nvme-core: put ctrl ref when module ref get fail

stable inclusion
from linux-4.19.151
commit b6df5afc3d81e34d32f0b092d59b7fe8915d824b

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

commit 4bab6909 upstream.

When try_module_get() fails in the nvme_dev_open() it returns without
releasing the ctrl reference which was taken earlier.

Put the ctrl reference which is taken before calling the
try_module_get() in the error return code path.

Fixes: 52a3974f "nvme-core: get/put ctrl and transport module in nvme_dev_open/release()"
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/nvme/host/core.c

@@ -2585,8 +2585,10 @@ static int nvme_dev_open(struct inode *inode, struct file *file)
 	}
 
 	nvme_get_ctrl(ctrl);
-	if (!try_module_get(ctrl->ops->module))
+	if (!try_module_get(ctrl->ops->module)) {
+		nvme_put_ctrl(ctrl);
 		return -EINVAL;
+	}
 
 	file->private_data = ctrl;
 	return 0;