patch-2.4.6 linux/include/asm-mips/bitops.h

• Lines: 760
• Date: Mon Jul 2 13:56:40 2001
• Orig file: v2.4.5/linux/include/asm-mips/bitops.h
• Orig date: Wed Jul 5 22:15:26 2000

diff -u --recursive --new-file v2.4.5/linux/include/asm-mips/bitops.h linux/include/asm-mips/bitops.h
@@ -1,10 +1,10 @@
-/* $Id: bitops.h,v 1.7 1999/08/19 22:56:33 ralf Exp $
- *
+/*
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (c) 1994 - 1997, 1999  Ralf Baechle (ralf@gnu.org)
+ * Copyright (c) 1994 - 1997, 1999, 2000  Ralf Baechle (ralf@gnu.org)
+ * Copyright (c) 2000  Silicon Graphics, Inc.
  */
 #ifndef _ASM_BITOPS_H
 #define _ASM_BITOPS_H
@@ -19,6 +19,12 @@
 #include <linux/config.h>
 
 /*
+ * clear_bit() doesn't provide any barrier for the compiler.
+ */
+#define smp_mb__before_clear_bit()	barrier()
+#define smp_mb__after_clear_bit()	barrier()
+
+/*
  * Only disable interrupt for kernel mode stuff to keep usermode stuff
  * that dares to use kernel include files alive.
  */
@@ -35,25 +41,6 @@
 #define __bi_restore_flags(x)
 #endif /* __KERNEL__ */
 
-/*
- * Note that the bit operations are defined on arrays of 32 bit sized
- * elements.  With respect to a future 64 bit implementation it is
- * wrong to use long *.  Use u32 * or int *.
- */
-extern __inline__ void set_bit(int nr, void *addr);
-extern __inline__ void clear_bit(int nr, void *addr);
-extern __inline__ void change_bit(int nr, void *addr);
-extern __inline__ int test_and_set_bit(int nr, void *addr);
-extern __inline__ int test_and_clear_bit(int nr, void *addr);
-extern __inline__ int test_and_change_bit(int nr, void *addr);
-
-extern __inline__ int test_bit(int nr, const void *addr);
-#ifndef __MIPSEB__
-extern __inline__ int find_first_zero_bit (void *addr, unsigned size);
-#endif
-extern __inline__ int find_next_zero_bit (void * addr, int size, int offset);
-extern __inline__ unsigned long ffz(unsigned long word);
-
 #if defined(CONFIG_CPU_HAS_LLSC)
 
 #include <asm/mipsregs.h>
@@ -64,92 +51,281 @@
  */
 
 /*
- * The following functions will only work for the R4000!
- */
+ * set_bit - Atomically set a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * This function is atomic and may not be reordered.  See __set_bit()
+ * if you do not require the atomic guarantees.
+ * Note that @nr may be almost arbitrarily large; this function is not
+ * restricted to acting on a single-word quantity.
+ */
+extern __inline__ void
+set_bit(int nr, volatile void *addr)
+{
+	unsigned long *m = ((unsigned long *) addr) + (nr >> 5);
+	unsigned long temp;
+
+	__asm__ __volatile__(
+		"1:\tll\t%0, %1\t\t# set_bit\n\t"
+		"or\t%0, %2\n\t"
+		"sc\t%0, %1\n\t"
+		"beqz\t%0, 1b"
+		: "=&r" (temp), "=m" (*m)
+		: "ir" (1UL << (nr & 0x1f)), "m" (*m));
+}
 
-extern __inline__ void set_bit(int nr, void *addr)
+/*
+ * __set_bit - Set a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * Unlike set_bit(), this function is non-atomic and may be reordered.
+ * If it's called on the same region of memory simultaneously, the effect
+ * may be that only one operation succeeds.
+ */
+extern __inline__ void __set_bit(int nr, volatile void * addr)
 {
-	int	mask, mw;
+	unsigned long * m = ((unsigned long *) addr) + (nr >> 5);
 
-	addr += ((nr >> 3) & ~3);
-	mask = 1 << (nr & 0x1f);
-	do {
-		mw = load_linked(addr);
-	} while (!store_conditional(addr, mw|mask));
+	*m |= 1UL << (nr & 31);
+}
+
+/*
+ * clear_bit - Clears a bit in memory
+ * @nr: Bit to clear
+ * @addr: Address to start counting from
+ *
+ * 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()
+ * in order to ensure changes are visible on other processors.
+ */
+extern __inline__ void
+clear_bit(int nr, volatile void *addr)
+{
+	unsigned long *m = ((unsigned long *) addr) + (nr >> 5);
+	unsigned long temp;
+
+	__asm__ __volatile__(
+		"1:\tll\t%0, %1\t\t# clear_bit\n\t"
+		"and\t%0, %2\n\t"
+		"sc\t%0, %1\n\t"
+		"beqz\t%0, 1b\n\t"
+		: "=&r" (temp), "=m" (*m)
+		: "ir" (~(1UL << (nr & 0x1f))), "m" (*m));
 }
 
-extern __inline__ void clear_bit(int nr, void *addr)
+/*
+ * change_bit - Toggle a bit in memory
+ * @nr: Bit to clear
+ * @addr: Address to start counting from
+ *
+ * change_bit() is atomic and may not be reordered.
+ * Note that @nr may be almost arbitrarily large; this function is not
+ * restricted to acting on a single-word quantity.
+ */
+extern __inline__ void
+change_bit(int nr, volatile void *addr)
+{
+	unsigned long *m = ((unsigned long *) addr) + (nr >> 5);
+	unsigned long temp;
+
+	__asm__ __volatile__(
+		"1:\tll\t%0, %1\t\t# change_bit\n\t"
+		"xor\t%0, %2\n\t"
+		"sc\t%0, %1\n\t"
+		"beqz\t%0, 1b"
+		: "=&r" (temp), "=m" (*m)
+		: "ir" (1UL << (nr & 0x1f)), "m" (*m));
+}
+
+/*
+ * __change_bit - Toggle a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * Unlike change_bit(), this function is non-atomic and may be reordered.
+ * If it's called on the same region of memory simultaneously, the effect
+ * may be that only one operation succeeds.
+ */
+extern __inline__ void __change_bit(int nr, volatile void * addr)
 {
-	int	mask, mw;
+	unsigned long * m = ((unsigned long *) addr) + (nr >> 5);
 
-	addr += ((nr >> 3) & ~3);
-	mask = 1 << (nr & 0x1f);
-	do {
-		mw = load_linked(addr);
-		}
-	while (!store_conditional(addr, mw & ~mask));
+	*m ^= 1UL << (nr & 31);
 }
 
-extern __inline__ void change_bit(int nr, void *addr)
+/*
+ * test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.  
+ * It also implies a memory barrier.
+ */
+extern __inline__ int
+test_and_set_bit(int nr, volatile void *addr)
 {
-	int	mask, mw;
+	unsigned long *m = ((unsigned long *) addr) + (nr >> 5);
+	unsigned long temp, res;
 
-	addr += ((nr >> 3) & ~3);
-	mask = 1 << (nr & 0x1f);
-	do {
-		mw = load_linked(addr);
-	} while (!store_conditional(addr, mw ^ mask));
+	__asm__ __volatile__(
+		".set\tnoreorder\t\t# test_and_set_bit\n"
+		"1:\tll\t%0, %1\n\t"
+		"or\t%2, %0, %3\n\t"
+		"sc\t%2, %1\n\t"
+		"beqz\t%2, 1b\n\t"
+		" and\t%2, %0, %3\n\t"
+		".set\treorder"
+		: "=&r" (temp), "=m" (*m), "=&r" (res)
+		: "r" (1UL << (nr & 0x1f)), "m" (*m)
+		: "memory");
+
+	return res != 0;
 }
 
-extern __inline__ int test_and_set_bit(int nr, void *addr)
+/*
+ * __test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.  
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail.  You must protect multiple accesses with a lock.
+ */
+extern __inline__ int __test_and_set_bit(int nr, volatile void * addr)
 {
-	int	mask, retval, mw;
+	int mask, retval;
+	volatile int *a = addr;
 
-	addr += ((nr >> 3) & ~3);
+	a += nr >> 5;
 	mask = 1 << (nr & 0x1f);
-	do {
-		mw = load_linked(addr);
-		retval = (mask & mw) != 0;
-	} while (!store_conditional(addr, mw|mask));
+	retval = (mask & *a) != 0;
+	*a |= mask;
 
 	return retval;
 }
 
-extern __inline__ int test_and_clear_bit(int nr, void *addr)
+/*
+ * test_and_clear_bit - Clear a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.  
+ * It also implies a memory barrier.
+ */
+extern __inline__ int
+test_and_clear_bit(int nr, volatile void *addr)
+{
+	unsigned long *m = ((unsigned long *) addr) + (nr >> 5);
+	unsigned long temp, res;
+
+	__asm__ __volatile__(
+		".set\tnoreorder\t\t# test_and_clear_bit\n"
+		"1:\tll\t%0, %1\n\t"
+		"or\t%2, %0, %3\n\t"
+		"xor\t%2, %3\n\t"
+		"sc\t%2, %1\n\t"
+		"beqz\t%2, 1b\n\t"
+		" and\t%2, %0, %3\n\t"
+		".set\treorder"
+		: "=&r" (temp), "=m" (*m), "=&r" (res)
+		: "r" (1UL << (nr & 0x1f)), "m" (*m)
+		: "memory");
+
+	return res != 0;
+}
+
+/*
+ * __test_and_clear_bit - Clear a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.  
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail.  You must protect multiple accesses with a lock.
+ */
+extern __inline__ int __test_and_clear_bit(int nr, volatile void * addr)
 {
-	int	mask, retval, mw;
+	int	mask, retval;
+	volatile int	*a = addr;
 
-	addr += ((nr >> 3) & ~3);
+	a += nr >> 5;
 	mask = 1 << (nr & 0x1f);
-	do {
-		mw = load_linked(addr);
-		retval = (mask & mw) != 0;
-		}
-	while (!store_conditional(addr, mw & ~mask));
+	retval = (mask & *a) != 0;
+	*a &= ~mask;
 
 	return retval;
 }
 
-extern __inline__ int test_and_change_bit(int nr, void *addr)
+/*
+ * test_and_change_bit - Change a bit and return its new value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.  
+ * It also implies a memory barrier.
+ */
+extern __inline__ int
+test_and_change_bit(int nr, volatile void *addr)
+{
+	unsigned long *m = ((unsigned long *) addr) + (nr >> 5);
+	unsigned long temp, res;
+
+	__asm__ __volatile__(
+		".set\tnoreorder\t\t# test_and_change_bit\n"
+		"1:\tll\t%0, %1\n\t"
+		"xor\t%2, %0, %3\n\t"
+		"sc\t%2, %1\n\t"
+		"beqz\t%2, 1b\n\t"
+		" and\t%2, %0, %3\n\t"
+		".set\treorder"
+		: "=&r" (temp), "=m" (*m), "=&r" (res)
+		: "r" (1UL << (nr & 0x1f)), "m" (*m)
+		: "memory");
+
+	return res != 0;
+}
+
+/*
+ * __test_and_change_bit - Change a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.  
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail.  You must protect multiple accesses with a lock.
+ */
+extern __inline__ int __test_and_change_bit(int nr, volatile void * addr)
 {
-	int	mask, retval, mw;
+	int	mask, retval;
+	volatile int	*a = addr;
 
-	addr += ((nr >> 3) & ~3);
+	a += nr >> 5;
 	mask = 1 << (nr & 0x1f);
-	do {
-		mw = load_linked(addr);
-		retval = (mask & mw) != 0;
-	} while (!store_conditional(addr, mw ^ mask));
+	retval = (mask & *a) != 0;
+	*a ^= mask;
 
 	return retval;
 }
 
 #else /* MIPS I */
 
-extern __inline__ void set_bit(int nr, void * addr)
+/*
+ * set_bit - Atomically set a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * This function is atomic and may not be reordered.  See __set_bit()
+ * if you do not require the atomic guarantees.
+ * Note that @nr may be almost arbitrarily large; this function is not
+ * restricted to acting on a single-word quantity.
+ */
+extern __inline__ void set_bit(int nr, volatile void * addr)
 {
 	int	mask;
-	int	*a = addr;
+	volatile int	*a = addr;
 	__bi_flags;
 
 	a += nr >> 5;
@@ -159,10 +335,39 @@
 	__bi_restore_flags(flags);
 }
 
-extern __inline__ void clear_bit(int nr, void * addr)
+/*
+ * __set_bit - Set a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * Unlike set_bit(), this function is non-atomic and may be reordered.
+ * If it's called on the same region of memory simultaneously, the effect
+ * may be that only one operation succeeds.
+ */
+extern __inline__ void __set_bit(int nr, volatile void * addr)
 {
 	int	mask;
-	int	*a = addr;
+	volatile int	*a = addr;
+
+	a += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	*a |= mask;
+}
+
+/*
+ * clear_bit - Clears a bit in memory
+ * @nr: Bit to clear
+ * @addr: Address to start counting from
+ *
+ * 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()
+ * in order to ensure changes are visible on other processors.
+ */
+extern __inline__ void clear_bit(int nr, volatile void * addr)
+{
+	int	mask;
+	volatile int	*a = addr;
 	__bi_flags;
 
 	a += nr >> 5;
@@ -172,10 +377,19 @@
 	__bi_restore_flags(flags);
 }
 
-extern __inline__ void change_bit(int nr, void * addr)
+/*
+ * change_bit - Toggle a bit in memory
+ * @nr: Bit to clear
+ * @addr: Address to start counting from
+ *
+ * change_bit() is atomic and may not be reordered.
+ * Note that @nr may be almost arbitrarily large; this function is not
+ * restricted to acting on a single-word quantity.
+ */
+extern __inline__ void change_bit(int nr, volatile void * addr)
 {
 	int	mask;
-	int	*a = addr;
+	volatile int	*a = addr;
 	__bi_flags;
 
 	a += nr >> 5;
@@ -185,10 +399,34 @@
 	__bi_restore_flags(flags);
 }
 
-extern __inline__ int test_and_set_bit(int nr, void * addr)
+/*
+ * __change_bit - Toggle a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * Unlike change_bit(), this function is non-atomic and may be reordered.
+ * If it's called on the same region of memory simultaneously, the effect
+ * may be that only one operation succeeds.
+ */
+extern __inline__ void __change_bit(int nr, volatile void * addr)
+{
+	unsigned long * m = ((unsigned long *) addr) + (nr >> 5);
+
+	*m ^= 1UL << (nr & 31);
+}
+
+/*
+ * test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.  
+ * It also implies a memory barrier.
+ */
+extern __inline__ int test_and_set_bit(int nr, volatile void * addr)
 {
 	int	mask, retval;
-	int	*a = addr;
+	volatile int	*a = addr;
 	__bi_flags;
 
 	a += nr >> 5;
@@ -201,10 +439,40 @@
 	return retval;
 }
 
-extern __inline__ int test_and_clear_bit(int nr, void * addr)
+/*
+ * __test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.  
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail.  You must protect multiple accesses with a lock.
+ */
+extern __inline__ int __test_and_set_bit(int nr, volatile void * addr)
+{
+	int	mask, retval;
+	volatile int	*a = addr;
+
+	a += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	retval = (mask & *a) != 0;
+	*a |= mask;
+
+	return retval;
+}
+
+/*
+ * test_and_clear_bit - Clear a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.  
+ * It also implies a memory barrier.
+ */
+extern __inline__ int test_and_clear_bit(int nr, volatile void * addr)
 {
 	int	mask, retval;
-	int	*a = addr;
+	volatile int	*a = addr;
 	__bi_flags;
 
 	a += nr >> 5;
@@ -217,10 +485,40 @@
 	return retval;
 }
 
-extern __inline__ int test_and_change_bit(int nr, void * addr)
+/*
+ * __test_and_clear_bit - Clear a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.  
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail.  You must protect multiple accesses with a lock.
+ */
+extern __inline__ int __test_and_clear_bit(int nr, volatile void * addr)
 {
 	int	mask, retval;
-	int	*a = addr;
+	volatile int	*a = addr;
+
+	a += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	retval = (mask & *a) != 0;
+	*a &= ~mask;
+
+	return retval;
+}
+
+/*
+ * test_and_change_bit - Change a bit and return its new value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.  
+ * It also implies a memory barrier.
+ */
+extern __inline__ int test_and_change_bit(int nr, volatile void * addr)
+{
+	int	mask, retval;
+	volatile int	*a = addr;
 	__bi_flags;
 
 	a += nr >> 5;
@@ -233,14 +531,41 @@
 	return retval;
 }
 
+/*
+ * __test_and_change_bit - Change a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.  
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail.  You must protect multiple accesses with a lock.
+ */
+extern __inline__ int __test_and_change_bit(int nr, volatile void * addr)
+{
+	int	mask, retval;
+	volatile int	*a = addr;
+
+	a += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	retval = (mask & *a) != 0;
+	*a ^= mask;
+
+	return retval;
+}
+
 #undef __bi_flags
-#undef __bi_cli()
-#undef __bi_save_flags(x)
-#undef __bi_restore_flags(x)
+#undef __bi_cli
+#undef __bi_save_flags
+#undef __bi_restore_flags
 
 #endif /* MIPS I */
 
-extern __inline__ int test_bit(int nr, const void *addr)
+/*
+ * test_bit - Determine whether a bit is set
+ * @nr: bit number to test
+ * @addr: Address to start counting from
+ */
+extern __inline__ int test_bit(int nr, volatile void *addr)
 {
 	return ((1UL << (nr & 31)) & (((const unsigned int *) addr)[nr >> 5])) != 0;
 }
@@ -249,6 +574,14 @@
 
 /* Little endian versions. */
 
+/*
+ * find_first_zero_bit - find the first zero bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum size to search
+ *
+ * Returns the bit-number of the first zero bit, not the number of the byte
+ * containing a bit.
+ */
 extern __inline__ int find_first_zero_bit (void *addr, unsigned size)
 {
 	unsigned long dummy;
@@ -285,18 +618,20 @@
 		".set\tat\n\t"
 		".set\treorder\n"
 		"2:"
-		: "=r" (res),
-		  "=r" (dummy),
-		  "=r" (addr)
-		: "0" ((signed int) 0),
-		  "1" ((unsigned int) 0xffffffff),
-		  "2" (addr),
-		  "r" (size)
+		: "=r" (res), "=r" (dummy), "=r" (addr)
+		: "0" ((signed int) 0), "1" ((unsigned int) 0xffffffff),
+		  "2" (addr), "r" (size)
 		: "$1");
 
 	return res;
 }
 
+/*
+ * find_next_zero_bit - find the first zero bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The maximum size to search
+ */
 extern __inline__ int find_next_zero_bit (void * addr, int size, int offset)
 {
 	unsigned int *p = ((unsigned int *) addr) + (offset >> 5);
@@ -320,11 +655,8 @@
 			".set\tat\n\t"
 			".set\treorder\n"
 			"1:"
-			: "=r" (set),
-			  "=r" (dummy)
-			: "0" (0),
-			  "1" (1 << bit),
-			  "r" (*p)
+			: "=r" (set), "=r" (dummy)
+			: "0" (0), "1" (1 << bit), "r" (*p)
 			: "$1");
 		if (set < (32 - bit))
 			return set + offset;
@@ -341,8 +673,10 @@
 #endif /* !(__MIPSEB__) */
 
 /*
- * ffz = Find First Zero in word. Undefined if no zero exists,
- * so code should check against ~0UL first..
+ * ffz - find first zero in word.
+ * @word: The word to search
+ *
+ * Undefined if no zero exists, so code should check against ~0UL first.
  */
 extern __inline__ unsigned long ffz(unsigned long word)
 {
@@ -370,8 +704,11 @@
 
 #ifdef __KERNEL__
 
-/*
- * ffs: find first bit set. This is defined the same way as
+/**
+ * ffs - find first bit set
+ * @x: the word to search
+ *
+ * This is defined the same way as
  * the libc and compiler builtin ffs routines, therefore
  * differs in spirit from the above ffz (man ffs).
  */
@@ -379,8 +716,10 @@
 #define ffs(x) generic_ffs(x)
 
 /*
- * hweightN: returns the hamming weight (i.e. the number
- * of bits set) of a N-bit word
+ * hweightN - returns the hamming weight of a N-bit word
+ * @x: the word to weigh
+ *
+ * The Hamming Weight of a number is the total number of bits set in it.
  */
 
 #define hweight32(x) generic_hweight32(x)
@@ -390,14 +729,12 @@
 #endif /* __KERNEL__ */
 
 #ifdef __MIPSEB__
-/* For now I steal the Sparc C versions, no need for speed, just need to
- * get it working.
- */
-/* find_next_zero_bit() finds the first zero bit in a bit string of length
- * 'size' bits, starting the search at bit 'offset'. This is largely based
- * on Linus's ALPHA routines, which are pretty portable BTW.
+/*
+ * find_next_zero_bit - find the first zero bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The maximum size to search
  */
-
 extern __inline__ int find_next_zero_bit(void *addr, int size, int offset)
 {
 	unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
@@ -438,6 +775,18 @@
  * holds on the Sparc as it does for the ALPHA.
  */
 
+#if 0 /* Fool kernel-doc since it doesn't do macros yet */
+/*
+ * find_first_zero_bit - find the first zero bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum size to search
+ *
+ * Returns the bit-number of the first zero bit, not the number of the byte
+ * containing a bit.
+ */
+extern int find_first_zero_bit (void *addr, unsigned size);
+#endif
+
 #define find_first_zero_bit(addr, size) \
         find_next_zero_bit((addr), (size), 0)
 
@@ -451,7 +800,6 @@
 	int		mask, retval, flags;
 	unsigned char	*ADDR = (unsigned char *) addr;
 
-	ADDR += nr >> 3;
 	mask = 1 << (nr & 0x07);
 	save_and_cli(flags);
 	retval = (mask & *ADDR) != 0;