This patch implements a function scsi_resurrect_device()
which elevates a sdev from state SDEV_CANCEL back into
SDEV_RUNNING.
So during a scan any sdev in SDEV_DEL is put into
SDEV_CANCEL and then scsi_resurrect_device() is called.
This will put the device into SDEV_RUNNING and the scan
can proceed.
To allow this the state machine has to be expanded, as no
transistion out of SDEV_CANCEL into SDEV_RUNNING and from
SDEV_DEL into SDEV_CANCEL are now perfectly possible.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/scsi/scsi.c | 3 ++
drivers/scsi/scsi_lib.c | 2 +
drivers/scsi/scsi_scan.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 58 insertions(+), 0 deletions(-)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 4c1e313..11f0f0d 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -950,6 +950,9 @@ struct scsi_device *scsi_device_lookup_b
spin_lock_irqsave(shost->host_lock, flags);
sdev = __scsi_device_lookup_by_target(starget, lun);
+ /* This triggers a resurrection of the sdev */
+ if (sdev && sdev->sdev_state == SDEV_DEL)
+ scsi_device_set_state(sdev, SDEV_CANCEL);
if (sdev && scsi_device_get(sdev))
sdev = NULL;
spin_unlock_irqrestore(shost->host_lock, flags);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index bb32747..d1dc7ce 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1954,6 +1954,7 @@ scsi_device_set_state(struct scsi_device
case SDEV_OFFLINE:
case SDEV_QUIESCE:
case SDEV_BLOCK:
+ case SDEV_CANCEL:
break;
default:
goto illegal;
@@ -1999,6 +2000,7 @@ scsi_device_set_state(struct scsi_device
case SDEV_QUIESCE:
case SDEV_OFFLINE:
case SDEV_BLOCK:
+ case SDEV_DEL:
break;
default:
goto illegal;
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index bf62089..a97c889 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -735,6 +735,52 @@ int scsi_configure_device(struct scsi_de
}
/**
+ * scsi_resurrect_device - resurrect a deleted scsi_device
+ * @sdev: The scsi_device to resurrect
+ *
+ * Description:
+ * Elevate a deleted scsi_device back to SDEV_RUNNING.
+ * The scsi_device has to be in SDEV_CANCEL.
+ * The resurrection process calls scsi_configure_device()
+ * to setup transport and LLDD and then attaches it to sysfs
+ * with scsi_sysfs_add_sdev().
+ * On success the device is in SDEV_RUNNING and ready to
+ * accept I/O.
+ * On failure the device is put back into SDEV_CANCEL.
+ * It should be set to SDEV_DEL afterwards by eg.
+ * a call to scsi_destroy_device().
+ *
+ * Return:
+ * 0 On Success
+ * <0 On failure.
+ *
+ **/
+int scsi_resurrect_device(struct scsi_device *sdev)
+{
+ int ret = 0;
+
+ /* Ignore devices not in state SDEV_CANCEL */
+ if (sdev->sdev_state != SDEV_CANCEL)
+ return 0;
+
+ ret = scsi_configure_device(sdev);
+ if (ret)
+ return ret;
+
+ /*
+ * Ok, the device is now all set up, we can
+ * register it and tell the rest of the kernel
+ * about it.
+ */
+ ret = scsi_sysfs_add_sdev(sdev);
+
+ if (ret)
+ scsi_device_set_state(sdev, SDEV_CANCEL);
+
+ return ret;
+}
+
+/**
* scsi_add_lun - allocate and fully initialze a scsi_device
* @sdevscan: holds information to be stored in the new scsi_device
* @sdevnew: store the address of the newly allocated scsi_device
@@ -1013,6 +1059,10 @@ static int scsi_probe_and_add_lun(struct
*/
sdev = scsi_device_lookup_by_target(starget, lun);
if (sdev) {
+ if (scsi_resurrect_device(sdev)) {
+ scsi_destroy_device(sdev);
+ return SCSI_SCAN_NO_RESPONSE;
+ }
if (rescan || sdev->sdev_state != SDEV_CREATED) {
SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
"scsi scan: device exists on %s\n",
@@ -1330,6 +1380,9 @@ static int scsi_report_lun_scan(struct s
return 0;
if (scsi_device_get(sdev))
return 0;
+ } else if (scsi_resurrect_device(sdev)) {
+ scsi_destroy_device(sdev);
+ return 0;
}
sprintf(devname, "host %d channel %d id %d",
--
1.4.3.4
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