From: Stafford Horne <shorne@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jonas Bonn <jonas@southpole.se>,
linux-xtensa@linux-xtensa.org,
Vladimir Murzin <vladimir.murzin@arm.com>,
linux-parisc@vger.kernel.org, Vineet Gupta <vgupta@synopsys.com>,
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,
linux-snps-arc@lists.infradead.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 3/7] openrisc: remove the partial DMA_ATTR_NON_CONSISTENT support
Date: Sun, 16 Jun 2019 18:17:24 +0900 [thread overview]
Message-ID: <20190616091724.GL2358@lianli.shorne-pla.net> (raw)
In-Reply-To: <20190614144431.21760-4-hch@lst.de>
On Fri, Jun 14, 2019 at 04:44:27PM +0200, Christoph Hellwig wrote:
> 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.
The below looks good. I am always happy to what looks like legacy copy & paste
cruft.
Acked-by: Stafford Horne <shorne@gmail.com>
> 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
>
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next prev parent reply other threads:[~2019-06-16 9:17 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 ` [PATCH 1/7] arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support Christoph Hellwig
2019-06-24 14:23 ` 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 [this message]
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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