From: Guenter Roeck <linux@roeck-us.net>
To: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Zhang Rui <rui.zhang@intel.com>,
Eduardo Valentin <eduardo.valentin@ti.com>,
Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH] thermal: Fix KELVIN_TO_CELSIUS macro
Date: Sun, 23 Mar 2014 21:14:56 -0700 [thread overview]
Message-ID: <1395634496-25040-1-git-send-email-linux@roeck-us.net> (raw)
It is always a good idea to use paranthesis around macro parameters
to avoid undesired side effects.
In this specific case, KELVIN_TO_CELSIUS() is used in
drivers/platform/x86/asus-wmi.c with parameter "value & 0xFFFF",
which due to operator evaluation order causes more or less random
results.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
include/linux/thermal.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index f7e11c7..02488c9 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -41,8 +41,8 @@
#define THERMAL_NO_LIMIT THERMAL_CSTATE_INVALID
/* Unit conversion macros */
-#define KELVIN_TO_CELSIUS(t) (long)(((long)t-2732 >= 0) ? \
- ((long)t-2732+5)/10 : ((long)t-2732-5)/10)
+#define KELVIN_TO_CELSIUS(t) (long)(((long)(t)-2732 >= 0) ? \
+ ((long)(t)-2732+5)/10 : ((long)(t)-2732-5)/10)
#define CELSIUS_TO_KELVIN(t) ((t)*10+2732)
/* Adding event notification support elements */
--
1.7.9.7
next reply other threads:[~2014-03-24 4:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-24 4:14 Guenter Roeck [this message]
2014-03-24 4:25 ` [PATCH] thermal: Fix KELVIN_TO_CELSIUS macro Joe Perches
2014-03-24 5:30 ` Guenter Roeck
2014-04-03 2:40 ` Zhang Rui
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