To: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
       linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
       linux-scsi@vger.kernel.org, davem@davemloft.net,
       james.bottomley@steeleye.com, ralf@linux-mips.org
Subject: Re: [PATCH 1/2] DMA buffer alignment annotations
References: <20071221023010.C56B7DDDF3@ozlabs.org>
	<20071221093905.GB31115@flint.arm.linux.org.uk>
From: Roland Dreier <rdreier@cisco.com>
Date: Fri, 21 Dec 2007 08:58:50 -0800
In-Reply-To: <20071221093905.GB31115@flint.arm.linux.org.uk> (Russell King's message of "Fri, 21 Dec 2007 09:39:05 +0000")
Message-ID: <adafxxwx9v9.fsf@cisco.com>
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 > > +#define __dma_aligned	  	__attribute__((aligned(ARCH_MIN_DMA_ALIGNMENT)))
 > > +#define __dma_buffer		__dma_buffer_line(__LINE__)
 > > +#define __dma_buffer_line(line)	__dma_aligned;\
 > > +				char __dma_pad_##line[0] __dma_aligned

 > You introduce __dma_buffer_line() if ARCH_MIN_DMA_ALIGNMENT is set but
 > not if it isn't...

__dma_buffer_line() is just an internal implementation detail to take
care of string pasting properly.  Perhaps there should be a comment
warning people not to use it directly.

 - R.
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