144b9c135b
eieio is only a store - store ordering. When used to order an unlock operation loads may leak out of the critical region. This is potentially buggy, one example is if a user wants to atomically read a couple of values. We can solve this with an lwsync which orders everything except store - load. I removed the (now unused) EIEIO_ON_SMP macros and the c versions isync_on_smp and eieio_on_smp now we dont use them. I also removed some old comments that were used to identify inline spinlocks in assembly, they dont make sense now our locks are out of line. Another interesting thing was that read_unlock was using an eieio even though the rest of the spinlock code had already been converted to use lwsync. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
430 lines
12 KiB
C
430 lines
12 KiB
C
/*
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* PowerPC atomic bit operations.
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*
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* Merged version by David Gibson <david@gibson.dropbear.id.au>.
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* Based on ppc64 versions by: Dave Engebretsen, Todd Inglett, Don
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* Reed, Pat McCarthy, Peter Bergner, Anton Blanchard. They
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* originally took it from the ppc32 code.
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*
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* Within a word, bits are numbered LSB first. Lot's of places make
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* this assumption by directly testing bits with (val & (1<<nr)).
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* This can cause confusion for large (> 1 word) bitmaps on a
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* big-endian system because, unlike little endian, the number of each
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* bit depends on the word size.
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*
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* The bitop functions are defined to work on unsigned longs, so for a
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* ppc64 system the bits end up numbered:
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* |63..............0|127............64|191...........128|255...........196|
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* and on ppc32:
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* |31.....0|63....31|95....64|127...96|159..128|191..160|223..192|255..224|
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*
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* There are a few little-endian macros used mostly for filesystem
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* bitmaps, these work on similar bit arrays layouts, but
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* byte-oriented:
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* |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56|
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*
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* The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit
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* number field needs to be reversed compared to the big-endian bit
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* fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b).
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _ASM_POWERPC_BITOPS_H
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#define _ASM_POWERPC_BITOPS_H
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#ifdef __KERNEL__
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#include <linux/compiler.h>
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#include <asm/atomic.h>
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#include <asm/asm-compat.h>
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#include <asm/synch.h>
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/*
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* clear_bit doesn't imply a memory barrier
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*/
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#define smp_mb__before_clear_bit() smp_mb()
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#define smp_mb__after_clear_bit() smp_mb()
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#define BITOP_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
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#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
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#define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
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static __inline__ void set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long old;
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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__asm__ __volatile__(
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"1:" PPC_LLARX "%0,0,%3 # set_bit\n"
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"or %0,%0,%2\n"
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PPC405_ERR77(0,%3)
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PPC_STLCX "%0,0,%3\n"
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"bne- 1b"
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: "=&r"(old), "=m"(*p)
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: "r"(mask), "r"(p), "m"(*p)
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: "cc" );
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}
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static __inline__ void clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long old;
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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__asm__ __volatile__(
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"1:" PPC_LLARX "%0,0,%3 # clear_bit\n"
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"andc %0,%0,%2\n"
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PPC405_ERR77(0,%3)
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PPC_STLCX "%0,0,%3\n"
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"bne- 1b"
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: "=&r"(old), "=m"(*p)
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: "r"(mask), "r"(p), "m"(*p)
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: "cc" );
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}
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static __inline__ void change_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long old;
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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__asm__ __volatile__(
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"1:" PPC_LLARX "%0,0,%3 # change_bit\n"
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"xor %0,%0,%2\n"
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PPC405_ERR77(0,%3)
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PPC_STLCX "%0,0,%3\n"
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"bne- 1b"
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: "=&r"(old), "=m"(*p)
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: "r"(mask), "r"(p), "m"(*p)
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: "cc" );
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}
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static __inline__ int test_and_set_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long old, t;
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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__asm__ __volatile__(
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LWSYNC_ON_SMP
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"1:" PPC_LLARX "%0,0,%3 # test_and_set_bit\n"
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"or %1,%0,%2 \n"
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PPC405_ERR77(0,%3)
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PPC_STLCX "%1,0,%3 \n"
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"bne- 1b"
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ISYNC_ON_SMP
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: "=&r" (old), "=&r" (t)
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: "r" (mask), "r" (p)
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: "cc", "memory");
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return (old & mask) != 0;
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}
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static __inline__ int test_and_clear_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long old, t;
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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__asm__ __volatile__(
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LWSYNC_ON_SMP
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"1:" PPC_LLARX "%0,0,%3 # test_and_clear_bit\n"
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"andc %1,%0,%2 \n"
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PPC405_ERR77(0,%3)
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PPC_STLCX "%1,0,%3 \n"
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"bne- 1b"
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ISYNC_ON_SMP
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: "=&r" (old), "=&r" (t)
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: "r" (mask), "r" (p)
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: "cc", "memory");
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return (old & mask) != 0;
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}
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static __inline__ int test_and_change_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long old, t;
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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__asm__ __volatile__(
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LWSYNC_ON_SMP
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"1:" PPC_LLARX "%0,0,%3 # test_and_change_bit\n"
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"xor %1,%0,%2 \n"
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PPC405_ERR77(0,%3)
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PPC_STLCX "%1,0,%3 \n"
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"bne- 1b"
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ISYNC_ON_SMP
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: "=&r" (old), "=&r" (t)
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: "r" (mask), "r" (p)
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: "cc", "memory");
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return (old & mask) != 0;
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}
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static __inline__ void set_bits(unsigned long mask, unsigned long *addr)
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{
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unsigned long old;
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__asm__ __volatile__(
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"1:" PPC_LLARX "%0,0,%3 # set_bits\n"
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"or %0,%0,%2\n"
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PPC_STLCX "%0,0,%3\n"
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"bne- 1b"
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: "=&r" (old), "=m" (*addr)
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: "r" (mask), "r" (addr), "m" (*addr)
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: "cc");
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}
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/* Non-atomic versions */
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static __inline__ int test_bit(unsigned long nr,
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__const__ volatile unsigned long *addr)
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{
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return 1UL & (addr[BITOP_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
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}
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static __inline__ void __set_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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*p |= mask;
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}
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static __inline__ void __clear_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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*p &= ~mask;
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}
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static __inline__ void __change_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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*p ^= mask;
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}
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static __inline__ int __test_and_set_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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unsigned long old = *p;
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*p = old | mask;
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return (old & mask) != 0;
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}
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static __inline__ int __test_and_clear_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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unsigned long old = *p;
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*p = old & ~mask;
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return (old & mask) != 0;
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}
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static __inline__ int __test_and_change_bit(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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unsigned long old = *p;
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*p = old ^ mask;
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return (old & mask) != 0;
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}
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/*
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* Return the zero-based bit position (LE, not IBM bit numbering) of
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* the most significant 1-bit in a double word.
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*/
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static __inline__ int __ilog2(unsigned long x)
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{
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int lz;
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asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x));
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return BITS_PER_LONG - 1 - lz;
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}
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/*
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* Determines the bit position of the least significant 0 bit in the
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* specified double word. The returned bit position will be
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* zero-based, starting from the right side (63/31 - 0).
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*/
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static __inline__ unsigned long ffz(unsigned long x)
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{
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/* no zero exists anywhere in the 8 byte area. */
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if ((x = ~x) == 0)
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return BITS_PER_LONG;
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/*
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* Calculate the bit position of the least signficant '1' bit in x
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* (since x has been changed this will actually be the least signficant
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* '0' bit in * the original x). Note: (x & -x) gives us a mask that
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* is the least significant * (RIGHT-most) 1-bit of the value in x.
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*/
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return __ilog2(x & -x);
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}
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static __inline__ int __ffs(unsigned long x)
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{
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return __ilog2(x & -x);
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}
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/*
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* ffs: find first bit set. This is defined the same way as
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* the libc and compiler builtin ffs routines, therefore
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* differs in spirit from the above ffz (man ffs).
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*/
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static __inline__ int ffs(int x)
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{
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unsigned long i = (unsigned long)x;
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return __ilog2(i & -i) + 1;
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}
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/*
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* fls: find last (most-significant) bit set.
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* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static __inline__ int fls(unsigned int x)
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{
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int lz;
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asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
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return 32 - lz;
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}
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#define fls64(x) generic_fls64(x)
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/*
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* hweightN: returns the hamming weight (i.e. the number
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* of bits set) of a N-bit word
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*/
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#define hweight64(x) generic_hweight64(x)
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#define hweight32(x) generic_hweight32(x)
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#define hweight16(x) generic_hweight16(x)
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#define hweight8(x) generic_hweight8(x)
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#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
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unsigned long find_next_zero_bit(const unsigned long *addr,
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unsigned long size, unsigned long offset);
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/**
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* find_first_bit - find the first set bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit-number of the first set bit, not the number of the byte
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* containing a bit.
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*/
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#define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
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unsigned long find_next_bit(const unsigned long *addr,
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unsigned long size, unsigned long offset);
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/* Little-endian versions */
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static __inline__ int test_le_bit(unsigned long nr,
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__const__ unsigned long *addr)
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{
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__const__ unsigned char *tmp = (__const__ unsigned char *) addr;
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return (tmp[nr >> 3] >> (nr & 7)) & 1;
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}
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#define __set_le_bit(nr, addr) \
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__set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define __clear_le_bit(nr, addr) \
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__clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define test_and_set_le_bit(nr, addr) \
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test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define test_and_clear_le_bit(nr, addr) \
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test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define __test_and_set_le_bit(nr, addr) \
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__test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define __test_and_clear_le_bit(nr, addr) \
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__test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define find_first_zero_le_bit(addr, size) find_next_zero_le_bit((addr), (size), 0)
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unsigned long find_next_zero_le_bit(const unsigned long *addr,
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unsigned long size, unsigned long offset);
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/* Bitmap functions for the ext2 filesystem */
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#define ext2_set_bit(nr,addr) \
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__test_and_set_le_bit((nr), (unsigned long*)addr)
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#define ext2_clear_bit(nr, addr) \
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__test_and_clear_le_bit((nr), (unsigned long*)addr)
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#define ext2_set_bit_atomic(lock, nr, addr) \
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test_and_set_le_bit((nr), (unsigned long*)addr)
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#define ext2_clear_bit_atomic(lock, nr, addr) \
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test_and_clear_le_bit((nr), (unsigned long*)addr)
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#define ext2_test_bit(nr, addr) test_le_bit((nr),(unsigned long*)addr)
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#define ext2_find_first_zero_bit(addr, size) \
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find_first_zero_le_bit((unsigned long*)addr, size)
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#define ext2_find_next_zero_bit(addr, size, off) \
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find_next_zero_le_bit((unsigned long*)addr, size, off)
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/* Bitmap functions for the minix filesystem. */
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#define minix_test_and_set_bit(nr,addr) \
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__test_and_set_le_bit(nr, (unsigned long *)addr)
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#define minix_set_bit(nr,addr) \
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__set_le_bit(nr, (unsigned long *)addr)
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#define minix_test_and_clear_bit(nr,addr) \
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__test_and_clear_le_bit(nr, (unsigned long *)addr)
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#define minix_test_bit(nr,addr) \
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test_le_bit(nr, (unsigned long *)addr)
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#define minix_find_first_zero_bit(addr,size) \
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find_first_zero_le_bit((unsigned long *)addr, size)
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/*
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* Every architecture must define this function. It's the fastest
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* way of searching a 140-bit bitmap where the first 100 bits are
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* unlikely to be set. It's guaranteed that at least one of the 140
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* bits is cleared.
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*/
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static inline int sched_find_first_bit(const unsigned long *b)
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{
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#ifdef CONFIG_PPC64
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if (unlikely(b[0]))
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return __ffs(b[0]);
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if (unlikely(b[1]))
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return __ffs(b[1]) + 64;
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return __ffs(b[2]) + 128;
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#else
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if (unlikely(b[0]))
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return __ffs(b[0]);
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if (unlikely(b[1]))
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return __ffs(b[1]) + 32;
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if (unlikely(b[2]))
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return __ffs(b[2]) + 64;
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if (b[3])
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return __ffs(b[3]) + 96;
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return __ffs(b[4]) + 128;
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#endif
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}
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_BITOPS_H */
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