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From: Christoph Hellwig <hch@lst.de>
To: Vineet Gupta <vgupta@synopsys.com>
Cc: Jonas Bonn <jonas@southpole.se>,
	Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
	Stafford Horne <shorne@gmail.com>, Helge Deller <deller@gmx.de>,
	Vladimir Murzin <vladimir.murzin@arm.com>,
	linux-snps-arc@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	openrisc@lists.librecores.org, linux-parisc@vger.kernel.org,
	linux-xtensa@linux-xtensa.org, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 3/7] openrisc: remove the partial DMA_ATTR_NON_CONSISTENT support
Date: Fri, 14 Jun 2019 16:44:27 +0200
Message-ID: <20190614144431.21760-4-hch@lst.de> (raw)
In-Reply-To: <20190614144431.21760-1-hch@lst.de>

The openrisc DMA code supports DMA_ATTR_NON_CONSISTENT allocations, but
does not provide a cache_sync operation.  This means any user of it
will never be able to actually transfer cache ownership and thus cause
coherency bugs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/openrisc/kernel/dma.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
index f79457cb3741..9f25fd0fbb5d 100644
--- a/arch/openrisc/kernel/dma.c
+++ b/arch/openrisc/kernel/dma.c
@@ -98,15 +98,13 @@ arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 
 	va = (unsigned long)page;
 
-	if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0) {
-		/*
-		 * We need to iterate through the pages, clearing the dcache for
-		 * them and setting the cache-inhibit bit.
-		 */
-		if (walk_page_range(va, va + size, &walk)) {
-			free_pages_exact(page, size);
-			return NULL;
-		}
+	/*
+	 * We need to iterate through the pages, clearing the dcache for
+	 * them and setting the cache-inhibit bit.
+	 */
+	if (walk_page_range(va, va + size, &walk)) {
+		free_pages_exact(page, size);
+		return NULL;
 	}
 
 	return (void *)va;
@@ -122,10 +120,8 @@ arch_dma_free(struct device *dev, size_t size, void *vaddr,
 		.mm = &init_mm
 	};
 
-	if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0) {
-		/* walk_page_range shouldn't be able to fail here */
-		WARN_ON(walk_page_range(va, va + size, &walk));
-	}
+	/* walk_page_range shouldn't be able to fail here */
+	WARN_ON(walk_page_range(va, va + size, &walk));
 
 	free_pages_exact(vaddr, size);
 }
-- 
2.20.1


  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-14 14:44 handle "special" dma allocation in common code Christoph Hellwig
2019-06-14 14:44 ` [PATCH 1/7] arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support Christoph Hellwig
2019-06-14 14:44 ` [PATCH 2/7] arc: " Christoph Hellwig
2019-06-14 14:44 ` Christoph Hellwig [this message]
2019-06-16  9:17   ` [PATCH 3/7] openrisc: " Stafford Horne
2019-06-14 14:44 ` [PATCH 4/7] dma-mapping: add a dma_alloc_need_uncached helper Christoph Hellwig
2019-06-14 14:44 ` [PATCH 5/7] dma-direct: handle DMA_ATTR_NON_CONSISTENT in common code Christoph Hellwig
2019-06-14 14:44 ` [PATCH 6/7] dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING " Christoph Hellwig
2019-06-14 14:44 ` [PATCH 7/7] arc: use the generic remapping allocator for coherent DMA allocations Christoph Hellwig
2019-06-14 18:05   ` Eugeniy Paltsev
2019-06-15  8:35     ` hch

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