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authorChristoph Hellwig <hch@lst.de>2019-08-26 11:23:44 +0200
committerChristoph Hellwig <hch@lst.de>2019-09-11 12:43:27 +0200
commitc9b6180dbf9ab3fef15ec5482997c99b0c762cd1 (patch)
treeefa80f37e1046ae17172b1736b67c9f0b0aa5f23 /include/xen/arm
parentswiotlb-xen: remove xen_swiotlb_dma_mmap and xen_swiotlb_dma_get_sgtable (diff)
downloadlinux-dev-c9b6180dbf9ab3fef15ec5482997c99b0c762cd1.tar.xz
linux-dev-c9b6180dbf9ab3fef15ec5482997c99b0c762cd1.zip
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_valid method a well, and document the scheme with a single improved comment in xen_dma_map_page. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Diffstat (limited to 'include/xen/arm')
-rw-r--r--include/xen/arm/page-coherent.h31
1 files changed, 9 insertions, 22 deletions
diff --git a/include/xen/arm/page-coherent.h b/include/xen/arm/page-coherent.h
index a840d6949a87..a8d9c0678c27 100644
--- a/include/xen/arm/page-coherent.h
+++ b/include/xen/arm/page-coherent.h
@@ -53,23 +53,17 @@ 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);
/*
- * Dom0 is mapped 1:1, while the Linux page can span across
- * multiple Xen pages, it's not possible for it to contain a
- * mix of local and foreign Xen pages. So if the first xen_pfn
- * == mfn the page is local otherwise it's a foreign page
- * grant-mapped in dom0. If the page is local we can safely
- * call the native dma_ops function, otherwise we call the xen
- * specific function.
+ * Dom0 is mapped 1:1, and while the Linux page can span across multiple
+ * Xen pages, it is not possible for it to contain a mix of local and
+ * foreign Xen pages. Calling pfn_valid on a foreign mfn will always
+ * return false, so if pfn_valid returns true the pages is local and we
+ * can use the native dma-direct functions, otherwise we call the Xen
+ * specific version.
*/
- 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);
@@ -79,14 +73,7 @@ static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
unsigned long pfn = PFN_DOWN(handle);
- /*
- * Dom0 is mapped 1:1, while the Linux page can be spanned accross
- * multiple Xen page, it's not possible to have a mix of local and
- * foreign Xen page. Dom0 is mapped 1:1, so calling pfn_valid on a
- * foreign mfn will always return false. If the page is local we can
- * safely call the native dma_ops function, otherwise we call the xen
- * specific function.
- */
+
if (pfn_valid(pfn))
dma_direct_unmap_page(hwdev, handle, size, dir, attrs);
else