From: Christoph Hellwig <hch@infradead.org>
To: David Stevens <stevensd@chromium.org>
Cc: Robin Murphy <robin.murphy@arm.com>,
Will Deacon <will@kernel.org>,
linux-kernel@vger.kernel.org, Tom Murphy <murphyt7@tcd.ie>,
iommu@lists.linux-foundation.org
Subject: Re: [PATCH v3 3/5] dma-iommu: add SKIP_CPU_SYNC after syncing
Date: Wed, 11 Aug 2021 07:07:25 +0100 [thread overview]
Message-ID: <YRNpHcskc0Vv1ofa@infradead.org> (raw)
In-Reply-To: <20210811024247.1144246-4-stevensd@google.com>
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 4f0cc4a0a61f..be0214b1455c 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -859,8 +859,11 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
> static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
> size_t size, enum dma_data_direction dir, unsigned long attrs)
> {
> - if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
> + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
> iommu_dma_sync_single_for_cpu(dev, dma_handle, size, dir);
> + attrs |= DMA_ATTR_SKIP_CPU_SYNC;
> + }
> +
> __iommu_dma_unmap_swiotlb(dev, dma_handle, size, dir, attrs);
I don't think this is the correct way to go. Instead just call the
raw cache sync helper instead of iommu_dma_sync_single_for_cpu, similar
to what dma-direct does. Same for the map side.
next prev parent reply other threads:[~2021-08-11 6:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-11 2:42 [PATCH v3 0/5] Fixes for dma-iommu swiotlb bounce buffers David Stevens
2021-08-11 2:42 ` [PATCH v3 1/5] dma-iommu: fix sync_sg with swiotlb David Stevens
2021-08-11 5:57 ` Christoph Hellwig
2021-08-11 18:22 ` Robin Murphy
2021-08-11 2:42 ` [PATCH v3 2/5] dma-iommu: fix arch_sync_dma for map David Stevens
2021-08-11 6:01 ` Christoph Hellwig
2021-08-11 18:47 ` Robin Murphy
2021-08-12 9:21 ` David Stevens
2021-08-12 10:38 ` Robin Murphy
2021-08-11 2:42 ` [PATCH v3 3/5] dma-iommu: add SKIP_CPU_SYNC after syncing David Stevens
2021-08-11 6:07 ` Christoph Hellwig [this message]
2021-08-11 19:00 ` Robin Murphy
2021-08-11 2:42 ` [PATCH v3 4/5] dma-iommu: Check CONFIG_SWIOTLB more broadly David Stevens
2021-08-11 19:02 ` Robin Murphy
2021-08-11 2:42 ` [PATCH v3 5/5] dma-iommu: account for min_align_mask David Stevens
2021-08-11 9:26 ` Mi, Dapeng1
2021-08-11 19:12 ` Robin Murphy
2021-08-12 1:45 ` David Stevens
2021-08-12 9:57 ` Robin Murphy
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