From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755980Ab0IRUCR (ORCPT ); Sat, 18 Sep 2010 16:02:17 -0400 Received: from smtp102.sbc.mail.ac4.yahoo.com ([76.13.13.241]:26959 "HELO smtp102.sbc.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754161Ab0IRUCJ (ORCPT ); Sat, 18 Sep 2010 16:02:09 -0400 X-Yahoo-SMTP: fzDSGlOswBCWnIOrNw7KwwK1j9PqyNbe5PtLKiS4dDU.UNl_t6bdEZu9tTLW X-YMail-OSG: qrHJVRMVM1mI5j0t2PH11ahIhUbjAVg4aHZ.JMymNlcfySt cKVXDVFK5.lpo_6awWpyJz4vIU2nKhKRpih8soxnpV12HwKdoI6pm64gzw.h Tyh1b6.LoAiyXwAr1AM1.Lp5.DGA0RuGnh6k_X3F75bYXTtn9bsZWEdmflcX Qug2PJ1Ue8PRTHnOM3t_PDafYMhTZI6ktZqClLbCv4KgPO8VUff9JzIUB0dC stk5yyDUC6p75k6OTxNJRV17qPCpMYnHppgjkc7DlYrnvdp3QprO7gLg- X-Yahoo-Newman-Property: ymail-3 Subject: Re: [PATCH v2 01/11] scsi: Convert struct Scsi_Host->cmd_serial_number to atomic_t From: "Nicholas A. Bellinger" To: Mike Christie Cc: Joe Eykholt , linux-scsi , linux-kernel , Vasu Dev , Tim Chen , Andi Kleen , Matthew Wilcox , James Bottomley , James Smart , Andrew Vasquez , FUJITA Tomonori , Hannes Reinecke , Christoph Hellwig In-Reply-To: <4C9427B6.9050404@cs.wisc.edu> References: <1284747709-20862-1-git-send-email-nab@linux-iscsi.org> <4C93BB8E.2080501@cisco.com> <4C9427B6.9050404@cs.wisc.edu> Content-Type: text/plain Date: Sat, 18 Sep 2010 12:57:58 -0700 Message-Id: <1284839878.13344.300.camel@haakon2.linux-iscsi.org> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2010-09-17 at 21:45 -0500, Mike Christie wrote: > On 09/17/2010 02:03 PM, Joe Eykholt wrote: > > > > How about instead of adding use_serial_number, let's just have the > > drivers that want a serial number call scsi_cmd_get_serial() > > I think this sounds better. > In that case I will go ahead and add explict scsi_cmd_get_serial() calls to the LLDs that use struct scsi_cmnd->serial_number in anything beyond an obvious and simple informational purpose. > You could also convert drivers to the host tagging if you needed a > unique id for each command sent to a host. Hmmm, what does this entail again..? > > > and stop calling it from scsi_dispatch_cmd()? AFAICT, it's only > > used in debug messages in some drivers. I didn't find other usages > > but didn't do an exhaustive search. > > The comments for serial_number say that it is only supposed to be used > for debugging printks and most drivers use it for that. So I would suppose it would be OK for those drivers to continue to printk serial_number to show the internal serial_number allocation is now disabled by default. > However, it looks like mpt and dpt_i2o are using it for error handling > and/or lookup type of operations. I think the mpt* uses are not needed > in the abort checks. > In that case, then adding an explict scsi_cmd_get_serial() call in mpt* and dpt_i20 ->queuecommand() callers would be a good first step. > And eata is using it for ordering and tracking or something. It could > probably be converted to the host tagging if or what you suggested if it > needs the uniqueue id. Adding an explict scsi_cmd_get_serial() for eata for now, and we can consider LLD canidates for host tag conversion as a future step. > > zfcp looks like it copies it. It does not look like the driver needs it. > Ok, I will look at removing it's usage in zfcp or if necessary add an the explict scsi_cmd_get_serial() call. > scsi_error.c uses it in scsi_try_to_abort_cmd to check if a command has > completed, but I think that can be done by checking if REQ_ATOM_COMPLETE > is set. Hmmm, good catch here. Jejb and hch, does this item work for you..? If so then I will take another peek for any ML uses of a struct scsi_cmnd->serial_number that need to be addressed, and include Joe's and Mike's recommendations into a v3 series. Thanks for your comments here Mike! --nab