[PATCH 2/5] forcedeth: interrupt handling cleanup

Jeff Garzik
2007-10-06T15:14:22Z

commit a606d2a111cdf948da5d69eb1de5526c5c2dafef
Author: Jeff Garzik <jeff@garzik.org>
Date: Fri Oct 5 22:56:05 2007 -0400

[netdrvr] forcedeth: interrupt handling cleanup

* nv_nic_irq_optimized() and nv_nic_irq_other() were complete duplicates
of nv_nic_irq(), with the exception of one function call. Consolidate
all three into a single interrupt handler, deleting a lot of redundant
code.

* greatly simplify irq handler locking.

Prior to this change, the irq handler(s) would acquire and release
np->lock for each action (RX, TX, other events).

For the common case -- RX or TX work -- the lock is always acquired,
making all successive acquire/release combinations largely redundant.

Acquire the lock at the beginning of the irq handler, and release it at
the end of the irq handler. This is simple, easy, and obvious.

* remove irq handler work loop.

All interesting events emanating from the irq handler either have
their own work loops, or they poke a timer into action.

Therefore, delete the pointless master interrupt handler work loop.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/forcedeth.c | 325 +++++++++++-------------------------------------
1 file changed, 77 insertions(+), 248 deletions(-)

a606d2a111cdf948da5d69eb1de5526c5c2dafef
diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index 49906cc..1d1a5f5 100644
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -2917,208 +2917,110 @@ static void nv_link_irq(struct net_device *dev)
dprintk(KERN_DEBUG "%s: link change notification done.\n", dev->name);
}

-static irqreturn_t nv_nic_irq(int foo, void *data)
+static irqreturn_t __nv_nic_irq(struct net_device *dev, bool optimized)
{
- struct net_device *dev = (struct net_device *) data;
struct fe_priv *np = netdev_priv(dev);
u8 __iomem *base = get_hwbase(dev);
u32 events;
- int i;
+ int handled = 0;

- dprintk(KERN_DEBUG "%s: nv_nic_irq\n", dev->name);
+ dprintk(KERN_DEBUG "%s: nv_nic_irq%s\n", dev->name,
+ optimized ? "_optimized" : "");

- for (i=0; ; i++) {
- if (!(np->msi_flags & NV_MSI_X_ENABLED)) {
- events = readl(base + NvRegIrqStatus) & NVREG_IRQSTAT_MASK;
- writel(NVREG_IRQSTAT_MASK, base + NvRegIrqStatus);
- } else {
- events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQSTAT_MASK;
- writel(NVREG_IRQSTAT_MASK, base + NvRegMSIXIrqStatus);
- }
- dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, events);
- if (!(events & np->irqmask))
- break;
+ spin_lock(&np->lock);

- spin_lock(&np->lock);
- nv_tx_done(dev);
- spin_unlock(&np->lock);
+ if (!(np->msi_flags & NV_MSI_X_ENABLED)) {
+ events = readl(base + NvRegIrqStatus) & NVREG_IRQSTAT_MASK;
+ writel(NVREG_IRQSTAT_MASK, base + NvRegIrqStatus);
+ } else {
+ events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQSTAT_MASK;
+ writel(NVREG_IRQSTAT_MASK, base + NvRegMSIXIrqStatus);
+ }

- if (events & NVREG_IRQ_RX_ALL) {
- netif_rx_schedule(dev, &np->napi);
+ dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, events);

- /* Disable furthur receive irq's */
- spin_lock(&np->lock);
- np->irqmask &= ~NVREG_IRQ_RX_ALL;
+ if (!(events & np->irqmask))
+ goto out;

- if (np->msi_flags & NV_MSI_X_ENABLED)
- writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
- else
- writel(np->irqmask, base + NvRegIrqMask);
- spin_unlock(&np->lock);
- }
- if (unlikely(events & NVREG_IRQ_LINK)) {
- spin_lock(&np->lock);
- nv_link_irq(dev);
- spin_unlock(&np->lock);
- }
- if (unlikely(np->need_linktimer && time_after(jiffies, np->link_timeout))) {
- spin_lock(&np->lock);
- nv_linkchange(dev);
- spin_unlock(&np->lock);
- np->link_timeout = jiffies + LINK_TIMEOUT;
- }
- if (unlikely(events & (NVREG_IRQ_TX_ERR))) {
- dprintk(KERN_DEBUG "%s: received irq with events 0x%x. Probably TX fail.\n",
- dev->name, events);
- }
- if (unlikely(events & (NVREG_IRQ_UNKNOWN))) {
- printk(KERN_DEBUG "%s: received irq with unknown events 0x%x. Please report\n",
- dev->name, events);
- }
- if (unlikely(events & NVREG_IRQ_RECOVER_ERROR)) {
- spin_lock(&np->lock);
- /* disable interrupts on the nic */
- if (!(np->msi_flags & NV_MSI_X_ENABLED))
- writel(0, base + NvRegIrqMask);
- else
- writel(np->irqmask, base + NvRegIrqMask);
- pci_push(base);
+ if (optimized)
+ nv_tx_done_optimized(dev, TX_WORK_PER_LOOP);
+ else
+ nv_tx_done(dev);

- if (!np->in_shutdown) {
- np->nic_poll_irq = np->irqmask;
- np->recover_error = 1;
- mod_timer(&np->nic_poll, jiffies + POLL_WAIT);
- }
- spin_unlock(&np->lock);
- break;
- }
- if (unlikely(i > max_interrupt_work)) {
- spin_lock(&np->lock);
- /* disable interrupts on the nic */
- if (!(np->msi_flags & NV_MSI_X_ENABLED))
- writel(0, base + NvRegIrqMask);
- else
- writel(np->irqmask, base + NvRegIrqMask);
- pci_push(base);
+ if (events & NVREG_IRQ_RX_ALL) {
+ netif_rx_schedule(dev, &np->napi);

- if (!np->in_shutdown) {
- np->nic_poll_irq = np->irqmask;
- mod_timer(&np->nic_poll, jiffies + POLL_WAIT);
- }
- spin_unlock(&np->lock);
- printk(KERN_DEBUG "%s: too many iterations (%d) in nv_nic_irq.\n", dev->name, i);
- break;
- }
+ /* Disable furthur receive irq's */
+ np->irqmask &= ~NVREG_IRQ_RX_ALL;

+ if (np->msi_flags & NV_MSI_X_ENABLED)
+ writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
+ else
+ writel(np->irqmask, base + NvRegIrqMask);
}
- dprintk(KERN_DEBUG "%s: nv_nic_irq completed\n", dev->name);

- return IRQ_RETVAL(i);
-}
+ if (unlikely(events & NVREG_IRQ_LINK))
+ nv_link_irq(dev);

-/**
- * All _optimized functions are used to help increase performance
- * (reduce CPU and increase throughput). They use descripter version 3,
- * compiler directives, and reduce memory accesses.
- */
-static irqreturn_t nv_nic_irq_optimized(int foo, void *data)
-{
- struct net_device *dev = (struct net_device *) data;
- struct fe_priv *np = netdev_priv(dev);
- u8 __iomem *base = get_hwbase(dev);
- u32 events;
- int i;
+ if (unlikely(np->need_linktimer && time_after(jiffies, np->link_timeout))) {
+ nv_linkchange(dev);
+ np->link_timeout = jiffies + LINK_TIMEOUT;
+ }

- dprintk(KERN_DEBUG "%s: nv_nic_irq_optimized\n", dev->name);
+ if (unlikely(events & (NVREG_IRQ_TX_ERR))) {
+ dprintk(KERN_DEBUG "%s: received irq with events 0x%x. "
+ "Probably TX fail.\n",
+ dev->name, events);
+ }

- for (i=0; ; i++) {
- if (!(np->msi_flags & NV_MSI_X_ENABLED)) {
- events = readl(base + NvRegIrqStatus) & NVREG_IRQSTAT_MASK;
- writel(NVREG_IRQSTAT_MASK, base + NvRegIrqStatus);
- } else {
- events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQSTAT_MASK;
- writel(NVREG_IRQSTAT_MASK, base + NvRegMSIXIrqStatus);
- }
- dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, events);
- if (!(events & np->irqmask))
- break;
+ if (unlikely(events & (NVREG_IRQ_UNKNOWN))) {
+ printk(KERN_DEBUG "%s: received irq with unknown events 0x%x. "
+ "Please report\n",
+ dev->name, events);
+ }

- spin_lock(&np->lock);
- nv_tx_done_optimized(dev, TX_WORK_PER_LOOP);
- spin_unlock(&np->lock);
+ if (unlikely(events & NVREG_IRQ_RECOVER_ERROR)) {
+ /* disable interrupts on the nic */
+ if (!(np->msi_flags & NV_MSI_X_ENABLED))
+ writel(0, base + NvRegIrqMask);
+ else
+ writel(np->irqmask, base + NvRegIrqMask);
+ pci_push(base);

- if (events & NVREG_IRQ_RX_ALL) {
- netif_rx_schedule(dev, &np->napi);
+ if (!np->in_shutdown) {
+ np->nic_poll_irq = np->irqmask;
+ np->recover_error = 1;
+ mod_timer(&np->nic_poll, jiffies + POLL_WAIT);
+ }
+ }

- /* Disable furthur receive irq's */
- spin_lock(&np->lock);
- np->irqmask &= ~NVREG_IRQ_RX_ALL;
+ handled = 1;

- if (np->msi_flags & NV_MSI_X_ENABLED)
- writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
- else
- writel(np->irqmask, base + NvRegIrqMask);
- spin_unlock(&np->lock);
- }
- if (unlikely(events & NVREG_IRQ_LINK)) {
- spin_lock(&np->lock);
- nv_link_irq(dev);
- spin_unlock(&np->lock);
- }
- if (unlikely(np->need_linktimer && time_after(jiffies, np->link_timeout))) {
- spin_lock(&np->lock);
- nv_linkchange(dev);
- spin_unlock(&np->lock);
- np->link_timeout = jiffies + LINK_TIMEOUT;
- }
- if (unlikely(events & (NVREG_IRQ_TX_ERR))) {
- dprintk(KERN_DEBUG "%s: received irq with events 0x%x. Probably TX fail.\n",
- dev->name, events);
- }
- if (unlikely(events & (NVREG_IRQ_UNKNOWN))) {
- printk(KERN_DEBUG "%s: received irq with unknown events 0x%x. Please report\n",
- dev->name, events);
- }
- if (unlikely(events & NVREG_IRQ_RECOVER_ERROR)) {
- spin_lock(&np->lock);
- /* disable interrupts on the nic */
- if (!(np->msi_flags & NV_MSI_X_ENABLED))
- writel(0, base + NvRegIrqMask);
- else
- writel(np->irqmask, base + NvRegIrqMask);
- pci_push(base);
+out:
+ spin_unlock(&np->lock);

- if (!np->in_shutdown) {
- np->nic_poll_irq = np->irqmask;
- np->recover_error = 1;
- mod_timer(&np->nic_poll, jiffies + POLL_WAIT);
- }
- spin_unlock(&np->lock);
- break;
- }
+ dprintk(KERN_DEBUG "%s: nv_nic_irq%s completed\n", dev->name,
+ optimized ? "_optimized" : "");

- if (unlikely(i > max_interrupt_work)) {
- spin_lock(&np->lock);
- /* disable interrupts on the nic */
- if (!(np->msi_flags & NV_MSI_X_ENABLED))
- writel(0, base + NvRegIrqMask);
- else
- writel(np->irqmask, base + NvRegIrqMask);
- pci_push(base);
+ return IRQ_RETVAL(handled);
+}

- if (!np->in_shutdown) {
- np->nic_poll_irq = np->irqmask;
- mod_timer(&np->nic_poll, jiffies + POLL_WAIT);
- }
- spin_unlock(&np->lock);
- printk(KERN_DEBUG "%s: too many iterations (%d) in nv_nic_irq.\n", dev->name, i);
- break;
- }
+static irqreturn_t nv_nic_irq(int foo, void *data)
+{
+ struct net_device *dev = data;
+ return __nv_nic_irq(dev, false);
+}

- }
- dprintk(KERN_DEBUG "%s: nv_nic_irq_optimized completed\n", dev->name);
+static irqreturn_t nv_nic_irq_optimized(int foo, void *data)
+{
+ struct net_device *dev = data;
+ return __nv_nic_irq(dev, true);
+}

- return IRQ_RETVAL(i);
+static irqreturn_t nv_nic_irq_other(int foo, void *data)
+{
+ struct net_device *dev = (struct net_device *) data;
+ return __nv_nic_irq(dev, true);
}

static irqreturn_t nv_nic_irq_tx(int foo, void *data)
@@ -3227,79 +3129,6 @@ static irqreturn_t nv_nic_irq_rx(int foo, void *data)
return IRQ_HANDLED;
}

-static irqreturn_t nv_nic_irq_other(int foo, void *data)
-{
- struct net_device *dev = (struct net_device *) data;
- struct fe_priv *np = netdev_priv(dev);
- u8 __iomem *base = get_hwbase(dev);
- u32 events;
- int i;
- unsigned long flags;
-
- dprintk(KERN_DEBUG "%s: nv_nic_irq_other\n", dev->name);
-
- for (i=0; ; i++) {
- events = readl(base + NvRegMSIXIrqStatus) & NVREG_IRQ_OTHER;
- writel(NVREG_IRQ_OTHER, base + NvRegMSIXIrqStatus);
- dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, events);
- if (!(events & np->irqmask))
- break;
-
- /* check tx in case we reached max loop limit in tx isr */
- spin_lock_irqsave(&np->lock, flags);
- nv_tx_done_optimized(dev, TX_WORK_PER_LOOP);
- spin_unlock_irqrestore(&np->lock, flags);
-
- if (events & NVREG_IRQ_LINK) {
- spin_lock_irqsave(&np->lock, flags);
- nv_link_irq(dev);
- spin_unlock_irqrestore(&np->lock, flags);
- }
- if (np->need_linktimer && time_after(jiffies, np->link_timeout)) {
- spin_lock_irqsave(&np->lock, flags);
- nv_linkchange(dev);
- spin_unlock_irqrestore(&np->lock, flags);
- np->link_timeout = jiffies + LINK_TIMEOUT;
- }
- if (events & NVREG_IRQ_RECOVER_ERROR) {
- spin_lock_irq(&np->lock);
- /* disable interrupts on the nic */
- writel(NVREG_IRQ_OTHER, base + NvRegIrqMask);
- pci_push(base);
-
- if (!np->in_shutdown) {
- np->nic_poll_irq |= NVREG_IRQ_OTHER;
- np->recover_error = 1;
- mod_timer(&np->nic_poll, jiffies + POLL_WAIT);
- }
- spin_unlock_irq(&np->lock);
- break;
- }
- if (events & (NVREG_IRQ_UNKNOWN)) {
- printk(KERN_DEBUG "%s: received irq with unknown events 0x%x. Please report\n",
- dev->name, events);
- }
- if (unlikely(i > max_interrupt_work)) {
- spin_lock_irqsave(&np->lock, flags);
- /* disable interrupts on the nic */
- writel(NVREG_IRQ_OTHER, base + NvRegIrqMask);
- pci_push(base);
-
- if (!np->in_shutdown) {
- np->nic_poll_irq |= NVREG_IRQ_OTHER;
- mod_timer(&np->nic_poll, jiffies + POLL_WAIT);
- }
- spin_unlock_irqrestore(&np->lock, flags);
- printk(KERN_DEBUG "%s: too many iterations (%d) in nv_nic_irq_other.\n", dev->name, i);
- break;
- }
-
- }
- dprintk(KERN_DEBUG "%s: nv_nic_irq_other completed\n", dev->name);
-
- return IRQ_RETVAL(i);
-}
-
static irqreturn_t nv_nic_irq_test(int foo, void *data)
{
struct net_device *dev = (struct net_device *) data;