linux/lib/irq_poll.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Functions related to interrupt-poll handling in the block layer. This
 * is similar to NAPI for network devices.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bio.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/irq_poll.h>
#include <linux/delay.h>

static unsigned int irq_poll_budget __read_mostly = …;

static DEFINE_PER_CPU(struct list_head, blk_cpu_iopoll);

/**
 * irq_poll_sched - Schedule a run of the iopoll handler
 * @iop:      The parent iopoll structure
 *
 * Description:
 *     Add this irq_poll structure to the pending poll list and trigger the
 *     raise of the blk iopoll softirq.
 **/
void irq_poll_sched(struct irq_poll *iop)
{ … }
EXPORT_SYMBOL(…);

/**
 * __irq_poll_complete - Mark this @iop as un-polled again
 * @iop:      The parent iopoll structure
 *
 * Description:
 *     See irq_poll_complete(). This function must be called with interrupts
 *     disabled.
 **/
static void __irq_poll_complete(struct irq_poll *iop)
{ … }

/**
 * irq_poll_complete - Mark this @iop as un-polled again
 * @iop:      The parent iopoll structure
 *
 * Description:
 *     If a driver consumes less than the assigned budget in its run of the
 *     iopoll handler, it'll end the polled mode by calling this function. The
 *     iopoll handler will not be invoked again before irq_poll_sched()
 *     is called.
 **/
void irq_poll_complete(struct irq_poll *iop)
{ … }
EXPORT_SYMBOL(…);

static void __latent_entropy irq_poll_softirq(void)
{ … }

/**
 * irq_poll_disable - Disable iopoll on this @iop
 * @iop:      The parent iopoll structure
 *
 * Description:
 *     Disable io polling and wait for any pending callbacks to have completed.
 **/
void irq_poll_disable(struct irq_poll *iop)
{ … }
EXPORT_SYMBOL(…);

/**
 * irq_poll_enable - Enable iopoll on this @iop
 * @iop:      The parent iopoll structure
 *
 * Description:
 *     Enable iopoll on this @iop. Note that the handler run will not be
 *     scheduled, it will only mark it as active.
 **/
void irq_poll_enable(struct irq_poll *iop)
{ … }
EXPORT_SYMBOL(…);

/**
 * irq_poll_init - Initialize this @iop
 * @iop:      The parent iopoll structure
 * @weight:   The default weight (or command completion budget)
 * @poll_fn:  The handler to invoke
 *
 * Description:
 *     Initialize and enable this irq_poll structure.
 **/
void irq_poll_init(struct irq_poll *iop, int weight, irq_poll_fn *poll_fn)
{ … }
EXPORT_SYMBOL(…);

static int irq_poll_cpu_dead(unsigned int cpu)
{ … }

static __init int irq_poll_setup(void)
{ … }
subsys_initcall(irq_poll_setup);