Date: Thu, 2 Mar 2006 11:45:26 +0000
From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Pierre Ossman <drzeus-list@drzeus.cx>
Cc: Jens Axboe <axboe@suse.de>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: How to map high memory for block io
Message-ID: <20060302114526.GC14017@flint.arm.linux.org.uk>
Mail-Followup-To: Pierre Ossman <drzeus-list@drzeus.cx>,
	Jens Axboe <axboe@suse.de>, LKML <linux-kernel@vger.kernel.org>
References: <20060129152228.GF13831@suse.de> <43DDC6F9.6070007@drzeus.cx> <20060130080930.GB4209@suse.de> <43DFAEC6.3090205@drzeus.cx> <20060301232913.GC4024@flint.arm.linux.org.uk> <44069E3A.4000907@drzeus.cx> <20060302094153.GA14017@flint.arm.linux.org.uk> <4406C044.4080201@drzeus.cx> <20060302100409.GB14017@flint.arm.linux.org.uk> <4406C845.8000603@drzeus.cx>
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On Thu, Mar 02, 2006 at 11:26:13AM +0100, Pierre Ossman wrote:
> This I know. My beef is the readability of:
> 
> if (do_dma)
>     *dev->dma_mask = DEVICE_DMA_MASK;
> else
>     *dev->dma_mask = 0;
> 
> I.e. we use dma_mask even though we don't do DMA.

Not a lot we can do about the readability issue - we end up with code
like that in some layer of the MMC.  If it's in mmc_queue, it might be:

        u64 limit = BLK_BOUNCE_HIGH;

        if (host->caps & MMC_CAP_DMA &&
	    host->dev->dma_mask && *host->dev->dma_mask)
                limit = *host->dev->dma_mask;

which is equally as (un)readable as your code.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core
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