linux-stable/include/linux/irq_work.h
Sebastian Andrzej Siewior 09089db798 irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT
On PREEMPT_RT most items are processed as LAZY via softirq context.
Avoid to spin-wait for them because irq_work_sync() could have higher
priority and not allow the irq-work to be completed.

Wait additionally for !IRQ_WORK_HARD_IRQ irq_work items on PREEMPT_RT.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211006111852.1514359-5-bigeasy@linutronix.de
2021-10-15 11:25:18 +02:00

75 lines
2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_IRQ_WORK_H
#define _LINUX_IRQ_WORK_H
#include <linux/smp_types.h>
#include <linux/rcuwait.h>
/*
* An entry can be in one of four states:
*
* free NULL, 0 -> {claimed} : free to be used
* claimed NULL, 3 -> {pending} : claimed to be enqueued
* pending next, 3 -> {busy} : queued, pending callback
* busy NULL, 2 -> {free, claimed} : callback in progress, can be claimed
*/
struct irq_work {
struct __call_single_node node;
void (*func)(struct irq_work *);
struct rcuwait irqwait;
};
#define __IRQ_WORK_INIT(_func, _flags) (struct irq_work){ \
.node = { .u_flags = (_flags), }, \
.func = (_func), \
.irqwait = __RCUWAIT_INITIALIZER(irqwait), \
}
#define IRQ_WORK_INIT(_func) __IRQ_WORK_INIT(_func, 0)
#define IRQ_WORK_INIT_LAZY(_func) __IRQ_WORK_INIT(_func, IRQ_WORK_LAZY)
#define IRQ_WORK_INIT_HARD(_func) __IRQ_WORK_INIT(_func, IRQ_WORK_HARD_IRQ)
#define DEFINE_IRQ_WORK(name, _f) \
struct irq_work name = IRQ_WORK_INIT(_f)
static inline
void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
{
*work = IRQ_WORK_INIT(func);
}
static inline bool irq_work_is_pending(struct irq_work *work)
{
return atomic_read(&work->node.a_flags) & IRQ_WORK_PENDING;
}
static inline bool irq_work_is_busy(struct irq_work *work)
{
return atomic_read(&work->node.a_flags) & IRQ_WORK_BUSY;
}
static inline bool irq_work_is_hard(struct irq_work *work)
{
return atomic_read(&work->node.a_flags) & IRQ_WORK_HARD_IRQ;
}
bool irq_work_queue(struct irq_work *work);
bool irq_work_queue_on(struct irq_work *work, int cpu);
void irq_work_tick(void);
void irq_work_sync(struct irq_work *work);
#ifdef CONFIG_IRQ_WORK
#include <asm/irq_work.h>
void irq_work_run(void);
bool irq_work_needs_cpu(void);
void irq_work_single(void *arg);
#else
static inline bool irq_work_needs_cpu(void) { return false; }
static inline void irq_work_run(void) { }
static inline void irq_work_single(void *arg) { }
#endif
#endif /* _LINUX_IRQ_WORK_H */