From: Julia Lawall <julia.lawall@lip6.fr>
To: Christoph Hellwig <hch@lst.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Luis Chamberlain <mcgrof@kernel.org>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: remove dma_zalloc_coherent
Date: Tue, 8 Jan 2019 14:56:59 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1901081456370.6130@hadrien> (raw)
In-Reply-To: <alpine.DEB.2.20.1901081453380.6130@hadrien>
On Tue, 8 Jan 2019, Julia Lawall wrote:
>
>
> On Tue, 8 Jan 2019, Christoph Hellwig wrote:
>
> > Hi Linus and world,
> >
> > We've always had a weird situation around dma_zalloc_coherent. To
> > safely support mapping the allocations to userspace major architectures
> > like x86 and arm have always zeroed allocations from dma_alloc_coherent,
> > but a couple other architectures were missing that zeroing either always
> > or in corner cases. Then later we grew anothe dma_zalloc_coherent
> > interface to explicitly request zeroing, but that just added __GFP_ZERO
> > to the allocation flags, which for some allocators that didn't end
> > up using the page allocator ended up being a no-op and still not
> > zeroing the allocations.
> >
> > So for this merge window I fixed up all remaining architectures to zero
> > the memory in dma_alloc_coherent, and made dma_zalloc_coherent a no-op
> > wrapper around dma_alloc_coherent, which fixes all of the above issues.
> >
> > dma_zalloc_coherent is now pointless and can go away, and Luis helped
> > me writing a cocchinelle script and patch series to kill it, which I
> > think we should apply now just after -rc1 to finally settle these
> > issue.
> >
> > The script that generated the first patch is included here:
> >
> > @ replace_dma_zalloc_coherent @
> > expression dev, size, data, handle, flags;
> > @@
> >
> > -dma_zalloc_coherent(dev, size, handle, flags)
> > +dma_alloc_coherent(dev, size, handle, flags)
>
> Great. We should also update api/alloc/zalloc-simple.cocci. The message
> could just say that the z version is no longer needed.
Oops, I see that you already took care of it. Thanks!
julia
next prev parent reply other threads:[~2019-01-08 13:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-08 13:06 remove dma_zalloc_coherent Christoph Hellwig
2019-01-08 13:06 ` [PATCH 1/3] cross-tree: phase out dma_zalloc_coherent() Christoph Hellwig
2019-01-08 13:07 ` [PATCH 2/3] cross-tree: phase out dma_zalloc_coherent() on headers Christoph Hellwig
2019-01-08 14:30 ` Julia Lawall
2019-01-08 13:07 ` [PATCH 3/3] dma-mapping: remove dma_zalloc_coherent() Christoph Hellwig
2019-01-08 14:29 ` Julia Lawall
2019-01-08 13:55 ` remove dma_zalloc_coherent Julia Lawall
2019-01-08 13:56 ` Julia Lawall [this message]
2019-01-11 18:16 ` 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.2.20.1901081456370.6130@hadrien \
--to=julia.lawall@lip6.fr \
--cc=hch@lst.de \
--cc=iommu@lists.linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mcgrof@kernel.org \
--cc=torvalds@linux-foundation.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).