diff options
Diffstat (limited to 'fs/timerfd.c')
-rw-r--r-- | fs/timerfd.c | 261 |
1 files changed, 195 insertions, 66 deletions
diff --git a/fs/timerfd.c b/fs/timerfd.c index dffeb3795af1..929312180dd0 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -8,6 +8,7 @@ * */ +#include <linux/alarmtimer.h> #include <linux/file.h> #include <linux/poll.h> #include <linux/init.h> @@ -22,10 +23,14 @@ #include <linux/anon_inodes.h> #include <linux/timerfd.h> #include <linux/syscalls.h> +#include <linux/compat.h> #include <linux/rcupdate.h> struct timerfd_ctx { - struct hrtimer tmr; + union { + struct hrtimer tmr; + struct alarm alarm; + } t; ktime_t tintv; ktime_t moffs; wait_queue_head_t wqh; @@ -40,14 +45,19 @@ struct timerfd_ctx { 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 enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr) +static void timerfd_triggered(struct timerfd_ctx *ctx) { - struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr); unsigned long flags; spin_lock_irqsave(&ctx->wqh.lock, flags); @@ -55,10 +65,25 @@ static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr) 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 @@ -106,8 +131,9 @@ static bool timerfd_canceled(struct timerfd_ctx *ctx) static void timerfd_setup_cancel(struct timerfd_ctx *ctx, int flags) { - if (ctx->clockid == CLOCK_REALTIME && (flags & TFD_TIMER_ABSTIME) && - (flags & TFD_TIMER_CANCEL_ON_SET)) { + 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); @@ -123,7 +149,11 @@ static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx) { ktime_t remaining; - remaining = hrtimer_expires_remaining(&ctx->tmr); + 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; } @@ -141,11 +171,28 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags, ctx->expired = 0; ctx->ticks = 0; ctx->tintv = timespec_to_ktime(ktmr->it_interval); - hrtimer_init(&ctx->tmr, clockid, htmode); - hrtimer_set_expires(&ctx->tmr, texp); - ctx->tmr.function = timerfd_tmrproc; + + 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) { - hrtimer_start(&ctx->tmr, texp, htmode); + 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; } @@ -157,7 +204,11 @@ static int timerfd_release(struct inode *inode, struct file *file) struct timerfd_ctx *ctx = file->private_data; timerfd_remove_cancel(ctx); - hrtimer_cancel(&ctx->tmr); + + if (isalarm(ctx)) + alarm_cancel(&ctx->t.alarm); + else + hrtimer_cancel(&ctx->t.tmr); kfree_rcu(ctx, rcu); return 0; } @@ -214,9 +265,15 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count, * callback to avoid DoS attacks specifying a very * short timer period. */ - ticks += hrtimer_forward_now(&ctx->tmr, - ctx->tintv) - 1; - hrtimer_restart(&ctx->tmr); + 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; @@ -234,19 +291,17 @@ static const struct file_operations timerfd_fops = { .llseek = noop_llseek, }; -static struct file *timerfd_fget(int fd) +static int timerfd_fget(int fd, struct fd *p) { - struct file *file; - - file = fget(fd); - if (!file) - return ERR_PTR(-EBADF); - if (file->f_op != &timerfd_fops) { - fput(file); - return ERR_PTR(-EINVAL); + struct fd f = fdget(fd); + if (!f.file) + return -EBADF; + if (f.file->f_op != &timerfd_fops) { + fdput(f); + return -EINVAL; } - - return file; + *p = f; + return 0; } SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) @@ -260,7 +315,9 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) if ((flags & ~TFD_CREATE_FLAGS) || (clockid != CLOCK_MONOTONIC && - clockid != CLOCK_REALTIME)) + clockid != CLOCK_REALTIME && + clockid != CLOCK_REALTIME_ALARM && + clockid != CLOCK_BOOTTIME_ALARM)) return -EINVAL; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); @@ -269,7 +326,15 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) init_waitqueue_head(&ctx->wqh); ctx->clockid = clockid; - hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS); + + 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_get_monotonic_offset(); ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx, @@ -280,27 +345,23 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) return ufd; } -SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags, - const struct itimerspec __user *, utmr, - struct itimerspec __user *, otmr) +static int do_timerfd_settime(int ufd, int flags, + const struct itimerspec *new, + struct itimerspec *old) { - struct file *file; + struct fd f; struct timerfd_ctx *ctx; - struct itimerspec ktmr, kotmr; int ret; - if (copy_from_user(&ktmr, utmr, sizeof(ktmr))) - return -EFAULT; - if ((flags & ~TFD_SETTIME_FLAGS) || - !timespec_valid(&ktmr.it_value) || - !timespec_valid(&ktmr.it_interval)) + !timespec_valid(&new->it_value) || + !timespec_valid(&new->it_interval)) return -EINVAL; - file = timerfd_fget(ufd); - if (IS_ERR(file)) - return PTR_ERR(file); - ctx = file->private_data; + ret = timerfd_fget(ufd, &f); + if (ret) + return ret; + ctx = f.file->private_data; timerfd_setup_cancel(ctx, flags); @@ -310,8 +371,14 @@ SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags, */ for (;;) { spin_lock_irq(&ctx->wqh.lock); - if (hrtimer_try_to_cancel(&ctx->tmr) >= 0) - break; + + 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(); } @@ -322,48 +389,110 @@ SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags, * 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) - hrtimer_forward_now(&ctx->tmr, ctx->tintv); + 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); + } - kotmr.it_value = ktime_to_timespec(timerfd_get_remaining(ctx)); - kotmr.it_interval = ktime_to_timespec(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, &ktmr); + ret = timerfd_setup(ctx, flags, new); spin_unlock_irq(&ctx->wqh.lock); - fput(file); - if (otmr && copy_to_user(otmr, &kotmr, sizeof(kotmr))) - return -EFAULT; - + fdput(f); return ret; } -SYSCALL_DEFINE2(timerfd_gettime, int, ufd, struct itimerspec __user *, otmr) +static int do_timerfd_gettime(int ufd, struct itimerspec *t) { - struct file *file; + struct fd f; struct timerfd_ctx *ctx; - struct itimerspec kotmr; - - file = timerfd_fget(ufd); - if (IS_ERR(file)) - return PTR_ERR(file); - ctx = file->private_data; + 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; - ctx->ticks += - hrtimer_forward_now(&ctx->tmr, ctx->tintv) - 1; - hrtimer_restart(&ctx->tmr); + + if (isalarm(ctx)) { + ctx->ticks += + alarm_forward_now( + &ctx->t.alarm, ctx->tintv) - 1; + alarm_restart(&ctx->t.alarm); + } else { + ctx->ticks += + hrtimer_forward_now(&ctx->t.tmr, ctx->tintv) + - 1; + hrtimer_restart(&ctx->t.tmr); + } } - kotmr.it_value = ktime_to_timespec(timerfd_get_remaining(ctx)); - kotmr.it_interval = ktime_to_timespec(ctx->tintv); + t->it_value = ktime_to_timespec(timerfd_get_remaining(ctx)); + t->it_interval = ktime_to_timespec(ctx->tintv); spin_unlock_irq(&ctx->wqh.lock); - fput(file); + fdput(f); + return 0; +} + +SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags, + const struct itimerspec __user *, utmr, + struct itimerspec __user *, otmr) +{ + struct itimerspec new, old; + int ret; + + if (copy_from_user(&new, utmr, sizeof(new))) + return -EFAULT; + ret = do_timerfd_settime(ufd, flags, &new, &old); + if (ret) + return ret; + if (otmr && copy_to_user(otmr, &old, sizeof(old))) + return -EFAULT; + return ret; +} + +SYSCALL_DEFINE2(timerfd_gettime, int, ufd, struct itimerspec __user *, otmr) +{ + struct itimerspec kotmr; + int ret = do_timerfd_gettime(ufd, &kotmr); + if (ret) + return ret; return copy_to_user(otmr, &kotmr, sizeof(kotmr)) ? -EFAULT: 0; } +#ifdef CONFIG_COMPAT +COMPAT_SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags, + const struct compat_itimerspec __user *, utmr, + struct compat_itimerspec __user *, otmr) +{ + struct itimerspec new, old; + int ret; + + if (get_compat_itimerspec(&new, utmr)) + return -EFAULT; + ret = do_timerfd_settime(ufd, flags, &new, &old); + if (ret) + return ret; + if (otmr && put_compat_itimerspec(otmr, &old)) + return -EFAULT; + return ret; +} + +COMPAT_SYSCALL_DEFINE2(timerfd_gettime, int, ufd, + struct compat_itimerspec __user *, otmr) +{ + struct itimerspec kotmr; + int ret = do_timerfd_gettime(ufd, &kotmr); + if (ret) + return ret; + return put_compat_itimerspec(otmr, &kotmr) ? -EFAULT: 0; +} +#endif |