nvme: fix controller instance leak

mainline inclusion
from mainline-v5.9
commit 192f6c29
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5986O
CVE: NA

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

If the driver has to unbind from the controller for an early failure
before the subsystem has been set up, there won't be a subsystem holding
the controller's instance, so the controller needs to free its own
instance in this case.

Fixes: 733e4b69 ("nvme: Assign subsys instance from first ctrl")
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NXibo.Wang <wangxb12@chinatelecom.cn>

drivers/nvme/host/core.c

@@ -3838,7 +3838,7 @@ static void nvme_free_ctrl(struct device *dev)
 		container_of(dev, struct nvme_ctrl, ctrl_device);
 	struct nvme_subsystem *subsys = ctrl->subsys;
 
-	if (subsys && ctrl->instance != subsys->instance)
+	if (!subsys || ctrl->instance != subsys->instance)
 		ida_simple_remove(&nvme_instance_ida, ctrl->instance);
 
 	kfree(ctrl->effects);