From a6130a78669e06c1f66cbf5b4b02320667a56762 Mon Sep 17 00:00:00 2001
From: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Date: Wed, 30 May 2012 12:27:12 +0530
Subject: [PATCH] ath6kl: Fix unstable downlink throughput

There is frequent downlink throughput drop to 0 when operating
at the signal level between -42dBm to -53dBm. This has been root
caused to the delay in releasing pending a-mpdu subframes in
reorder buffer. Right now the timeout value is 400ms, there
is also a race condition where timeout handler can be delayed
to run at an extra timeout interval. This patch reduces the
timout interval to reasonable 100ms and makes sure releasing
pending frames are not skipped in the timeout handler by removing
the flag (rxtid->progress) which can delay the timeout logic.

Reported-by: Yu Yanzhi <yanzhiy@qca.qualcomm.com>
Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
---
 drivers/net/wireless/ath/ath6kl/core.h |  3 +-
 drivers/net/wireless/ath/ath6kl/txrx.c | 42 +++++++++++---------------
 2 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/drivers/net/wireless/ath/ath6kl/core.h b/drivers/net/wireless/ath/ath6kl/core.h
index 12441f7d90365..b3eee10cf016a 100644
--- a/drivers/net/wireless/ath/ath6kl/core.h
+++ b/drivers/net/wireless/ath/ath6kl/core.h
@@ -215,7 +215,7 @@ enum ath6kl_hw_flags {
 
 #define AGGR_NUM_OF_FREE_NETBUFS    16
 
-#define AGGR_RX_TIMEOUT     400	/* in ms */
+#define AGGR_RX_TIMEOUT     100	/* in ms */
 
 #define WMI_TIMEOUT (2 * HZ)
 
@@ -264,7 +264,6 @@ struct skb_hold_q {
 
 struct rxtid {
 	bool aggr;
-	bool progress;
 	bool timer_mon;
 	u16 win_sz;
 	u16 seq_next;
diff --git a/drivers/net/wireless/ath/ath6kl/txrx.c b/drivers/net/wireless/ath/ath6kl/txrx.c
index 974c51053a714..7dfa0fd86d7b1 100644
--- a/drivers/net/wireless/ath/ath6kl/txrx.c
+++ b/drivers/net/wireless/ath/ath6kl/txrx.c
@@ -1186,28 +1186,25 @@ static bool aggr_process_recv_frm(struct aggr_info_conn *agg_conn, u8 tid,
 	aggr_deque_frms(agg_conn, tid, 0, 1);
 
 	if (agg_conn->timer_scheduled)
-		rxtid->progress = true;
-	else {
-		spin_lock_bh(&rxtid->lock);
-		for (idx = 0 ; idx < rxtid->hold_q_sz; idx++) {
-			if (rxtid->hold_q[idx].skb) {
-				/*
-				 * There is a frame in the queue and no
-				 * timer so start a timer to ensure that
-				 * the frame doesn't remain stuck
-				 * forever.
-				 */
-				agg_conn->timer_scheduled = true;
-				mod_timer(&agg_conn->timer,
-					  (jiffies +
-					   HZ * (AGGR_RX_TIMEOUT) / 1000));
-				rxtid->progress = false;
-				rxtid->timer_mon = true;
-				break;
-			}
+		return is_queued;
+
+	spin_lock_bh(&rxtid->lock);
+	for (idx = 0 ; idx < rxtid->hold_q_sz; idx++) {
+		if (rxtid->hold_q[idx].skb) {
+			/*
+			 * There is a frame in the queue and no
+			 * timer so start a timer to ensure that
+			 * the frame doesn't remain stuck
+			 * forever.
+			 */
+			agg_conn->timer_scheduled = true;
+			mod_timer(&agg_conn->timer,
+				  (jiffies + (HZ * AGGR_RX_TIMEOUT) / 1000));
+			rxtid->timer_mon = true;
+			break;
 		}
-		spin_unlock_bh(&rxtid->lock);
 	}
+	spin_unlock_bh(&rxtid->lock);
 
 	return is_queued;
 }
@@ -1612,7 +1609,7 @@ static void aggr_timeout(unsigned long arg)
 		rxtid = &aggr_conn->rx_tid[i];
 		stats = &aggr_conn->stat[i];
 
-		if (!rxtid->aggr || !rxtid->timer_mon || rxtid->progress)
+		if (!rxtid->aggr || !rxtid->timer_mon)
 			continue;
 
 		stats->num_timeouts++;
@@ -1635,7 +1632,6 @@ static void aggr_timeout(unsigned long arg)
 				if (rxtid->hold_q[j].skb) {
 					aggr_conn->timer_scheduled = true;
 					rxtid->timer_mon = true;
-					rxtid->progress = false;
 					break;
 				}
 			}
@@ -1666,7 +1662,6 @@ static void aggr_delete_tid_state(struct aggr_info_conn *aggr_conn, u8 tid)
 		aggr_deque_frms(aggr_conn, tid, 0, 0);
 
 	rxtid->aggr = false;
-	rxtid->progress = false;
 	rxtid->timer_mon = false;
 	rxtid->win_sz = 0;
 	rxtid->seq_next = 0;
@@ -1745,7 +1740,6 @@ void aggr_conn_init(struct ath6kl_vif *vif, struct aggr_info *aggr_info,
 	for (i = 0; i < NUM_OF_TIDS; i++) {
 		rxtid = &aggr_conn->rx_tid[i];
 		rxtid->aggr = false;
-		rxtid->progress = false;
 		rxtid->timer_mon = false;
 		skb_queue_head_init(&rxtid->q);
 		spin_lock_init(&rxtid->lock);
-- 
2.39.5