Re: [PATCH] tree wide: Use kvfree() than conditional kfree()/vfree()

Russell King - ARM Linux
2015-11-09T16:07:52Z

On Mon, Nov 09, 2015 at 08:56:10PM +0900, Tetsuo Handa wrote:
> There are many locations that do
>
> if (memory_was_allocated_by_vmalloc)
> vfree(ptr);
> else
> kfree(ptr);
>
> but kvfree() can handle both kmalloc()ed memory and vmalloc()ed memory
> using is_vmalloc_addr(). Unless callers have special reasons, we can
> replace this branch with kvfree(). Please check and reply if you found
> problems.
>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Cc: Russell King <linux@arm.linux.org.uk> # arm

Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>

In so far as this ARM specific change looks reasonable. Thanks.

> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index e62400e..492bf3e 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1200,10 +1200,7 @@ error:
> while (i--)
> if (pages[i])
> __free_pages(pages[i], 0);
> - if (array_size <= PAGE_SIZE)
> - kfree(pages);
> - else
> - vfree(pages);
> + kvfree(pages);
> return NULL;
> }
>
> @@ -1211,7 +1208,6 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages,
> size_t size, struct dma_attrs *attrs)
> {
> int count = size >> PAGE_SHIFT;
> - int array_size = count * sizeof(struct page *);
> int i;
>
> if (dma_get_attr(DMA_ATTR_FORCE_CONTIGUOUS, attrs)) {
> @@ -1222,10 +1218,7 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages,
> __free_pages(pages[i], 0);
> }
>
> - if (array_size <= PAGE_SIZE)
> - kfree(pages);
> - else
> - vfree(pages);
> + kvfree(pages);
> return 0;
> }
>

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