forked from mirrors/linux
c5bcab7558
Add local_lock_nested_bh() locking. It is based on local_lock_t and the naming follows the preempt_disable_nested() example. For !PREEMPT_RT + !LOCKDEP it is a per-CPU annotation for locking assumptions based on local_bh_disable(). The macro is optimized away during compilation. For !PREEMPT_RT + LOCKDEP the local_lock_nested_bh() is reduced to the usual lock-acquire plus lockdep_assert_in_softirq() - ensuring that BH is disabled. For PREEMPT_RT local_lock_nested_bh() acquires the specified per-CPU lock. It does not disable CPU migration because it relies on local_bh_disable() disabling CPU migration. With LOCKDEP it performans the usual lockdep checks as with !PREEMPT_RT. Due to include hell the softirq check has been moved spinlock.c. The intention is to use this locking in places where locking of a per-CPU variable relies on BH being disabled. Instead of treating disabled bottom halves as a big per-CPU lock, PREEMPT_RT can use this to reduce the locking scope to what actually needs protecting. A side effect is that it also documents the protection scope of the per-CPU variables. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20240620132727.660738-3-bigeasy@linutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
75 lines
2 KiB
C
75 lines
2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_LOCAL_LOCK_H
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#define _LINUX_LOCAL_LOCK_H
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#include <linux/local_lock_internal.h>
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/**
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* local_lock_init - Runtime initialize a lock instance
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*/
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#define local_lock_init(lock) __local_lock_init(lock)
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/**
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* local_lock - Acquire a per CPU local lock
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* @lock: The lock variable
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*/
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#define local_lock(lock) __local_lock(lock)
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/**
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* local_lock_irq - Acquire a per CPU local lock and disable interrupts
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* @lock: The lock variable
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*/
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#define local_lock_irq(lock) __local_lock_irq(lock)
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/**
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* local_lock_irqsave - Acquire a per CPU local lock, save and disable
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* interrupts
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* @lock: The lock variable
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* @flags: Storage for interrupt flags
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*/
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#define local_lock_irqsave(lock, flags) \
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__local_lock_irqsave(lock, flags)
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/**
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* local_unlock - Release a per CPU local lock
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* @lock: The lock variable
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*/
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#define local_unlock(lock) __local_unlock(lock)
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/**
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* local_unlock_irq - Release a per CPU local lock and enable interrupts
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* @lock: The lock variable
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*/
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#define local_unlock_irq(lock) __local_unlock_irq(lock)
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/**
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* local_unlock_irqrestore - Release a per CPU local lock and restore
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* interrupt flags
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* @lock: The lock variable
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* @flags: Interrupt flags to restore
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*/
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#define local_unlock_irqrestore(lock, flags) \
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__local_unlock_irqrestore(lock, flags)
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DEFINE_GUARD(local_lock, local_lock_t __percpu*,
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local_lock(_T),
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local_unlock(_T))
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DEFINE_GUARD(local_lock_irq, local_lock_t __percpu*,
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local_lock_irq(_T),
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local_unlock_irq(_T))
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DEFINE_LOCK_GUARD_1(local_lock_irqsave, local_lock_t __percpu,
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local_lock_irqsave(_T->lock, _T->flags),
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local_unlock_irqrestore(_T->lock, _T->flags),
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unsigned long flags)
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#define local_lock_nested_bh(_lock) \
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__local_lock_nested_bh(_lock)
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#define local_unlock_nested_bh(_lock) \
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__local_unlock_nested_bh(_lock)
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DEFINE_GUARD(local_lock_nested_bh, local_lock_t __percpu*,
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local_lock_nested_bh(_T),
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local_unlock_nested_bh(_T))
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#endif
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