This is the main part. This patch implements a function
scsi_resurrect_device() which puts a sdev in state SDEV_CANCEL
back into SDEV_RUNNING.
So during scan any device in state SDEV_DEL (ie waiting to be
deleted) will be put back into SDEV_RUNNING and normal scanning
can continue on these devices. Of course there is a high likelyhood
that the device will drop back into SDEV_DEL afterwards, but it is
perfectly useable during the scan operation.
For this to work I actually had to modify the allowed state
transitions, as it's now perfectly possible to move back from
SDEV_DEL into SDEV_CANCEL.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/scsi/scsi.c | 3 ++
drivers/scsi/scsi_lib.c | 2 +
drivers/scsi/scsi_scan.c | 52 +++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 56 insertions(+), 1 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 1f5a07b..4288572 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1945,6 +1945,7 @@ scsi_device_set_state(struct scsi_device
case SDEV_OFFLINE:
case SDEV_QUIESCE:
case SDEV_BLOCK:
+ case SDEV_CANCEL:
break;
default:
goto illegal;
@@ -1990,6 +1991,7 @@ 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 2653015..75b8a78 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -698,7 +698,7 @@ static int scsi_probe_lun(struct scsi_de
* Description:
* Configure an existing scsi_device. This function
* elevates a scsi_device from state SDEV_CREATED or
- * SDEV_DEL into SDEV_RUNNING.
+ * SDEV_CANCEL into SDEV_RUNNING.
*
* Return:
* 0 On Success
@@ -723,6 +723,49 @@ 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.
+ * A deleted scsi_device (ie in state SDEV_DEL) is only
+ * deleted from the internal list when the ->release
+ * function of the corresponding kobj structure is called.
+ * Until that time it will stay visible to the host.
+ * Whenever a scan has been initiated we thus have to
+ * put this device back to SDEV_RUNNING and proceed
+ * as with normal sdevs. It might be dropping back to
+ * SDEV_DEL after scanning is completed, but is perfectly
+ * useable during that time.
+ *
+ * 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) {
+ scsi_destroy_device(sdev);
+ return ret;
+ }
+
+ /*
+ * Ok, the device is now all set up, we can
+ * register it and tell the rest of the kernel
+ * about it.
+ */
+ return scsi_sysfs_add_sdev(sdev);
+}
+
+/**
* 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
@@ -1002,6 +1045,10 @@ static int scsi_probe_and_add_lun(struct
*/
sdev = scsi_device_lookup_by_target(starget, lun);
if (sdev) {
+ if (scsi_resurrect_device(sdev)) {
+ scsi_device_put(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",
@@ -1319,6 +1366,9 @@ static int scsi_report_lun_scan(struct s
return 0;
if (scsi_device_get(sdev))
return 0;
+ } else if (scsi_resurrect_device(sdev)) {
+ scsi_device_put(sdev);
+ return 0;
}
sprintf(devname, "host %d channel %d id %d",
--
1.4.3.4
-
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