From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: [PATCHv2] scsi: disable automatic target scan Date: Tue, 15 Mar 2016 08:19:42 +0100 Message-ID: <1458026382-43338-1-git-send-email-hare@suse.de> Return-path: Received: from mx2.suse.de ([195.135.220.15]:52677 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932557AbcCOHTp (ORCPT ); Tue, 15 Mar 2016 03:19:45 -0400 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Martin K. Petersen" Cc: Christoph Hellwig , James Bottomley , linux-scsi@vger.kernel.org, Hannes Reinecke 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 'rescan' 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 --- drivers/scsi/scsi_scan.c | 25 ++++++++++++++++++------- drivers/scsi/scsi_sysfs.c | 3 ++- drivers/scsi/scsi_transport_fc.c | 3 ++- drivers/scsi/scsi_transport_iscsi.c | 2 +- drivers/scsi/scsi_transport_sas.c | 4 ++-- include/scsi/scsi_device.h | 6 ++++++ 6 files changed, 31 insertions(+), 12 deletions(-) diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 97074c9..54dc517 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -96,10 +96,13 @@ MODULE_PARM_DESC(max_luns, #define SCSI_SCAN_TYPE_DEFAULT "sync" #endif -char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT; +char scsi_scan_type[7] = SCSI_SCAN_TYPE_DEFAULT; -module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), S_IRUGO); -MODULE_PARM_DESC(scan, "sync, async or none"); +module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), + S_IRUGO|S_IWUSR); +MODULE_PARM_DESC(scan, "sync, async, manual, or none. " + "Setting to 'manual' disables automatic scanning, but allows " + "for manual device scan via the 'scan' sysfs attribute."); static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ + 18; @@ -1040,7 +1043,8 @@ static unsigned char *scsi_inq_str(unsigned char *buf, unsigned char *inq, * @lun: LUN of target device * @bflagsp: store bflags here if not NULL * @sdevp: probe the LUN corresponding to this scsi_device - * @rescan: if nonzero skip some code only needed on first scan + * @rescan: if greater than SCSI_SCAN_NONE skip some code only + * needed on first scan * @hostdata: passed to scsi_alloc_sdev() * * Description: @@ -1069,7 +1073,7 @@ static int scsi_probe_and_add_lun(struct scsi_target *starget, */ sdev = scsi_device_lookup_by_target(starget, lun); if (sdev) { - if (rescan || !scsi_device_created(sdev)) { + if (rescan > SCSI_SCAN_NONE || !scsi_device_created(sdev)) { SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev, "scsi scan: device exists on %s\n", dev_name(&sdev->sdev_gendev))); @@ -1604,7 +1608,9 @@ static void __scsi_scan_target(struct device *parent, unsigned int channel, * @channel: channel to scan * @id: target id to scan * @lun: Specific LUN to scan or SCAN_WILD_CARD - * @rescan: passed to LUN scanning routines + * @rescan: passed to LUN scanning routines; SCSI_SCAN_NONE for no rescan, + * SCSI_SCAN_RESCAN to rescan existing LUNs, and SCSI_SCAN_MANUAL + * to force scanning even if 'scan=manual' is set. * * Description: * Scan the target id on @parent, @channel, and @id. Scan at least LUN 0, @@ -1621,6 +1627,10 @@ void scsi_scan_target(struct device *parent, unsigned int channel, if (strncmp(scsi_scan_type, "none", 4) == 0) return; + if (rescan < SCSI_SCAN_MANUAL && + strncmp(scsi_scan_type, "manual", 6) == 0) + return; + mutex_lock(&shost->scan_mutex); if (!shost->async_scan) scsi_complete_async_scans(); @@ -1844,7 +1854,8 @@ void scsi_scan_host(struct Scsi_Host *shost) { struct async_scan_data *data; - if (strncmp(scsi_scan_type, "none", 4) == 0) + if (strncmp(scsi_scan_type, "none", 4) == 0 || + strncmp(scsi_scan_type, "manual", 6) == 0) return; if (scsi_autopm_get_host(shost) < 0) return; diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 92ffd24..3b2045f 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -143,7 +143,8 @@ static int scsi_scan(struct Scsi_Host *shost, const char *str) if (shost->transportt->user_scan) res = shost->transportt->user_scan(shost, channel, id, lun); else - res = scsi_scan_host_selected(shost, channel, id, lun, 1); + res = scsi_scan_host_selected(shost, channel, id, lun, + SCSI_SCAN_MANUAL); return res; } diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c index 8a88226..3482a55 100644 --- a/drivers/scsi/scsi_transport_fc.c +++ b/drivers/scsi/scsi_transport_fc.c @@ -2110,7 +2110,8 @@ fc_user_scan_tgt(struct Scsi_Host *shost, uint channel, uint id, u64 lun) if ((channel == rport->channel) && (id == rport->scsi_target_id)) { spin_unlock_irqrestore(shost->host_lock, flags); - scsi_scan_target(&rport->dev, channel, id, lun, 1); + scsi_scan_target(&rport->dev, channel, id, lun, + SCSI_SCAN_MANUAL); return; } } diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c index 4414816..f4c16dc 100644 --- a/drivers/scsi/scsi_transport_iscsi.c +++ b/drivers/scsi/scsi_transport_iscsi.c @@ -1819,7 +1819,7 @@ static int iscsi_user_scan_session(struct device *dev, void *data) (scan_data->id == SCAN_WILD_CARD || scan_data->id == id)) scsi_scan_target(&session->dev, 0, id, - scan_data->lun, 1); + scan_data->lun, SCSI_SCAN_MANUAL); } user_scan_exit: diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c index b6f958193..d8d38e6 100644 --- a/drivers/scsi/scsi_transport_sas.c +++ b/drivers/scsi/scsi_transport_sas.c @@ -1739,8 +1739,8 @@ static int sas_user_scan(struct Scsi_Host *shost, uint channel, if ((channel == SCAN_WILD_CARD || channel == 0) && (id == SCAN_WILD_CARD || id == rphy->scsi_target_id)) { - scsi_scan_target(&rphy->dev, 0, - rphy->scsi_target_id, lun, 1); + scsi_scan_target(&rphy->dev, 0, rphy->scsi_target_id, + lun, SCSI_SCAN_MANUAL); } } mutex_unlock(&sas_host->lock); diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index c067019..f954272 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -50,6 +50,12 @@ enum scsi_device_state { SDEV_CREATED_BLOCK, /* same as above but for created devices */ }; +enum scsi_scan_mode { + SCSI_SCAN_NONE = 0, + SCSI_SCAN_RESCAN, + SCSI_SCAN_MANUAL, +}; + enum scsi_device_event { SDEV_EVT_MEDIA_CHANGE = 1, /* media has changed */ SDEV_EVT_INQUIRY_CHANGE_REPORTED, /* 3F 03 UA reported */ -- 1.8.5.6