Re: [PATCH Linux 2.6.12-rc5-mm2 08/09] blk: update IDE to use the new blk_ordered.

From: Jeff Garzik <jgarzik@pobox.com>
To: Tejun Heo <htejun@gmail.com>
Cc: axboe@suse.de, James.Bottomley@steeleye.com, bzolnier@gmail.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH Linux 2.6.12-rc5-mm2 08/09] blk: update IDE to use the new blk_ordered.
Date: Sun, 05 Jun 2005 02:47:43 -0400	[thread overview]
Message-ID: <42A2A00F.9050402@pobox.com> (raw)
In-Reply-To: <20050605055337.ADD601D4@htj.dyndns.org>

Tejun Heo wrote:
> @@ -176,6 +176,18 @@ static ide_startstop_t __ide_do_rw_disk(
>  			lba48 = 0;
>  	}
>  
> +	if (blk_fua_rq(rq) &&
> +	    (!rq_data_dir(rq) || !drive->select.b.lba || !lba48)) {
> +		if (!rq_data_dir(rq))
> +			printk(KERN_WARNING "%s: FUA READ unsupported\n",
> +			       drive->name);
> +		else
> +			printk(KERN_WARNING "%s: FUA request received but "
> +			       "cannot use LBA48\n", drive->name);
> +		ide_end_request(drive, 0, 0);
> +		return ide_stopped;
> +	}
> +

Does this string of tests really need to be added to the main fast path?

It would be better to simply guarantee that this check need never exist 
in the IDE driver, by guaranteeing that the block layer will never send 
a FUA-READ command to a driver that does not wish it.

	Jeff