From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Garzik <jgarzik@pobox.com>
Subject: Re: [PATCH] add extra inquiry byte 56 data to struct scsi_device
Date: Fri, 20 Aug 2004 23:21:48 -0400
Sender: linux-scsi-owner@vger.kernel.org
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To: James Bottomley <James.Bottomley@SteelEye.com>
Cc: SCSI Mailing List <linux-scsi@vger.kernel.org>

James Bottomley wrote:
> +	if (sdev->inquiry_len > 56) {
> +		if (inq_result[56] & 0x04)
> +			sdev->ppr = 1;
> +		if ((inq_result[56] & 0x0c) == 0x04)
> +			sdev->dt_only = 1;
> +		if (inq_result[56] & 0x01)
> +			sdev->ius = 1;
> +		if (inq_result[56] & 0x02)
> +			sdev->qas = 1;
> +	}


Do you forsee ever adding more feature bits like this?

It seems to me that a more maintainable approach is to cache relevant 
INQUIRY data in a buffer, and then create accessor macros for 
programmers' use.

That way you don't have to keep adding members (really, mnemonics) to a 
data structure, and associated initialization code, each time the 
mid-layer or some low-level drivers want to test a new feature bit. 
Initialization via memcpy is easy and automatic.

	Jeff