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powerpc: Fix irq_free_virt by adjusting bounds before loop

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Instead of looping over each irq and checking against the irq array
bounds, adjust the bounds before looping.

The old code will not free any irq if the irq + count is above
irq_virq_count because the test in the loop is testing irq + count
instead of irq + i.

This code checks the limits to avoid unsigned integer overflows.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Milton Miller 2011-05-24 20:34:18 +00:00 committed by Benjamin Herrenschmidt
parent 9b78825158
commit 4dd6029001
1 changed files with 13 additions and 4 deletions
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17
arch/powerpc/kernel/irq.c
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@ -1007,14 +1007,23 @@ void irq_free_virt(unsigned int virq, unsigned int count)
WARN_ON (virq < NUM_ISA_INTERRUPTS);
WARN_ON (count == 0 || (virq + count) > irq_virq_count);
if (virq < NUM_ISA_INTERRUPTS) {
if (virq + count < NUM_ISA_INTERRUPTS)
return;
count =- NUM_ISA_INTERRUPTS - virq;
virq = NUM_ISA_INTERRUPTS;
}
if (count > irq_virq_count || virq > irq_virq_count - count) {
if (virq > irq_virq_count)
return;
count = irq_virq_count - virq;
}
raw_spin_lock_irqsave(&irq_big_lock, flags);
for (i = virq; i < (virq + count); i++) {
struct irq_host *host;
if (i < NUM_ISA_INTERRUPTS ||
(virq + count) > irq_virq_count)
continue;
host = irq_map[i].host;
irq_map[i].hwirq = host->inval_irq;
smp_wmb();