Re: [PATCH] kmemcheck: add hooks for page- and sg-dma-mappings

Pekka Enberg
2009-02-21T16:27:18Z

Vegard Nossum wrote:
> This is needed for page allocator support to prevent false positives
> when accessing pages which are dma-mapped.
>
> Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
> ---
> arch/x86/include/asm/dma-mapping.h | 6 ++++++
> 1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
> index 830bb0e..713a002 100644
> --- a/arch/x86/include/asm/dma-mapping.h
> +++ b/arch/x86/include/asm/dma-mapping.h
> @@ -117,7 +117,12 @@ dma_map_sg(struct device *hwdev, struct scatterlist *sg,
> {
> struct dma_mapping_ops *ops = get_dma_ops(hwdev);
>
> + struct scatterlist *s;
> + int i;
> +
> BUG_ON(!valid_dma_direction(direction));
> + for_each_sg(sg, s, nents, i)
> + kmemcheck_mark_initialized(sg_virt(s), s->length);
> return ops->map_sg(hwdev, sg, nents, direction);
> }
>
> @@ -215,6 +220,7 @@ static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
> struct dma_mapping_ops *ops = get_dma_ops(dev);
>
> BUG_ON(!valid_dma_direction(direction));
> + kmemcheck_mark_initialized(page_address(page) + offset, size);
> return ops->map_single(dev, page_to_phys(page) + offset,
> size, direction);
> }

What's with the new BUG_ON() calls here?