On Thu, Jan 10, 2019 at 02:09:36PM -0700, Khalid Aziz wrote:
> From: Juerg Haefliger <juerg.haefliger@xxxxxxxxxxxxx>
>
> v6: * guard against lookup_xpfo() returning NULL
>
> CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Signed-off-by: Juerg Haefliger <juerg.haefliger@xxxxxxxxxxxxx>
> Signed-off-by: Tycho Andersen <tycho@xxxxxxxxxx>
> Signed-off-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> ---
> include/linux/xpfo.h | 4 ++++
> kernel/dma/swiotlb.c | 3 ++-
> mm/xpfo.c | 15 +++++++++++++++
> 3 files changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/xpfo.h b/include/linux/xpfo.h
> index a39259ce0174..e38b823f44e3 100644
> --- a/include/linux/xpfo.h
> +++ b/include/linux/xpfo.h
> @@ -35,6 +35,8 @@ void xpfo_kunmap(void *kaddr, struct page *page);
> void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp);
> void xpfo_free_pages(struct page *page, int order);
>
> +bool xpfo_page_is_unmapped(struct page *page);
> +
> #else /* !CONFIG_XPFO */
>
> static inline void xpfo_kmap(void *kaddr, struct page *page) { }
> @@ -42,6 +44,8 @@ static inline void xpfo_kunmap(void *kaddr, struct page *page) { }
> static inline void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp) { }
> static inline void xpfo_free_pages(struct page *page, int order) { }
>
> +static inline bool xpfo_page_is_unmapped(struct page *page) { return false; }
> +
> #endif /* CONFIG_XPFO */
>
> #endif /* _LINUX_XPFO_H */
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 045930e32c0e..820a54b57491 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -396,8 +396,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
> {
> unsigned long pfn = PFN_DOWN(orig_addr);
> unsigned char *vaddr = phys_to_virt(tlb_addr);
> + struct page *page = pfn_to_page(pfn);
>
> - if (PageHighMem(pfn_to_page(pfn))) {
> + if (PageHighMem(page) || xpfo_page_is_unmapped(page)) {
> /* The buffer does not have a mapping. Map it in and copy */
> unsigned int offset = orig_addr & ~PAGE_MASK;
> char *buffer;
> diff --git a/mm/xpfo.c b/mm/xpfo.c
> index bff24afcaa2e..cdbcbac582d5 100644
> --- a/mm/xpfo.c
> +++ b/mm/xpfo.c
> @@ -220,3 +220,18 @@ void xpfo_kunmap(void *kaddr, struct page *page)
> spin_unlock(&xpfo->maplock);
> }
> EXPORT_SYMBOL(xpfo_kunmap);
> +
> +bool xpfo_page_is_unmapped(struct page *page)
> +{
> + struct xpfo *xpfo;
> +
> + if (!static_branch_unlikely(&xpfo_inited))
> + return false;
> +
> + xpfo = lookup_xpfo(page);
> + if (unlikely(!xpfo) && !xpfo->inited)
> + return false;
> +
> + return test_bit(XPFO_PAGE_UNMAPPED, &xpfo->flags);
> +}
> +EXPORT_SYMBOL(xpfo_page_is_unmapped);
> --
> 2.17.1
>
