forcedeth: fix irq clearing and napi spin lock changes

This patch clears the irqstatus register with the exact same events it
has read from it. Since the read-write operation is not atomic, a new
irqstatus bit could have been set in between these operations and would
then be cleared accidentally.

Secondly, we now don't need any spin lock protection when
scheduling/completing napi poll as the isr will not execute anymore (as
we turn off all interrupts now).

Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 14 deletions

diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index 28fc3357268a..514aaf189af9 100644
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -3464,10 +3464,10 @@ static irqreturn_t nv_nic_irq(int foo, void *data)
 
         if (!(np->msi_flags & NV_MSI_X_ENABLED)) {
                 np->events = readl(base + NvRegIrqStatus);
-                writel(NVREG_IRQSTAT_MASK, base + NvRegIrqStatus);
+                writel(np->events, base + NvRegIrqStatus);
         } else {
                 np->events = readl(base + NvRegMSIXIrqStatus);
-                writel(NVREG_IRQSTAT_MASK, base + NvRegMSIXIrqStatus);
+                writel(np->events, base + NvRegMSIXIrqStatus);
         }
         dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, np->events);
         if (!(np->events & np->irqmask))
@@ -3476,15 +3476,12 @@ static irqreturn_t nv_nic_irq(int foo, void *data)
         nv_msi_workaround(np);
 
 #ifdef CONFIG_FORCEDETH_NAPI
-        spin_lock(&np->lock);
         napi_schedule(&np->napi);
 
         /* Disable furthur irq's
            (msix not enabled with napi) */
         writel(0, base + NvRegIrqMask);
 
-        spin_unlock(&np->lock);
-
 #else
         do
         {
@@ -3568,10 +3565,10 @@ static irqreturn_t nv_nic_irq_optimized(int foo, void *data)
 
         if (!(np->msi_flags & NV_MSI_X_ENABLED)) {
                 np->events = readl(base + NvRegIrqStatus);
-                writel(NVREG_IRQSTAT_MASK, base + NvRegIrqStatus);
+                writel(np->events, base + NvRegIrqStatus);
         } else {
                 np->events = readl(base + NvRegMSIXIrqStatus);
-                writel(NVREG_IRQSTAT_MASK, base + NvRegMSIXIrqStatus);
+                writel(np->events, base + NvRegMSIXIrqStatus);
         }
         dprintk(KERN_DEBUG "%s: irq: %08x\n", dev->name, np->events);
         if (!(np->events & np->irqmask))
@@ -3580,15 +3577,12 @@ static irqreturn_t nv_nic_irq_optimized(int foo, void *data)
         nv_msi_workaround(np);
 
 #ifdef CONFIG_FORCEDETH_NAPI
-        spin_lock(&np->lock);
         napi_schedule(&np->napi);
 
         /* Disable furthur irq's
            (msix not enabled with napi) */
         writel(0, base + NvRegIrqMask);
 
-        spin_unlock(&np->lock);
-
 #else
         do
         {
@@ -3758,13 +3752,9 @@ static int nv_napi_poll(struct napi_struct *napi, int budget)
         if (rx_work < budget) {
                 /* re-enable interrupts
                    (msix not enabled in napi) */
-                spin_lock_irqsave(&np->lock, flags);
-
                 __napi_complete(napi);
 
                 writel(np->irqmask, base + NvRegIrqMask);
-
-                spin_unlock_irqrestore(&np->lock, flags);
         }
         return rx_work;
 }