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genirq: generic chip: Use DIV_ROUND_UP to calculate numchips 

The number of interrupts in a domain may be not divisible by the
number of interrupts each chip handles. Integer division may truncate
the result, thus use DIV_ROUND_UP to count numchips.

Seems all users of irq_alloc_domain_generic_chips() in current code do
not have this issue. I just found the issue while reading the code.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: http://lkml.kernel.org/r/1373015592.18252.2.camel@phoenix
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Axel Lin 2013-07-05 17:13:12 +08:00 committed by Thomas Gleixner
parent 5b8aae489a
commit 002fca5df1
1 changed files with 1 additions and 1 deletions
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2
kernel/irq/generic-chip.c
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@ -278,7 +278,7 @@ int irq_alloc_domain_generic_chips(struct irq_domain *d, int irqs_per_chip,
if (d->revmap_type != IRQ_DOMAIN_MAP_LINEAR)
return -EINVAL;
numchips = d->revmap_data.linear.size / irqs_per_chip;
numchips = DIV_ROUND_UP(d->revmap_data.linear.size, irqs_per_chip);
if (!numchips)
return -EINVAL;