mwifiex: adjust high/low water marks for tx_pending queue

This is to fix an issue that the throughput of the higher priority
stream gets dropped when a lower priority stream is present.

Signed-off-by: Marc Yang <yangyang@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/main.h

@@ -69,7 +69,8 @@ struct mwifiex_drv_mode {
 #define MWIFIEX_TIMER_10S			10000
 #define MWIFIEX_TIMER_1S			1000
 
-#define MAX_TX_PENDING      60
+#define MAX_TX_PENDING      100
+#define LOW_TX_PENDING      80
 
 #define MWIFIEX_UPLD_SIZE               (2312)
 

drivers/net/wireless/mwifiex/txrx.c

@@ -140,7 +140,9 @@ int mwifiex_write_data_complete(struct mwifiex_adapter *adapter,
 	} else {
 		priv->stats.tx_errors++;
 	}
-	atomic_dec(&adapter->tx_pending);
+
+	if (atomic_dec_return(&adapter->tx_pending) >= LOW_TX_PENDING)
+		goto done;
 
 	for (i = 0; i < adapter->priv_num; i++) {