From 8d4ac39df09c6f8078af60cd0ddd7b2435728e72 Mon Sep 17 00:00:00 2001 From: Vlastimil Setka Date: Mon, 23 Feb 2015 11:30:29 -0600 Subject: [PATCH] altera_tse: Fixes in NAPI and interrupt handling paths Incorrect NAPI polling caused WARNING at net/core/dev.c net_rx_action. Some stability issues were also seen at high throughput and system load before this patch. This patch contains several changes in altera_tse_main.c: - tse_rx() is fixed to not process more than `limit` frames - tse_poll() is refactored to match NAPI logic - only received frames are counted for return value - removed bogus condition `(rxcomplete >= budget || txcomplete > 0)` - replace by: if (rxcomplete < budget) -> call __napi_complete and enable irq - altera_isr() - replace spin_lock_irqsave() by spin_lock() - we are in isr - use spinlocks just over irq manipulation, not over __napi_schedule - reset IRQ first, then disable and schedule napi This is a cleaned up resubmission from Vlastimil's recent submission. Signed-off-by: Vlastimil Setka Signed-off-by: Roman Pisl Signed-off-by: Vince Bridgers Signed-off-by: David S. Miller --- drivers/net/ethernet/altera/altera_tse_main.c | 45 +++++++++---------- 1 file changed, 22 insertions(+), 23 deletions(-) diff --git a/drivers/net/ethernet/altera/altera_tse_main.c b/drivers/net/ethernet/altera/altera_tse_main.c index f3d784a3463d..6725dc00750b 100644 --- a/drivers/net/ethernet/altera/altera_tse_main.c +++ b/drivers/net/ethernet/altera/altera_tse_main.c @@ -376,7 +376,8 @@ static int tse_rx(struct altera_tse_private *priv, int limit) u16 pktlength; u16 pktstatus; - while ((rxstatus = priv->dmaops->get_rx_status(priv)) != 0) { + while (((rxstatus = priv->dmaops->get_rx_status(priv)) != 0) && + (count < limit)) { pktstatus = rxstatus >> 16; pktlength = rxstatus & 0xffff; @@ -491,28 +492,27 @@ static int tse_poll(struct napi_struct *napi, int budget) struct altera_tse_private *priv = container_of(napi, struct altera_tse_private, napi); int rxcomplete = 0; - int txcomplete = 0; unsigned long int flags; - txcomplete = tse_tx_complete(priv); + tse_tx_complete(priv); rxcomplete = tse_rx(priv, budget); - if (rxcomplete >= budget || txcomplete > 0) - return rxcomplete; + if (rxcomplete < budget) { - napi_gro_flush(napi, false); - __napi_complete(napi); + napi_gro_flush(napi, false); + __napi_complete(napi); - netdev_dbg(priv->dev, - "NAPI Complete, did %d packets with budget %d\n", - txcomplete+rxcomplete, budget); + netdev_dbg(priv->dev, + "NAPI Complete, did %d packets with budget %d\n", + rxcomplete, budget); - spin_lock_irqsave(&priv->rxdma_irq_lock, flags); - priv->dmaops->enable_rxirq(priv); - priv->dmaops->enable_txirq(priv); - spin_unlock_irqrestore(&priv->rxdma_irq_lock, flags); - return rxcomplete + txcomplete; + spin_lock_irqsave(&priv->rxdma_irq_lock, flags); + priv->dmaops->enable_rxirq(priv); + priv->dmaops->enable_txirq(priv); + spin_unlock_irqrestore(&priv->rxdma_irq_lock, flags); + } + return rxcomplete; } /* DMA TX & RX FIFO interrupt routing @@ -521,7 +521,6 @@ static irqreturn_t altera_isr(int irq, void *dev_id) { struct net_device *dev = dev_id; struct altera_tse_private *priv; - unsigned long int flags; if (unlikely(!dev)) { pr_err("%s: invalid dev pointer\n", __func__); @@ -529,20 +528,20 @@ static irqreturn_t altera_isr(int irq, void *dev_id) } priv = netdev_priv(dev); - /* turn off desc irqs and enable napi rx */ - spin_lock_irqsave(&priv->rxdma_irq_lock, flags); + spin_lock(&priv->rxdma_irq_lock); + /* reset IRQs */ + priv->dmaops->clear_rxirq(priv); + priv->dmaops->clear_txirq(priv); + spin_unlock(&priv->rxdma_irq_lock); if (likely(napi_schedule_prep(&priv->napi))) { + spin_lock(&priv->rxdma_irq_lock); priv->dmaops->disable_rxirq(priv); priv->dmaops->disable_txirq(priv); + spin_unlock(&priv->rxdma_irq_lock); __napi_schedule(&priv->napi); } - /* reset IRQs */ - priv->dmaops->clear_rxirq(priv); - priv->dmaops->clear_txirq(priv); - - spin_unlock_irqrestore(&priv->rxdma_irq_lock, flags); return IRQ_HANDLED; } -- 2.20.1