All of lore.kernel.org
 help / color / mirror / Atom feed
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.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: David Stevens <stevensd@chromium.org>
Cc: Will Deacon <will@kernel.org>,
	iommu@lists.linux-foundation.org,
	Robin Murphy <robin.murphy@arm.com>,
	linux-kernel@vger.kernel.org, Tom Murphy <murphyt7@tcd.ie>
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.
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2021-08-11  6:08 UTC|newest]

Thread overview: 38+ 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 ` David Stevens
2021-08-11  2:42 ` [PATCH v3 1/5] dma-iommu: fix sync_sg with swiotlb David Stevens
2021-08-11  2:42   ` David Stevens
2021-08-11  5:57   ` Christoph Hellwig
2021-08-11  5:57     ` Christoph Hellwig
2021-08-11 18:22     ` Robin Murphy
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  2:42   ` David Stevens
2021-08-11  6:01   ` Christoph Hellwig
2021-08-11  6:01     ` Christoph Hellwig
2021-08-11 18:47   ` Robin Murphy
2021-08-11 18:47     ` Robin Murphy
2021-08-12  9:21     ` David Stevens
2021-08-12  9:21       ` David Stevens
2021-08-12 10:38       ` Robin Murphy
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  2:42   ` David Stevens
2021-08-11  6:07   ` Christoph Hellwig [this message]
2021-08-11  6:07     ` Christoph Hellwig
2021-08-11 19:00   ` Robin Murphy
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  2:42   ` David Stevens
2021-08-11 19:02   ` Robin Murphy
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  2:42   ` David Stevens
2021-08-11  9:26   ` Mi, Dapeng1
2021-08-11  9:26     ` Mi, Dapeng1
2021-08-11 19:12   ` Robin Murphy
2021-08-11 19:12     ` Robin Murphy
2021-08-12  1:45     ` David Stevens
2021-08-12  1:45       ` David Stevens
2021-08-12  9:57       ` Robin Murphy
2021-08-12  9:57         ` Robin Murphy

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YRNpHcskc0Vv1ofa@infradead.org \
    --to=hch@infradead.org \
    --cc=iommu@lists.linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=murphyt7@tcd.ie \
    --cc=robin.murphy@arm.com \
    --cc=stevensd@chromium.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.