linux-kernel - [PATCH v2 5/8] minmax: Factor out the zero-extension logic from umin/umax.

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Message-ID: <3e11fa68f33b4fb5beec1fc3f41b123e@AcuMS.aculab.com>
Date: Sun, 28 Jul 2024 14:21:27 +0000
From: David Laight <David.Laight@...LAB.COM>
To: "'linux-kernel@...r.kernel.org'" <linux-kernel@...r.kernel.org>
CC: 'Linus Torvalds' <torvalds@...uxfoundation.org>, 'Jens Axboe'
	<axboe@...nel.dk>, "'Matthew Wilcox (Oracle)'" <willy@...radead.org>,
	'Christoph Hellwig' <hch@...radead.org>, 'Andrew Morton'
	<akpm@...ux-foundation.org>, 'Andy Shevchenko'
	<andriy.shevchenko@...ux.intel.com>, 'Dan Carpenter'
	<dan.carpenter@...aro.org>, 'Arnd Bergmann' <arnd@...nel.org>,
	"'Jason@...c4.com'" <Jason@...c4.com>, "'pedro.falcato@...il.com'"
	<pedro.falcato@...il.com>, 'Mateusz Guzik' <mjguzik@...il.com>,
	"'linux-mm@...ck.org'" <linux-mm@...ck.org>, 'Lorenzo Stoakes'
	<lorenzo.stoakes@...cle.com>
Subject: [PATCH v2 5/8] minmax: Factor out the zero-extension logic from
 umin/umax.

The '+ 0u + 0ul + 0ull' to zero extend to 64bit on both 32bit and
64bit systems was replicated 4 times.
Factor out and then join up some 'not overlong' lines.

Signed-off-by: David Laight <david.laight@...lab.com>
---
v2 - no change

 include/linux/minmax.h | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index b9b5348a3879..a0c948ad576d 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -72,22 +72,26 @@
  */
 #define max(x, y)	__careful_cmp(max, x, y)
 
+/*
+ * Zero extend a non-negative value to 64bits.
+ * Undefined for negative values.
+ * The extension to 64 bits is often optimised away.
+ */
+#define __zero_extend(x) ((x) + 0u + 0ul + 0ull)
+
 /**
  * umin - return minimum of two non-negative values
- *   Signed types are zero extended to match a larger unsigned type.
  * @x: first value
  * @y: second value
  */
-#define umin(x, y)	\
-	__careful_cmp(min, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
+#define umin(x, y)	__careful_cmp(min, __zero_extend(x), __zero_extend(y))
 
 /**
  * umax - return maximum of two non-negative values
  * @x: first value
  * @y: second value
  */
-#define umax(x, y)	\
-	__careful_cmp(max, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
+#define umax(x, y)	__careful_cmp(max, __zero_extend(x), __zero_extend(y))
 
 /**
  * min3 - return minimum of three values
-- 
2.17.1

-
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