From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH] bugfix for an underflow condition in usb storage & isd200.c Date: Wed, 06 Feb 2008 17:01:09 -0600 Message-ID: <1202338869.3112.138.camel@localhost.localdomain> References: Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from accolon.hansenpartnership.com ([76.243.235.52]:57704 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758246AbYBFXBP (ORCPT ); Wed, 6 Feb 2008 18:01:15 -0500 In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Alan Stern Cc: Matthew Dharm , Boaz Harrosh , Mark Glines , USB list , linux-scsi On Wed, 2008-02-06 at 17:18 -0500, Alan Stern wrote: > On Wed, 6 Feb 2008, Matthew Dharm wrote: > > > Maybe this is a crazy question, but... > > > > Why is this not in the SCSI core? > > Or even in the block core? > > > It's hardly USB-specific, and I'm > > willing to bet that there are other HCDs (at least spb2) which need to do > > this sort of thing... > > James, do you have any idea? > > What we're talking about is a routine that provides drivers a simple > way to access the data in a scatter-gather buffer (which may lie in > highmem or otherwise not be easily reachable). The idea is that some > commands are emulated by the driver rather than carried out by the > device, and the driver needs some way to stick the results in the > transfer buffer. Isn't that what scsi_kmap_sg() is designed for ... or do you need something slightly different? James