linux-kernel - [PATCH 08/11] swiotlb-xen: use the same foreign page check everywhere

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Message-Id: <20190816130013.31154-9-hch@lst.de>
Date:   Fri, 16 Aug 2019 15:00:10 +0200
From:   Christoph Hellwig <hch@....de>
To:     Stefano Stabellini <sstabellini@...nel.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:     x86@...nel.org, linux-arm-kernel@...ts.infradead.org,
        xen-devel@...ts.xenproject.org, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 08/11] swiotlb-xen: use the same foreign page check everywhere

xen_dma_map_page uses a different and more complicated check for
foreign pages than the other three cache maintainance helpers.
Switch it to the simpler pfn_vali method a well.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 include/xen/page-coherent.h | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/include/xen/page-coherent.h b/include/xen/page-coherent.h
index 7c32944de051..0f4d468e7a89 100644
--- a/include/xen/page-coherent.h
+++ b/include/xen/page-coherent.h
@@ -43,14 +43,9 @@ static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
 	     dma_addr_t dev_addr, unsigned long offset, size_t size,
 	     enum dma_data_direction dir, unsigned long attrs)
 {
-	unsigned long page_pfn = page_to_xen_pfn(page);
-	unsigned long dev_pfn = XEN_PFN_DOWN(dev_addr);
-	unsigned long compound_pages =
-		(1<<compound_order(page)) * XEN_PFN_PER_PAGE;
-	bool local = (page_pfn <= dev_pfn) &&
-		(dev_pfn - page_pfn < compound_pages);
+	unsigned long pfn = PFN_DOWN(dev_addr);
 
-	if (local)
+	if (pfn_valid(pfn))
 		dma_direct_map_page(hwdev, page, offset, size, dir, attrs);
 	else
 		__xen_dma_map_page(hwdev, page, dev_addr, offset, size, dir, attrs);
-- 
2.20.1