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* [PATCH] scsi: disable automatic target scan
@ 2016-03-11 15:33 Hannes Reinecke
  2016-03-14  8:08 ` Johannes Thumshirn
  2016-03-14 23:57 ` Martin K. Petersen
  0 siblings, 2 replies; 6+ messages in thread
From: Hannes Reinecke @ 2016-03-11 15:33 UTC (permalink / raw)
  To: Martin K. Petersen
  Cc: Christoph Hellwig, James Bottomley, linux-scsi, 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 scan_type 'disabled', which work like
'none', but can be overriden by setting the 'rescan' value
from scsi_scan_target to '2'.
And it updates all relevant callers to set the 'rescan' value
to '2' if invoked via the 'scan' option in sysfs.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/scsi_scan.c            | 17 ++++++++++++-----
 drivers/scsi/scsi_sysfs.c           |  2 +-
 drivers/scsi/scsi_transport_fc.c    |  2 +-
 drivers/scsi/scsi_transport_iscsi.c |  2 +-
 drivers/scsi/scsi_transport_sas.c   |  2 +-
 5 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 97074c9..929204b 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -96,10 +96,11 @@ 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[9] = 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, disabled, or none");
 
 static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ + 18;
 
@@ -1604,7 +1605,9 @@ 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; 0 for no rescan, 1 to rescan
+ *              existing LUNs, and 2 to override any 'scan_disabled' setting
+ *              from the host.
  *
  * Description:
  *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
@@ -1621,6 +1624,9 @@ void scsi_scan_target(struct device *parent, unsigned int channel,
 	if (strncmp(scsi_scan_type, "none", 4) == 0)
 		return;
 
+	if (rescan < 2 && strncmp(scsi_scan_type, "disabled", 8) == 0)
+		return;
+
 	mutex_lock(&shost->scan_mutex);
 	if (!shost->async_scan)
 		scsi_complete_async_scans();
@@ -1844,7 +1850,8 @@ 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, "disabled", 8) == 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..d805d55 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -143,7 +143,7 @@ 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, 2);
 	return res;
 }
 
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 8a88226..018b2da 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -2110,7 +2110,7 @@ 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, 2);
 			return;
 		}
 	}
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 4414816..2941598 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, 2);
 	}
 
 user_scan_exit:
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index deb3fde..1e0664f 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -1740,7 +1740,7 @@ 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);
+					 rphy->scsi_target_id, lun, 2);
 		}
 	}
 	mutex_unlock(&sas_host->lock);
-- 
1.8.5.6


^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-03-15  6:53 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-03-11 15:33 [PATCH] scsi: disable automatic target scan Hannes Reinecke
2016-03-14  8:08 ` Johannes Thumshirn
2016-03-14 23:57 ` Martin K. Petersen
2016-03-15  6:47   ` Hannes Reinecke
2016-03-15  6:48     ` Christoph Hellwig
2016-03-15  6:53       ` Hannes Reinecke

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