Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b0447ecb authored by Doug Berger's avatar Doug Berger Committed by David S. Miller
Browse files

net: bcmgenet: relax lock constraints to reduce IRQ latency 



Since the ring locks are not used in a hard IRQ context it is often
not necessary to disable global IRQs while waiting on a lock.

Using less restrictive lock and unlock calls improves the real-time
responsiveness of the system.

Signed-off-by: default avatarDoug Berger <opendmb@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d215dbac

drivers/net/ethernet/broadcom/genet/bcmgenet.c

+10 −15
Original line number Diff line number Diff line
@@ -1405,11 +1405,10 @@ static unsigned int bcmgenet_tx_reclaim(struct net_device *dev, 
				struct bcmgenet_tx_ring *ring)

{

	unsigned int released;

	unsigned long flags;



	spin_lock_irqsave(&ring->lock, flags);

	spin_lock_bh(&ring->lock);

	released = __bcmgenet_tx_reclaim(dev, ring);

	spin_unlock_irqrestore(&ring->lock, flags);

	spin_unlock_bh(&ring->lock);



	return released;

}
@@ -1420,15 +1419,14 @@ static int bcmgenet_tx_poll(struct napi_struct *napi, int budget) 
		container_of(napi, struct bcmgenet_tx_ring, napi);

	unsigned int work_done = 0;

	struct netdev_queue *txq;

	unsigned long flags;



	spin_lock_irqsave(&ring->lock, flags);

	spin_lock(&ring->lock);

	work_done = __bcmgenet_tx_reclaim(ring->priv->dev, ring);

	if (ring->free_bds > (MAX_SKB_FRAGS + 1)) {

		txq = netdev_get_tx_queue(ring->priv->dev, ring->queue);

		netif_tx_wake_queue(txq);

	}

	spin_unlock_irqrestore(&ring->lock, flags);

	spin_unlock(&ring->lock);



	if (work_done == 0) {

		napi_complete(napi);
@@ -1523,7 +1521,6 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct bcmgenet_tx_ring *ring = NULL;

	struct enet_cb *tx_cb_ptr;

	struct netdev_queue *txq;

	unsigned long flags = 0;

	int nr_frags, index;

	dma_addr_t mapping;

	unsigned int size;
@@ -1550,7 +1547,7 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev) 


	nr_frags = skb_shinfo(skb)->nr_frags;



	spin_lock_irqsave(&ring->lock, flags);

	spin_lock(&ring->lock);

	if (ring->free_bds <= (nr_frags + 1)) {

		if (!netif_tx_queue_stopped(txq)) {

			netif_tx_stop_queue(txq);
@@ -1645,7 +1642,7 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev) 
		bcmgenet_tdma_ring_writel(priv, ring->index,

					  ring->prod_index, TDMA_PROD_INDEX);

out:

	spin_unlock_irqrestore(&ring->lock, flags);

	spin_unlock(&ring->lock);



	return ret;
@@ -2520,17 +2517,16 @@ static int bcmgenet_init_dma(struct bcmgenet_priv *priv) 
/* Interrupt bottom half */

static void bcmgenet_irq_task(struct work_struct *work)

{

	unsigned long flags;

	unsigned int status;

	struct bcmgenet_priv *priv = container_of(

			work, struct bcmgenet_priv, bcmgenet_irq_work);



	netif_dbg(priv, intr, priv->dev, "%s\n", __func__);



	spin_lock_irqsave(&priv->lock, flags);

	spin_lock_irq(&priv->lock);

	status = priv->irq0_stat;

	priv->irq0_stat = 0;

	spin_unlock_irqrestore(&priv->lock, flags);

	spin_unlock_irq(&priv->lock);



	/* Link UP/DOWN event */

	if (status & UMAC_IRQ_LINK_EVENT)
@@ -2927,7 +2923,6 @@ static void bcmgenet_dump_tx_queue(struct bcmgenet_tx_ring *ring) 
	u32 p_index, c_index, intsts, intmsk;

	struct netdev_queue *txq;

	unsigned int free_bds;

	unsigned long flags;

	bool txq_stopped;



	if (!netif_msg_tx_err(priv))
@@ -2935,7 +2930,7 @@ static void bcmgenet_dump_tx_queue(struct bcmgenet_tx_ring *ring) 


	txq = netdev_get_tx_queue(priv->dev, ring->queue);



	spin_lock_irqsave(&ring->lock, flags);

	spin_lock(&ring->lock);

	if (ring->index == DESC_INDEX) {

		intsts = ~bcmgenet_intrl2_0_readl(priv, INTRL2_CPU_MASK_STATUS);

		intmsk = UMAC_IRQ_TXDMA_DONE | UMAC_IRQ_TXDMA_MBDONE;
@@ -2947,7 +2942,7 @@ static void bcmgenet_dump_tx_queue(struct bcmgenet_tx_ring *ring) 
	p_index = bcmgenet_tdma_ring_readl(priv, ring->index, TDMA_PROD_INDEX);

	txq_stopped = netif_tx_queue_stopped(txq);

	free_bds = ring->free_bds;

	spin_unlock_irqrestore(&ring->lock, flags);

	spin_unlock(&ring->lock);



	netif_err(priv, tx_err, priv->dev, "Ring %d queue %d status summary\n"

		  "TX queue status: %s, interrupts: %s\n"