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

[David Rientjes]

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;

How is this different than leaving the formal to have a signed type, i.e. 
drop your patch, and testing for count <= 0 instead?
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