[PATCH] remove powerpc bitops in favor of existing generic bitops

There already exists a big endian safe bitops implementation in
lib/find_next_bit.c.  The code in it is 90%+ common with the powerpc
specific version, so the powerpc version is redundant.  This patch
makes the necessary changes to use the generic bitops in powerpc, and
removes the powerpc specific version.
Signed-off-by: Jon Mason <jdmason@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/Kconfig

@@ -45,6 +45,10 @@ config GENERIC_CALIBRATE_DELAY
 	bool
 	default y
 
+config GENERIC_FIND_NEXT_BIT
+	bool
+	default y
+
 config PPC
 	bool
 	default y

arch/powerpc/lib/Makefile

@@ -7,7 +7,6 @@ obj-y			:= string.o strcase.o
 obj-$(CONFIG_PPC32)	+= div64.o copy_32.o checksum_32.o
 endif
 
-obj-y			+= bitops.o
 obj-$(CONFIG_PPC64)	+= checksum_64.o copypage_64.o copyuser_64.o \
 			   memcpy_64.o usercopy_64.o mem_64.o string.o \
 			   strcase.o

arch/powerpc/lib/bitops.c

-#include <linux/types.h>
-#include <linux/module.h>
-#include <asm/byteorder.h>
-#include <asm/bitops.h>
-
-/**
- * find_next_bit - find the next set 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
- */
-unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
-			    unsigned long offset)
-{
-	const unsigned long *p = addr + BITOP_WORD(offset);
-	unsigned long result = offset & ~(BITS_PER_LONG-1);
-	unsigned long tmp;
-
-	if (offset >= size)
-		return size;
-	size -= result;
-	offset %= BITS_PER_LONG;
-	if (offset) {
-		tmp = *(p++);
-		tmp &= (~0UL << offset);
-		if (size < BITS_PER_LONG)
-			goto found_first;
-		if (tmp)
-			goto found_middle;
-		size -= BITS_PER_LONG;
-		result += BITS_PER_LONG;
-	}
-	while (size & ~(BITS_PER_LONG-1)) {
-		if ((tmp = *(p++)))
-			goto found_middle;
-		result += BITS_PER_LONG;
-		size -= BITS_PER_LONG;
-	}
-	if (!size)
-		return result;
-	tmp = *p;
-
-found_first:
-	tmp &= (~0UL >> (BITS_PER_LONG - size));
-	if (tmp == 0UL)		/* Are any bits set? */
-		return result + size;	/* Nope. */
-found_middle:
-	return result + __ffs(tmp);
-}
-EXPORT_SYMBOL(find_next_bit);
-
-/*
- * This implementation of find_{first,next}_zero_bit was stolen from
- * Linus' asm-alpha/bitops.h.
- */
-unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
-				 unsigned long offset)
-{
-	const unsigned long *p = addr + BITOP_WORD(offset);
-	unsigned long result = offset & ~(BITS_PER_LONG-1);
-	unsigned long tmp;
-
-	if (offset >= size)
-		return size;
-	size -= result;
-	offset %= BITS_PER_LONG;
-	if (offset) {
-		tmp = *(p++);
-		tmp |= ~0UL >> (BITS_PER_LONG - offset);
-		if (size < BITS_PER_LONG)
-			goto found_first;
-		if (~tmp)
-			goto found_middle;
-		size -= BITS_PER_LONG;
-		result += BITS_PER_LONG;
-	}
-	while (size & ~(BITS_PER_LONG-1)) {
-		if (~(tmp = *(p++)))
-			goto found_middle;
-		result += BITS_PER_LONG;
-		size -= BITS_PER_LONG;
-	}
-	if (!size)
-		return result;
-	tmp = *p;
-
-found_first:
-	tmp |= ~0UL << size;
-	if (tmp == ~0UL)	/* Are any bits zero? */
-		return result + size;	/* Nope. */
-found_middle:
-	return result + ffz(tmp);
-}
-EXPORT_SYMBOL(find_next_zero_bit);
-
-static inline unsigned int ext2_ilog2(unsigned int x)
-{
-	int lz;
-
-	asm("cntlzw %0,%1": "=r"(lz):"r"(x));
-	return 31 - lz;
-}
-
-static inline unsigned int ext2_ffz(unsigned int x)
-{
-	u32 rc;
-	if ((x = ~x) == 0)
-		return 32;
-	rc = ext2_ilog2(x & -x);
-	return rc;
-}
-
-unsigned long find_next_zero_le_bit(const unsigned long *addr,
-				    unsigned long size, unsigned long offset)
-{
-	const unsigned int *p = ((const unsigned int *)addr) + (offset >> 5);
-	unsigned int result = offset & ~31;
-	unsigned int tmp;
-
-	if (offset >= size)
-		return size;
-	size -= result;
-	offset &= 31;
-	if (offset) {
-		tmp = cpu_to_le32p(p++);
-		tmp |= ~0U >> (32 - offset);	/* bug or feature ? */
-		if (size < 32)
-			goto found_first;
-		if (tmp != ~0)
-			goto found_middle;
-		size -= 32;
-		result += 32;
-	}
-	while (size >= 32) {
-		if ((tmp = cpu_to_le32p(p++)) != ~0)
-			goto found_middle;
-		result += 32;
-		size -= 32;
-	}
-	if (!size)
-		return result;
-	tmp = cpu_to_le32p(p);
-found_first:
-	tmp |= ~0 << size;
-	if (tmp == ~0)		/* Are any bits zero? */
-		return result + size;	/* Nope. */
-found_middle:
-	return result + ext2_ffz(tmp);
-}
-EXPORT_SYMBOL(find_next_zero_le_bit);

arch/ppc/Kconfig

@@ -40,6 +40,10 @@ config GENERIC_NVRAM
 	bool
 	default y
 
+config GENERIC_FIND_NEXT_BIT
+	bool
+	default y
+
 config SCHED_NO_NO_OMIT_FRAME_POINTER
 	bool
 	default y

include/asm-powerpc/bitops.h

@@ -288,8 +288,8 @@ static __inline__ int test_le_bit(unsigned long nr,
 #define __test_and_clear_le_bit(nr, addr) \
 	__test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
 
-#define find_first_zero_le_bit(addr, size) find_next_zero_le_bit((addr), (size), 0)
-unsigned long find_next_zero_le_bit(const unsigned long *addr,
+#define find_first_zero_le_bit(addr, size) generic_find_next_zero_le_bit((addr), (size), 0)
+unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,
 				    unsigned long size, unsigned long offset);
 
 /* Bitmap functions for the ext2 filesystem */
@@ -309,7 +309,7 @@ unsigned long find_next_zero_le_bit(const unsigned long *addr,
 #define ext2_find_first_zero_bit(addr, size) \
 	find_first_zero_le_bit((unsigned long*)addr, size)
 #define ext2_find_next_zero_bit(addr, size, off) \
-	find_next_zero_le_bit((unsigned long*)addr, size, off)
+	generic_find_next_zero_le_bit((unsigned long*)addr, size, off)
 
 /* Bitmap functions for the minix filesystem.  */