mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 22:02:28 +00:00
timerfd: Add alarm timers
Add support for clocks CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM, thereby enabling wakeup alarm timers via file descriptors. Signed-off-by: Todd Poynor <toddpoynor@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
Todd Poynor
John Stultz
parent
6cffe00f7d
commit
11ffa9d606
131
fs/timerfd.c
131
fs/timerfd.c
@ -8,6 +8,7 @@
|
||||
*
|
||||
*/
|
||||
|
||||
#include <linux/alarmtimer.h>
|
||||
#include <linux/file.h>
|
||||
#include <linux/poll.h>
|
||||
#include <linux/init.h>
|
||||
@ -26,7 +27,10 @@
|
||||
#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;
|
||||
@ -41,14 +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);
|
||||
@ -56,10 +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
|
||||
@ -107,8 +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);
|
||||
@ -124,7 +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;
|
||||
}
|
||||
|
||||
@ -142,11 +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;
|
||||
}
|
||||
@ -158,7 +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;
|
||||
}
|
||||
@ -215,9 +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;
|
||||
@ -259,7 +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);
|
||||
@ -268,7 +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,
|
||||
@ -305,8 +371,14 @@ static int do_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();
|
||||
}
|
||||
@ -317,8 +389,12 @@ static int do_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);
|
||||
}
|
||||
|
||||
old->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
|
||||
old->it_interval = ktime_to_timespec(ctx->tintv);
|
||||
@ -345,9 +421,18 @@ static int do_timerfd_gettime(int ufd, struct itimerspec *t)
|
||||
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);
|
||||
}
|
||||
}
|
||||
t->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
|
||||
t->it_interval = ktime_to_timespec(ctx->tintv);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user