linux-kernel - Re: [PATCH 4/5] radeon/ttm/PCIe: Use dma

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20110128150310.GA29440@dumpdata.com>
Date:	Fri, 28 Jan 2011 10:03:11 -0500
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Jerome Glisse <j.glisse@...il.com>
Cc:	dri-devel@...ts.freedesktop.org, thomas@...pmail.org,
	airlied@...ux.ie, linux-kernel@...r.kernel.org,
	Alex Deucher <alexdeucher@...il.com>,
	Jerome Glisse <jglisse@...hat.com>, konrad@...nok.org
Subject: Re: [PATCH 4/5] radeon/ttm/PCIe: Use dma_addr if TTM has set it.

On Fri, Jan 28, 2011 at 09:42:48AM -0500, Jerome Glisse wrote:
> On Thu, Jan 27, 2011 at 4:20 PM, Konrad Rzeszutek Wilk
> <konrad.wilk@...cle.com> wrote:
> > On Fri, Jan 07, 2011 at 12:11:43PM -0500, Konrad Rzeszutek Wilk wrote:
> >> If the TTM layer has used the DMA API to setup pages that are
> >> TTM_PAGE_FLAG_DMA32 (look at patch titled: "ttm: Utilize the dma_addr_t
> >> array for pages that are to in DMA32 pool."), lets use it
> >> when programming the GART in the PCIe type cards.
> >>
> >> This patch skips doing the pci_map_page (and pci_unmap_page) if
> >> there is a DMA addresses passed in for that page. If the dma_address
> >> is zero (or DMA_ERROR_CODE), then we continue on with our old
> >> behaviour.
> >
> > Hey Jerome,
> >
> > I should have CC-ed you earlier but missed that and instead just
> > CC-ed the mailing list. I was wondering what your thoughts are
> > about this patchset? Thomas took a look at the patchset and he is OK
> > but more eyes never hurt.
> >
> > FYI, for clarity I hadn't made the old calls that got moved due
> > to adding of "{" checkpatch.pl compliant. It complains about it being
> > past 80 characters. I can naturally fix that up, but thought
> > that it might detract from the nature of the patch.
> 
> What happen when we don't ask dma32 alloc to ttm ? Will this still
> work in virtualized environnement ?

You mean if we don't pass in the TTM_PAGE_FLAG_DMA32? It will go back
to using the old mechanism - which is to allocate page using
alloc_page(GFP_HIGHUSER). Which should be OK in baremetal or
virtualized environment - and as long as the driver uses the page
for non-DMA type things, or the graphic card is 64-bit capable at which
point it has no trouble reaching it.

> 
> Code looks good but GART stuff can be picky, i will try to do a full
> scale testing in next couple week.

Thank you! Much appreciated. Would it be OK if I pinged you in two weeks
time just in case?
--
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/