linux-kernel - [PATCH v4 2/3] lib: move find_last_bit to lib/find_next

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Date:	Tue, 17 Feb 2015 05:35:42 +0300
From:	Yury Norov <yury.norov@...il.com>
To:	linux@...izon.com, klimov.linux@...il.com, linux@...musvillemoes.dk
Cc:	akpm@...ux-foundation.org, davem@...emloft.net,
	dborkman@...hat.com, hannes@...essinduktion.org,
	laijs@...fujitsu.com, msalter@...hat.com,
	takahiro.akashi@...aro.org, tgraf@...g.ch,
	valentinrothberg@...il.com, yury.norov@...il.com,
	linux-kernel@...r.kernel.org, chris@...is-wilson.co.uk
Subject: [PATCH v4 2/3] lib: move find_last_bit to lib/find_next_bit.c

Currently all 'find_*_bit' family is located in lib/find_next_bit.c,
except 'find_last_bit', which is in lib/find_last_bit.c. It seems,
there's no major benefit to have it separated.
---
 lib/Makefile        |  2 +-
 lib/find_last_bit.c | 42 ------------------------------------------
 lib/find_next_bit.c | 27 ++++++++++++++++++++++++++-
 3 files changed, 27 insertions(+), 44 deletions(-)
 delete mode 100644 lib/find_last_bit.c

diff --git a/lib/Makefile b/lib/Makefile
index 87eb3bf..9dafcd5 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -25,7 +25,7 @@ obj-y	+= lockref.o
 obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
 	 bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \
 	 gcd.o lcm.o list_sort.o uuid.o flex_array.o clz_ctz.o \
-	 bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \
+	 bsearch.o find_next_bit.o llist.o memweight.o kfifo.o \
 	 percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o
 obj-y += string_helpers.o
 obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
diff --git a/lib/find_last_bit.c b/lib/find_last_bit.c
deleted file mode 100644
index edbb281..0000000
--- a/lib/find_last_bit.c
+++ /dev/null
@@ -1,42 +0,0 @@
-/* find_last_bit.c: fallback find next bit implementation
- *
- * Copyright (C) 2008 IBM Corporation
- * Written by Rusty Russell <rusty@...tcorp.com.au>
- * (Inspired by David Howell's find_next_bit implementation)
- *
- * Rewritten by Yury Norov <yury.norov@...il.com> to decrease
- * size and improve performance, 2015.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#include <linux/bitops.h>
-#include <linux/export.h>
-#include <linux/kernel.h>
-
-#define LOW_BITS_MASK(nr) (~0UL >> -(nr))
-
-#ifndef find_last_bit
-
-unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
-{
-	if (size) {
-		unsigned long val = LOW_BITS_MASK(size % BITS_PER_LONG);
-		unsigned long idx = (size-1) / BITS_PER_LONG;
-
-		do {
-			val &= addr[idx];
-			if (val)
-				return idx * BITS_PER_LONG + __fls(val);
-
-			val = ~0ul;
-		} while (idx--);
-	}
-	return size;
-}
-EXPORT_SYMBOL(find_last_bit);
-
-#endif
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
index 1f5f108..627d0ec 100644
--- a/lib/find_next_bit.c
+++ b/lib/find_next_bit.c
@@ -1,8 +1,12 @@
-/* find_next_bit.c: fallback find next bit implementation
+/* bit search implementation
  *
  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@...hat.com)
  *
+ * Copyright (C) 2008 IBM Corporation
+ * 'find_last_bit' is written by Rusty Russell <rusty@...tcorp.com.au>
+ * (Inspired by David Howell's find_next_bit implementation)
+ *
  * Rewritten by Yury Norov <yury.norov@...il.com> to decrease
  * size and improve performance, 2015.
  *
@@ -17,6 +21,7 @@
 #include <linux/kernel.h>
 
 #define HIGH_BITS_MASK(nr)		(~0UL << (nr))
+#define LOW_BITS_MASK(nr)		(~0UL >> -(nr))
 
 #if !defined(find_next_bit) || !defined(find_next_zero_bit)
 
@@ -108,6 +113,26 @@ unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size)
 EXPORT_SYMBOL(find_first_zero_bit);
 #endif
 
+#ifndef find_last_bit
+unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
+{
+	if (size) {
+		unsigned long val = LOW_BITS_MASK(size % BITS_PER_LONG);
+		unsigned long idx = (size-1) / BITS_PER_LONG;
+
+		do {
+			val &= addr[idx];
+			if (val)
+				return idx * BITS_PER_LONG + __fls(val);
+
+			val = ~0ul;
+		} while (idx--);
+	}
+	return size;
+}
+EXPORT_SYMBOL(find_last_bit);
+#endif
+
 #ifdef __BIG_ENDIAN
 
 /* include/linux/byteorder does not support "unsigned long" type */
-- 
2.1.0

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