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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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cb0f80039f
cpumap needs to set, clear, and test the lowest bit in skb pointer in various places. To make these checks less noisy, add pointer friendly bitop macros that also do some typechecking to sanitize the argument. These wrap the non-atomic bitops __set_bit, __clear_bit, and test_bit but for pointer arguments. Pointer's address has to be passed in and it is treated as an unsigned long *, since width and representation of pointer and unsigned long match on targets Linux supports. They are prefixed with double underscore to indicate lack of atomicity. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210702111825.491065-3-memxor@gmail.com
340 lines
8.5 KiB
C
340 lines
8.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_BITOPS_H
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#define _LINUX_BITOPS_H
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#include <asm/types.h>
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#include <linux/bits.h>
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#include <linux/typecheck.h>
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#include <uapi/linux/kernel.h>
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/* Set bits in the first 'n' bytes when loaded from memory */
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#ifdef __LITTLE_ENDIAN
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# define aligned_byte_mask(n) ((1UL << 8*(n))-1)
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#else
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# define aligned_byte_mask(n) (~0xffUL << (BITS_PER_LONG - 8 - 8*(n)))
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#endif
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#define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
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#define BITS_TO_LONGS(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(long))
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#define BITS_TO_U64(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u64))
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#define BITS_TO_U32(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u32))
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#define BITS_TO_BYTES(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(char))
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extern unsigned int __sw_hweight8(unsigned int w);
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extern unsigned int __sw_hweight16(unsigned int w);
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extern unsigned int __sw_hweight32(unsigned int w);
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extern unsigned long __sw_hweight64(__u64 w);
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/*
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* Include this here because some architectures need generic_ffs/fls in
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* scope
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*/
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#include <asm/bitops.h>
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#define for_each_set_bit(bit, addr, size) \
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for ((bit) = find_first_bit((addr), (size)); \
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(bit) < (size); \
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(bit) = find_next_bit((addr), (size), (bit) + 1))
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/* same as for_each_set_bit() but use bit as value to start with */
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#define for_each_set_bit_from(bit, addr, size) \
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for ((bit) = find_next_bit((addr), (size), (bit)); \
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(bit) < (size); \
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(bit) = find_next_bit((addr), (size), (bit) + 1))
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#define for_each_clear_bit(bit, addr, size) \
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for ((bit) = find_first_zero_bit((addr), (size)); \
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(bit) < (size); \
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(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
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/* same as for_each_clear_bit() but use bit as value to start with */
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#define for_each_clear_bit_from(bit, addr, size) \
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for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
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(bit) < (size); \
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(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
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/**
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* for_each_set_clump8 - iterate over bitmap for each 8-bit clump with set bits
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* @start: bit offset to start search and to store the current iteration offset
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* @clump: location to store copy of current 8-bit clump
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* @bits: bitmap address to base the search on
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* @size: bitmap size in number of bits
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*/
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#define for_each_set_clump8(start, clump, bits, size) \
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for ((start) = find_first_clump8(&(clump), (bits), (size)); \
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(start) < (size); \
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(start) = find_next_clump8(&(clump), (bits), (size), (start) + 8))
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static inline int get_bitmask_order(unsigned int count)
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{
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int order;
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order = fls(count);
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return order; /* We could be slightly more clever with -1 here... */
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}
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static __always_inline unsigned long hweight_long(unsigned long w)
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{
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return sizeof(w) == 4 ? hweight32(w) : hweight64((__u64)w);
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}
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/**
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* rol64 - rotate a 64-bit value left
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* @word: value to rotate
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* @shift: bits to roll
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*/
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static inline __u64 rol64(__u64 word, unsigned int shift)
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{
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return (word << (shift & 63)) | (word >> ((-shift) & 63));
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}
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/**
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* ror64 - rotate a 64-bit value right
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* @word: value to rotate
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* @shift: bits to roll
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*/
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static inline __u64 ror64(__u64 word, unsigned int shift)
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{
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return (word >> (shift & 63)) | (word << ((-shift) & 63));
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}
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/**
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* rol32 - rotate a 32-bit value left
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* @word: value to rotate
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* @shift: bits to roll
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*/
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static inline __u32 rol32(__u32 word, unsigned int shift)
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{
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return (word << (shift & 31)) | (word >> ((-shift) & 31));
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}
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/**
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* ror32 - rotate a 32-bit value right
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* @word: value to rotate
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* @shift: bits to roll
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*/
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static inline __u32 ror32(__u32 word, unsigned int shift)
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{
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return (word >> (shift & 31)) | (word << ((-shift) & 31));
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}
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/**
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* rol16 - rotate a 16-bit value left
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* @word: value to rotate
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* @shift: bits to roll
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*/
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static inline __u16 rol16(__u16 word, unsigned int shift)
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{
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return (word << (shift & 15)) | (word >> ((-shift) & 15));
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}
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/**
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* ror16 - rotate a 16-bit value right
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* @word: value to rotate
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* @shift: bits to roll
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*/
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static inline __u16 ror16(__u16 word, unsigned int shift)
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{
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return (word >> (shift & 15)) | (word << ((-shift) & 15));
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}
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/**
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* rol8 - rotate an 8-bit value left
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* @word: value to rotate
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* @shift: bits to roll
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*/
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static inline __u8 rol8(__u8 word, unsigned int shift)
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{
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return (word << (shift & 7)) | (word >> ((-shift) & 7));
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}
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/**
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* ror8 - rotate an 8-bit value right
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* @word: value to rotate
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* @shift: bits to roll
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*/
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static inline __u8 ror8(__u8 word, unsigned int shift)
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{
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return (word >> (shift & 7)) | (word << ((-shift) & 7));
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}
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/**
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* sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
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* @value: value to sign extend
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* @index: 0 based bit index (0<=index<32) to sign bit
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*
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* This is safe to use for 16- and 8-bit types as well.
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*/
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static __always_inline __s32 sign_extend32(__u32 value, int index)
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{
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__u8 shift = 31 - index;
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return (__s32)(value << shift) >> shift;
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}
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/**
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* sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
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* @value: value to sign extend
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* @index: 0 based bit index (0<=index<64) to sign bit
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*/
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static __always_inline __s64 sign_extend64(__u64 value, int index)
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{
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__u8 shift = 63 - index;
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return (__s64)(value << shift) >> shift;
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}
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static inline unsigned fls_long(unsigned long l)
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{
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if (sizeof(l) == 4)
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return fls(l);
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return fls64(l);
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}
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static inline int get_count_order(unsigned int count)
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{
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if (count == 0)
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return -1;
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return fls(--count);
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}
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/**
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* get_count_order_long - get order after rounding @l up to power of 2
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* @l: parameter
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*
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* it is same as get_count_order() but with long type parameter
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*/
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static inline int get_count_order_long(unsigned long l)
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{
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if (l == 0UL)
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return -1;
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return (int)fls_long(--l);
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}
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/**
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* __ffs64 - find first set bit in a 64 bit word
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* @word: The 64 bit word
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*
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* On 64 bit arches this is a synonym for __ffs
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* The result is not defined if no bits are set, so check that @word
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* is non-zero before calling this.
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*/
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static inline unsigned long __ffs64(u64 word)
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{
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#if BITS_PER_LONG == 32
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if (((u32)word) == 0UL)
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return __ffs((u32)(word >> 32)) + 32;
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#elif BITS_PER_LONG != 64
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#error BITS_PER_LONG not 32 or 64
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#endif
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return __ffs((unsigned long)word);
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}
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/**
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* assign_bit - Assign value to a bit in memory
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* @nr: the bit to set
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* @addr: the address to start counting from
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* @value: the value to assign
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*/
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static __always_inline void assign_bit(long nr, volatile unsigned long *addr,
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bool value)
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{
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if (value)
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set_bit(nr, addr);
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else
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clear_bit(nr, addr);
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}
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static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
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bool value)
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{
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if (value)
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__set_bit(nr, addr);
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else
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__clear_bit(nr, addr);
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}
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/**
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* __ptr_set_bit - Set bit in a pointer's value
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* @nr: the bit to set
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* @addr: the address of the pointer variable
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*
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* Example:
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* void *p = foo();
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* __ptr_set_bit(bit, &p);
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*/
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#define __ptr_set_bit(nr, addr) \
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({ \
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typecheck_pointer(*(addr)); \
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__set_bit(nr, (unsigned long *)(addr)); \
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})
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/**
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* __ptr_clear_bit - Clear bit in a pointer's value
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* @nr: the bit to clear
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* @addr: the address of the pointer variable
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*
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* Example:
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* void *p = foo();
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* __ptr_clear_bit(bit, &p);
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*/
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#define __ptr_clear_bit(nr, addr) \
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({ \
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typecheck_pointer(*(addr)); \
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__clear_bit(nr, (unsigned long *)(addr)); \
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})
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/**
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* __ptr_test_bit - Test bit in a pointer's value
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* @nr: the bit to test
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* @addr: the address of the pointer variable
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*
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* Example:
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* void *p = foo();
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* if (__ptr_test_bit(bit, &p)) {
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* ...
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* } else {
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* ...
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* }
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*/
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#define __ptr_test_bit(nr, addr) \
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({ \
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typecheck_pointer(*(addr)); \
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test_bit(nr, (unsigned long *)(addr)); \
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})
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#ifdef __KERNEL__
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#ifndef set_mask_bits
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#define set_mask_bits(ptr, mask, bits) \
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({ \
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const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \
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typeof(*(ptr)) old__, new__; \
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\
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do { \
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old__ = READ_ONCE(*(ptr)); \
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new__ = (old__ & ~mask__) | bits__; \
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} while (cmpxchg(ptr, old__, new__) != old__); \
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\
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old__; \
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})
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#endif
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#ifndef bit_clear_unless
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#define bit_clear_unless(ptr, clear, test) \
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({ \
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const typeof(*(ptr)) clear__ = (clear), test__ = (test);\
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typeof(*(ptr)) old__, new__; \
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\
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do { \
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old__ = READ_ONCE(*(ptr)); \
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new__ = old__ & ~clear__; \
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} while (!(old__ & test__) && \
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cmpxchg(ptr, old__, new__) != old__); \
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\
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!(old__ & test__); \
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})
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#endif
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#endif /* __KERNEL__ */
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#endif
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