Re: [PATCH] cma: use unsigned type for count argument

From: Michal Nazarewicz
Date: Wed Dec 26 2012 - 21:05:50 EST


> On Sat, 22 Dec 2012, Michal Nazarewicz wrote:
>> So I think just adding the following, should be sufficient to make
>> everyone happy:
>>
>> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
>> index e34e3e0..e91743b 100644
>> --- a/drivers/base/dma-contiguous.c
>> +++ b/drivers/base/dma-contiguous.c
>> @@ -320,7 +320,7 @@ struct page *dma_alloc_from_contiguous(struct device *dev, unsigned int count,
>> pr_debug("%s(cma %p, count %u, align %u)\n", __func__, (void *)cma,
>> count, align);
>>
>> - if (!count)
>> + if (!count || count > INT_MAX)
>> return NULL;
>>
>> mask = (1 << align) - 1;
>
On Thu, Dec 27 2012, David Rientjes <rientjes@xxxxxxxxxx> wrote:
> How is this different than leaving the formal to have a signed type, i.e.
> drop your patch, and testing for count <= 0 instead?

Not much different I guess. I don't have strong opinions to be honest,
except that I feel unsigned is the proper type to use, on top of which
I think bitmap_set() should use unsigned, so in case anyone ever bothers
to change it, CMA will be ready. :P

--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, MichaÅ âmina86â Nazarewicz (o o)
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