5 files changed, 78 insertions, 12 deletions
diff --git a/include/asm-generic/bitops/atomic.h b/include/asm-generic/bitops/atomic.h
index 9ae6c34dc19..49673510b48 100644
--- a/include/asm-generic/bitops/atomic.h
+++ b/include/asm-generic/bitops/atomic.h
@@ -80,7 +80,7 @@ static inline void set_bit(int nr, volatile unsigned long *addr)
  *
  * clear_bit() is atomic and may not be reordered.  However, it does
  * not contain a memory barrier, so if it is used for locking purposes,
- * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
+ * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic()
  * in order to ensure changes are visible on other processors.
  */
 static inline void clear_bit(int nr, volatile unsigned long *addr)
diff --git a/include/asm-generic/bitops/const_hweight.h b/include/asm-generic/bitops/const_hweight.h
index fa2a50b7ee6..0a7e0662347 100644
--- a/include/asm-generic/bitops/const_hweight.h
+++ b/include/asm-generic/bitops/const_hweight.h
@@ -5,14 +5,15 @@
  * Compile time versions of __arch_hweightN()
  */
 #define __const_hweight8(w)		\
-      (	(!!((w) & (1ULL << 0))) +	\
-	(!!((w) & (1ULL << 1))) +	\
-	(!!((w) & (1ULL << 2))) +	\
-	(!!((w) & (1ULL << 3))) +	\
-	(!!((w) & (1ULL << 4))) +	\
-	(!!((w) & (1ULL << 5))) +	\
-	(!!((w) & (1ULL << 6))) +	\
-	(!!((w) & (1ULL << 7)))	)
+	((unsigned int)			\
+	 ((!!((w) & (1ULL << 0))) +	\
+	  (!!((w) & (1ULL << 1))) +	\
+	  (!!((w) & (1ULL << 2))) +	\
+	  (!!((w) & (1ULL << 3))) +	\
+	  (!!((w) & (1ULL << 4))) +	\
+	  (!!((w) & (1ULL << 5))) +	\
+	  (!!((w) & (1ULL << 6))) +	\
+	  (!!((w) & (1ULL << 7)))))
 
 #define __const_hweight16(w) (__const_hweight8(w)  + __const_hweight8((w)  >> 8 ))
 #define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16))
diff --git a/include/asm-generic/bitops/count_zeros.h b/include/asm-generic/bitops/count_zeros.h
new file mode 100644
index 00000000000..97520d21fe6
--- /dev/null
+++ b/include/asm-generic/bitops/count_zeros.h
@@ -0,0 +1,57 @@
+/* Count leading and trailing zeros functions
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_
+#define _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_
+
+#include <asm/bitops.h>
+
+/**
+ * count_leading_zeros - Count the number of zeros from the MSB back
+ * @x: The value
+ *
+ * Count the number of leading zeros from the MSB going towards the LSB in @x.
+ *
+ * If the MSB of @x is set, the result is 0.
+ * If only the LSB of @x is set, then the result is BITS_PER_LONG-1.
+ * If @x is 0 then the result is COUNT_LEADING_ZEROS_0.
+ */
+static inline int count_leading_zeros(unsigned long x)
+{
+	if (sizeof(x) == 4)
+		return BITS_PER_LONG - fls(x);
+	else
+		return BITS_PER_LONG - fls64(x);
+}
+
+#define COUNT_LEADING_ZEROS_0 BITS_PER_LONG
+
+/**
+ * count_trailing_zeros - Count the number of zeros from the LSB forwards
+ * @x: The value
+ *
+ * Count the number of trailing zeros from the LSB going towards the MSB in @x.
+ *
+ * If the LSB of @x is set, the result is 0.
+ * If only the MSB of @x is set, then the result is BITS_PER_LONG-1.
+ * If @x is 0 then the result is COUNT_TRAILING_ZEROS_0.
+ */
+static inline int count_trailing_zeros(unsigned long x)
+{
+#define COUNT_TRAILING_ZEROS_0 (-1)
+
+	if (sizeof(x) == 4)
+		return ffs(x);
+	else
+		return (x != 0) ? __ffs(x) : COUNT_TRAILING_ZEROS_0;
+}
+
+#endif /* _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_ */
diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h
index 71c778033f5..998d4d544f1 100644
--- a/include/asm-generic/bitops/find.h
+++ b/include/asm-generic/bitops/find.h
@@ -7,6 +7,9 @@
  * @addr: The address to base the search on
  * @offset: The bitnumber to start searching at
  * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
  */
 extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
 		size, unsigned long offset);
@@ -18,6 +21,9 @@ extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
  * @addr: The address to base the search on
  * @offset: The bitnumber to start searching at
  * @size: The bitmap size in bits
+ *
+ * Returns the bit number of the next zero bit
+ * If no bits are zero, returns @size.
  */
 extern unsigned long find_next_zero_bit(const unsigned long *addr, unsigned
 		long size, unsigned long offset);
@@ -28,9 +34,10 @@ extern unsigned long find_next_zero_bit(const unsigned long *addr, unsigned
 /**
  * find_first_bit - find the first set bit in a memory region
  * @addr: The address to start the search at
- * @size: The maximum size to search
+ * @size: The maximum number of bits to search
  *
  * Returns the bit number of the first set bit.
+ * If no bits are set, returns @size.
  */
 extern unsigned long find_first_bit(const unsigned long *addr,
 				    unsigned long size);
@@ -38,9 +45,10 @@ extern unsigned long find_first_bit(const unsigned long *addr,
 /**
  * find_first_zero_bit - find the first cleared bit in a memory region
  * @addr: The address to start the search at
- * @size: The maximum size to search
+ * @size: The maximum number of bits to search
  *
  * Returns the bit number of the first cleared bit.
+ * If no bits are zero, returns @size.
  */
 extern unsigned long find_first_zero_bit(const unsigned long *addr,
 					 unsigned long size);
diff --git a/include/asm-generic/bitops/lock.h b/include/asm-generic/bitops/lock.h
index 308a9e22c80..c30266e9480 100644
--- a/include/asm-generic/bitops/lock.h
+++ b/include/asm-generic/bitops/lock.h
@@ -20,7 +20,7 @@
  */
 #define clear_bit_unlock(nr, addr)	\
 do {					\
-	smp_mb__before_clear_bit();	\
+	smp_mb__before_atomic();	\
 	clear_bit(nr, addr);		\
 } while (0)