From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Christie <michaelc@cs.wisc.edu>
Subject: Re: Actually using the sg table/chain code
Date: Fri, 22 Feb 2008 10:13:45 -0600
Message-ID: <47BEF4B9.2010401@cs.wisc.edu>
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To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <jens.axboe@oracle.com>, linux-scsi <linux-scsi@vger.kernel.org>

James Bottomley wrote:
> Yes, I can buy the argument for filesystem I/Os.  What about tapes which
> currently use the block queue and have internal home grown stuff to
> handle larger transfers ... how are they supposed to set the larger
> default sector size?  Just modify the bare q->max_sectors?
> 

Sorry for the late response. I have been doing userspace stuff and not 
keeping up with linux-scsi :(

For scsi tape and passthrough (any place we use REQ_TYPE_BLOCK_PC like 
with st or sg or block/scsi_ioctl or bsg), the block/bio/scatterlist 
building code ignores q->max_sectors and uses q->max_hw_sectors.