From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- include/asm-generic/bitops/lock.h | 94 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 include/asm-generic/bitops/lock.h (limited to 'include/asm-generic/bitops/lock.h') diff --git a/include/asm-generic/bitops/lock.h b/include/asm-generic/bitops/lock.h new file mode 100644 index 000000000..630f2f6b9 --- /dev/null +++ b/include/asm-generic/bitops/lock.h @@ -0,0 +1,94 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_BITOPS_LOCK_H_ +#define _ASM_GENERIC_BITOPS_LOCK_H_ + +#include +#include +#include + +/** + * arch_test_and_set_bit_lock - Set a bit and return its old value, for lock + * @nr: Bit to set + * @addr: Address to count from + * + * This operation is atomic and provides acquire barrier semantics if + * the returned value is 0. + * It can be used to implement bit locks. + */ +static __always_inline int +arch_test_and_set_bit_lock(unsigned int nr, volatile unsigned long *p) +{ + long old; + unsigned long mask = BIT_MASK(nr); + + p += BIT_WORD(nr); + if (READ_ONCE(*p) & mask) + return 1; + + old = arch_atomic_long_fetch_or_acquire(mask, (atomic_long_t *)p); + return !!(old & mask); +} + + +/** + * arch_clear_bit_unlock - Clear a bit in memory, for unlock + * @nr: the bit to set + * @addr: the address to start counting from + * + * This operation is atomic and provides release barrier semantics. + */ +static __always_inline void +arch_clear_bit_unlock(unsigned int nr, volatile unsigned long *p) +{ + p += BIT_WORD(nr); + arch_atomic_long_fetch_andnot_release(BIT_MASK(nr), (atomic_long_t *)p); +} + +/** + * arch___clear_bit_unlock - Clear a bit in memory, for unlock + * @nr: the bit to set + * @addr: the address to start counting from + * + * A weaker form of clear_bit_unlock() as used by __bit_lock_unlock(). If all + * the bits in the word are protected by this lock some archs can use weaker + * ops to safely unlock. + * + * See for example x86's implementation. + */ +static inline void +arch___clear_bit_unlock(unsigned int nr, volatile unsigned long *p) +{ + unsigned long old; + + p += BIT_WORD(nr); + old = READ_ONCE(*p); + old &= ~BIT_MASK(nr); + arch_atomic_long_set_release((atomic_long_t *)p, old); +} + +/** + * arch_clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom + * byte is negative, for unlock. + * @nr: the bit to clear + * @addr: the address to start counting from + * + * This is a bit of a one-trick-pony for the filemap code, which clears + * PG_locked and tests PG_waiters, + */ +#ifndef arch_clear_bit_unlock_is_negative_byte +static inline bool arch_clear_bit_unlock_is_negative_byte(unsigned int nr, + volatile unsigned long *p) +{ + long old; + unsigned long mask = BIT_MASK(nr); + + p += BIT_WORD(nr); + old = arch_atomic_long_fetch_andnot_release(mask, (atomic_long_t *)p); + return !!(old & BIT(7)); +} +#define arch_clear_bit_unlock_is_negative_byte arch_clear_bit_unlock_is_negative_byte +#endif + +#include + +#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */ -- cgit v1.2.3