From: Stefano Stabellini <sstabellini@kernel.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: hch@lst.de, konrad.wilk@oracle.com, m.szyprowski@samsung.com,
john.stultz@linaro.org, iommu@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, sstabellini@kernel.org
Subject: Re: [PATCH v2 2/2] swiotlb: Skip cache maintenance on map error
Date: Tue, 27 Nov 2018 12:38:49 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.10.1811271238290.4577@sstabellini-ThinkPad-X260> (raw)
In-Reply-To: <cc6d91acc357235cbd6e0e134382c58caa188801.1542812807.git.robin.murphy@arm.com>
On Wed, 21 Nov 2018, Robin Murphy wrote:
> If swiotlb_bounce_page() failed, calling arch_sync_dma_for_device() may
> lead to such delights as performing cache maintenance on whatever
> address phys_to_virt(SWIOTLB_MAP_ERROR) looks like, which is typically
> outside the kernel memory map and goes about as well as expected.
>
> Don't do that.
>
> Fixes: a4a4330db46a ("swiotlb: add support for non-coherent DMA")
> Tested-by: John Stultz <john.stultz@linaro.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
> ---
>
> v2: Collect tags
>
> kernel/dma/swiotlb.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 5731daa09a32..045930e32c0e 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -679,7 +679,8 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
> }
>
> if (!dev_is_dma_coherent(dev) &&
> - (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
> + (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0 &&
> + dev_addr != DIRECT_MAPPING_ERROR)
> arch_sync_dma_for_device(dev, phys, size, dir);
>
> return dev_addr;
> --
> 2.19.1.dirty
>
next prev parent reply other threads:[~2018-11-27 20:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-21 16:00 [PATCH v2 0/2] SWIOTLB fixes for 4.20 Robin Murphy
2018-11-21 16:00 ` [PATCH v2 1/2] dma-direct: Make DIRECT_MAPPING_ERROR viable for SWIOTLB Robin Murphy
2018-11-21 16:00 ` [PATCH v2 2/2] swiotlb: Skip cache maintenance on map error Robin Murphy
2018-11-27 20:38 ` Stefano Stabellini [this message]
2018-11-21 17:49 ` [PATCH v2 0/2] SWIOTLB fixes for 4.20 Christoph Hellwig
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=alpine.DEB.2.10.1811271238290.4577@sstabellini-ThinkPad-X260 \
--to=sstabellini@kernel.org \
--cc=hch@lst.de \
--cc=iommu@lists.linux-foundation.org \
--cc=john.stultz@linaro.org \
--cc=konrad.wilk@oracle.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=m.szyprowski@samsung.com \
--cc=robin.murphy@arm.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).