From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: [PATCH 3/6] scsi tgt: add partial mappings support to bio_map_user Date: Thu, 16 Feb 2006 14:00:34 -0600 Message-ID: <43F4D9E2.5030703@cs.wisc.edu> References: <1140119620.20193.51.camel@max> <20060216195917.GY4203@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from sabe.cs.wisc.edu ([128.105.6.20]:54688 "EHLO sabe.cs.wisc.edu") by vger.kernel.org with ESMTP id S964889AbWBPUAl (ORCPT ); Thu, 16 Feb 2006 15:00:41 -0500 In-Reply-To: <20060216195917.GY4203@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jens Axboe Cc: linux-scsi@vger.kernel.org Jens Axboe wrote: > On Thu, Feb 16 2006, Mike Christie wrote: > >>Subject: [PATCH] block layer: add partial mappings support to bio_map_user >> >>For target mode we could end up with the case where we get very large >>request from the initiator. The request could be so large that we >>cannot transfer all the data in one operation. For example the >>HBA's segment or max_sector limits might limit us to a 1 MB transfer. >>To send a 5 MB command then we need to transfer the command chunk by chunk. >> >>To do this, tgt core will map in as much data as possible into a bio, >>send this off, then when that transfer is completed we send off another >>request/bio. To be able to pack as much data into a bio as possible >>we need bio_map_user to support partially mapped bios. The attached patch >>just adds a new argument to the those functions and if set will not >>return a failure if the bio is partially mapped. > > > Drop the partial flag and just always allow it, fixing up the few > in-kernel users we have. > ok will do.