On Fri, Feb 19 2016, Rabin Vincent wrote:
> Split out the logic in cma_release() which checks if the page is in the
> contiguous area to a new function which can be called separately. ARM
> will use this.
>
> Signed-off-by: Rabin Vincent <rabin.vincent@xxxxxxxx>
> ---
> include/linux/cma.h | 12 ++++++++++++
> mm/cma.c | 27 +++++++++++++++++++--------
> 2 files changed, 31 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 29f9e77..6e7fd2d 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -27,5 +27,17 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
> unsigned int order_per_bit,
> struct cma **res_cma);
> extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align);
> +
> extern bool cma_release(struct cma *cma, const struct page *pages, unsigned int count);
> +#ifdef CONFIG_CMA
> +extern bool in_cma(struct cma *cma, const struct page *pages,
> + unsigned int count);
> +#else
> +static inline bool in_cma(struct cma *cma, const struct page *pages,
> + unsigned int count)
> +{
> + return false;
> +}
> +#endif
> +
> #endif
> diff --git a/mm/cma.c b/mm/cma.c
> index ea506eb..55cda16 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -426,6 +426,23 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
> return page;
> }
>
> +bool in_cma(struct cma *cma, const struct page *pages, unsigned int count)
Should it instead take pfn as an argument instead of a page? IIRC
page_to_pfn may be expensive on some architectures and with this patch,
cma_release will call it twice.
Or maybe in_cma could return a pfn, something like (error checking
stripped):
unsigned long pfn in_cma(struct cma *cma, const struct page *page,
unsgined count)
{
unsigned long pfn = page_to_pfn(page);
if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
return 0;
VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
return pfn;
}
Is pfn == 0 guaranteed to be invalid?
> +{
> + unsigned long pfn;
> +
> + if (!cma || !pages)
> + return false;
> +
> + pfn = page_to_pfn(pages);
> +
> + if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> + return false;
> +
> + VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> +
> + return true;
> +}
> +
> /**
> * cma_release() - release allocated pages
> * @cma: Contiguous memory region for which the allocation is performed.
> @@ -440,18 +457,12 @@ bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
> {
> unsigned long pfn;
>
> - if (!cma || !pages)
> - return false;
> -
> pr_debug("%s(page %p)\n", __func__, (void *)pages);
>
> - pfn = page_to_pfn(pages);
> -
> - if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> + if (!in_cma(cma, pages, count))
> return false;
>
> - VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> -
> + pfn = page_to_pfn(pages);
> free_contig_range(pfn, count);
> cma_clear_bitmap(cma, pfn, count);
> trace_cma_release(pfn, pages, count);
> --
> 2.7.0
>
--
Best regards
Liege of Serenely Enlightened Majesty of Computer Science,
ミハウ “mina86” ナザレヴイツ <mpn@xxxxxxxxxx> <xmpp:mina86@xxxxxxxxxx>
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