From: Christoph Hellwig <hch@lst.de>
To: Vineet Gupta <vgupta@synopsys.com>
Cc: Jonas Bonn <jonas@southpole.se>,
linux-xtensa@linux-xtensa.org,
Vladimir Murzin <vladimir.murzin@arm.com>,
linux-parisc@vger.kernel.org, Helge Deller <deller@gmx.de>,
linux-kernel@vger.kernel.org,
Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
iommu@lists.linux-foundation.org, openrisc@lists.librecores.org,
Stafford Horne <shorne@gmail.com>,
linux-snps-arc@lists.infradead.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/7] arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support
Date: Fri, 14 Jun 2019 16:44:25 +0200 [thread overview]
Message-ID: <20190614144431.21760-2-hch@lst.de> (raw)
In-Reply-To: <20190614144431.21760-1-hch@lst.de>
The arm-nommu 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/arm/mm/dma-mapping-nommu.c | 24 +++---------------------
1 file changed, 3 insertions(+), 21 deletions(-)
diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index f304b10e23a4..bc003df45546 100644
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -39,18 +39,7 @@ static void *arm_nommu_dma_alloc(struct device *dev, size_t size,
unsigned long attrs)
{
- void *ret;
-
- /*
- * Try generic allocator first if we are advertised that
- * consistency is not required.
- */
-
- if (attrs & DMA_ATTR_NON_CONSISTENT)
- return dma_direct_alloc_pages(dev, size, dma_handle, gfp,
- attrs);
-
- ret = dma_alloc_from_global_coherent(size, dma_handle);
+ void *ret = dma_alloc_from_global_coherent(size, dma_handle);
/*
* dma_alloc_from_global_coherent() may fail because:
@@ -70,16 +59,9 @@ static void arm_nommu_dma_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr,
unsigned long attrs)
{
- if (attrs & DMA_ATTR_NON_CONSISTENT) {
- dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
- } else {
- int ret = dma_release_from_global_coherent(get_order(size),
- cpu_addr);
-
- WARN_ON_ONCE(ret == 0);
- }
+ int ret = dma_release_from_global_coherent(get_order(size), cpu_addr);
- return;
+ WARN_ON_ONCE(ret == 0);
}
static int arm_nommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
--
2.20.1
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next prev parent reply other threads:[~2019-06-14 14:44 UTC|newest]
Thread overview: 18+ 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 ` Christoph Hellwig [this message]
2019-06-24 14:23 ` [PATCH 1/7] arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support Vladimir Murzin
2019-06-25 6:13 ` Christoph Hellwig
2019-06-14 14:44 ` [PATCH 2/7] arc: " Christoph Hellwig
2019-06-14 14:44 ` [PATCH 3/7] openrisc: " Christoph Hellwig
2019-06-16 9:17 ` 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
2019-06-16 10:08 ` Hillf Danton
2019-06-25 6:11 ` Christoph Hellwig
2019-06-25 12:23 ` Helge Deller
2019-06-25 12:28 ` Christoph Hellwig
2019-06-14 14:44 ` [PATCH 6/7] dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING " Christoph Hellwig
2019-06-29 15:09 ` Guenter Roeck
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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