From: "Ewan D. Milne" <emilne@xxxxxxxxxx>
This patch adds the capability to configure the kernel to
automatically remove LUNs when a rescan of a SCSI target
finds that LUNs that were previously reported are no longer
being reported. This is only done when a target is scanned
using REPORT LUNS, to avoid removing LUNs due to transport
errors (in other words, the target must be accessible).
Signed-off-by: Ewan D. Milne <emilne@xxxxxxxxxx>
---
drivers/scsi/Kconfig | 8 +++++++
drivers/scsi/scsi_scan.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 62 insertions(+)
diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 5d1e614..9642c87 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -292,6 +292,14 @@ config SCSI_ENHANCED_UA
primarily useful when storage arrays that can be reconfigured
are attached to the system, otherwise you can say N here.
+config SCSI_AUTOMATIC_LUN_REMOVAL
+ bool "Automatic LUN removal"
+ depends on SCSI
+ help
+ If you want LUNs to be automatically removed when a SCSI target
+ is rescanned and the REPORT LUNS result indicates that LUNs are
+ no longer present, say Y. Otherwise, say N.
+
menu "SCSI Transports"
depends on SCSI
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 1bbbc43..a0d0d97 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1318,6 +1318,11 @@ static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
struct scsi_device *sdev;
struct Scsi_Host *shost = dev_to_shost(&starget->dev);
int ret = 0;
+#ifdef CONFIG_SCSI_AUTOMATIC_LUN_REMOVAL
+ unsigned long flags;
+ struct scsi_device *sdev_i;
+ bool found;
+#endif
/*
* Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
@@ -1490,6 +1495,55 @@ static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
}
}
+#ifdef CONFIG_SCSI_AUTOMATIC_LUN_REMOVAL
+ /*
+ * See if all of the LUNs that we know about on the target are
+ * still being reported in the REPORT LUNS data. If any are not,
+ * they have been removed from the target. Remove those LUNs.
+ *
+ * We only do this for REPORT LUNS scanning, because we do not
+ * want to remove LUNs if they are inaccessible due to a transport
+ * error. Here, the target has responded to a command.
+ */
+restart:
+ spin_lock_irqsave(shost->host_lock, flags);
+ list_for_each_entry(sdev_i, &starget->devices, same_target_siblings) {
+ /*
+ * Don't remove the sdev used for the REPORT LUNS command here.
+ * It will be removed at the end of the function if necessary.
+ */
+ if (sdev_i == sdev)
+ continue;
+ if (sdev_i->sdev_state == SDEV_DEL)
+ continue;
+ found = 0;
+ for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
+ lun = scsilun_to_int(lunp);
+ if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4))
+ continue;
+ else if (lun > sdev->host->max_lun)
+ continue;
+ else if (lun == sdev_i->lun) {
+ found = 1;
+ break;
+ }
+ }
+ if (!found) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ sdev_printk(KERN_INFO, sdev_i,
+ "LUN %d is no longer present, removing\n",
+ sdev_i->lun);
+ __scsi_remove_device(sdev_i);
+ /*
+ * Once the device has been removed, the iterator
+ * is no longer valid and we have to start again.
+ */
+ goto restart;
+ }
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
+#endif
+
out_err:
kfree(lun_data);
out:
--
1.7.11.7
--
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