In MKDEV macro, if mi is larger than MINORMASK, the major will be affected by mi. For example, set dev = MKDEV(2, (1U << MINORBITS)), then MAJOR(dev) will be equal to 3, incorrectly. Here, we mask mi with MINORMASK in MKDEV macro. Signed-off-by: Zhiqiang Liu <liuzhiqiang26@xxxxxxxxxx> --- include/linux/kdev_t.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/kdev_t.h b/include/linux/kdev_t.h index 85b5151911cf..40a9423720b2 100644 --- a/include/linux/kdev_t.h +++ b/include/linux/kdev_t.h @@ -9,7 +9,7 @@ #define MAJOR(dev) ((unsigned int) ((dev) >> MINORBITS)) #define MINOR(dev) ((unsigned int) ((dev) & MINORMASK)) -#define MKDEV(ma,mi) (((ma) << MINORBITS) | (mi)) +#define MKDEV(ma, mi) (((ma) << MINORBITS) | ((mi) & MINORMASK)) #define print_dev_t(buffer, dev) \ sprintf((buffer), "%u:%u\n", MAJOR(dev), MINOR(dev)) -- 2.19.1
