linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 *  fs/timerfd.c

 *

 *  Copyright (C) 2007  Davide Libenzi <davidel@xmailserver.org>

 *

 *

 *  Thanks to Thomas Gleixner for code reviews and useful comments.

 *

 */

​

#include <linux/alarmtimer.h>

#include <linux/file.h>

#include <linux/poll.h>

#include <linux/init.h>

#include <linux/fs.h>

#include <linux/sched.h>

#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/list.h>

#include <linux/spinlock.h>

#include <linux/time.h>

#include <linux/hrtimer.h>

#include <linux/anon_inodes.h>

#include <linux/timerfd.h>

#include <linux/syscalls.h>

#include <linux/compat.h>

#include <linux/rcupdate.h>

​

struct timerfd_ctx {

    union {

        struct hrtimer tmr;

        struct alarm alarm;

    } t;

    ktime_t tintv;

    ktime_t moffs;

    wait_queue_head_t wqh;

    u64 ticks;

    int clockid;

    short unsigned expired;

    short unsigned settime_flags;   /* to show in fdinfo */

    struct rcu_head rcu;

    struct list_head clist;

    spinlock_t cancel_lock;

    bool might_cancel;

};

​

static LIST_HEAD(cancel_list);

static DEFINE_SPINLOCK(cancel_lock);

​

static inline bool isalarm(struct timerfd_ctx *ctx)

{

    return ctx->clockid == CLOCK_REALTIME_ALARM ||

        ctx->clockid == CLOCK_BOOTTIME_ALARM;

}

​

/*

 * This gets called when the timer event triggers. We set the "expired"

 * flag, but we do not re-arm the timer (in case it's necessary,

 * tintv != 0) until the timer is accessed.

 */

static void timerfd_triggered(struct timerfd_ctx *ctx)

{

    unsigned long flags;

​

    spin_lock_irqsave(&ctx->wqh.lock, flags);

    ctx->expired = 1;

    ctx->ticks++;

    wake_up_locked_poll(&ctx->wqh, EPOLLIN);

    spin_unlock_irqrestore(&ctx->wqh.lock, flags);

}

​

static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)

{

    struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx,

                           t.tmr);

    timerfd_triggered(ctx);

    return HRTIMER_NORESTART;

}

​

static enum alarmtimer_restart timerfd_alarmproc(struct alarm *alarm,

    ktime_t now)

{

    struct timerfd_ctx *ctx = container_of(alarm, struct timerfd_ctx,

                           t.alarm);

    timerfd_triggered(ctx);

    return ALARMTIMER_NORESTART;

}

​

/*

 * Called when the clock was set to cancel the timers in the cancel

 * list. This will wake up processes waiting on these timers. The