Actually, total amount of available minor number for a single major is MINORMARK + 1. So expand minor range when registering chrdev region. Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx> --- samples/vfio-mdev/mbochs.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index ca7960adf5a3..b038aa9f5a70 100644 --- a/samples/vfio-mdev/mbochs.c +++ b/samples/vfio-mdev/mbochs.c @@ -1448,13 +1448,13 @@ static int __init mbochs_dev_init(void) { int ret = 0; - ret = alloc_chrdev_region(&mbochs_devt, 0, MINORMASK, MBOCHS_NAME); + ret = alloc_chrdev_region(&mbochs_devt, 0, MINORMASK + 1, MBOCHS_NAME); if (ret < 0) { pr_err("Error: failed to register mbochs_dev, err: %d\n", ret); return ret; } cdev_init(&mbochs_cdev, &vd_fops); - cdev_add(&mbochs_cdev, mbochs_devt, MINORMASK); + cdev_add(&mbochs_cdev, mbochs_devt, MINORMASK + 1); pr_info("%s: major %d\n", __func__, MAJOR(mbochs_devt)); mbochs_class = class_create(THIS_MODULE, MBOCHS_CLASS_NAME); @@ -1483,7 +1483,7 @@ static int __init mbochs_dev_init(void) class_destroy(mbochs_class); failed1: cdev_del(&mbochs_cdev); - unregister_chrdev_region(mbochs_devt, MINORMASK); + unregister_chrdev_region(mbochs_devt, MINORMASK + 1); return ret; } @@ -1494,7 +1494,7 @@ static void __exit mbochs_dev_exit(void) device_unregister(&mbochs_dev); cdev_del(&mbochs_cdev); - unregister_chrdev_region(mbochs_devt, MINORMASK); + unregister_chrdev_region(mbochs_devt, MINORMASK + 1); class_destroy(mbochs_class); mbochs_class = NULL; } -- 2.20.1