scsi: iscsi: Report unbind session event when the target has been removed

stable inclusion
from linux-4.19.119
commit 8d1eb1fbdb350575987cfb28ed7715999c1a783e

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

[ Upstream commit 13e60d3b ]

If the daemon is restarted or crashes while logging out of a session, the
unbind session event sent by the kernel is not processed and is lost.  When
the daemon starts again, the session can't be unbound because the daemon is
waiting for the event message. However, the kernel has already logged out
and the event will not be resent.

When iscsid restart is complete, logout session reports error:

Logging out of session [sid: 6, target: iqn.xxxxx, portal: xx.xx.xx.xx,3260]
iscsiadm: Could not logout of [sid: 6, target: iscsiadm -m node iqn.xxxxx, portal: xx.xx.xx.xx,3260].
iscsiadm: initiator reported error (9 - internal error)
iscsiadm: Could not logout of all requested sessions

Make sure the unbind event is emitted.

[mkp: commit desc and applied by hand since patch was mangled]

Link: https://lore.kernel.org/r/4eab1771-2cb3-8e79-b31c-923652340e99@huawei.comReviewed-by: NLee Duncan <lduncan@suse.com>
Signed-off-by: NWu Bo <wubo40@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/scsi/scsi_transport_iscsi.c

@@ -2010,7 +2010,7 @@ static void __iscsi_unbind_session(struct work_struct *work)
 	if (session->target_id == ISCSI_MAX_TARGET) {
 		spin_unlock_irqrestore(&session->lock, flags);
 		mutex_unlock(&ihost->mutex);
-		return;
+		goto unbind_session_exit;
 	}
 
 	target_id = session->target_id;
@@ -2022,6 +2022,8 @@ static void __iscsi_unbind_session(struct work_struct *work)
 		ida_simple_remove(&iscsi_sess_ida, target_id);
 
 	scsi_remove_target(&session->dev);
+
+unbind_session_exit:
 	iscsi_session_event(session, ISCSI_KEVENT_UNBIND_SESSION);
 	ISCSI_DBG_TRANS_SESSION(session, "Completed target removal\n");
 }