linux-kernel - [PATCH] fanotify_user: use upper_32

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Date:   Thu, 25 Mar 2021 09:37:43 +0100
From:   Christian Brauner <brauner@...nel.org>
To:     Jan Kara <jack@...e.cz>, Amir Goldstein <amir73il@...il.com>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Christian Brauner <christian.brauner@...ntu.com>
Subject: [PATCH] fanotify_user: use upper_32_bits() to verify mask

From: Christian Brauner <christian.brauner@...ntu.com>

I don't see an obvious reason why the upper 32 bit check needs to be
open-coded this way. Switch to upper_32_bits() which is more idiomatic and
should conceptually be the same check.

Cc: Amir Goldstein <amir73il@...il.com>
Cc: Jan Kara <jack@...e.cz>
Signed-off-by: Christian Brauner <christian.brauner@...ntu.com>
---
 fs/notify/fanotify/fanotify_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 9e0c1afac8bd..d5683fa9d495 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1126,7 +1126,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 		 __func__, fanotify_fd, flags, dfd, pathname, mask);
 
 	/* we only use the lower 32 bits as of right now. */
-	if (mask & ((__u64)0xffffffff << 32))
+	if (upper_32_bits(mask))
 		return -EINVAL;
 
 	if (flags & ~FANOTIFY_MARK_FLAGS)

base-commit: 0d02ec6b3136c73c09e7859f0d0e4e2c4c07b49b
-- 
2.27.0