Re: [PATCH 2/4] dmapool: Validate parameters to dma_pool_create

From: roel
Date: Wed Sep 26 2007 - 15:47:54 EST


Matthew Wilcox wrote:
> Check that 'align' is a power of two, like the API specifies.
> Align 'size' to 'align' correctly -- the current code has an off-by-one.
> The ALIGN macro in kernel.h doesn't.
>
> Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
> ---
> mm/dmapool.c | 15 ++++++++-------
> 1 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/mm/dmapool.c b/mm/dmapool.c
> index a359b5e..f5d12a7 100644
> --- a/mm/dmapool.c
> +++ b/mm/dmapool.c
> @@ -107,17 +107,18 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
> {
> struct dma_pool *retval;
>
> - if (align == 0)
> + if (align == 0) {
> align = 1;
> - if (size == 0)
> + } else if (align & (align - 1)) {
> return NULL;
> - else if (size < align)
> - size = align;
> - else if ((size % align) != 0) {
> - size += align + 1;
> - size &= ~(align - 1);
> }
>
> + if (size == 0)
> + return NULL;

The brackets in the first if/else are not required, and you could combine the two statements:

if (align == 0)
align = 1;
else if (align & (align - 1) || size == 0)
return NULL;
> +
> + if ((size % align) != 0)
> + size = ALIGN(size, align);
> +
> if (allocation == 0) {
> if (PAGE_SIZE < size)
> allocation = size;

-
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