linux-kernel - [PATCH 05/31] x86/pci-calgary: handle page-less SG entries

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Date:	Wed, 12 Aug 2015 09:05:24 +0200
From:	Christoph Hellwig <hch@....de>
To:	torvalds@...ux-foundation.org, axboe@...nel.dk
Cc:	dan.j.williams@...el.com, vgupta@...opsys.com,
	hskinnemoen@...il.com, egtvedt@...fundet.no, realmz6@...il.com,
	dhowells@...hat.com, monstr@...str.eu, x86@...nel.org,
	dwmw2@...radead.org, alex.williamson@...hat.com,
	grundler@...isc-linux.org, linux-kernel@...r.kernel.org,
	linux-arch@...r.kernel.org, linux-alpha@...r.kernel.org,
	linux-ia64@...r.kernel.org, linux-metag@...r.kernel.org,
	linux-mips@...ux-mips.org, linux-parisc@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org, linux-s390@...r.kernel.org,
	sparclinux@...r.kernel.org, linux-xtensa@...ux-xtensa.org,
	linux-nvdimm@...1.01.org, linux-media@...r.kernel.org
Subject: [PATCH 05/31] x86/pci-calgary: handle page-less SG entries

For the iommu offset we just need and offset into the page.  Calculate
that using the physical address instead of using the virtual address
so that we don't require a virtual mapping.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 arch/x86/kernel/pci-calgary_64.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index 0497f71..8f1581d 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -368,16 +368,14 @@ static int calgary_map_sg(struct device *dev, struct scatterlist *sg,
 {
 	struct iommu_table *tbl = find_iommu_table(dev);
 	struct scatterlist *s;
-	unsigned long vaddr;
+	unsigned long paddr;
 	unsigned int npages;
 	unsigned long entry;
 	int i;
 
 	for_each_sg(sg, s, nelems, i) {
-		BUG_ON(!sg_page(s));
-
-		vaddr = (unsigned long) sg_virt(s);
-		npages = iommu_num_pages(vaddr, s->length, PAGE_SIZE);
+		paddr = sg_phys(s);
+		npages = iommu_num_pages(paddr, s->length, PAGE_SIZE);
 
 		entry = iommu_range_alloc(dev, tbl, npages);
 		if (entry == DMA_ERROR_CODE) {
@@ -389,7 +387,7 @@ static int calgary_map_sg(struct device *dev, struct scatterlist *sg,
 		s->dma_address = (entry << PAGE_SHIFT) | s->offset;
 
 		/* insert into HW table */
-		tce_build(tbl, entry, npages, vaddr & PAGE_MASK, dir);
+		tce_build(tbl, entry, npages, paddr & PAGE_MASK, dir);
 
 		s->dma_length = s->length;
 	}
-- 
1.9.1

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