From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Maier Subject: Re: [PATCHv2] scsi: disable automatic target scan Date: Tue, 15 Mar 2016 12:48:52 +0100 Message-ID: <56E7F6A4.7090201@linux.vnet.ibm.com> References: <1458026382-43338-1-git-send-email-hare@suse.de> <56E7EBFF.9030305@linux.vnet.ibm.com> <56E7F1C3.7030801@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from e06smtp12.uk.ibm.com ([195.75.94.108]:42623 "EHLO e06smtp12.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934440AbcCOLs7 convert rfc822-to-8bit (ORCPT ); Tue, 15 Mar 2016 07:48:59 -0400 Received: from localhost by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 15 Mar 2016 11:48:57 -0000 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id BD1102190046 for ; Tue, 15 Mar 2016 11:48:36 +0000 (GMT) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u2FBmsxh51708078 for ; Tue, 15 Mar 2016 11:48:54 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u2FBmqAc032663 for ; Tue, 15 Mar 2016 05:48:54 -0600 In-Reply-To: <56E7F1C3.7030801@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke , "Martin K. Petersen" Cc: Christoph Hellwig , James Bottomley , linux-scsi@vger.kernel.org On 03/15/2016 12:28 PM, Hannes Reinecke wrote: > On 03/15/2016 12:03 PM, Steffen Maier wrote: >> On 03/15/2016 08:19 AM, Hannes Reinecke wrote: >>> On larger installations it is useful to disable automatic LUN >>> scanning, and only add the required LUNs via udev rules. >>> This can speed up bootup dramatically. >>> >>> This patch introduces a new scan module parameter value 'manual', >>> which works like 'none', but can be overriden by setting the 'resca= n' >>> value from scsi_scan_target to 'SCSI_SCAN_MANUAL'. >>> And it updates all relevant callers to set the 'rescan' value >>> to 'SCSI_SCAN_MANUAL' if invoked via the 'scan' option in sysfs. >>> >>> Signed-off-by: Hannes Reinecke >> In particular, the following might be necessary in order not to >> break zfcp manual LUN addition (as long as zfcp still has its own >> unit_add sysfs interface; completely replacing it with the solution >> here is not easy because it breaks the zfcp sysfs user interface): >> >>> void zfcp_unit_scsi_scan(struct zfcp_unit *unit) >>> { >>> struct fc_rport *rport =3D unit->port->rport; >>> u64 lun; >>> >>> lun =3D scsilun_to_int((struct scsi_lun *) &unit->fcp_lun); >>> >>> if (rport && rport->port_state =3D=3D FC_PORTSTATE_ONLINE) >>> - scsi_scan_target(&rport->dev, 0, rport->scsi_target_id, >>> lun, 1); >>> + scsi_scan_target(&rport->dev, 0, rport->scsi_target_id, >>> lun, >>> + SCSI_SCAN_MANUAL); >>> } > As for zfcp: it also relies on the 'user_scan' callback from > scsi_transport_fc, so it will fall under the same rules as any > 'normal' FC HBA. I'm not sure, since zfcp needs to continue to support HBA hardware=20 virtualization without NPIV. The zfcp unit_add sysfs interface is kind of a peer of your common code= =20 scsi scan interface interface. I think, for zfcp users, a unit_add need= s=20 to be sufficient. It would be strange to additionally have them also=20 write the same LUN into the Scsi_Host's scan sysfs attribute, i.e.=20 having to double configure things. > But I do think we can tie the 'scan' module parameter with the > 'allow_lun_scan' parameter from zfcp; both are now doing essentially > the same. Eg the 'allow_lun_scan' parameter could take it's default > value from the 'scan' parameter. > In the long run we might want to check if and how the global 'scan' > parameter can be moved down to a host parameter, which then would > eliminate the need for a zfcp-specific parameter. I need to think about this. --=20 Mit freundlichen Gr=C3=BC=C3=9Fen / Kind regards Steffen Maier Linux on z Systems Development IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschaeftsfuehrung: Dirk Wittkopp Sitz der Gesellschaft: Boeblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html