linux-kernel - Re: [PATCH v4 9/9] x86: convert dma_map_ops to support mapping a __pfn

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150609065854.GD10167@lst.de>
Date:	Tue, 9 Jun 2015 08:58:54 +0200
From:	Christoph Hellwig <hch@....de>
To:	Dan Williams <dan.j.williams@...el.com>
Cc:	linux-kernel@...r.kernel.org, axboe@...nel.dk, boaz@...xistor.com,
	david@...morbit.com, linux-arch@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, arnd@...db.de,
	ross.zwisler@...ux.intel.com,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	benh@...nel.crashing.org, linux-nvdimm@...ts.01.org,
	heiko.carstens@...ibm.com, hch@....de, tj@...nel.org,
	paulus@...ba.org, hpa@...or.com, schwidefsky@...ibm.com,
	willy@...ux.intel.com, akpm@...ux-foundation.org,
	torvalds@...ux-foundation.org, mingo@...nel.org
Subject: Re: [PATCH v4 9/9] x86: convert dma_map_ops to support mapping a
	__pfn_t.

On Fri, Jun 05, 2015 at 05:19:55PM -0400, Dan Williams wrote:
> As long as a dma_map_sg() implementation avoids sg_page() conversions it
> can support scatterlists that carry "page-less" __pfn_t entries.
> However, a couple implementations require that __pfn_t_has_page() is
> always true. The Xen swiotlb implementation's entanglements with ARM and
> the Calgary MMUs requirement to have a pre-existing virtual mapping make
> them unable to support this conversion (i.e. these now have 'depends on
> !HAVE_DMA_PFN').

That's why we really need a whole kernel conversion and not just a piecemail
one.  Given how trivial this patch is that doesn't look like a too big
task ayway.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/