Date: Mon, 7 Jun 2004 09:03:07 -0700 (PDT)
From: Linus Torvalds <torvalds@osdl.org>
To: Thomas Gleixner <tglx@linutronix.de>
cc: Greg Weeks <greg.weeks@timesys.com>,
       linux-arm-kernel@lists.arm.linux.org.uk, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2.4] jffs2 aligment problems
In-Reply-To: <200406071736.53101.tglx@linutronix.de>
Message-ID: <Pine.LNX.4.58.0406070900010.6162@ppc970.osdl.org>
References: <40C484F9.20504@timesys.com> <200406071736.53101.tglx@linutronix.de>
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On Mon, 7 Jun 2004, Thomas Gleixner wrote:
>
> On Monday 07 June 2004 17:08, Greg Weeks wrote:
> > This fixed some jffs2 alignment problems we saw on an IXP425 based
> > XScale board. I just got pinged that I was supposed to post this patch
> > in case anyone else finds it usefull. This was against a modified 2.4.19
> > kernel.
> 
> Enable CONFIG_ALIGNMENT_TRAP instead of tweaking the code. 
> JFFS2 / MTD must be allowed to do unaligned access

Wrong.

Pleas fix jffs2 to use the proper "get_unaligned()"/"put_unaligned()"  
instead.

Emulating unaligned accesses with traps (even even the architecture
supports it, which isn't universally true) is _stupid_ when we have 
perfectly well-defined macros for them that do it faster and are 
_designed_ for this.

On architectures where it doesn't matter, the macros just do the access, 
so it's not like you're slowing anything down.

		Linus
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