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 <hare@xxxxxxx>
---
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
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