Re: [patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
On Thu, 2007-03-15 at 16:02 -0700, Davide Libenzi wrote: > > > + /* > > > + * When we call this, the initialization must be complete, since > > > + * aino_getfd() will install the fd. > > > + */ > > > + error = aino_getfd(, , , "[timerfd]", > > > +_fops, ctx); > > > + if (error) > > > + goto err_ctxfree; > > > > Again: Please turn this around. No need to start the timer before we > > know, that everything works. > > The timerfd_setup() is not locked, so we need to make sure everything is > setup, before advertising the fd (and aino_getfd does that). Right. Did not think about the bad boys peeking at file descriptors :) tglx - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
On Thu, 2007-03-15 at 16:02 -0700, Davide Libenzi wrote: + /* + * When we call this, the initialization must be complete, since + * aino_getfd() will install the fd. + */ + error = aino_getfd(ufd, inode, file, [timerfd], +timerfd_fops, ctx); + if (error) + goto err_ctxfree; Again: Please turn this around. No need to start the timer before we know, that everything works. The timerfd_setup() is not locked, so we need to make sure everything is setup, before advertising the fd (and aino_getfd does that). Right. Did not think about the bad boys peeking at file descriptors :) tglx - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
On Thu, 15 Mar 2007, Thomas Gleixner wrote:
> Davide,
>
> On Wed, 2007-03-14 at 15:19 -0700, Davide Libenzi wrote:
>
> > +static int timerfd_tmrproc(struct hrtimer *htmr)
> > +{
> > + struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
> > + int rval = HRTIMER_NORESTART;
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(>lock, flags);
> > + ctx->ticks++;
> > + wake_up_locked(>wqh);
> > + if (ctx->tintv.tv64 != 0) {
> > + hrtimer_forward(htmr, htmr->base->softirq_time, ctx->tintv);
>
> Sorry, I missed that in the first reviews. Please use
> hrtimer_cb_get_time(htmr) instead of htmr->base->softirq_time, so this
> is high res timer safe.
Heh, I was actually looking for a function instead of peeking over the
tiemr strcture, but 2.6.20 did not have. Rebased over 2.6.21-rc3 now, so I
can use it.
> > + rval = HRTIMER_RESTART;
> > + }
> > + spin_unlock_irqrestore(>lock, flags);
> > +
> > + return rval;
> > +}
> > +
> > +
> > +static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
> > +const struct itimerspec *ktmr)
> > +{
>
> Make this void, returns 0 anyway
Ack
> > + enum hrtimer_mode htmode;
> > +
> > + htmode = (flags & TFD_TIMER_ABSTIME) ? HRTIMER_ABS: HRTIMER_REL;
> > +
> > + ctx->ticks = 0;
> > + ctx->clockid = clockid;
> > + ctx->flags = flags;
> > + ctx->texp = timespec_to_ktime(ktmr->it_value);
>
> clockid is stored in the timer on setup, so no need to store it again.
> expiry time and flags are not used after setup.
>
> Please remove those fields.
Ack
> > + if (ufd == -1) {
> > + ctx = kmem_cache_alloc(timerfd_ctx_cachep, GFP_KERNEL);
> > + if (!ctx)
> > + return -ENOMEM;
> > +
> > + init_waitqueue_head(>wqh);
> > + spin_lock_init(>lock);
> > + ctx->clockid = -1;
> > +
> > + error = timerfd_setup(ctx, clockid, flags, );
> > + if (error)
> > + goto err_ctxfree;
>
> Timer setup can not fail
Ack, the new version can't.
> > + /*
> > +* When we call this, the initialization must be complete, since
> > +* aino_getfd() will install the fd.
> > +*/
> > + error = aino_getfd(, , , "[timerfd]",
> > + _fops, ctx);
> > + if (error)
> > + goto err_ctxfree;
>
> Again: Please turn this around. No need to start the timer before we
> know, that everything works.
The timerfd_setup() is not locked, so we need to make sure everything is
setup, before advertising the fd (and aino_getfd does that).
> > + kmem_cache_free(timerfd_ctx_cachep, ctx);
> > +}
> > +
> > +
> > +static int timerfd_close(struct inode *inode, struct file *file)
> > +{
> > + timerfd_cleanup(file->private_data);
> > + return 0;
> > +}
> > +
>
> Please move the timerfd_cleanup code into close().
I usually prefer to have a cleanup function that works on the file's data,
but I moved the code in the release function now.
Thx for the review! I'll repost a new version based on 2.6.21-rc3 ...
- Davide
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Re: [patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
Davide,
On Wed, 2007-03-14 at 15:19 -0700, Davide Libenzi wrote:
> +static int timerfd_tmrproc(struct hrtimer *htmr)
> +{
> + struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
> + int rval = HRTIMER_NORESTART;
> + unsigned long flags;
> +
> + spin_lock_irqsave(>lock, flags);
> + ctx->ticks++;
> + wake_up_locked(>wqh);
> + if (ctx->tintv.tv64 != 0) {
> + hrtimer_forward(htmr, htmr->base->softirq_time, ctx->tintv);
Sorry, I missed that in the first reviews. Please use
hrtimer_cb_get_time(htmr) instead of htmr->base->softirq_time, so this
is high res timer safe.
> + rval = HRTIMER_RESTART;
> + }
> + spin_unlock_irqrestore(>lock, flags);
> +
> + return rval;
> +}
> +
> +
> +static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
> + const struct itimerspec *ktmr)
> +{
Make this void, returns 0 anyway
> + enum hrtimer_mode htmode;
> +
> + htmode = (flags & TFD_TIMER_ABSTIME) ? HRTIMER_ABS: HRTIMER_REL;
> +
> + ctx->ticks = 0;
> + ctx->clockid = clockid;
> + ctx->flags = flags;
> + ctx->texp = timespec_to_ktime(ktmr->it_value);
clockid is stored in the timer on setup, so no need to store it again.
expiry time and flags are not used after setup.
Please remove those fields.
> + ctx->tintv = timespec_to_ktime(ktmr->it_interval);
> + hrtimer_init(>tmr, ctx->clockid, htmode);
> + ctx->tmr.expires = ctx->texp;
> + ctx->tmr.function = timerfd_tmrproc;
> + if (ctx->texp.tv64 != 0)
> + hrtimer_start(>tmr, ctx->texp, htmode);
> +
> + return 0;
> +}
> +
> + if (ufd == -1) {
> + ctx = kmem_cache_alloc(timerfd_ctx_cachep, GFP_KERNEL);
> + if (!ctx)
> + return -ENOMEM;
> +
> + init_waitqueue_head(>wqh);
> + spin_lock_init(>lock);
> + ctx->clockid = -1;
> +
> + error = timerfd_setup(ctx, clockid, flags, );
> + if (error)
> + goto err_ctxfree;
Timer setup can not fail
> + /*
> + * When we call this, the initialization must be complete, since
> + * aino_getfd() will install the fd.
> + */
> + error = aino_getfd(, , , "[timerfd]",
> +_fops, ctx);
> + if (error)
> + goto err_ctxfree;
Again: Please turn this around. No need to start the timer before we
know, that everything works.
> + } else {
> + file = fget(ufd);
> + if (!file)
> + return -EBADF;
> + ctx = file->private_data;
> + if (file->f_op != _fops) {
> + fput(file);
> + return -EINVAL;
> + }
> + /*
> + * We need to stop the existing timer before reprogramming
> + * it to the new values.
> + */
> + for (;;) {
> + spin_lock_irq(>lock);
> + if (hrtimer_try_to_cancel(>tmr) >= 0)
> + break;
> + spin_unlock_irq(>lock);
> + cpu_relax();
> + }
> + /*
> + * Re-program the timer to the new value ...
> + */
> + error = timerfd_setup(ctx, clockid, flags, );
Timer setup can not fail
> + spin_unlock_irq(>lock);
> + fput(file);
> + if (error)
> + return error;
> + }
> +
> + return ufd;
> +
> +err_ctxfree:
> + timerfd_cleanup(ctx);
> + return error;
> +}
> +
> +
> +static void timerfd_cleanup(struct timerfd_ctx *ctx)
> +{
> + if (ctx->clockid >= 0)
> + hrtimer_cancel(>tmr);
You don't have a file descriptor, when the setup failed. So the timer is
always initialized.
> + kmem_cache_free(timerfd_ctx_cachep, ctx);
> +}
> +
> +
> +static int timerfd_close(struct inode *inode, struct file *file)
> +{
> + timerfd_cleanup(file->private_data);
> + return 0;
> +}
> +
Please move the timerfd_cleanup code into close().
tglx
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Re: [patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
Davide,
On Wed, 2007-03-14 at 15:19 -0700, Davide Libenzi wrote:
+static int timerfd_tmrproc(struct hrtimer *htmr)
+{
+ struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
+ int rval = HRTIMER_NORESTART;
+ unsigned long flags;
+
+ spin_lock_irqsave(ctx-lock, flags);
+ ctx-ticks++;
+ wake_up_locked(ctx-wqh);
+ if (ctx-tintv.tv64 != 0) {
+ hrtimer_forward(htmr, htmr-base-softirq_time, ctx-tintv);
Sorry, I missed that in the first reviews. Please use
hrtimer_cb_get_time(htmr) instead of htmr-base-softirq_time, so this
is high res timer safe.
+ rval = HRTIMER_RESTART;
+ }
+ spin_unlock_irqrestore(ctx-lock, flags);
+
+ return rval;
+}
+
+
+static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
+ const struct itimerspec *ktmr)
+{
Make this void, returns 0 anyway
+ enum hrtimer_mode htmode;
+
+ htmode = (flags TFD_TIMER_ABSTIME) ? HRTIMER_ABS: HRTIMER_REL;
+
+ ctx-ticks = 0;
+ ctx-clockid = clockid;
+ ctx-flags = flags;
+ ctx-texp = timespec_to_ktime(ktmr-it_value);
clockid is stored in the timer on setup, so no need to store it again.
expiry time and flags are not used after setup.
Please remove those fields.
+ ctx-tintv = timespec_to_ktime(ktmr-it_interval);
+ hrtimer_init(ctx-tmr, ctx-clockid, htmode);
+ ctx-tmr.expires = ctx-texp;
+ ctx-tmr.function = timerfd_tmrproc;
+ if (ctx-texp.tv64 != 0)
+ hrtimer_start(ctx-tmr, ctx-texp, htmode);
+
+ return 0;
+}
+
+ if (ufd == -1) {
+ ctx = kmem_cache_alloc(timerfd_ctx_cachep, GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ init_waitqueue_head(ctx-wqh);
+ spin_lock_init(ctx-lock);
+ ctx-clockid = -1;
+
+ error = timerfd_setup(ctx, clockid, flags, ktmr);
+ if (error)
+ goto err_ctxfree;
Timer setup can not fail
+ /*
+ * When we call this, the initialization must be complete, since
+ * aino_getfd() will install the fd.
+ */
+ error = aino_getfd(ufd, inode, file, [timerfd],
+timerfd_fops, ctx);
+ if (error)
+ goto err_ctxfree;
Again: Please turn this around. No need to start the timer before we
know, that everything works.
+ } else {
+ file = fget(ufd);
+ if (!file)
+ return -EBADF;
+ ctx = file-private_data;
+ if (file-f_op != timerfd_fops) {
+ fput(file);
+ return -EINVAL;
+ }
+ /*
+ * We need to stop the existing timer before reprogramming
+ * it to the new values.
+ */
+ for (;;) {
+ spin_lock_irq(ctx-lock);
+ if (hrtimer_try_to_cancel(ctx-tmr) = 0)
+ break;
+ spin_unlock_irq(ctx-lock);
+ cpu_relax();
+ }
+ /*
+ * Re-program the timer to the new value ...
+ */
+ error = timerfd_setup(ctx, clockid, flags, ktmr);
Timer setup can not fail
+ spin_unlock_irq(ctx-lock);
+ fput(file);
+ if (error)
+ return error;
+ }
+
+ return ufd;
+
+err_ctxfree:
+ timerfd_cleanup(ctx);
+ return error;
+}
+
+
+static void timerfd_cleanup(struct timerfd_ctx *ctx)
+{
+ if (ctx-clockid = 0)
+ hrtimer_cancel(ctx-tmr);
You don't have a file descriptor, when the setup failed. So the timer is
always initialized.
+ kmem_cache_free(timerfd_ctx_cachep, ctx);
+}
+
+
+static int timerfd_close(struct inode *inode, struct file *file)
+{
+ timerfd_cleanup(file-private_data);
+ return 0;
+}
+
Please move the timerfd_cleanup code into close().
tglx
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Re: [patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
On Thu, 15 Mar 2007, Thomas Gleixner wrote:
Davide,
On Wed, 2007-03-14 at 15:19 -0700, Davide Libenzi wrote:
+static int timerfd_tmrproc(struct hrtimer *htmr)
+{
+ struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
+ int rval = HRTIMER_NORESTART;
+ unsigned long flags;
+
+ spin_lock_irqsave(ctx-lock, flags);
+ ctx-ticks++;
+ wake_up_locked(ctx-wqh);
+ if (ctx-tintv.tv64 != 0) {
+ hrtimer_forward(htmr, htmr-base-softirq_time, ctx-tintv);
Sorry, I missed that in the first reviews. Please use
hrtimer_cb_get_time(htmr) instead of htmr-base-softirq_time, so this
is high res timer safe.
Heh, I was actually looking for a function instead of peeking over the
tiemr strcture, but 2.6.20 did not have. Rebased over 2.6.21-rc3 now, so I
can use it.
+ rval = HRTIMER_RESTART;
+ }
+ spin_unlock_irqrestore(ctx-lock, flags);
+
+ return rval;
+}
+
+
+static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
+const struct itimerspec *ktmr)
+{
Make this void, returns 0 anyway
Ack
+ enum hrtimer_mode htmode;
+
+ htmode = (flags TFD_TIMER_ABSTIME) ? HRTIMER_ABS: HRTIMER_REL;
+
+ ctx-ticks = 0;
+ ctx-clockid = clockid;
+ ctx-flags = flags;
+ ctx-texp = timespec_to_ktime(ktmr-it_value);
clockid is stored in the timer on setup, so no need to store it again.
expiry time and flags are not used after setup.
Please remove those fields.
Ack
+ if (ufd == -1) {
+ ctx = kmem_cache_alloc(timerfd_ctx_cachep, GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ init_waitqueue_head(ctx-wqh);
+ spin_lock_init(ctx-lock);
+ ctx-clockid = -1;
+
+ error = timerfd_setup(ctx, clockid, flags, ktmr);
+ if (error)
+ goto err_ctxfree;
Timer setup can not fail
Ack, the new version can't.
+ /*
+* When we call this, the initialization must be complete, since
+* aino_getfd() will install the fd.
+*/
+ error = aino_getfd(ufd, inode, file, [timerfd],
+ timerfd_fops, ctx);
+ if (error)
+ goto err_ctxfree;
Again: Please turn this around. No need to start the timer before we
know, that everything works.
The timerfd_setup() is not locked, so we need to make sure everything is
setup, before advertising the fd (and aino_getfd does that).
+ kmem_cache_free(timerfd_ctx_cachep, ctx);
+}
+
+
+static int timerfd_close(struct inode *inode, struct file *file)
+{
+ timerfd_cleanup(file-private_data);
+ return 0;
+}
+
Please move the timerfd_cleanup code into close().
I usually prefer to have a cleanup function that works on the file's data,
but I moved the code in the release function now.
Thx for the review! I'll repost a new version based on 2.6.21-rc3 ...
- Davide
-
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[patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
This patch introduces a new system call for timers events delivered
though file descriptors. This allows timer event to be used with
standard POSIX poll(2), select(2) and read(2). As a consequence of
supporting the Linux f_op->poll subsystem, they can be used with
epoll(2) too.
The system call is defined as:
int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr);
The "ufd" parameter allows for re-use (re-programming) of an existing
timerfd w/out going through the close/open cycle (same as signalfd).
If "ufd" is -1, s new file descriptor will be created, otherwise the
existing "ufd" will be re-programmed.
The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME.
The time specified in the "utmr->it_value" parameter is the expiry
time for the timer.
If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute
time, otherwise it's a relative time.
If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0,
tv_nsec == 0), this is the period at which the following ticks should
be generated.
The "utmr->it_interval" should be set to zero if only one tick is requested.
Setting the "utmr->it_value" to zero will disable the timer, or will create
a timerfd without the timer enabled.
The function returns the new (or same, in case "ufd" is a valid timerfd
descriptor) file, or -1 in case of error.
As stated before, the timerfd file descriptor supports poll(2), select(2)
and epoll(2). When a timer event happened on the timerfd, a POLLIN mask
will be returned.
The read(2) call can be used, and it will return a u32 variable holding
the number of "ticks" that happened on the interface since the last call
to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN
will be returned if no ticks happened.
A quick test program, shows timerfd working correctly on my amd64 box:
http://www.xmailserver.org/timerfd-test.c
Signed-off-by: Davide Libenzi
- Davide
Index: linux-2.6.20.ep2/fs/timerfd.c
===
--- /dev/null 1970-01-01 00:00:00.0 +
+++ linux-2.6.20.ep2/fs/timerfd.c 2007-03-12 11:47:01.0 -0700
@@ -0,0 +1,273 @@
+/*
+ * fs/timerfd.c
+ *
+ * Copyright (C) 2007 Davide Libenzi
+ *
+ *
+ * Thanks to Thomas Gleixner for code review and useful comments.
+ *
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+#include
+
+
+
+struct timerfd_ctx {
+ struct hrtimer tmr;
+ int clockid;
+ int flags;
+ ktime_t texp, tintv;
+ spinlock_t lock;
+ wait_queue_head_t wqh;
+ unsigned long ticks;
+};
+
+
+static int timerfd_tmrproc(struct hrtimer *htmr);
+static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
+const struct itimerspec *ktmr);
+static void timerfd_cleanup(struct timerfd_ctx *ctx);
+static int timerfd_close(struct inode *inode, struct file *file);
+static unsigned int timerfd_poll(struct file *file, poll_table *wait);
+static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
+ loff_t *ppos);
+
+
+
+static const struct file_operations timerfd_fops = {
+ .release= timerfd_close,
+ .poll = timerfd_poll,
+ .read = timerfd_read,
+};
+static struct kmem_cache *timerfd_ctx_cachep;
+
+
+
+static int timerfd_tmrproc(struct hrtimer *htmr)
+{
+ struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
+ int rval = HRTIMER_NORESTART;
+ unsigned long flags;
+
+ spin_lock_irqsave(>lock, flags);
+ ctx->ticks++;
+ wake_up_locked(>wqh);
+ if (ctx->tintv.tv64 != 0) {
+ hrtimer_forward(htmr, htmr->base->softirq_time, ctx->tintv);
+ rval = HRTIMER_RESTART;
+ }
+ spin_unlock_irqrestore(>lock, flags);
+
+ return rval;
+}
+
+
+static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
+const struct itimerspec *ktmr)
+{
+ enum hrtimer_mode htmode;
+
+ htmode = (flags & TFD_TIMER_ABSTIME) ? HRTIMER_ABS: HRTIMER_REL;
+
+ ctx->ticks = 0;
+ ctx->clockid = clockid;
+ ctx->flags = flags;
+ ctx->texp = timespec_to_ktime(ktmr->it_value);
+ ctx->tintv = timespec_to_ktime(ktmr->it_interval);
+ hrtimer_init(>tmr, ctx->clockid, htmode);
+ ctx->tmr.expires = ctx->texp;
+ ctx->tmr.function = timerfd_tmrproc;
+ if (ctx->texp.tv64 != 0)
+ hrtimer_start(>tmr, ctx->texp, htmode);
+
+ return 0;
+}
+
+
+asmlinkage long sys_timerfd(int ufd, int clockid, int flags,
+ const struct itimerspec __user *utmr)
+{
+ int error;
+ struct timerfd_ctx *ctx;
+ struct file *file;
+ struct inode *inode;
+ struct itimerspec ktmr;
+
+
[patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
This patch introduces a new system call for timers events delivered
though file descriptors. This allows timer event to be used with
standard POSIX poll(2), select(2) and read(2). As a consequence of
supporting the Linux f_op-poll subsystem, they can be used with
epoll(2) too.
The system call is defined as:
int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr);
The ufd parameter allows for re-use (re-programming) of an existing
timerfd w/out going through the close/open cycle (same as signalfd).
If ufd is -1, s new file descriptor will be created, otherwise the
existing ufd will be re-programmed.
The clockid parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME.
The time specified in the utmr-it_value parameter is the expiry
time for the timer.
If the TFD_TIMER_ABSTIME flag is set in flags, this is an absolute
time, otherwise it's a relative time.
If the time specified in the utmr-it_interval is not zero (.tv_sec == 0,
tv_nsec == 0), this is the period at which the following ticks should
be generated.
The utmr-it_interval should be set to zero if only one tick is requested.
Setting the utmr-it_value to zero will disable the timer, or will create
a timerfd without the timer enabled.
The function returns the new (or same, in case ufd is a valid timerfd
descriptor) file, or -1 in case of error.
As stated before, the timerfd file descriptor supports poll(2), select(2)
and epoll(2). When a timer event happened on the timerfd, a POLLIN mask
will be returned.
The read(2) call can be used, and it will return a u32 variable holding
the number of ticks that happened on the interface since the last call
to read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN
will be returned if no ticks happened.
A quick test program, shows timerfd working correctly on my amd64 box:
http://www.xmailserver.org/timerfd-test.c
Signed-off-by: Davide Libenzi davidel@xmailserver.org
- Davide
Index: linux-2.6.20.ep2/fs/timerfd.c
===
--- /dev/null 1970-01-01 00:00:00.0 +
+++ linux-2.6.20.ep2/fs/timerfd.c 2007-03-12 11:47:01.0 -0700
@@ -0,0 +1,273 @@
+/*
+ * fs/timerfd.c
+ *
+ * Copyright (C) 2007 Davide Libenzi davidel@xmailserver.org
+ *
+ *
+ * Thanks to Thomas Gleixner for code review and useful comments.
+ *
+ */
+
+#include linux/file.h
+#include linux/poll.h
+#include linux/slab.h
+#include linux/init.h
+#include linux/fs.h
+#include linux/mount.h
+#include linux/module.h
+#include linux/kernel.h
+#include linux/signal.h
+#include linux/list.h
+#include linux/spinlock.h
+#include linux/time.h
+#include linux/hrtimer.h
+#include linux/jiffies.h
+#include linux/anon_inodes.h
+#include linux/timerfd.h
+
+#include asm/uaccess.h
+
+
+
+struct timerfd_ctx {
+ struct hrtimer tmr;
+ int clockid;
+ int flags;
+ ktime_t texp, tintv;
+ spinlock_t lock;
+ wait_queue_head_t wqh;
+ unsigned long ticks;
+};
+
+
+static int timerfd_tmrproc(struct hrtimer *htmr);
+static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
+const struct itimerspec *ktmr);
+static void timerfd_cleanup(struct timerfd_ctx *ctx);
+static int timerfd_close(struct inode *inode, struct file *file);
+static unsigned int timerfd_poll(struct file *file, poll_table *wait);
+static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
+ loff_t *ppos);
+
+
+
+static const struct file_operations timerfd_fops = {
+ .release= timerfd_close,
+ .poll = timerfd_poll,
+ .read = timerfd_read,
+};
+static struct kmem_cache *timerfd_ctx_cachep;
+
+
+
+static int timerfd_tmrproc(struct hrtimer *htmr)
+{
+ struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
+ int rval = HRTIMER_NORESTART;
+ unsigned long flags;
+
+ spin_lock_irqsave(ctx-lock, flags);
+ ctx-ticks++;
+ wake_up_locked(ctx-wqh);
+ if (ctx-tintv.tv64 != 0) {
+ hrtimer_forward(htmr, htmr-base-softirq_time, ctx-tintv);
+ rval = HRTIMER_RESTART;
+ }
+ spin_unlock_irqrestore(ctx-lock, flags);
+
+ return rval;
+}
+
+
+static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
+const struct itimerspec *ktmr)
+{
+ enum hrtimer_mode htmode;
+
+ htmode = (flags TFD_TIMER_ABSTIME) ? HRTIMER_ABS: HRTIMER_REL;
+
+ ctx-ticks = 0;
+ ctx-clockid = clockid;
+ ctx-flags = flags;
+ ctx-texp = timespec_to_ktime(ktmr-it_value);
+ ctx-tintv = timespec_to_ktime(ktmr-it_interval);
+ hrtimer_init(ctx-tmr, ctx-clockid, htmode);
+ ctx-tmr.expires = ctx-texp;
+ ctx-tmr.function = timerfd_tmrproc;
+ if (ctx-texp.tv64 != 0)
+ hrtimer_start(ctx-tmr, ctx-texp, htmode);
+
+ return 0;
+}
+
+
+asmlinkage long
