linux-kernel - Re: [PATCH] mm: dmapool: use provided gfp flags for all dma_alloc

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: <50AB600C.5010801@samsung.com>
Date:	Tue, 20 Nov 2012 11:48:44 +0100
From:	Marek Szyprowski <m.szyprowski@...sung.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Jason Cooper <jason@...edaemon.net>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Michal Hocko <mhocko@...e.cz>, Mel Gorman <mgorman@...e.de>,
	Johannes Weiner <hannes@...xchg.org>,
	linux-arm-kernel@...ts.infradead.org,
	linaro-mm-sig@...ts.linaro.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Andrew Lunn <andrew@...n.ch>, Arnd Bergmann <arnd@...db.de>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Soren Moch <smoch@....de>,
	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
Subject: Re: [PATCH] mm: dmapool: use provided gfp flags for all
 dma_alloc_coherent() calls

Hello,

On 11/19/2012 11:48 PM, Andrew Morton wrote:
> On Sun, 18 Nov 2012 19:18:46 -0500
> Jason Cooper <jason@...edaemon.net> wrote:
>
> > I've added the maintainers for mm/*.  Hopefully they can let us know if
> > this is good for v3.8...
>
> As Marek has inexplicably put this patch into linux-next via his tree,
> we don't appear to be getting a say in the matter!

I've just put this patch to linux-next via my dma-mapping tree to give it
some testing asap to check if other changes to arm dma-mapping are required
or not.

> The patch looks good to me.  That open-coded wait loop predates the
> creation of bitkeeper tree(!) but doesn't appear to be needed.  There
> will perhaps be some behavioural changes observable for GFP_KERNEL
> callers as dma_pool_alloc() will no longer dip into page reserves but I
> see nothing special about dma_pool_alloc() which justifies doing that
> anyway.
>
> The patch makes pool->waitq and its manipulation obsolete, but it
> failed to remove all that stuff.

Right, I missed that part, I will update it asap.

> The changelog failed to describe the problem which Soren reported.
> That should be included, and as the problem sounds fairly serious we
> might decide to backport the fix into -stable kernels.

Ok, I will extend the changelog.

> dma_pool_alloc()'s use of a local "struct dma_page *page" is
> distressing - MM developers very much expect a local called "page" to
> have type "struct page *".  But that's a separate issue.

I will prepare a separate patch cleaning it. I was also a bit surprised
by such naming scheme, but it is probably related to the fact that this
come has not been touched much since a very ancient times.

> As this patch is already in -next and is stuck there for two more
> weeks I can't (or at least won't) merge this patch, so I can't help
> with any of the above.

I will fix both issues in the next version of the patch. Would like to
merge it to your tree or should I keep it in my dma-mapping tree?

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center


--
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/