From: Christoph Hellwig <hch@lst.de>
To: Gavin Li <gavinli@thegavinli.com>
Cc: Christoph Hellwig <hch@lst.de>,
Shawn Anastasio <shawn@anastas.io>,
Michael Ellerman <mpe@ellerman.id.au>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Paul Burton <paul.burton@mips.com>,
James Hogan <jhogan@kernel.org>,
linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Gavin Li <git@thegavinli.com>
Subject: Re: [PATCH 1/2] dma-mapping: fix page attributes for dma_mmap_*
Date: Tue, 6 Aug 2019 07:12:42 +0200 [thread overview]
Message-ID: <20190806051242.GA13269@lst.de> (raw)
In-Reply-To: <CA+GxvY5C_rrukCzC5K-h72bePyW8PS_Rfj3uxh-K6UrcAextUQ@mail.gmail.com>
On Mon, Aug 05, 2019 at 07:55:44PM -0700, Gavin Li wrote:
> > /* create a coherent mapping */
> > ret = dma_common_contiguous_remap(page, size, VM_USERMAP,
> > - arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs),
> > + dma_pgprot(dev, PAGE_KERNEL, attrs),
> > __builtin_return_address(0));
> > if (!ret) {
> > __dma_direct_free_pages(dev, size, page);
>
> Is dma_common_contiguous_remap() still necessary in the
> DMA_ATTR_NON_CONSISTENT case? I would presume it would be fine to just
> return a linearly mapped address in that case.
It would not be required for a real DMA_ATTR_NON_CONSISTENT
implementation. But only parisc and mips actually properly implement
DMA_ATTR_NON_CONSISTENT, everyone ignores it. Given that the API is
a little ill defined and I have a better replacement in the pipeline
I don't want to start implementing it for other architectures now.
next prev parent reply other threads:[~2019-08-06 5:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-05 8:01 fix default dma_mmap_* pgprot v2 Christoph Hellwig
2019-08-05 8:01 ` [PATCH 1/2] dma-mapping: fix page attributes for dma_mmap_* Christoph Hellwig
2019-08-05 9:10 ` Catalin Marinas
[not found] ` <CAP_+7SzPdNCMKuuXMjHjpCzxsey2YWR_e6mTAWtNSZ6kKBvKFw@mail.gmail.com>
2019-08-06 2:55 ` Gavin Li
2019-08-06 5:12 ` Christoph Hellwig [this message]
2019-08-06 19:39 ` Shawn Anastasio
2019-08-07 6:04 ` Christoph Hellwig
2019-08-07 11:45 ` Shawn Anastasio
2019-08-05 8:01 ` [PATCH 2/2] MIPS: remove support for DMA_ATTR_WRITE_COMBINE Christoph Hellwig
2019-08-05 8:06 ` Sergei Shtylyov
2019-08-07 6:16 fix default dma_mmap_* pgprot v3 Christoph Hellwig
2019-08-07 6:16 ` [PATCH 1/2] dma-mapping: fix page attributes for dma_mmap_* 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=20190806051242.GA13269@lst.de \
--to=hch@lst.de \
--cc=catalin.marinas@arm.com \
--cc=gavinli@thegavinli.com \
--cc=git@thegavinli.com \
--cc=jhogan@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=paul.burton@mips.com \
--cc=robin.murphy@arm.com \
--cc=shawn@anastas.io \
--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 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).