We need to call put_device if cdev_device_add failed, otherwise
kmemleak has below report.

[<0000000024c71758>] kmem_cache_alloc_trace+0x233/0x480
[<00000000ad2813ed>] device_add+0x7ff/0xe10
[<0000000035bc54c4>] cdev_device_add+0x72/0xa0
[<000000006c9aa1e8>] nvme_cdev_add+0xa9/0xf0 [nvme_core]
[<000000003c4d492d>] nvme_mpath_set_live+0x251/0x290 [nvme_core]
[<00000000889a58da>] nvme_mpath_add_disk+0x268/0x320 [nvme_core]
[<00000000192e7161>] nvme_alloc_ns+0x669/0xac0 [nvme_core]
[<000000007a1a6041>] nvme_validate_or_alloc_ns+0x156/0x280 [nvme_core]
[<000000003a763c35>] nvme_scan_work+0x221/0x3c0 [nvme_core]
[<000000009ff10706>] process_one_work+0x5cf/0xb10
[<000000000644ee25>] worker_thread+0x7a/0x680
[<00000000285ebd2f>] kthread+0x1c6/0x210
[<00000000e297c6ea>] ret_from_fork+0x22/0x30

Fixes: 2637baed7801 ("nvme: introduce generic per-namespace chardev")
Signed-off-by: Guoqing Jiang <redacted>
---
drivers/nvme/host/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 522c9b229f80..2e8da13c842c 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c

@@ -3485,8 +3485,10 @@ int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,

	cdev_init(cdev, fops);
	cdev->owner = owner;
	ret = cdev_device_add(cdev, cdev_device);
-	if (ret)
+	if (ret) {
+		put_device(cdev_device);
		ida_simple_remove(&nvme_ns_chr_minor_ida, minor);
+	}
	return ret;
}

-- 
2.25.1