From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Mon, 5 Apr 2010 21:02:38 +0000 (+0200)
Subject: compat: Backport clamp
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=97da2ad6bfc2855bb6700f1c8ed000c332b9ce7d;p=openwrt%2Fstaging%2Fblogic.git

compat: Backport clamp

This is needed by the ath5k driver.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---

diff --git a/include/linux/compat-2.6.26.h b/include/linux/compat-2.6.26.h
index 2bee30eca755..825117742ba8 100644
--- a/include/linux/compat-2.6.26.h
+++ b/include/linux/compat-2.6.26.h
@@ -47,6 +47,24 @@
 extern int dev_set_name(struct device *dev, const char *name, ...)
 			__attribute__((format(printf, 2, 3)));
 
+/**
+ * clamp - return a value clamped to a given range with strict typechecking
+ * @val: current value
+ * @min: minimum allowable value
+ * @max: maximum allowable value
+ *
+ * This macro does strict typechecking of min/max to make sure they are of the
+ * same type as val.  See the unnecessary pointer comparisons.
+ */
+#define clamp(val, min, max) ({			\
+	typeof(val) __val = (val);		\
+	typeof(min) __min = (min);		\
+	typeof(max) __max = (max);		\
+	(void) (&__val == &__min);		\
+	(void) (&__val == &__max);		\
+	__val = __val < __min ? __min: __val;	\
+	__val > __max ? __max: __val; })
+
 /**
  * clamp_t - return a value clamped to a given range using a given type
  * @type: the type of variable to use