netdev - Re: [PATCH] net: ethernet: mediatek: enhance the locking using the lightweight ones

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Message-ID: <d2456ca1-189e-3440-9f3b-6646fcbd82e5@phrozen.org>
Date:	Thu, 11 Aug 2016 16:28:40 +0200
From:	John Crispin <john@...ozen.org>
To:	sean.wang@...iatek.com
Cc:	keyhaede@...il.com, netdev@...r.kernel.org,
	linux-mediatek@...ts.infradead.org, davem@...emloft.net,
	Felix Fietkau <nbd@....name>
Subject: Re: [PATCH] net: ethernet: mediatek: enhance the locking using the
 lightweight ones



On 11/08/2016 11:51, sean.wang@...iatek.com wrote:
> From: Sean Wang <sean.wang@...iatek.com>
> 
> Since these critical sections protected by page_lock are all entered
> from the user context or bottom half context, they can be replaced
> with the spin_lock() or spin_lock_bh instead of spin_lock_irqsave().
> 
> Signed-off-by: Sean Wang <sean.wang@...iatek.com>

I gave this a quick spin on my board and it worked fine

Acked-by: John Crispin <john@...ozen.org>

> ---
>  drivers/net/ethernet/mediatek/mtk_eth_soc.c |   19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> index b57ae3a..3a4726e 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -353,18 +353,17 @@ static int mtk_set_mac_address(struct net_device *dev, void *p)
>  	int ret = eth_mac_addr(dev, p);
>  	struct mtk_mac *mac = netdev_priv(dev);
>  	const char *macaddr = dev->dev_addr;
> -	unsigned long flags;
>  
>  	if (ret)
>  		return ret;
>  
> -	spin_lock_irqsave(&mac->hw->page_lock, flags);
> +	spin_lock_bh(&mac->hw->page_lock);
>  	mtk_w32(mac->hw, (macaddr[0] << 8) | macaddr[1],
>  		MTK_GDMA_MAC_ADRH(mac->id));
>  	mtk_w32(mac->hw, (macaddr[2] << 24) | (macaddr[3] << 16) |
>  		(macaddr[4] << 8) | macaddr[5],
>  		MTK_GDMA_MAC_ADRL(mac->id));
> -	spin_unlock_irqrestore(&mac->hw->page_lock, flags);
> +	spin_unlock_bh(&mac->hw->page_lock);
>  
>  	return 0;
>  }
> @@ -748,7 +747,6 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
>  	struct mtk_eth *eth = mac->hw;
>  	struct mtk_tx_ring *ring = &eth->tx_ring;
>  	struct net_device_stats *stats = &dev->stats;
> -	unsigned long flags;
>  	bool gso = false;
>  	int tx_num;
>  
> @@ -756,14 +754,14 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
>  	 * however we have 2 queues running on the same ring so we need to lock
>  	 * the ring access
>  	 */
> -	spin_lock_irqsave(&eth->page_lock, flags);
> +	spin_lock(&eth->page_lock);
>  
>  	tx_num = mtk_cal_txd_req(skb);
>  	if (unlikely(atomic_read(&ring->free_count) <= tx_num)) {
>  		mtk_stop_queue(eth);
>  		netif_err(eth, tx_queued, dev,
>  			  "Tx Ring full when queue awake!\n");
> -		spin_unlock_irqrestore(&eth->page_lock, flags);
> +		spin_unlock(&eth->page_lock);
>  		return NETDEV_TX_BUSY;
>  	}
>  
> @@ -788,12 +786,12 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
>  	if (unlikely(atomic_read(&ring->free_count) <= ring->thresh))
>  		mtk_stop_queue(eth);
>  
> -	spin_unlock_irqrestore(&eth->page_lock, flags);
> +	spin_unlock(&eth->page_lock);
>  
>  	return NETDEV_TX_OK;
>  
>  drop:
> -	spin_unlock_irqrestore(&eth->page_lock, flags);
> +	spin_unlock(&eth->page_lock);
>  	stats->tx_dropped++;
>  	dev_kfree_skb(skb);
>  	return NETDEV_TX_OK;
> @@ -1347,16 +1345,15 @@ static int mtk_open(struct net_device *dev)
>  
>  static void mtk_stop_dma(struct mtk_eth *eth, u32 glo_cfg)
>  {
> -	unsigned long flags;
>  	u32 val;
>  	int i;
>  
>  	/* stop the dma engine */
> -	spin_lock_irqsave(&eth->page_lock, flags);
> +	spin_lock_bh(&eth->page_lock);
>  	val = mtk_r32(eth, glo_cfg);
>  	mtk_w32(eth, val & ~(MTK_TX_WB_DDONE | MTK_RX_DMA_EN | MTK_TX_DMA_EN),
>  		glo_cfg);
> -	spin_unlock_irqrestore(&eth->page_lock, flags);
> +	spin_unlock_bh(&eth->page_lock);
>  
>  	/* wait for dma stop */
>  	for (i = 0; i < 10; i++) {
>