6 +537,16 @@  static void wl1271_irq_work(struct work_struct *work)
 			    (wl->tx_results_count & 0xff))
 				wl1271_tx_complete(wl);
 
+			/* Check if any tx blocks were freed */
+			if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags) &&
+					!skb_queue_empty(&wl->tx_queue)) {
+				/*
+				 * In order to avoid starvation of the TX path,
+				 * call the work function directly.
+				 */
+				wl1271_tx_work_locked(wl);
+			}
+
 			wl1271_rx(wl, wl->fw_status);
 		}
 
@@ -867,7 +877,8 @@  static int wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 	 * before that, the tx_work will not be initialized!
 	 */
 
-	ieee80211_queue_work(wl->hw, &wl->tx_work);
+	if (!test_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags))
+		ieee80211_queue_work(wl->hw, &wl->tx_work);
 
 	/*
 	 * The workqueue is slow to process the tx_queue and we need stop
diff --git a/drivers/net/wireless/wl12xx/wl1271_tx.c b/drivers/net/wireless/wl12xx/wl1271_tx.c
index b13b373..cf32a77 100644
--- a/drivers/net/wireless/wl12xx/wl1271_tx.c
+++ b/drivers/net/wireless/wl12xx/wl1271_tx.c
@@ -204,9 +204,8 @@  u32 wl1271_tx_enabled_rates_get(struct wl1271 *wl, u32 rate_set)
 	return enabled_rates;
 }
 
-void wl1271_tx_work(struct work_struct *work)
+void wl1271_tx_work_locked(struct wl1271 *wl)
 {
-	struct wl1271 *wl = container_of(work, struct wl1271, tx_work);
 	struct sk_buff *skb;
 	bool woken_up = false;
 	u32 sta_rates = 0;
@@ -223,8 +222,6 @@  void wl1271_tx_work(struct work_struct *work)
 		spin_unlock_irqrestore(&wl->wl_lock, flags);
 	}
 
-	mutex_lock(&wl->mutex);
-
 	if (unlikely(wl->state == WL1271_STATE_OFF))
 		goto out;
 
@@ -260,6 +257,8 @@  void wl1271_tx_work(struct work_struct *work)
 			 * Queue back last skb, and stop aggregating.
 			 */
 			skb_queue_head(&wl->tx_queue, skb);
+			/* No work left, avoid scheduling redundant tx work */
+			set_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags);
 			goto out_ack;
 		} else if (ret < 0) {
 			dev_kfree_skb(skb);
@@ -283,7 +282,14 @@  out_ack:
 out:
 	if (woken_up)
 		wl1271_ps_elp_sleep(wl);
+}
 
+void wl1271_tx_work(struct work_struct *work)
+{
+	struct wl1271 *wl = container_of(work, struct wl1271, tx_work);
+
+	mutex_lock(&wl->mutex);
+	wl1271_tx_work_locked(wl);
 	mutex_unlock(&wl->mutex);
 }
 
diff --git a/drivers/net/wireless/wl12xx/wl1271_tx.h b/drivers/net/wireless/wl12xx/wl1271_tx.h
index d12a129..f1c9065 100644
--- a/drivers/net/wireless/wl12xx/wl1271_tx.h
+++ b/drivers/net/wireless/wl12xx/wl1271_tx.h
@@ -140,6 +140,7 @@  static inline int wl1271_tx_get_queue(int queue)
 }
 
 void wl1271_tx_work(struct work_struct *work);
+void wl1271_tx_work_locked(struct wl1271 *wl);
 void wl1271_tx_complete(struct wl1271 *wl);
 void wl1271_tx_reset(struct wl1271 *wl);
 void wl1271_tx_flush(struct wl1271 *wl);