scsi: core: Allow state transitions from OFFLINE to BLOCKED

mainline inclusion
from mainline-4.20-rc1
commit a33e5bfb29721015349a3864c91abe11f6195d5c
category: bugfix
bugzilla: 10015
CVE: NA

---------------------------

When an RSCN gets delayed (or not being sent at all), the transport class
will detect an error, EH kicks in, and eventually will be setting the
device to offline.  If we receive an RSCN after that, the device will
stay in 'offline'.  This patch allows for an 'offline' to 'blocked'
transition, thereby allowing the device to become active again.
Signed-off-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Nzhengbin <zhengbin13@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/scsi/scsi_lib.c

@@ -2762,6 +2762,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
 		switch (oldstate) {
 		case SDEV_RUNNING:
 		case SDEV_CREATED_BLOCK:
+		case SDEV_OFFLINE:
 			break;
 		default:
 			goto illegal;