linux-kernel - Re: [PATCH] atmel_spi: support zero length transfer (resend)

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: <20080329175651.311b4f6d@hskinnemo-gx620.norway.atmel.com>
Date:	Sat, 29 Mar 2008 17:56:51 +0100
From:	Haavard Skinnemoen <haavard.skinnemoen@...el.com>
To:	Atsushi Nemoto <anemo@....ocn.ne.jp>
Cc:	David Brownell <david-b@...bell.net>,
	spi-devel-general@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	marc.pignat@...s.ch, nforrester@...i.edu
Subject: Re: [PATCH] atmel_spi: support zero length transfer (resend)

Atsushi Nemoto <anemo@....ocn.ne.jp> wrote:
> A spi transfer with zero length is not invalid.  For example, such
> transfer (len == 0 && delay_usecs != 0) can be used to achieve delay
> before first CLK edge after chipselect assertion.
> 
> Signed-off-by: Atsushi Nemoto <anemo@....ocn.ne.jp>
> ---
> Though some discussion about zero length transfer were raised by this
> patch last time, I think there were no explicit objection to this
> patch itself.

Well, the patch doesn't seem to do any harm, but I can't see much of a
point to it either if zero-length transfers aren't going to be
allowed...

Also, if the length is zero, the driver will end up doing a memset with
length zero at some point. Is that allowed?

Haavard
--
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/