From: Sebastien Dugue <[EMAIL PROTECTED]>
Date: Tue, 22 Jul 2008 13:05:24 +0200
Subject: [PATCH][RT] powerpc - XICS: move the call to irq_radix_revmap from 
xics_startup to xics_host_map

  This patch moves the insertion of an irq into the reverse mapping radix tree
from xics_startup() into xics_host_map().

  The reason for this change is that xics_startup() is called with preemption
disabled (which is not the case for xics_host_map()) which is a problem under a
preempt-rt kernel as we cannot even allocate GFP_ATOMIC memory for the radix 
tree
nodes.


Signed-off-by: Sebastien Dugue <[EMAIL PROTECTED]>
Cc: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
Cc: Paul Mackerras <[EMAIL PROTECTED]>
Cc: Michael Ellerman <[EMAIL PROTECTED]>

---
 arch/powerpc/platforms/pseries/xics.c |   18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

Index: linux-2.6.25.8-rt7/arch/powerpc/platforms/pseries/xics.c
===================================================================
--- linux-2.6.25.8-rt7.orig/arch/powerpc/platforms/pseries/xics.c
+++ linux-2.6.25.8-rt7/arch/powerpc/platforms/pseries/xics.c
@@ -311,12 +311,6 @@ static void xics_mask_irq(unsigned int v
 
 static unsigned int xics_startup(unsigned int virq)
 {
-       unsigned int irq;
-
-       /* force a reverse mapping of the interrupt so it gets in the cache */
-       irq = (unsigned int)irq_map[virq].hwirq;
-       irq_radix_revmap(xics_host, irq);
-
        /* unmask it */
        xics_unmask_irq(virq);
        return 0;
@@ -529,8 +523,14 @@ static int xics_host_match(struct irq_ho
 static int xics_host_map_direct(struct irq_host *h, unsigned int virq,
                                irq_hw_number_t hw)
 {
+       unsigned int irq;
+
        pr_debug("xics: map_direct virq %d, hwirq 0x%lx\n", virq, hw);
 
+       /* force a reverse mapping of the interrupt so it gets in the cache */
+       irq = (unsigned int)irq_map[virq].hwirq;
+       irq_radix_revmap(xics_host, irq);
+
        get_irq_desc(virq)->status |= IRQ_LEVEL;
        set_irq_chip_and_handler(virq, &xics_pic_direct, handle_fasteoi_irq);
        return 0;
@@ -539,8 +539,14 @@ static int xics_host_map_direct(struct i
 static int xics_host_map_lpar(struct irq_host *h, unsigned int virq,
                              irq_hw_number_t hw)
 {
+       unsigned int irq;
+
        pr_debug("xics: map_direct virq %d, hwirq 0x%lx\n", virq, hw);
 
+       /* force a reverse mapping of the interrupt so it gets in the cache */
+       irq = (unsigned int)irq_map[virq].hwirq;
+       irq_radix_revmap(xics_host, irq);
+
        get_irq_desc(virq)->status |= IRQ_LEVEL;
        set_irq_chip_and_handler(virq, &xics_pic_lpar, handle_fasteoi_irq);
        return 0;
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