linux-kernel - Re: [PATCH 4/7] mmc: at91_mci: add multiwrite switch

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: <20080609124249.349995df@mjolnir.drzeus.cx>
Date:	Mon, 9 Jun 2008 12:42:49 +0200
From:	Pierre Ossman <drzeus@...eus.cx>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
Cc:	Nicolas Ferre <nicolas.ferre@...el.com>,
	Linux Kernel list <linux-kernel@...r.kernel.org>,
	Andrew Victor <linux@...im.org.za>,
	Eric BENARD <ebenard@...e.fr>,
	ARM Linux Mailing List 
	<linux-arm-kernel@...ts.arm.linux.org.uk>
Subject: Re: [PATCH 4/7] mmc: at91_mci: add multiwrite switch

On Sun, 1 Jun 2008 15:42:52 +0100
Russell King - ARM Linux <linux@....linux.org.uk> wrote:

> If Pierre wants to remove the MULTIWRITE flag, I'd like to hear his
> solution for the pxamci driver, where the only way to ascertain how
> many bytes were transmitted may be to walk the SG list comparing the
> DMA pointer with what was in the hardware DMA engine at the time.
> Maybe.

You set bytes_xfered to 0. As mentioned in my previous mail, I had a
chat with Jens about this and upper layers can only expect to get the
lower bound in how many bytes were written. Other hardware/drivers
already behaves like this so there is no point in crippling the MMC
layer in an effort to give nicer guarantees.

This is why I asked people to audit their drivers to make sure it's
the lower bound that's returned, but I've not received much in the way
of replies.

Rgds
Pierre

Download attachment "signature.asc" of type "application/pgp-signature" (198 bytes)