fanotify: remove unneeded sub-zero check for unsigned value

Unsigned size_t len in copy_fid_info_to_user is checked
for negative value. This check is redundant as it is
always false.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 5e469c8 ("fanotify: copy event fid info to user")
Signed-off-by: Nikita Kiryushin <kiryushin@ancud.ru>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <d296ff1c-dcf7-4813-994b-3c4369debb7d@ancud.ru>

Author: nkiryushin

fs/notify/fanotify/fanotify_user.c

@@ -502,7 +502,7 @@ static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
 	}
 
 	/* Pad with 0's */
-	WARN_ON_ONCE(len < 0 || len >= FANOTIFY_EVENT_ALIGN);
+	WARN_ON_ONCE(len >= FANOTIFY_EVENT_ALIGN);
 	if (len > 0 && clear_user(buf, len))
 		return -EFAULT;