Message-Id: <20160311062953.571397512@redhat.com>
User-Agent: quilt/0.64
Date: Fri, 11 Mar 2016 14:21:57 +0800
From: dyoung@redhat.com
To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
        d.hatayama@jp.fujitsu.com, bhe@redhat.com, vgoyal@redhat.com
Cc: dyoung@redhat.com, kexec@lists.infradead.org
Subject: [PATCH 1/2] [PATCH 1/2] Introduce new macros min_lt and max_lt for comparing with
 larger type
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A useful use case for min_t and max_t is comparing two values with larger
type. For example comparing an u64 and an u32, usually we do not want to
truncate the u64, so we need use min_t or max_t with u64.

To simplify the usage introducing two more macros min_lt and max_lt,
'lt' means larger type.

Signed-off-by: Dave Young <dyoung@redhat.com>
---
 include/linux/kernel.h |   13 +++++++++++++
 1 file changed, 13 insertions(+)

--- linux.orig/include/linux/kernel.h
+++ linux/include/linux/kernel.h
@@ -798,6 +798,19 @@ static inline void ftrace_dump(enum ftra
 	type __max2 = (y);			\
 	__max1 > __max2 ? __max1: __max2; })
 
+/*
+ * use type of larger size in min_lt and max_lt
+ */
+#define min_lt(x, y) ({			\
+	int sx = sizeof(typeof(x));             \
+	int sy = sizeof(typeof(y));             \
+	sx > sy ? min_t(typeof(x), x, y) : min_t(typeof(y), x, y); })
+
+#define max_lt(x, y) ({			\
+	int sx = sizeof(typeof(x));             \
+	int sy = sizeof(typeof(y));             \
+	sx > sy ? max_t(typeof(x), x, y) : max_t(typeof(y), x, y); })
+
 /**
  * clamp_t - return a value clamped to a given range using a given type
  * @type: the type of variable to use