From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: [PATCH][RFC] scsi_transport_fc: Implement I_T nexus reset Date: Fri, 07 Dec 2012 12:58:34 -0600 Message-ID: <50C23C5A.9090907@cs.wisc.edu> References: <1354891880-16159-1-git-send-email-hare@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from sabe.cs.wisc.edu ([128.105.6.20]:38292 "EHLO sabe.cs.wisc.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751844Ab2LGTA0 (ORCPT ); Fri, 7 Dec 2012 14:00:26 -0500 In-Reply-To: <1354891880-16159-1-git-send-email-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke Cc: linux-scsi@vger.kernel.org, James Smart , Andrew Vasquez , Chad Dupuis , James Bottomley On 12/07/2012 08:51 AM, Hannes Reinecke wrote: > 'Bus reset' is not really applicable to FibreChannel, as > the concept of a bus doesn't apply. Hence all FC LLDD > simulate a 'bus reset' by sending a target reset to each > attached remote port, causing error handling to spill > over to unaffected devices. > > This patch implements a 'I_T nexus reset' handler, > which attempts to reset the I_T nexus to the remote > port. This way only the affected remote ports are > reset; other ports are left untouched. Is the I_T nexus reset we are doing in this patch supposed to be the same one defined in SAM? Was the I_T nexus reset TMF added to SAM at the same time the target reset one was removed? In SAM 4 and 5 there is no target reset anymore is there? I think we should just kill the bus reset use from the FC drivers. Add a new I_T nexus reset callout to the scsi_host_template or to the scsi_transport_template. Then have scsi-ml call just either target reset eh callout or I_T nexus eh reset callout depending on what the target supports. To figure out what the target supports could we do a REPORTED SUPPORTED TASK MANAGEMENT FUNCTION command. If the target supports that command and reports that the target supports the I_T nexus reset TMF then call that eh callback, else drop down to older target reset eh callback. It seems that if we do I_T nexus reset we do not need to also do a target reset do we? > @@ -3266,8 +3271,8 @@ fc_timeout_fail_rport_io(struct work_struct *work) > if (rport->port_state != FC_PORTSTATE_BLOCKED) > return; > > - rport->flags |= FC_RPORT_FAST_FAIL_TIMEDOUT; > fc_terminate_rport_io(rport); > + rport->flags |= FC_RPORT_FAST_FAIL_TIMEDOUT; > } > What was the reason for moving this? For the eh case in this patch was it causing IO to be failed with DID_TRANSPORT_FAILFAST when we wanted it failed with some other error.