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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 <setka@vsis.cz>
Signed-off-by: Roman Pisl <rpisl@kky.zcu.cz>
Signed-off-by: Vince Bridgers <vbridger@opensource.altera.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlastimil Setka 2015-02-23 11:30:29 -06:00 committed by David S. Miller
parent fe6e4081a6
commit 8d4ac39df0
1 changed files with 25 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
drivers/net/ethernet/altera/altera_tse_main.c
View File

@ -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);
if (likely(napi_schedule_prep(&priv->napi))) {
priv->dmaops->disable_rxirq(priv);
priv->dmaops->disable_txirq(priv);
__napi_schedule(&priv->napi);
}
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);
}
spin_unlock_irqrestore(&priv->rxdma_irq_lock, flags);
return IRQ_HANDLED;
}