From: Paul Mackerras Below patch reuses the big-endian bitops for the little endian ones, and moves the ext2_{set,clear}_bit_atomic functions to be truly atomic instead of lock based. This requires that the bitmaps passed to the ext2_* bitop functions are 8-byte aligned. I have been assured that they will be 512-byte or 1024-byte aligned, and sparc and ppc32 also impose an alignment requirement on the bitmap. Signed-off-by: Olof Johansson Signed-off-by: Paul Mackerras Signed-off-by: Andrew Morton --- 25-akpm/include/asm-ppc64/bitops.h | 86 ++++++++++++------------------------- 1 files changed, 29 insertions(+), 57 deletions(-) diff -puN include/asm-ppc64/bitops.h~ppc64-better-little-endian-bitops include/asm-ppc64/bitops.h --- 25/include/asm-ppc64/bitops.h~ppc64-better-little-endian-bitops 2004-08-20 00:06:25.876136528 -0700 +++ 25-akpm/include/asm-ppc64/bitops.h 2004-08-20 00:06:25.881135768 -0700 @@ -22,6 +22,15 @@ * it will be a bad memory reference since we want to store in chunks * of unsigned long (64 bits here) size. * + * There are a few little-endian macros used mostly for filesystem bitmaps, + * these work on similar bit arrays layouts, but byte-oriented: + * + * |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56| + * + * The main difference is that bit 3-5 in the bit number field needs to be + * reversed compared to the big-endian bit fields. This can be achieved + * by XOR with 0b111000 (0x38). + * * 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 @@ -306,71 +315,34 @@ static __inline__ int test_le_bit(unsign return (ADDR[nr >> 3] >> (nr & 7)) & 1; } +#define test_and_clear_le_bit(nr, addr) \ + test_and_clear_bit((nr) ^ 0x38, (addr)) +#define test_and_set_le_bit(nr, addr) \ + test_and_set_bit((nr) ^ 0x38, (addr)) + /* * non-atomic versions */ -static __inline__ void __set_le_bit(unsigned long nr, unsigned long *addr) -{ - unsigned char *ADDR = (unsigned char *)addr; - ADDR += nr >> 3; - *ADDR |= 1 << (nr & 0x07); -} - -static __inline__ void __clear_le_bit(unsigned long nr, unsigned long *addr) -{ - unsigned char *ADDR = (unsigned char *)addr; - - ADDR += nr >> 3; - *ADDR &= ~(1 << (nr & 0x07)); -} - -static __inline__ int __test_and_set_le_bit(unsigned long nr, unsigned long *addr) -{ - int mask, retval; - unsigned char *ADDR = (unsigned char *)addr; - - ADDR += nr >> 3; - mask = 1 << (nr & 0x07); - retval = (mask & *ADDR) != 0; - *ADDR |= mask; - return retval; -} - -static __inline__ int __test_and_clear_le_bit(unsigned long nr, unsigned long *addr) -{ - int mask, retval; - unsigned char *ADDR = (unsigned char *)addr; - - ADDR += nr >> 3; - mask = 1 << (nr & 0x07); - retval = (mask & *ADDR) != 0; - *ADDR &= ~mask; - return retval; -} +#define __set_le_bit(nr, addr) \ + __set_bit((nr) ^ 0x38, (addr)) +#define __clear_le_bit(nr, addr) \ + __clear_bit((nr) ^ 0x38, (addr)) +#define __test_and_clear_le_bit(nr, addr) \ + __test_and_clear_bit((nr) ^ 0x38, (addr)) +#define __test_and_set_le_bit(nr, addr) \ + __test_and_set_bit((nr) ^ 0x38, (addr)) #define ext2_set_bit(nr,addr) \ - __test_and_set_le_bit((nr),(unsigned long*)addr) + __test_and_set_le_bit((nr), (unsigned long*)addr) #define ext2_clear_bit(nr, addr) \ - __test_and_clear_le_bit((nr),(unsigned long*)addr) + __test_and_clear_le_bit((nr), (unsigned long*)addr) + +#define ext2_set_bit_atomic(lock, nr, addr) \ + test_and_set_le_bit((nr), (unsigned long*)addr) +#define ext2_clear_bit_atomic(lock, nr, addr) \ + test_and_clear_le_bit((nr), (unsigned long*)addr) -#define ext2_set_bit_atomic(lock, nr, addr) \ - ({ \ - int ret; \ - spin_lock(lock); \ - ret = ext2_set_bit((nr), (addr)); \ - spin_unlock(lock); \ - ret; \ - }) - -#define ext2_clear_bit_atomic(lock, nr, addr) \ - ({ \ - int ret; \ - spin_lock(lock); \ - ret = ext2_clear_bit((nr), (addr)); \ - spin_unlock(lock); \ - ret; \ - }) #define ext2_test_bit(nr, addr) test_le_bit((nr),(unsigned long*)addr) #define ext2_find_first_zero_bit(addr, size) \ _