From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: SCSI reserve / release support for SG Date: Fri, 14 Nov 2003 22:19:40 +1000 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <3FB4C85C.9020907@torque.net> References: <3FB4BC92.D43703BE@in.ibm.com> Reply-To: dougg@torque.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from bunyip.cc.uq.edu.au ([130.102.2.1]:9999 "EHLO bunyip.cc.uq.edu.au") by vger.kernel.org with ESMTP id S262432AbTKNMUA (ORCPT ); Fri, 14 Nov 2003 07:20:00 -0500 In-Reply-To: <3FB4BC92.D43703BE@in.ibm.com> List-Id: linux-scsi@vger.kernel.org To: Sachin Sant Cc: linux-scsi@vger.kernel.org Sachin Sant wrote: > Does Current sg driver offer SCSI reserve/release command in its > open/close function. No. > I am trying to run on a SAN or Cluster environment > which requires support for this reserve/release command. BTW www.t10.org traffic suggests more sophisticated reserve/ release mechanisms are in the pipeline. IOWs a solution to your problem now could be an impediment a few years down the track. > If not then are there any plans to support reserve/release SCSI command > so that sg driver can provide these options for its users in its > open/close function It will make all I/O operation with sg driver more > reliable especially in data storage area. I'm getting this request from several angles. As someone wryly pointed out ... as if we haven't got enough trouble at the moment with the scsi subsystem implicitly issuing scsi commands :-) Seriously, I don't think issuing reserve/release SCSI commands on the open and close of a pass-through interface is a good idea. At a stretch it could be a non-default parameter on the sg driver [lk 2.4 via /proc/scsi/sg; in lk 2.6 ...] Just thinking about the implementation: currently sg will hold its data structures alive if an unexpected close (e.g. user control-C) occurs while a SCSI command is in flight. I guess the point of what you are suggesting is to issue another scsi command (i.e. release) in such a situation (and wait for it (potentially as well as a command in progress)). Doug Gilbert