powerpc: mpic: minor optimization of ipi handler

Jeff Garzik pointed out that we don't actually have to lookup the mpic instance since it's passed in as the interrupt handler data for IPIs.

Signed-off-by Olof Johansson <[email protected]>

arch/powerpc/sysdev/mpic.c +2 -3

index e479388..6bf56f4 100644
@@ -612,11 +612,10 @@ static inline void mpic_eoi(struct mpic *mpic)
 }
 
 #ifdef CONFIG_SMP
-static irqreturn_t mpic_ipi_action(int irq, void *dev_id)
+static irqreturn_t mpic_ipi_action(int irq, void *data)
 {
-	struct mpic *mpic;
+	struct mpic *mpic = data;
 
-	mpic = mpic_find(irq, NULL);
 	smp_message_recv(mpic_irq_to_hw(irq) - mpic->ipi_vecs[0]);
 
 	return IRQ_HANDLED;

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Quoted 2 lines · Olof Johansson

Jeff Garzik pointed out that we don't actually have to lookup the mpic instance since it's passed in as the interrupt handler data for IPIs.

Note that's typically one of the annoying case where we use "irq" for a good reasons, getting the way of Jeff attempt at removing this argument.

I suppose a working approach would be to have 4 mpic IPI handlers...

Quoted 9 lines · Benjamin Herrenschmidt

Quoted 2 lines · Olof Johansson

Jeff Garzik pointed out that we don't actually have to lookup the mpic instance since it's passed in as the interrupt handler data for IPIs.

Note that's typically one of the annoying case where we use "irq" for a good reasons, getting the way of Jeff attempt at removing this argument.

Quoted 1 line

I suppose a working approach would be to have 4 mpic IPI handlers...

We still need the _irq_, but we don't need to lookup the mpic based on it.

We knew the mpic pointer at irq setup time, and passed it in as the argument to pass to the handler. Doing a second lookup is just extra overhead, it should return the same controller:

Optimize MPIC IPIs, by passing in the IPI number as the argument to the handler, since all we did was translate it back based on which mpic the interrupt came though on (and that was always the primary mpic).

Signed-off-by Olof Johansson <[email protected]>

Oh, I see what you mean. You didn't make it easy to parse. :)

This should actually do the work.

-Olof

arch/powerpc/sysdev/mpic.c +6 -7

index e479388..a8d7c68 100644
@@ -614,10 +614,9 @@ static inline void mpic_eoi(struct mpic *mpic)
 #ifdef CONFIG_SMP
 static irqreturn_t mpic_ipi_action(int irq, void *data)
 {
-	struct mpic *mpic;
+	long ipi = (long)data;
 
-	mpic = mpic_find(irq, NULL);
-	smp_message_recv(mpic_irq_to_hw(irq) - mpic->ipi_vecs[0]);
+	smp_message_recv(ipi);
 
 	return IRQ_HANDLED;
 }

@@ -1457,7 +1456,7 @@ unsigned int mpic_get_irq(void)
 void mpic_request_ipis(void)
 {
 	struct mpic *mpic = mpic_primary;
-	int i, err;
+	long i, err;
 	static char *ipi_names[] = {
 		"IPI0 (call function)",
 		"IPI1 (reschedule)",

@@ -1472,14 +1471,14 @@ void mpic_request_ipis(void)
 		unsigned int vipi = irq_create_mapping(mpic->irqhost,
 						       mpic->ipi_vecs[0] + i);
 		if (vipi == NO_IRQ) {
-			printk(KERN_ERR "Failed to map IPI %d\n", i);
+			printk(KERN_ERR "Failed to map IPI %ld\n", i);
 			break;
 		}
 		err = request_irq(vipi, mpic_ipi_action,
 				  IRQF_DISABLED|IRQF_PERCPU,
-				  ipi_names[i], mpic);
+				  ipi_names[i], (void *)i);
 		if (err) {
-			printk(KERN_ERR "Request of irq %d for IPI %d failed\n",
+			printk(KERN_ERR "Request of irq %d for IPI %ld failed\n",
 			       vipi, i);
 			break;
 		}