linux-kernel - [PATCH v5 12/14] x86: Use physical address for DMA mapping

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Message-ID: <20251015-remove-map-page-v5-12-3bbfe3a25cdf@kernel.org>
Date: Wed, 15 Oct 2025 12:12:58 +0300
From: Leon Romanovsky <leon@...nel.org>
To: Marek Szyprowski <m.szyprowski@...sung.com>,
	Robin Murphy <robin.murphy@....com>,
	Russell King <linux@...linux.org.uk>,
	Juergen Gross <jgross@...e.com>,
	Stefano Stabellini <sstabellini@...nel.org>,
	Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
	Richard Henderson <richard.henderson@...aro.org>,
	Matt Turner <mattst88@...il.com>,
	Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	"James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
	Helge Deller <deller@....de>,
	Madhavan Srinivasan <maddy@...ux.ibm.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Geoff Levand <geoff@...radead.org>,
	"David S. Miller" <davem@...emloft.net>,
	Andreas Larsson <andreas@...sler.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>
Cc: iommu@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	xen-devel@...ts.xenproject.org,
	linux-alpha@...r.kernel.org,
	linux-mips@...r.kernel.org,
	linux-parisc@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org,
	sparclinux@...r.kernel.org,
	Jason Gunthorpe <jgg@...pe.ca>,
	Jason Gunthorpe <jgg@...dia.com>
Subject: [PATCH v5 12/14] x86: Use physical address for DMA mapping

From: Leon Romanovsky <leonro@...dia.com>

Perform mechanical conversion from DMA .map_page to .map_phys.

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Leon Romanovsky <leonro@...dia.com>
---
 arch/x86/kernel/amd_gart_64.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 3485d419c2f5..93a06307d953 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -222,13 +222,14 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
 }
 
 /* Map a single area into the IOMMU */
-static dma_addr_t gart_map_page(struct device *dev, struct page *page,
-				unsigned long offset, size_t size,
-				enum dma_data_direction dir,
+static dma_addr_t gart_map_phys(struct device *dev, phys_addr_t paddr,
+				size_t size, enum dma_data_direction dir,
 				unsigned long attrs)
 {
 	unsigned long bus;
-	phys_addr_t paddr = page_to_phys(page) + offset;
+
+	if (unlikely(attrs & DMA_ATTR_MMIO))
+		return DMA_MAPPING_ERROR;
 
 	if (!need_iommu(dev, paddr, size))
 		return paddr;
@@ -242,7 +243,7 @@ static dma_addr_t gart_map_page(struct device *dev, struct page *page,
 /*
  * Free a DMA mapping.
  */
-static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr,
+static void gart_unmap_phys(struct device *dev, dma_addr_t dma_addr,
 			    size_t size, enum dma_data_direction dir,
 			    unsigned long attrs)
 {
@@ -282,7 +283,7 @@ static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 	for_each_sg(sg, s, nents, i) {
 		if (!s->dma_length || !s->length)
 			break;
-		gart_unmap_page(dev, s->dma_address, s->dma_length, dir, 0);
+		gart_unmap_phys(dev, s->dma_address, s->dma_length, dir, 0);
 	}
 }
 
@@ -487,7 +488,7 @@ static void
 gart_free_coherent(struct device *dev, size_t size, void *vaddr,
 		   dma_addr_t dma_addr, unsigned long attrs)
 {
-	gart_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL, 0);
+	gart_unmap_phys(dev, dma_addr, size, DMA_BIDIRECTIONAL, 0);
 	dma_direct_free(dev, size, vaddr, dma_addr, attrs);
 }
 
@@ -668,8 +669,8 @@ static __init int init_amd_gatt(struct agp_kern_info *info)
 static const struct dma_map_ops gart_dma_ops = {
 	.map_sg				= gart_map_sg,
 	.unmap_sg			= gart_unmap_sg,
-	.map_page			= gart_map_page,
-	.unmap_page			= gart_unmap_page,
+	.map_phys			= gart_map_phys,
+	.unmap_phys			= gart_unmap_phys,
 	.alloc				= gart_alloc_coherent,
 	.free				= gart_free_coherent,
 	.mmap				= dma_common_mmap,

-- 
2.51.0