linux-stable/virt/lib/irqbypass.c
Thomas Gleixner d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00

264 lines
5.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* IRQ offload/bypass manager
*
* Copyright (C) 2015 Red Hat, Inc.
* Copyright (c) 2015 Linaro Ltd.
*
* Various virtualization hardware acceleration techniques allow bypassing or
* offloading interrupts received from devices around the host kernel. Posted
* Interrupts on Intel VT-d systems can allow interrupts to be received
* directly by a virtual machine. ARM IRQ Forwarding allows forwarded physical
* interrupts to be directly deactivated by the guest. This manager allows
* interrupt producers and consumers to find each other to enable this sort of
* bypass.
*/
#include <linux/irqbypass.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("IRQ bypass manager utility module");
static LIST_HEAD(producers);
static LIST_HEAD(consumers);
static DEFINE_MUTEX(lock);
/* @lock must be held when calling connect */
static int __connect(struct irq_bypass_producer *prod,
struct irq_bypass_consumer *cons)
{
int ret = 0;
if (prod->stop)
prod->stop(prod);
if (cons->stop)
cons->stop(cons);
if (prod->add_consumer)
ret = prod->add_consumer(prod, cons);
if (!ret) {
ret = cons->add_producer(cons, prod);
if (ret && prod->del_consumer)
prod->del_consumer(prod, cons);
}
if (cons->start)
cons->start(cons);
if (prod->start)
prod->start(prod);
return ret;
}
/* @lock must be held when calling disconnect */
static void __disconnect(struct irq_bypass_producer *prod,
struct irq_bypass_consumer *cons)
{
if (prod->stop)
prod->stop(prod);
if (cons->stop)
cons->stop(cons);
cons->del_producer(cons, prod);
if (prod->del_consumer)
prod->del_consumer(prod, cons);
if (cons->start)
cons->start(cons);
if (prod->start)
prod->start(prod);
}
/**
* irq_bypass_register_producer - register IRQ bypass producer
* @producer: pointer to producer structure
*
* Add the provided IRQ producer to the list of producers and connect
* with any matching token found on the IRQ consumers list.
*/
int irq_bypass_register_producer(struct irq_bypass_producer *producer)
{
struct irq_bypass_producer *tmp;
struct irq_bypass_consumer *consumer;
if (!producer->token)
return -EINVAL;
might_sleep();
if (!try_module_get(THIS_MODULE))
return -ENODEV;
mutex_lock(&lock);
list_for_each_entry(tmp, &producers, node) {
if (tmp->token == producer->token) {
mutex_unlock(&lock);
module_put(THIS_MODULE);
return -EBUSY;
}
}
list_for_each_entry(consumer, &consumers, node) {
if (consumer->token == producer->token) {
int ret = __connect(producer, consumer);
if (ret) {
mutex_unlock(&lock);
module_put(THIS_MODULE);
return ret;
}
break;
}
}
list_add(&producer->node, &producers);
mutex_unlock(&lock);
return 0;
}
EXPORT_SYMBOL_GPL(irq_bypass_register_producer);
/**
* irq_bypass_unregister_producer - unregister IRQ bypass producer
* @producer: pointer to producer structure
*
* Remove a previously registered IRQ producer from the list of producers
* and disconnect it from any connected IRQ consumer.
*/
void irq_bypass_unregister_producer(struct irq_bypass_producer *producer)
{
struct irq_bypass_producer *tmp;
struct irq_bypass_consumer *consumer;
if (!producer->token)
return;
might_sleep();
if (!try_module_get(THIS_MODULE))
return; /* nothing in the list anyway */
mutex_lock(&lock);
list_for_each_entry(tmp, &producers, node) {
if (tmp->token != producer->token)
continue;
list_for_each_entry(consumer, &consumers, node) {
if (consumer->token == producer->token) {
__disconnect(producer, consumer);
break;
}
}
list_del(&producer->node);
module_put(THIS_MODULE);
break;
}
mutex_unlock(&lock);
module_put(THIS_MODULE);
}
EXPORT_SYMBOL_GPL(irq_bypass_unregister_producer);
/**
* irq_bypass_register_consumer - register IRQ bypass consumer
* @consumer: pointer to consumer structure
*
* Add the provided IRQ consumer to the list of consumers and connect
* with any matching token found on the IRQ producer list.
*/
int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer)
{
struct irq_bypass_consumer *tmp;
struct irq_bypass_producer *producer;
if (!consumer->token ||
!consumer->add_producer || !consumer->del_producer)
return -EINVAL;
might_sleep();
if (!try_module_get(THIS_MODULE))
return -ENODEV;
mutex_lock(&lock);
list_for_each_entry(tmp, &consumers, node) {
if (tmp->token == consumer->token || tmp == consumer) {
mutex_unlock(&lock);
module_put(THIS_MODULE);
return -EBUSY;
}
}
list_for_each_entry(producer, &producers, node) {
if (producer->token == consumer->token) {
int ret = __connect(producer, consumer);
if (ret) {
mutex_unlock(&lock);
module_put(THIS_MODULE);
return ret;
}
break;
}
}
list_add(&consumer->node, &consumers);
mutex_unlock(&lock);
return 0;
}
EXPORT_SYMBOL_GPL(irq_bypass_register_consumer);
/**
* irq_bypass_unregister_consumer - unregister IRQ bypass consumer
* @consumer: pointer to consumer structure
*
* Remove a previously registered IRQ consumer from the list of consumers
* and disconnect it from any connected IRQ producer.
*/
void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer)
{
struct irq_bypass_consumer *tmp;
struct irq_bypass_producer *producer;
if (!consumer->token)
return;
might_sleep();
if (!try_module_get(THIS_MODULE))
return; /* nothing in the list anyway */
mutex_lock(&lock);
list_for_each_entry(tmp, &consumers, node) {
if (tmp != consumer)
continue;
list_for_each_entry(producer, &producers, node) {
if (producer->token == consumer->token) {
__disconnect(producer, consumer);
break;
}
}
list_del(&consumer->node);
module_put(THIS_MODULE);
break;
}
mutex_unlock(&lock);
module_put(THIS_MODULE);
}
EXPORT_SYMBOL_GPL(irq_bypass_unregister_consumer);