[PATCH] drivers/char: for hpet, add count checking, and ~0UL insteadof -1

From: Chen Gang
Date: Fri Nov 23 2012 - 04:45:39 EST



use ~0UL for unsigned long variable initialization, instead of -1.

add check for hdp->hd_nirqs within 32 (HPET_MAX_TIMERS).
the type of irqp->interrupt_count is u8.
the git diff not display the relative lines below.
hdp->hd_irq[hdp->hd_nirqs] = irq;
hdp->hd_nirqs++;
please check source code to get more information.


Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
---
drivers/char/hpet.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index dfd7876..fe6d4be 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -816,7 +816,7 @@ static unsigned long __hpet_calibrate(struct hpets *hpetp)

static unsigned long hpet_calibrate(struct hpets *hpetp)
{
- unsigned long ret = -1;
+ unsigned long ret = ~0UL;
unsigned long tmp;

/*
@@ -1001,6 +1001,9 @@ static acpi_status hpet_resources(struct acpi_resource *res, void *data)
irqp = &res->data.extended_irq;

for (i = 0; i < irqp->interrupt_count; i++) {
+ if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
+ break;
+
irq = acpi_register_gsi(NULL, irqp->interrupts[i],
irqp->triggering, irqp->polarity);
if (irq < 0)
--
1.7.10.4
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