From: Zhiqiang Liu <liuzhiqiang26@huawei.com>
To: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
<linux-block@vger.kernel.org>, <dhowells@redhat.com>,
<akpm@linux-foundation.org>, <torvalds@linux-foundation.org>
Cc: <bywxiaobai@163.com>, Mingfangsen <mingfangsen@huawei.com>,
Guiyao <guiyao@huawei.com>, zhangsaisai <zhangsaisai@huawei.com>,
renxudong <renxudong1@huawei.com>
Subject: [PATCH] kdev_t: mask mi with MINORMASK in MKDEV macro
Date: Fri, 10 Jan 2020 14:37:22 +0800 [thread overview]
Message-ID: <5d384dcb-5590-60f8-a4e1-efa6b8da151f@huawei.com> (raw)
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@huawei.com>
---
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
next reply other threads:[~2020-01-10 6:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 6:37 Zhiqiang Liu [this message]
2020-01-11 4:50 ` [PATCH] kdev_t: mask mi with MINORMASK in MKDEV macro Bart Van Assche
2020-01-12 8:21 ` Zhiqiang Liu
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