Message-ID: <4FEEDAA4.30105@nod.at>
Date: Sat, 30 Jun 2012 12:53:24 +0200
From: Richard Weinberger <richard@nod.at>
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To: Artem Bityutskiy <dedekind1@gmail.com>
CC: linux-mtd@lists.infradead.org, nyoushchenko@mvista.com,
        artem.bityutskiy@linux.intel.com, linux-kernel@vger.kernel.org,
        adrian.hunter@intel.com, Heinz.Egger@linutronix.de,
        thomas.wucher@linutronix.de, shmulik.ladkani@gmail.com,
        tglx@linutronix.de, Marius.Mazarel@ugal.ro, tim.bird@am.sony.com
Subject: Re: UBI fastmap updates
References: <1340982869-77042-1-git-send-email-richard@nod.at> <1341052998.2115.3.camel@koala>
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Am 30.06.2012 12:43, schrieb Artem Bityutskiy:
> On Fri, 2012-06-29 at 17:14 +0200, Richard Weinberger wrote:
>> This is the next round of UBI fastmap updates.
>>
>> Fastmap is now disabled by default.
>> If you attach an image it will not automatically convert it
>> to the fastmap format.
>> UBI has a new module parameter "fm_auto".
>> If set to 1 UBI will create a fastmap automatically on your
>> flash device.
>> Please see commit "Add a module parameter to enable fastmap"
>> for more details.
>=20
> One thing I've noticed is that you use vmalloc for some of the buffers
> you do I/O on (fm_raw). This is a problem for many ARM platforms becaus=
e
> they cannot do DMA on such buffers. The drivers have to implement
> various workarouns for this: either fall back to memcopies or do an
> extra copy to a DMA-able buffers.
>=20
> UBI and UBIFS already to I/O on vmalloc'ed buffers, an I am planning to=

> fix this, which is not easy. Would be great to not add more of these.

There are only two buffers which use vmalloc() both are used to hold the =
raw fastmap and have
the same size.
If it helps I could preallocate a buffer in ubi-> and use it in both func=
tions ubi_write_fastmap()
and ubi_scan_fastmap().

So basically you want me to get rid of any vmalloc()'ed buffer?
That's not easy.

Thanks,
//richard


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