/* * 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; 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.tv64 != 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(&ctx->wqh); 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 * wake-up requires ctx->ticks to be non zero, therefore we increment * it before calling wake_up_locked(). */void timerfd_clock_was_set(void){ ktime_t moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 }); struct timerfd_ctx *ctx; unsigned long flags; rcu_read_lock(); list_for_each_entry_rcu(ctx, &cancel_list, clist) { if (!ctx->might_cancel) continue; spin_lock_irqsave(&ctx->wqh.lock, flags); if (ctx->moffs.tv64 != moffs.tv64) { ctx->moffs.tv64 = KTIME_MAX; ctx->ticks++; wake_up_locked(&ctx->wqh); } spin_unlock_irqrestore(&ctx->wqh.lock, flags); } rcu_read_unlock();} static void timerfd_remove_cancel(struct timerfd_ctx *ctx){ if (ctx->might_cancel) { ctx->might_cancel = false; spin_lock(&cancel_lock); list_del_rcu(&ctx->clist); spin_unlock(&cancel_lock); }} static bool timerfd_canceled(struct timerfd_ctx *ctx){ if (!ctx->might_cancel || ctx->moffs.tv64 != KTIME_MAX) return false; ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 }); return true;} static void timerfd_setup_cancel(struct timerfd_ctx *ctx, int flags){ if ((ctx->clockid == CLOCK_REALTIME || ctx->clockid == CLOCK_REALTIME_ALARM) && (flags & TFD_TIMER_ABSTIME) && (flags & TFD_TIMER_CANCEL_ON_SET)) { if (!ctx->might_cancel) { ctx->might_cancel = true; spin_lock(&cancel_lock); list_add_rcu(&ctx->clist, &cancel_list); spin_unlock(&cancel_lock); } } else if (ctx->might_cancel) { timerfd_remove_cancel(ctx); }} static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx){ ktime_t remaining; if (isalarm(ctx)) remaining = alarm_expires_remaining(&ctx->t.alarm); else remaining = hrtimer_expires_remaining(&ctx->t.tmr); return remaining.tv64 < 0 ? ktime_set(0, 0): remaining;} static int timerfd_setup(struct timerfd_ctx *ctx, int flags, const struct itimerspec *ktmr){ enum hrtimer_mode htmode; ktime_t texp; int clockid = ctx->clockid; htmode = (flags & TFD_TIMER_ABSTIME) ? HRTIMER_MODE_ABS: HRTIMER_MODE_REL; texp = timespec_to_ktime(ktmr->it_value); ctx->expired = 0; ctx->ticks = 0; ctx->tintv = timespec_to_ktime(ktmr->it_interval); if (isalarm(ctx)) { alarm_init(&ctx->t.alarm, ctx->clockid == CLOCK_REALTIME_ALARM ? ALARM_REALTIME : ALARM_BOOTTIME, timerfd_alarmproc); } else { hrtimer_init(&ctx->t.tmr, clockid, htmode); hrtimer_set_expires(&ctx->t.tmr, texp); ctx->t.tmr.function = timerfd_tmrproc; } if (texp.tv64 != 0) { if (isalarm(ctx)) { if (flags & TFD_TIMER_ABSTIME) alarm_start(&ctx->t.alarm, texp); else alarm_start_relative(&ctx->t.alarm, texp); } else { hrtimer_start(&ctx->t.tmr, texp, htmode); } if (timerfd_canceled(ctx)) return -ECANCELED; } ctx->settime_flags = flags & TFD_SETTIME_FLAGS; return 0;} static int timerfd_release(struct inode *inode, struct file *file){ struct timerfd_ctx *ctx = file->private_data; timerfd_remove_cancel(ctx); if (isalarm(ctx)) alarm_cancel(&ctx->t.alarm); else hrtimer_cancel(&ctx->t.tmr); kfree_rcu(ctx, rcu); return 0;} static unsigned int timerfd_poll(struct file *file, poll_table *wait){ struct timerfd_ctx *ctx = file->private_data; unsigned int events = 0; unsigned long flags; poll_wait(file, &ctx->wqh, wait); spin_lock_irqsave(&ctx->wqh.lock, flags); if (ctx->ticks) events |= POLLIN; spin_unlock_irqrestore(&ctx->wqh.lock, flags); return events;} static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count, loff_t *ppos){ struct timerfd_ctx *ctx = file->private_data; ssize_t res; u64 ticks = 0; if (count < sizeof(ticks)) return -EINVAL; spin_lock_irq(&ctx->wqh.lock); if (file->f_flags & O_NONBLOCK) res = -EAGAIN; else res = wait_event_interruptible_locked_irq(ctx->wqh, ctx->ticks); /* * If clock has changed, we do not care about the * ticks and we do not rearm the timer. Userspace must * reevaluate anyway. */ if (timerfd_canceled(ctx)) { ctx->ticks = 0; ctx->expired = 0; res = -ECANCELED; } if (ctx->ticks) { ticks = ctx->ticks; if (ctx->expired && ctx->tintv.tv64) { /* * If tintv.tv64 != 0, this is a periodic timer that * needs to be re-armed. We avoid doing it in the timer * callback to avoid DoS attacks specifying a very * short timer period. */ if (isalarm(ctx)) { ticks += alarm_forward_now( &ctx->t.alarm, ctx->tintv) - 1; alarm_restart(&ctx->t.alarm); } else { ticks += hrtimer_forward_now(&ctx->t.tmr, ctx->tintv) - 1; hrtimer_restart(&ctx->t.tmr); } } ctx->expired = 0; ctx->ticks = 0; } spin_unlock_irq(&ctx->wqh.lock); if (ticks) res = put_user(ticks, (u64 __user *) buf) ? -EFAULT: sizeof(ticks); return res;} #ifdef CONFIG_PROC_FSstatic void timerfd_show(struct seq_file *m, struct file *file){ struct timerfd_ctx *ctx = file->private_data; struct itimerspec t; spin_lock_irq(&ctx->wqh.lock); t.it_value = ktime_to_timespec(timerfd_get_remaining(ctx)); t.it_interval = ktime_to_timespec(ctx->tintv); spin_unlock_irq(&ctx->wqh.lock); seq_printf(m, "clockid: %d\n" "ticks: %llu\n" "settime flags: 0%o\n" "it_value: (%llu, %llu)\n" "it_interval: (%llu, %llu)\n", ctx->clockid, (unsigned long long)ctx->ticks, ctx->settime_flags, (unsigned long long)t.it_value.tv_sec, (unsigned long long)t.it_value.tv_nsec, (unsigned long long)t.it_interval.tv_sec, (unsigned long long)t.it_interval.tv_nsec);}#else#define timerfd_show NULL#endif #ifdef CONFIG_CHECKPOINT_RESTOREstatic long timerfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg){ struct timerfd_ctx *ctx = file->private_data; int ret = 0; switch (cmd) { case TFD_IOC_SET_TICKS: { u64 ticks; if (copy_from_user(&ticks, (u64 __user *)arg, sizeof(ticks))) return -EFAULT; if (!ticks) return -EINVAL; spin_lock_irq(&ctx->wqh.lock); if (!timerfd_canceled(ctx)) { ctx->ticks = ticks; wake_up_locked(&ctx->wqh); } else ret = -ECANCELED; spin_unlock_irq(&ctx->wqh.lock); break; } default: ret = -ENOTTY; break; } return ret;}#else#define timerfd_ioctl NULL#endif static const struct file_operations timerfd_fops = { .release = timerfd_release, .poll = timerfd_poll, .read = timerfd_read, .llseek = noop_llseek, .show_fdinfo = timerfd_show, .unlocked_ioctl = timerfd_ioctl,}; static int timerfd_fget(int fd, struct fd *p){ struct fd f = fdget(fd); if (!f.file) return -EBADF; if (f.file->f_op != &timerfd_fops) { fdput(f); return -EINVAL; } *p = f; return 0;} SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags){ int ufd; struct timerfd_ctx *ctx; /* Check the TFD_* constants for consistency. */ BUILD_BUG_ON(TFD_CLOEXEC != O_CLOEXEC); BUILD_BUG_ON(TFD_NONBLOCK != O_NONBLOCK); if ((flags & ~TFD_CREATE_FLAGS) || (clockid != CLOCK_MONOTONIC && clockid != CLOCK_REALTIME && clockid != CLOCK_REALTIME_ALARM && clockid != CLOCK_BOOTTIME && clockid != CLOCK_BOOTTIME_ALARM)) return -EINVAL; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; init_waitqueue_head(&ctx->wqh); ctx->clockid = clockid; if (isalarm(ctx)) alarm_init(&ctx->t.alarm, ctx->clockid == CLOCK_REALTIME_ALARM ? ALARM_REALTIME : ALARM_BOOTTIME, timerfd_alarmproc); else hrtimer_init(&ctx->t.tmr, clockid, HRTIMER_MODE_ABS); ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 }); ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx, O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS)); if (ufd < 0) kfree(ctx); return ufd;} static int do_timerfd_settime(int ufd, int flags, const struct itimerspec *new, struct itimerspec *old){ struct fd f; struct timerfd_ctx *ctx; int ret; if ((flags & ~TFD_SETTIME_FLAGS) || !timespec_valid(&new->it_value) || !timespec_valid(&new->it_interval)) return -EINVAL; ret = timerfd_fget(ufd, &f); if (ret) return ret; ctx = f.file->private_data; timerfd_setup_cancel(ctx, flags); /* * We need to stop the existing timer before reprogramming * it to the new values. */ for (;;) { spin_lock_irq(&ctx->wqh.lock); if (isalarm(ctx)) { if (alarm_try_to_cancel(&ctx->t.alarm) >= 0) break; } else { if (hrtimer_try_to_cancel(&ctx->t.tmr) >= 0) break; } spin_unlock_irq(&ctx->wqh.lock); cpu_relax(); } /* * If the timer is expired and it's periodic, we need to advance it * because the caller may want to know the previous expiration time. * We do not update "ticks" and "expired" since the timer will be * re-programmed again in the following timerfd_setup() call. */ if (ctx->expired && ctx->tintv.tv64) { if (isalarm(ctx)) alarm_forward_now(&ctx->t.alarm, ctx->tintv); else hrtimer_forward_now(&ctx->t.tmr, ctx->tintv); } old->it_value = ktime_to_timespec(timerfd_get_remaining(ctx)); old->it_interval = ktime_to_timespec(ctx->tintv); /* * Re-program the timer to the new value ... */ ret = timerfd_setup(ctx, flags, new); spin_unlock_irq(&ctx->wqh.lock); fdput(f); return ret;} static int do_timerfd_gettime(int ufd, struct itimerspec *t){ struct fd f; struct timerfd_ctx *ctx; int ret = timerfd_fget(ufd, &f); if (ret) return ret; ctx = f.file->private_data; spin_lock_irq(&ctx->wqh.lock); if (ctx->expired && ctx->tintv.tv64) { ctx->expired = 0; if (isalarm(ctx)) { ctx->ticks += alarm_forward_now( &ctx->t.alarm, ctx->tintv) - 1; alarm_restart(&ctx->t.alarm); } else {Lines 1–500 of 568. Load more
/* * 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; 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.tv64 != 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(&ctx->wqh); 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 * wake-up requires ctx->ticks to be non zero, therefore we increment * it before calling wake_up_locked(). */ void timerfd_clock_was_set(void) { ktime_t moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 }); struct timerfd_ctx *ctx; unsigned long flags; rcu_read_lock(); list_for_each_entry_rcu(ctx, &cancel_list, clist) { if (!ctx->might_cancel) continue; spin_lock_irqsave(&ctx->wqh.lock, flags); if (ctx->moffs.tv64 != moffs.tv64) { ctx->moffs.tv64 = KTIME_MAX; ctx->ticks++; wake_up_locked(&ctx->wqh); } spin_unlock_irqrestore(&ctx->wqh.lock, flags); } rcu_read_unlock(); } static void timerfd_remove_cancel(struct timerfd_ctx *ctx) { if (ctx->might_cancel) { ctx->might_cancel = false; spin_lock(&cancel_lock); list_del_rcu(&ctx->clist); spin_unlock(&cancel_lock); } } static bool timerfd_canceled(struct timerfd_ctx *ctx) { if (!ctx->might_cancel || ctx->moffs.tv64 != KTIME_MAX) return false; ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 }); return true; } static void timerfd_setup_cancel(struct timerfd_ctx *ctx, int flags) { if ((ctx->clockid == CLOCK_REALTIME || ctx->clockid == CLOCK_REALTIME_ALARM) && (flags & TFD_TIMER_ABSTIME) && (flags & TFD_TIMER_CANCEL_ON_SET)) { if (!ctx->might_cancel) { ctx->might_cancel = true; spin_lock(&cancel_lock); list_add_rcu(&ctx->clist, &cancel_list); spin_unlock(&cancel_lock); } } else if (ctx->might_cancel) { timerfd_remove_cancel(ctx); } } static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx) { ktime_t remaining; if (isalarm(ctx)) remaining = alarm_expires_remaining(&ctx->t.alarm); else remaining = hrtimer_expires_remaining(&ctx->t.tmr); return remaining.tv64 < 0 ? ktime_set(0, 0): remaining; } static int timerfd_setup(struct timerfd_ctx *ctx, int flags, const struct itimerspec *ktmr) { enum hrtimer_mode htmode; ktime_t texp; int clockid = ctx->clockid; htmode = (flags & TFD_TIMER_ABSTIME) ? HRTIMER_MODE_ABS: HRTIMER_MODE_REL; texp = timespec_to_ktime(ktmr->it_value); ctx->expired = 0; ctx->ticks = 0; ctx->tintv = timespec_to_ktime(ktmr->it_interval); if (isalarm(ctx)) { alarm_init(&ctx->t.alarm, ctx->clockid == CLOCK_REALTIME_ALARM ? ALARM_REALTIME : ALARM_BOOTTIME, timerfd_alarmproc); } else { hrtimer_init(&ctx->t.tmr, clockid, htmode); hrtimer_set_expires(&ctx->t.tmr, texp); ctx->t.tmr.function = timerfd_tmrproc; } if (texp.tv64 != 0) { if (isalarm(ctx)) { if (flags & TFD_TIMER_ABSTIME) alarm_start(&ctx->t.alarm, texp); else alarm_start_relative(&ctx->t.alarm, texp); } else { hrtimer_start(&ctx->t.tmr, texp, htmode); } if (timerfd_canceled(ctx)) return -ECANCELED; } ctx->settime_flags = flags & TFD_SETTIME_FLAGS; return 0; } static int timerfd_release(struct inode *inode, struct file *file) { struct timerfd_ctx *ctx = file->private_data; timerfd_remove_cancel(ctx); if (isalarm(ctx)) alarm_cancel(&ctx->t.alarm); else hrtimer_cancel(&ctx->t.tmr); kfree_rcu(ctx, rcu); return 0; } static unsigned int timerfd_poll(struct file *file, poll_table *wait) { struct timerfd_ctx *ctx = file->private_data; unsigned int events = 0; unsigned long flags; poll_wait(file, &ctx->wqh, wait); spin_lock_irqsave(&ctx->wqh.lock, flags); if (ctx->ticks) events |= POLLIN; spin_unlock_irqrestore(&ctx->wqh.lock, flags); return events; } static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct timerfd_ctx *ctx = file->private_data; ssize_t res; u64 ticks = 0; if (count < sizeof(ticks)) return -EINVAL; spin_lock_irq(&ctx->wqh.lock); if (file->f_flags & O_NONBLOCK) res = -EAGAIN; else res = wait_event_interruptible_locked_irq(ctx->wqh, ctx->ticks); /* * If clock has changed, we do not care about the * ticks and we do not rearm the timer. Userspace must * reevaluate anyway. */ if (timerfd_canceled(ctx)) { ctx->ticks = 0; ctx->expired = 0; res = -ECANCELED; } if (ctx->ticks) { ticks = ctx->ticks; if (ctx->expired && ctx->tintv.tv64) { /* * If tintv.tv64 != 0, this is a periodic timer that * needs to be re-armed. We avoid doing it in the timer * callback to avoid DoS attacks specifying a very * short timer period. */ if (isalarm(ctx)) { ticks += alarm_forward_now( &ctx->t.alarm, ctx->tintv) - 1; alarm_restart(&ctx->t.alarm); } else { ticks += hrtimer_forward_now(&ctx->t.tmr, ctx->tintv) - 1; hrtimer_restart(&ctx->t.tmr); } } ctx->expired = 0; ctx->ticks = 0; } spin_unlock_irq(&ctx->wqh.lock); if (ticks) res = put_user(ticks, (u64 __user *) buf) ? -EFAULT: sizeof(ticks); return res; } #ifdef CONFIG_PROC_FS static void timerfd_show(struct seq_file *m, struct file *file) { struct timerfd_ctx *ctx = file->private_data; struct itimerspec t; spin_lock_irq(&ctx->wqh.lock); t.it_value = ktime_to_timespec(timerfd_get_remaining(ctx)); t.it_interval = ktime_to_timespec(ctx->tintv); spin_unlock_irq(&ctx->wqh.lock); seq_printf(m, "clockid: %d\n" "ticks: %llu\n" "settime flags: 0%o\n" "it_value: (%llu, %llu)\n" "it_interval: (%llu, %llu)\n", ctx->clockid, (unsigned long long)ctx->ticks, ctx->settime_flags, (unsigned long long)t.it_value.tv_sec, (unsigned long long)t.it_value.tv_nsec, (unsigned long long)t.it_interval.tv_sec, (unsigned long long)t.it_interval.tv_nsec); } #else #define timerfd_show NULL #endif #ifdef CONFIG_CHECKPOINT_RESTORE static long timerfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct timerfd_ctx *ctx = file->private_data; int ret = 0; switch (cmd) { case TFD_IOC_SET_TICKS: { u64 ticks; if (copy_from_user(&ticks, (u64 __user *)arg, sizeof(ticks))) return -EFAULT; if (!ticks) return -EINVAL; spin_lock_irq(&ctx->wqh.lock); if (!timerfd_canceled(ctx)) { ctx->ticks = ticks; wake_up_locked(&ctx->wqh); } else ret = -ECANCELED; spin_unlock_irq(&ctx->wqh.lock); break; } default: ret = -ENOTTY; break; } return ret; } #else #define timerfd_ioctl NULL #endif static const struct file_operations timerfd_fops = { .release = timerfd_release, .poll = timerfd_poll, .read = timerfd_read, .llseek = noop_llseek, .show_fdinfo = timerfd_show, .unlocked_ioctl = timerfd_ioctl, }; static int timerfd_fget(int fd, struct fd *p) { struct fd f = fdget(fd); if (!f.file) return -EBADF; if (f.file->f_op != &timerfd_fops) { fdput(f); return -EINVAL; } *p = f; return 0; } SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) { int ufd; struct timerfd_ctx *ctx; /* Check the TFD_* constants for consistency. */ BUILD_BUG_ON(TFD_CLOEXEC != O_CLOEXEC); BUILD_BUG_ON(TFD_NONBLOCK != O_NONBLOCK); if ((flags & ~TFD_CREATE_FLAGS) || (clockid != CLOCK_MONOTONIC && clockid != CLOCK_REALTIME && clockid != CLOCK_REALTIME_ALARM && clockid != CLOCK_BOOTTIME && clockid != CLOCK_BOOTTIME_ALARM)) return -EINVAL; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; init_waitqueue_head(&ctx->wqh); ctx->clockid = clockid; if (isalarm(ctx)) alarm_init(&ctx->t.alarm, ctx->clockid == CLOCK_REALTIME_ALARM ? ALARM_REALTIME : ALARM_BOOTTIME, timerfd_alarmproc); else hrtimer_init(&ctx->t.tmr, clockid, HRTIMER_MODE_ABS); ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 }); ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx, O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS)); if (ufd < 0) kfree(ctx); return ufd; } static int do_timerfd_settime(int ufd, int flags, const struct itimerspec *new, struct itimerspec *old) { struct fd f; struct timerfd_ctx *ctx; int ret; if ((flags & ~TFD_SETTIME_FLAGS) || !timespec_valid(&new->it_value) || !timespec_valid(&new->it_interval)) return -EINVAL; ret = timerfd_fget(ufd, &f); if (ret) return ret; ctx = f.file->private_data; timerfd_setup_cancel(ctx, flags); /* * We need to stop the existing timer before reprogramming * it to the new values. */ for (;;) { spin_lock_irq(&ctx->wqh.lock); if (isalarm(ctx)) { if (alarm_try_to_cancel(&ctx->t.alarm) >= 0) break; } else { if (hrtimer_try_to_cancel(&ctx->t.tmr) >= 0) break; } spin_unlock_irq(&ctx->wqh.lock); cpu_relax(); } /* * If the timer is expired and it's periodic, we need to advance it * because the caller may want to know the previous expiration time. * We do not update "ticks" and "expired" since the timer will be * re-programmed again in the following timerfd_setup() call. */ if (ctx->expired && ctx->tintv.tv64) { if (isalarm(ctx)) alarm_forward_now(&ctx->t.alarm, ctx->tintv); else hrtimer_forward_now(&ctx->t.tmr, ctx->tintv); } old->it_value = ktime_to_timespec(timerfd_get_remaining(ctx)); old->it_interval = ktime_to_timespec(ctx->tintv); /* * Re-program the timer to the new value ... */ ret = timerfd_setup(ctx, flags, new); spin_unlock_irq(&ctx->wqh.lock); fdput(f); return ret; } static int do_timerfd_gettime(int ufd, struct itimerspec *t) { struct fd f; struct timerfd_ctx *ctx; int ret = timerfd_fget(ufd, &f); if (ret) return ret; ctx = f.file->private_data; spin_lock_irq(&ctx->wqh.lock); if (ctx->expired && ctx->tintv.tv64) { ctx->expired = 0; if (isalarm(ctx)) { ctx->ticks += alarm_forward_now( &ctx->t.alarm, ctx->tintv) - 1; alarm_restart(&ctx->t.alarm); } else {