Timer notifications.

Timer notifications can be used for fine grained per-process time 
management, since interval timers are very inconvenient to use, 
and they are limited.

This subsystem uses high-resolution timers.

id.raw[0] is used as number of seconds
id.raw[1] is used as number of nanoseconds

Signed-off-by: Evgeniy Polyakov <[EMAIL PROTECTED]>

diff --git a/kernel/kevent/kevent_timer.c b/kernel/kevent/kevent_timer.c
new file mode 100644
index 0000000..c21a155
--- /dev/null
+++ b/kernel/kevent/kevent_timer.c
@@ -0,0 +1,114 @@
+/*
+ * 2006 Copyright (c) Evgeniy Polyakov <[EMAIL PROTECTED]>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/hrtimer.h>
+#include <linux/jiffies.h>
+#include <linux/kevent.h>
+
+struct kevent_timer
+{
+       struct hrtimer          ktimer;
+       struct kevent_storage   ktimer_storage;
+       struct kevent           *ktimer_event;
+};
+
+static int kevent_timer_func(struct hrtimer *timer)
+{
+       struct kevent_timer *t = container_of(timer, struct kevent_timer, 
ktimer);
+       struct kevent *k = t->ktimer_event;
+
+       kevent_storage_ready(&t->ktimer_storage, NULL, KEVENT_MASK_ALL);
+       hrtimer_forward(timer, timer->base->softirq_time,
+                       ktime_set(k->event.id.raw[0], k->event.id.raw[1]));
+       return HRTIMER_RESTART;
+}
+
+static struct lock_class_key kevent_timer_key;
+
+static int kevent_timer_enqueue(struct kevent *k)
+{
+       int err;
+       struct kevent_timer *t;
+
+       t = kmalloc(sizeof(struct kevent_timer), GFP_KERNEL);
+       if (!t)
+               return -ENOMEM;
+
+       hrtimer_init(&t->ktimer, CLOCK_MONOTONIC, HRTIMER_REL);
+       t->ktimer.expires = ktime_set(k->event.id.raw[0], k->event.id.raw[1]);
+       t->ktimer.function = kevent_timer_func;
+       t->ktimer_event = k;
+
+       err = kevent_storage_init(&t->ktimer, &t->ktimer_storage);
+       if (err)
+               goto err_out_free;
+       lockdep_set_class(&t->ktimer_storage.lock, &kevent_timer_key);
+
+       err = kevent_storage_enqueue(&t->ktimer_storage, k);
+       if (err)
+               goto err_out_st_fini;
+
+       hrtimer_start(&t->ktimer, t->ktimer.expires, HRTIMER_REL);
+
+       return 0;
+
+err_out_st_fini:
+       kevent_storage_fini(&t->ktimer_storage);
+err_out_free:
+       kfree(t);
+
+       return err;
+}
+
+static int kevent_timer_dequeue(struct kevent *k)
+{
+       struct kevent_storage *st = k->st;
+       struct kevent_timer *t = container_of(st, struct kevent_timer, 
ktimer_storage);
+
+       hrtimer_cancel(&t->ktimer);
+       kevent_storage_dequeue(st, k);
+       kfree(t);
+
+       return 0;
+}
+
+static int kevent_timer_callback(struct kevent *k)
+{
+       k->event.ret_data[0] = jiffies_to_msecs(jiffies);
+       return 1;
+}
+
+static int __init kevent_init_timer(void)
+{
+       struct kevent_callbacks tc = {
+               .callback = &kevent_timer_callback,
+               .enqueue = &kevent_timer_enqueue,
+               .dequeue = &kevent_timer_dequeue,
+               .flags = 0,
+       };
+
+       return kevent_add_callbacks(&tc, KEVENT_TIMER);
+}
+module_init(kevent_init_timer);
+

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