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 <milt...@bga.com>
---
I am not aware of any call sites where the difference matters; I
prepared the refactor while continuing work on the irq host extraction
and noticed the logic error during the code movement.
Index: work.git/arch/powerpc/kernel/irq.c
===================================================================
--- work.git.orig/arch/powerpc/kernel/irq.c 2011-05-24 21:15:55.350096024
-0500
+++ work.git/arch/powerpc/kernel/irq.c 2011-05-24 21:17:16.000097884 -0500
@@ -1007,14 +1007,23 @@ void irq_free_virt(unsigned int virq, un
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();
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