openwrt/target/linux/mediatek/patches-4.4/0092-net-next-mediatek-remove-superfluous-queue-wake-up-c.patch

From 538020913db04d199ce4d7e845444880e8200b5f Mon Sep 17 00:00:00 2001
From: John Crispin <john@phrozen.org>
Date: Tue, 3 May 2016 05:40:38 +0200
Subject: [PATCH 092/102] net-next: mediatek: remove superfluous queue wake up
 call

The code checks if the queue should be stopped because we are below the
threshold of free descriptors only to check if it should be started again.
If we do end up in a state where we are at the threshold limit, it makes
more sense to just stop the queue and wait for the next IRQ to trigger the
TX housekeeping again. There is no rush in enqueuing the next packet, it
needs to wait for all the others in the queue to be dispatched first
anyway.

Signed-off-by: John Crispin <john@phrozen.org>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -795,12 +795,9 @@ static int mtk_start_xmit(struct sk_buff
 	if (mtk_tx_map(skb, dev, tx_num, ring, gso) < 0)
 		goto drop;
 
-	if (unlikely(atomic_read(&ring->free_count) <= ring->thresh)) {
+	if (unlikely(atomic_read(&ring->free_count) <= ring->thresh))
 		mtk_stop_queue(eth);
-		if (unlikely(atomic_read(&ring->free_count) >
-			     ring->thresh))
-			mtk_wake_queue(eth);
-	}
+
 	spin_unlock_irqrestore(&eth->page_lock, flags);
 
 	return NETDEV_TX_OK;