nvme: release namespace head reference on error

mainline inclusion
from mainline-v5.8-rc1
commit ac262508
category: bugfix
bugzilla: NA
CVE: NA
Link: https://gitee.com/openeuler/kernel/issues/I1WGZE

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

If a namespace identification does not match the subsystem's head for
that NSID, release the reference that was taken when the matching head
was initially found.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NChao Leng <lengchao@huawei.com>
Reviewed-by: NJike Cheng <chengjike.cheng@huawei.com>
Signed-off-by: NLijie <lijie34@huawei.com>
Acked-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/nvme/host/core.c

@@ -3146,6 +3146,7 @@ static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
 				"IDs don't match for shared namespace %d\n",
 					nsid);
 			ret = -EINVAL;
+			nvme_put_ns_head(head);
 			goto out_unlock;
 		}
 	}