[PATCH] ppc64: Remove lpqueue pointer from the paca on iSeries

The iSeries code keeps a pointer to the ItLpQueue in its paca struct. But
all these pointers end up pointing to the one place, ie. xItLpQueue.

So remove the pointer from the paca struct and just refer to xItLpQueue
directly where needed.

The only complication is that the spread_lpevents logic was implemented by
having a NULL lpqueue pointer in the paca on CPUs that weren't supposed to
process events. Instead we just compare the spread_lpevents value to the
processor id to get the same behaviour.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

7 files changed, 19 insertions, 26 deletions

diff --git a/arch/ppc64/kernel/ItLpQueue.c b/arch/ppc64/kernel/ItLpQueue.c
index cdea00d7707..e90dca8bd13 100644
--- a/arch/ppc64/kernel/ItLpQueue.c
+++ b/arch/ppc64/kernel/ItLpQueue.c
@@ -69,15 +69,17 @@ struct HvLpEvent * ItLpQueue_getNextLpEvent( struct ItLpQueue * lpQueue )
 	return nextLpEvent;
 }
 
+unsigned long spread_lpevents = 1;
+
 int ItLpQueue_isLpIntPending( struct ItLpQueue * lpQueue )
 {
-	int retval = 0;
-	struct HvLpEvent * nextLpEvent;
-	if ( lpQueue ) {
-		nextLpEvent = (struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
-		retval = nextLpEvent->xFlags.xValid | lpQueue->xPlicOverflowIntPending;
-	}
-	return retval;
+	struct HvLpEvent *next_event;
+
+	if (smp_processor_id() >= spread_lpevents)
+		return 0;
+
+	next_event = (struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
+	return next_event->xFlags.xValid | lpQueue->xPlicOverflowIntPending;
 }
 
 void ItLpQueue_clearValid( struct HvLpEvent * event )
diff --git a/arch/ppc64/kernel/iSeries_setup.c b/arch/ppc64/kernel/iSeries_setup.c
index 86966ce76b5..2049b6dbafc 100644
--- a/arch/ppc64/kernel/iSeries_setup.c
+++ b/arch/ppc64/kernel/iSeries_setup.c
@@ -855,17 +855,15 @@ late_initcall(iSeries_src_init);
 
 static int set_spread_lpevents(char *str)
 {
-	unsigned long i;
 	unsigned long val = simple_strtoul(str, NULL, 0);
+	extern unsigned long spread_lpevents;
 
 	/*
 	 * The parameter is the number of processors to share in processing
 	 * lp events.
 	 */
 	if (( val > 0) && (val <= NR_CPUS)) {
-		for (i = 1; i < val; ++i)
-			paca[i].lpqueue_ptr = paca[0].lpqueue_ptr;
-
+		spread_lpevents = val;
 		printk("lpevent processing spread over %ld processors\n", val);
 	} else {
 		printk("invalid spread_lpevents %ld\n", val);
diff --git a/arch/ppc64/kernel/idle.c b/arch/ppc64/kernel/idle.c
index bdf13b4dc1c..63977a7a309 100644
--- a/arch/ppc64/kernel/idle.c
+++ b/arch/ppc64/kernel/idle.c
@@ -88,7 +88,7 @@ static int iSeries_idle(void)
 
 	while (1) {
 		if (lpaca->lppaca.shared_proc) {
-			if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
+			if (ItLpQueue_isLpIntPending(&xItLpQueue))
 				process_iSeries_events();
 			if (!need_resched())
 				yield_shared_processor();
@@ -100,7 +100,7 @@ static int iSeries_idle(void)
 
 				while (!need_resched()) {
 					HMT_medium();
-					if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
+					if (ItLpQueue_isLpIntPending(&xItLpQueue))
 						process_iSeries_events();
 					HMT_low();
 				}
diff --git a/arch/ppc64/kernel/irq.c b/arch/ppc64/kernel/irq.c
index 3defc8c33ad..b1e6acb02a9 100644
--- a/arch/ppc64/kernel/irq.c
+++ b/arch/ppc64/kernel/irq.c
@@ -269,7 +269,6 @@ out:
 void do_IRQ(struct pt_regs *regs)
 {
 	struct paca_struct *lpaca;
-	struct ItLpQueue *lpq;
 
 	irq_enter();
 
@@ -295,9 +294,8 @@ void do_IRQ(struct pt_regs *regs)
 		iSeries_smp_message_recv(regs);
 	}
 #endif /* CONFIG_SMP */
-	lpq = lpaca->lpqueue_ptr;
-	if (lpq && ItLpQueue_isLpIntPending(lpq))
-		lpevent_count += ItLpQueue_process(lpq, regs);
+	if (ItLpQueue_isLpIntPending(&xItLpQueue))
+		lpevent_count += ItLpQueue_process(&xItLpQueue, regs);
 
 	irq_exit();
 
diff --git a/arch/ppc64/kernel/mf.c b/arch/ppc64/kernel/mf.c
index d98bebf7042..d6a297a4feb 100644
--- a/arch/ppc64/kernel/mf.c
+++ b/arch/ppc64/kernel/mf.c
@@ -802,9 +802,8 @@ int mf_get_boot_rtc(struct rtc_time *tm)
 	/* We need to poll here as we are not yet taking interrupts */
 	while (rtc_data.busy) {
 		extern unsigned long lpevent_count;
-		struct ItLpQueue *lpq = get_paca()->lpqueue_ptr;
-		if (lpq && ItLpQueue_isLpIntPending(lpq))
-			lpevent_count += ItLpQueue_process(lpq, NULL);
+		if (ItLpQueue_isLpIntPending(&xItLpQueue))
+			lpevent_count += ItLpQueue_process(&xItLpQueue, NULL);
 	}
 	return rtc_set_tm(rtc_data.rc, rtc_data.ce_msg.ce_msg, tm);
 }
diff --git a/arch/ppc64/kernel/pacaData.c b/arch/ppc64/kernel/pacaData.c
index a3e0975c26c..ebfb517019e 100644
--- a/arch/ppc64/kernel/pacaData.c
+++ b/arch/ppc64/kernel/pacaData.c
@@ -45,7 +45,6 @@ extern unsigned long __toc_start;
 #ifdef CONFIG_PPC_ISERIES
 #define EXTRA_INITS(number, lpq)					    \
 	.lppaca_ptr = &paca[number].lppaca,				    \
-	.lpqueue_ptr = (lpq),		/* &xItLpQueue, */		    \
 	.reg_save_ptr = &paca[number].reg_save,				    \
 	.reg_save = {							    \
 		.xDesc = 0xd397d9e2,	/* "LpRS" */			    \
diff --git a/arch/ppc64/kernel/time.c b/arch/ppc64/kernel/time.c
index 2a532db9138..cdc43afb563 100644
--- a/arch/ppc64/kernel/time.c
+++ b/arch/ppc64/kernel/time.c
@@ -367,11 +367,8 @@ int timer_interrupt(struct pt_regs * regs)
 	set_dec(next_dec);
 
 #ifdef CONFIG_PPC_ISERIES
-	{
-		struct ItLpQueue *lpq = lpaca->lpqueue_ptr;
-		if (lpq && ItLpQueue_isLpIntPending(lpq))
-			lpevent_count += ItLpQueue_process(lpq, regs);
-	}
+	if (ItLpQueue_isLpIntPending(&xItLpQueue))
+		lpevent_count += ItLpQueue_process(&xItLpQueue, regs);
 #endif
 
 /* collect purr register values often, for accurate calculations */