From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- include/asm-generic/bitops/atomic.h | 70 +++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 include/asm-generic/bitops/atomic.h (limited to 'include/asm-generic/bitops/atomic.h') diff --git a/include/asm-generic/bitops/atomic.h b/include/asm-generic/bitops/atomic.h new file mode 100644 index 000000000..e076e079f --- /dev/null +++ b/include/asm-generic/bitops/atomic.h @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_BITOPS_ATOMIC_H_ +#define _ASM_GENERIC_BITOPS_ATOMIC_H_ + +#include +#include +#include + +/* + * Implementation of atomic bitops using atomic-fetch ops. + * See Documentation/atomic_bitops.txt for details. + */ + +static __always_inline void +arch_set_bit(unsigned int nr, volatile unsigned long *p) +{ + p += BIT_WORD(nr); + raw_atomic_long_or(BIT_MASK(nr), (atomic_long_t *)p); +} + +static __always_inline void +arch_clear_bit(unsigned int nr, volatile unsigned long *p) +{ + p += BIT_WORD(nr); + raw_atomic_long_andnot(BIT_MASK(nr), (atomic_long_t *)p); +} + +static __always_inline void +arch_change_bit(unsigned int nr, volatile unsigned long *p) +{ + p += BIT_WORD(nr); + raw_atomic_long_xor(BIT_MASK(nr), (atomic_long_t *)p); +} + +static __always_inline int +arch_test_and_set_bit(unsigned int nr, volatile unsigned long *p) +{ + long old; + unsigned long mask = BIT_MASK(nr); + + p += BIT_WORD(nr); + old = raw_atomic_long_fetch_or(mask, (atomic_long_t *)p); + return !!(old & mask); +} + +static __always_inline int +arch_test_and_clear_bit(unsigned int nr, volatile unsigned long *p) +{ + long old; + unsigned long mask = BIT_MASK(nr); + + p += BIT_WORD(nr); + old = raw_atomic_long_fetch_andnot(mask, (atomic_long_t *)p); + return !!(old & mask); +} + +static __always_inline int +arch_test_and_change_bit(unsigned int nr, volatile unsigned long *p) +{ + long old; + unsigned long mask = BIT_MASK(nr); + + p += BIT_WORD(nr); + old = raw_atomic_long_fetch_xor(mask, (atomic_long_t *)p); + return !!(old & mask); +} + +#include + +#endif /* _ASM_GENERIC_BITOPS_ATOMIC_H */ -- cgit v1.3.1