Subject: [take3 1/4] kevent: Core files.

From: Evgeniy Polyakov <[email-masked]>
Date: Thu, 3 Aug 2006 13:46:00 +0400

Core files.

This patch includes core kevent files:
 - userspace controlling
 - kernelspace interfaces
 - initialization
 - notification state machines

It might also inlclude parts from other subsystem (like network related
syscalls, so it is possible that it will not compile without other
patches applied).

Signed-off-by: Evgeniy Polyakov <[email-masked]>

diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
index dd63d47..0af988a 100644
--- a/arch/i386/kernel/syscall_table.S
+++ b/arch/i386/kernel/syscall_table.S
@@ -317,3 +317,7 @@ ENTRY(sys_call_table)
 	.long sys_tee			/* 315 */
 	.long sys_vmsplice
 	.long sys_move_pages
+	.long sys_aio_recv
+	.long sys_aio_send
+	.long sys_kevent_get_events
+	.long sys_kevent_ctl
diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
index 5d4a7d1..e157ad4 100644
--- a/arch/x86_64/ia32/ia32entry.S
+++ b/arch/x86_64/ia32/ia32entry.S
@@ -713,4 +713,8 @@ #endif
 	.quad sys_tee
 	.quad compat_sys_vmsplice
 	.quad compat_sys_move_pages
+	.quad sys_aio_recv
+	.quad sys_aio_send
+	.quad sys_kevent_get_events
+	.quad sys_kevent_ctl
 ia32_syscall_end:		
diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index fc1c8dd..a76e50d 100644
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -323,10 +323,14 @@ #define __NR_sync_file_range	314
 #define __NR_tee		315
 #define __NR_vmsplice		316
 #define __NR_move_pages		317
+#define __NR_aio_recv		318
+#define __NR_aio_send		319
+#define __NR_kevent_get_events	320
+#define __NR_kevent_ctl		321
 
 #ifdef __KERNEL__
 
-#define NR_syscalls 318
+#define NR_syscalls 322
 
 /*
  * user-visible error numbers are in the range -1 - -128: see
diff --git a/include/asm-x86_64/unistd.h b/include/asm-x86_64/unistd.h
index 94387c9..9a0b581 100644
--- a/include/asm-x86_64/unistd.h
+++ b/include/asm-x86_64/unistd.h
@@ -619,10 +619,18 @@ #define __NR_vmsplice		278
 __SYSCALL(__NR_vmsplice, sys_vmsplice)
 #define __NR_move_pages		279
 __SYSCALL(__NR_move_pages, sys_move_pages)
+#define __NR_aio_recv		280
+__SYSCALL(__NR_aio_recv, sys_aio_recv)
+#define __NR_aio_send		281
+__SYSCALL(__NR_aio_send, sys_aio_send)
+#define __NR_kevent_get_events	282
+__SYSCALL(__NR_kevent_get_events, sys_kevent_get_events)
+#define __NR_kevent_ctl		283
+__SYSCALL(__NR_kevent_ctl, sys_kevent_ctl)
 
 #ifdef __KERNEL__
 
-#define __NR_syscall_max __NR_move_pages
+#define __NR_syscall_max __NR_kevent_ctl
 
 #ifndef __NO_STUBS
 
diff --git a/include/linux/kevent.h b/include/linux/kevent.h
new file mode 100644
index 0000000..cb09726
--- /dev/null
+++ b/include/linux/kevent.h
@@ -0,0 +1,277 @@
+/*
+ * 	kevent.h
+ * 
+ * 2006 Copyright (c) Evgeniy Polyakov <[email-masked]>
+ * 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
+ */
+
+#ifndef __KEVENT_H
+#define __KEVENT_H
+
+/*
+ * Kevent request flags.
+ */
+
+#define KEVENT_REQ_ONESHOT	0x1		/* Process this event only once and then dequeue. */
+
+/*
+ * Kevent return flags.
+ */
+#define KEVENT_RET_BROKEN	0x1		/* Kevent is broken. */
+#define KEVENT_RET_DONE		0x2		/* Kevent processing was finished successfully. */
+
+/*
+ * Kevent type set.
+ */
+#define KEVENT_SOCKET 		0
+#define KEVENT_INODE		1
+#define KEVENT_TIMER		2
+#define KEVENT_POLL		3
+#define KEVENT_NAIO		4
+#define KEVENT_AIO		5
+#define	KEVENT_MAX		6
+
+/*
+ * Per-type event sets.
+ * Number of per-event sets should be exactly as number of kevent types.
+ */
+
+/*
+ * Timer events.
+ */
+#define	KEVENT_TIMER_FIRED	0x1
+
+/*
+ * Socket/network asynchronous IO events.
+ */
+#define	KEVENT_SOCKET_RECV	0x1
+#define	KEVENT_SOCKET_ACCEPT	0x2
+#define	KEVENT_SOCKET_SEND	0x4
+
+/*
+ * Inode events.
+ */
+#define	KEVENT_INODE_CREATE	0x1
+#define	KEVENT_INODE_REMOVE	0x2
+
+/*
+ * Poll events.
+ */
+#define	KEVENT_POLL_POLLIN	0x0001
+#define	KEVENT_POLL_POLLPRI	0x0002
+#define	KEVENT_POLL_POLLOUT	0x0004
+#define	KEVENT_POLL_POLLERR	0x0008
+#define	KEVENT_POLL_POLLHUP	0x0010
+#define	KEVENT_POLL_POLLNVAL	0x0020
+
+#define	KEVENT_POLL_POLLRDNORM	0x0040
+#define	KEVENT_POLL_POLLRDBAND	0x0080
+#define	KEVENT_POLL_POLLWRNORM	0x0100
+#define	KEVENT_POLL_POLLWRBAND	0x0200
+#define	KEVENT_POLL_POLLMSG	0x0400
+#define	KEVENT_POLL_POLLREMOVE	0x1000
+
+/*
+ * Asynchronous IO events.
+ */
+#define	KEVENT_AIO_BIO		0x1
+
+#define KEVENT_MASK_ALL		0xffffffff	/* Mask of all possible event values. */
+#define KEVENT_MASK_EMPTY	0x0		/* Empty mask of ready events. */
+
+struct kevent_id
+{
+	__u32		raw[2];
+};
+
+struct ukevent
+{
+	struct kevent_id	id;			/* Id of this request, e.g. socket number, file descriptor and so on... */
+	__u32			type;			/* Event type, e.g. KEVENT_SOCK, KEVENT_INODE, KEVENT_TIMER and so on... */
+	__u32			event;			/* Event itself, e.g. SOCK_ACCEPT, INODE_CREATED, TIMER_FIRED... */
+	__u32			req_flags;		/* Per-event request flags */
+	__u32			ret_flags;		/* Per-event return flags */
+	__u32			ret_data[2];		/* Event return data. Event originator fills it with anything it likes. */
+	union {
+		__u32		user[2];		/* User's data. It is not used, just copied to/from user. */
+		void		*ptr;
+	};
+};
+
+#define	KEVENT_CTL_ADD 		0
+#define	KEVENT_CTL_REMOVE	1
+#define	KEVENT_CTL_MODIFY	2
+#define	KEVENT_CTL_INIT		3
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/wait.h>
+#include <linux/kevent_storage.h>
+
+#define KEVENT_MAX_EVENTS	4096
+#define KEVENT_MIN_BUFFS_ALLOC	3
+
+struct inode;
+struct dentry;
+struct sock;
+
+struct kevent;
+struct kevent_storage;
+typedef int (* kevent_callback_t)(struct kevent *);
+
+/* @callback is called each time new event has been caught. */
+/* @enqueue is called each time new event is queued. */
+/* @dequeue is called each time event is dequeued. */
+
+struct kevent_callbacks {
+	kevent_callback_t	callback, enqueue, dequeue;
+};
+
+struct kevent
+{
+	struct ukevent		event;
+	spinlock_t		ulock;			/* This lock protects ukevent manipulations, e.g. ret_flags changes. */
+
+	struct list_head	kevent_entry;		/* Entry of user's queue. */
+	struct list_head	storage_entry;		/* Entry of origin's queue. */
+	struct list_head	ready_entry;		/* Entry of user's ready. */
+
+	struct kevent_user	*user;			/* User who requested this kevent. */
+	struct kevent_storage	*st;			/* Kevent container. */
+
+	struct kevent_callbacks	callbacks;
+
+	void			*priv;			/* Private data for different storages. 
+							 * poll()/select storage has a list of wait_queue_t containers 
+							 * for each ->poll() { poll_wait()' } here.
+							 */
+};
+
+extern struct kevent_callbacks kevent_registered_callbacks[];
+
+#define KEVENT_HASH_MASK	0xff
+
+struct kevent_user
+{
+	struct list_head	kevent_list[KEVENT_HASH_MASK+1];
+	spinlock_t		kevent_lock;
+	unsigned int		kevent_num;		/* Number of queued kevents. */
+
+	struct list_head	ready_list;		/* List of ready kevents. */
+	unsigned int		ready_num;		/* Number of ready kevents. */
+	spinlock_t 		ready_lock;		/* Protects all manipulations with ready queue. */
+
+	unsigned int		max_ready_num;		/* Requested number of kevents. */
+
+	struct mutex		ctl_mutex;		/* Protects against simultaneous kevent_user control manipulations. */
+	struct mutex		wait_mutex;		/* Protects against simultaneous kevent_user waits. */
+	wait_queue_head_t	wait;			/* Wait until some events are ready. */
+
+	atomic_t		refcnt;			/* Reference counter, increased for each new kevent. */
+	
+	unsigned long		*pring;			/* Array of pages forming mapped ring buffer */
+
+#ifdef CONFIG_KEVENT_USER_STAT
+	unsigned long		im_num;
+	unsigned long		wait_num;
+	unsigned long		total;
+#endif
+};
+
+struct kevent *kevent_alloc(gfp_t mask);
+void kevent_free(struct kevent *k);
+int kevent_enqueue(struct kevent *k);
+int kevent_dequeue(struct kevent *k);
+int kevent_init(struct kevent *k);
+void kevent_requeue(struct kevent *k);
+int kevent_break(struct kevent *k);
+
+void kevent_user_ring_add_event(struct kevent *k);
+
+void kevent_storage_ready(struct kevent_storage *st, 
+		kevent_callback_t ready_callback, u32 event);
+int kevent_storage_init(void *origin, struct kevent_storage *st);
+void kevent_storage_fini(struct kevent_storage *st);
+int kevent_storage_enqueue(struct kevent_storage *st, struct kevent *k);
+void kevent_storage_dequeue(struct kevent_storage *st, struct kevent *k);
+
+int kevent_user_add_ukevent(struct ukevent *uk, struct kevent_user *u);
+
+#ifdef CONFIG_KEVENT_INODE
+void kevent_inode_notify(struct inode *inode, u32 event);
+void kevent_inode_notify_parent(struct dentry *dentry, u32 event);
+void kevent_inode_remove(struct inode *inode);
+#else
+static inline void kevent_inode_notify(struct inode *inode, u32 event)
+{
+}
+static inline void kevent_inode_notify_parent(struct dentry *dentry, u32 event)
+{
+}
+static inline void kevent_inode_remove(struct inode *inode)
+{
+}
+#endif /* CONFIG_KEVENT_INODE */
+#ifdef CONFIG_KEVENT_SOCKET
+
+void kevent_socket_notify(struct sock *sock, u32 event);
+int kevent_socket_dequeue(struct kevent *k);
+int kevent_socket_enqueue(struct kevent *k);
+#define sock_async(__sk) sock_flag(__sk, SOCK_ASYNC)
+#else
+static inline void kevent_socket_notify(struct sock *sock, u32 event)
+{
+}
+#define sock_async(__sk)	({ (void)__sk; 0; })
+#endif
+
+#ifdef CONFIG_KEVENT_USER_STAT
+static inline void kevent_user_stat_init(struct kevent_user *u)
+{
+	u->wait_num = u->im_num = u->total = 0;
+}
+static inline void kevent_user_stat_print(struct kevent_user *u)
+{
+	pr_debug("%s: u=%p, wait=%lu, immediately=%lu, total=%lu.\n", 
+			__func__, u, u->wait_num, u->im_num, u->total);
+}
+static inline void kevent_user_stat_increase_im(struct kevent_user *u)
+{
+	u->im_num++;
+}
+static inline void kevent_user_stat_increase_wait(struct kevent_user *u)
+{
+	u->wait_num++;
+}
+static inline void kevent_user_stat_increase_total(struct kevent_user *u)
+{
+	u->total++;
+}
+#else
+#define kevent_user_stat_print(u)		({ (void) u;})
+#define kevent_user_stat_init(u)		({ (void) u;})
+#define kevent_user_stat_increase_im(u)		({ (void) u;})
+#define kevent_user_stat_increase_wait(u)	({ (void) u;})
+#define kevent_user_stat_increase_total(u)	({ (void) u;})
+#endif
+
+#endif /* __KERNEL__ */
+#endif /* __KEVENT_H */
diff --git a/include/linux/kevent_storage.h b/include/linux/kevent_storage.h
new file mode 100644
index 0000000..bd891f0
--- /dev/null
+++ b/include/linux/kevent_storage.h
@@ -0,0 +1,12 @@
+#ifndef __KEVENT_STORAGE_H
+#define __KEVENT_STORAGE_H
+
+struct kevent_storage
+{
+	void			*origin;		/* Originator's pointer, e.g. struct sock or struct file. Can be NULL. */
+	struct list_head	list;			/* List of queued kevents. */
+	unsigned int		qlen;			/* Number of queued kevents. */
+	spinlock_t		lock;			/* Protects users queue. */
+};
+
+#endif /* __KEVENT_STORAGE_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 008f04c..143f3b5 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -597,4 +597,9 @@ asmlinkage long sys_get_robust_list(int 
 asmlinkage long sys_set_robust_list(struct robust_list_head __user *head,
 				    size_t len);
 
+asmlinkage long sys_aio_recv(int ctl_fd, int s, void __user *buf, size_t size, unsigned flags);
+asmlinkage long sys_aio_send(int ctl_fd, int s, void __user *buf, size_t size, unsigned flags);
+asmlinkage long sys_kevent_get_events(int ctl_fd, unsigned int min, unsigned int max, 
+		unsigned int timeout, void __user *buf, unsigned flags);
+asmlinkage long sys_kevent_ctl(int ctl_fd, unsigned int cmd, unsigned int num, void __user *buf);
 #endif
diff --git a/init/Kconfig b/init/Kconfig
index a099fc6..c550fcc 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -218,6 +218,8 @@ config AUDITSYSCALL
 	  such as SELinux.  To use audit's filesystem watch feature, please
 	  ensure that INOTIFY is configured.
 
+source "kernel/kevent/Kconfig"
+
 config IKCONFIG
 	bool "Kernel .config support"
 	---help---
diff --git a/kernel/Makefile b/kernel/Makefile
index d62ec66..2d7a6dd 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_DETECT_SOFTLOCKUP) += softl
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
+obj-$(CONFIG_KEVENT) += kevent/
 obj-$(CONFIG_RELAY) += relay.o
 obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
 obj-$(CONFIG_TASKSTATS) += taskstats.o
diff --git a/kernel/kevent/Kconfig b/kernel/kevent/Kconfig
new file mode 100644
index 0000000..88b35af
--- /dev/null
+++ b/kernel/kevent/Kconfig
@@ -0,0 +1,57 @@
+config KEVENT
+	bool "Kernel event notification mechanism"
+	help
+	  This option enables event queue mechanism.
+	  It can be used as replacement for poll()/select(), AIO callback invocations,
+	  advanced timer notifications and other kernel object status changes.
+
+config KEVENT_USER_STAT
+	bool "Kevent user statistic"
+	depends on KEVENT
+	default N
+	help
+	  This option will turn kevent_user statistic collection on.
+	  Statistic data includes total number of kevent, number of kevents which are ready
+	  immediately at insertion time and number of kevents which were removed through
+	  readiness completion. It will be printed each time control kevent descriptor
+	  is closed.
+
+config KEVENT_SOCKET
+	bool "Kernel event notifications for sockets"
+	depends on NET && KEVENT
+	help
+	  This option enables notifications through KEVENT subsystem of 
+	  sockets operations, like new packet receiving conditions, ready for accept
+  	  conditions and so on.
+	
+config KEVENT_INODE
+	bool "Kernel event notifications for inodes"
+	depends on KEVENT
+	help
+	  This option enables notifications through KEVENT subsystem of 
+	  inode operations, like file creation, removal and so on.
+
+config KEVENT_TIMER
+	bool "Kernel event notifications for timers"
+	depends on KEVENT
+	help
+	  This option allows to use timers through KEVENT subsystem.
+
+config KEVENT_POLL
+	bool "Kernel event notifications for poll()/select()"
+	depends on KEVENT
+	help
+	  This option allows to use kevent subsystem for poll()/select() notifications.
+
+config KEVENT_NAIO
+	bool "Network asynchronous IO"
+	depends on KEVENT && KEVENT_SOCKET
+	help
+	  This option enables kevent based network asynchronous IO subsystem.
+
+config KEVENT_AIO
+	bool "Asynchronous IO"
+	depends on KEVENT
+	help
+	  This option allows to use kevent subsystem for AIO operations.
+	  AIO read is currently supported.
diff --git a/kernel/kevent/Makefile b/kernel/kevent/Makefile
new file mode 100644
index 0000000..d1ef9ba
--- /dev/null
+++ b/kernel/kevent/Makefile
@@ -0,0 +1,7 @@
+obj-y := kevent.o kevent_user.o
+obj-$(CONFIG_KEVENT_SOCKET) += kevent_socket.o
+obj-$(CONFIG_KEVENT_INODE) += kevent_inode.o
+obj-$(CONFIG_KEVENT_TIMER) += kevent_timer.o
+obj-$(CONFIG_KEVENT_POLL) += kevent_poll.o
+obj-$(CONFIG_KEVENT_NAIO) += kevent_naio.o
+obj-$(CONFIG_KEVENT_AIO) += kevent_aio.o
diff --git a/kernel/kevent/kevent.c b/kernel/kevent/kevent.c
new file mode 100644
index 0000000..8c71ca9
--- /dev/null
+++ b/kernel/kevent/kevent.c
@@ -0,0 +1,248 @@
+/*
+ * 	kevent.c
+ * 
+ * 2006 Copyright (c) Evgeniy Polyakov <[email-masked]>
+ * 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/mempool.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/kevent.h>
+
+static kmem_cache_t *kevent_cache;
+
+/*
+ * Attempts to add an event into appropriate origin's queue.
+ * Returns positive value if this event is ready immediately,
+ * negative value in case of error and zero if event has been queued.
+ * ->enqueue() callback must increase origin's reference counter.
+ */
+int kevent_enqueue(struct kevent *k)
+{
+	if (k->event.type >= KEVENT_MAX)
+		return -E2BIG;
+
+	if (!k->callbacks.enqueue) {
+		kevent_break(k);
+		return -EINVAL;
+	}
+	
+	return k->callbacks.enqueue(k);
+}
+
+/*
+ * Remove event from the appropriate queue.
+ * ->dequeue() callback must decrease origin's reference counter.
+ */
+int kevent_dequeue(struct kevent *k)
+{
+	if (k->event.type >= KEVENT_MAX)
+		return -E2BIG;
+	
+	if (!k->callbacks.dequeue) {
+		kevent_break(k);
+		return -EINVAL;
+	}
+
+	return k->callbacks.dequeue(k);
+}
+
+int kevent_break(struct kevent *k)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&k->ulock, flags);
+	k->event.ret_flags |= KEVENT_RET_BROKEN;
+	spin_unlock_irqrestore(&k->ulock, flags);
+	return 0;
+}
+
+struct kevent_callbacks kevent_registered_callbacks[KEVENT_MAX];
+
+/*
+ * Must be called before event is going to be added into some origin's queue.
+ * Initializes ->enqueue(), ->dequeue() and ->callback() callbacks.
+ * If failed, kevent should not be used or kevent_enqueue() will fail to add
+ * this kevent into origin's queue with setting
+ * KEVENT_RET_BROKEN flag in kevent->event.ret_flags.
+ */
+int kevent_init(struct kevent *k)
+{
+	spin_lock_init(&k->ulock);
+	k->kevent_entry.next = LIST_POISON1;
+	k->storage_entry.next = LIST_POISON1;
+	k->ready_entry.next = LIST_POISON1;
+
+	if (k->event.type >= KEVENT_MAX)
+		return -E2BIG;
+
+	k->callbacks = kevent_registered_callbacks[k->event.type];
+	if (!k->callbacks.callback) {
+		kevent_break(k);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Called from ->enqueue() callback when reference counter for given
+ * origin (socket, inode...) has been increased.
+ */
+int kevent_storage_enqueue(struct kevent_storage *st, struct kevent *k)
+{
+	unsigned long flags;
+
+	k->st = st;
+	spin_lock_irqsave(&st->lock, flags);
+	list_add_tail(&k->storage_entry, &st->list);
+	st->qlen++;
+	spin_unlock_irqrestore(&st->lock, flags);
+	return 0;
+}
+
+/*
+ * Dequeue kevent from origin's queue. 
+ * It does not decrease origin's reference counter in any way 
+ * and must be called before it, so storage itself must be valid.
+ * It is called from ->dequeue() callback.
+ */
+void kevent_storage_dequeue(struct kevent_storage *st, struct kevent *k)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&st->lock, flags);
+	if (k->storage_entry.next != LIST_POISON1) {
+		list_del(&k->storage_entry);
+		st->qlen--;
+	}
+	spin_unlock_irqrestore(&st->lock, flags);
+}
+
+static void __kevent_requeue(struct kevent *k, u32 event)
+{
+	int err, rem = 0;
+	unsigned long flags;
+
+	err = k->callbacks.callback(k);
+
+	spin_lock_irqsave(&k->ulock, flags);
+	if (err > 0) {
+		k->event.ret_flags |= KEVENT_RET_DONE;
+	} else if (err < 0) {
+		k->event.ret_flags |= KEVENT_RET_BROKEN;
+		k->event.ret_flags |= KEVENT_RET_DONE;
+	}
+	rem = (k->event.req_flags & KEVENT_REQ_ONESHOT);
+	if (!err)
+		err = (k->event.ret_flags & (KEVENT_RET_BROKEN|KEVENT_RET_DONE));
+	spin_unlock_irqrestore(&k->ulock, flags);
+
+	if (err) {
+		if (rem) {
+			list_del(&k->storage_entry);
+			k->st->qlen--;
+		}
+		
+		spin_lock_irqsave(&k->user->ready_lock, flags);
+		if (k->ready_entry.next == LIST_POISON1) {
+			kevent_user_ring_add_event(k);
+			list_add_tail(&k->ready_entry, &k->user->ready_list);
+			k->user->ready_num++;
+		}
+		spin_unlock_irqrestore(&k->user->ready_lock, flags);
+		wake_up(&k->user->wait);
+	}
+}
+
+void kevent_requeue(struct kevent *k)
+{
+	unsigned long flags;
+	
+	spin_lock_irqsave(&k->st->lock, flags);
+	__kevent_requeue(k, 0);
+	spin_unlock_irqrestore(&k->st->lock, flags);
+}
+
+/*
+ * Called each time some activity in origin (socket, inode...) is noticed.
+ */
+void kevent_storage_ready(struct kevent_storage *st, 
+		kevent_callback_t ready_callback, u32 event)
+{
+	struct kevent *k, *n;
+
+	spin_lock(&st->lock);
+	list_for_each_entry_safe(k, n, &st->list, storage_entry) {
+		if (ready_callback)
+			ready_callback(k);
+
+		if (event & k->event.event)
+			__kevent_requeue(k, event);
+	}
+	spin_unlock(&st->lock);
+}
+
+int kevent_storage_init(void *origin, struct kevent_storage *st)
+{
+	spin_lock_init(&st->lock);
+	st->origin = origin;
+	st->qlen = 0;
+	INIT_LIST_HEAD(&st->list);
+	return 0;
+}
+
+void kevent_storage_fini(struct kevent_storage *st)
+{
+	kevent_storage_ready(st, kevent_break, KEVENT_MASK_ALL);
+}
+
+struct kevent *kevent_alloc(gfp_t mask)
+{
+	return kmem_cache_alloc(kevent_cache, mask);
+}
+
+void kevent_free(struct kevent *k)
+{
+	kmem_cache_free(kevent_cache, k);
+}
+
+static int __init kevent_sys_init(void)
+{
+	int i;
+
+	kevent_cache = kmem_cache_create("kevent_cache", 
+			sizeof(struct kevent), 0, 0, NULL, NULL);
+	if (!kevent_cache)
+		panic("kevent: Unable to create a cache.\n");
+
+	for (i=0; i<ARRAY_SIZE(kevent_registered_callbacks); ++i) {
+		struct kevent_callbacks *c = &kevent_registered_callbacks[i];
+
+		c->callback = c->enqueue = c->dequeue = NULL;
+	}
+	
+	return 0;
+}
+
+late_initcall(kevent_sys_init);
diff --git a/kernel/kevent/kevent_user.c b/kernel/kevent/kevent_user.c
new file mode 100644
index 0000000..87ac367
--- /dev/null
+++ b/kernel/kevent/kevent_user.c
@@ -0,0 +1,876 @@
+/*
+ * 	kevent_user.c
+ * 
+ * 2006 Copyright (c) Evgeniy Polyakov <[email-masked]>
+ * 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/module.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/device.h>
+#include <linux/poll.h>
+#include <linux/kevent.h>
+#include <linux/jhash.h>
+#include <asm/io.h>
+
+static struct class *kevent_user_class;
+static char kevent_name[] = "kevent";
+static int kevent_user_major;
+
+static int kevent_user_open(struct inode *, struct file *);
+static int kevent_user_release(struct inode *, struct file *);
+static unsigned int kevent_user_poll(struct file *, struct poll_table_struct *);
+static int kevnet_user_mmap(struct file *, struct vm_area_struct *);
+
+static struct file_operations kevent_user_fops = {
+	.mmap		= kevnet_user_mmap,
+	.open		= kevent_user_open,
+	.release	= kevent_user_release,
+	.poll		= kevent_user_poll,
+	.owner		= THIS_MODULE,
+};
+
+static int kevent_get_sb(struct file_system_type *fs_type, 
+		int flags, const char *dev_name, void *data, struct vfsmount *mnt)
+{
+	/* So original magic... */
+	return get_sb_pseudo(fs_type, kevent_name, NULL, 0xabcdef, mnt);	
+}
+
+static struct file_system_type kevent_fs_type = {
+	.name		= kevent_name,
+	.get_sb		= kevent_get_sb,
+	.kill_sb	= kill_anon_super,
+};
+
+static struct vfsmount *kevent_mnt;
+
+static unsigned int kevent_user_poll(struct file *file, struct poll_table_struct *wait)
+{
+	struct kevent_user *u = file->private_data;
+	unsigned int mask;
+	
+	poll_wait(file, &u->wait, wait);
+	mask = 0;
+
+	if (u->ready_num)
+		mask |= POLLIN | POLLRDNORM;
+
+	return mask;
+}
+
+static inline void kevent_user_ring_set(struct kevent_user *u, unsigned int num)
+{
+	unsigned int *idx;
+	
+	idx = (unsigned int *)u->pring[0];
+	idx[0] = num;
+}
+
+/*
+ * Note that kevents does not exactly fill the page (each ukevent is 40 bytes),
+ * so we reuse 4 bytes at the begining of the first page to store index.
+ * Take that into account if you want to change size of struct ukevent.
+ */
+#define KEVENTS_ON_PAGE PAGE_SIZE/sizeof(struct ukevent)
+
+/*
+ * Called under kevent_user->ready_lock, so updates are always protected.
+ */
+void kevent_user_ring_add_event(struct kevent *k)
+{
+	unsigned int *idx_ptr, idx, pidx, off;
+	struct ukevent *ukev;
+	
+	idx_ptr = (unsigned int *)k->user->pring[0];
+	idx = idx_ptr[0];
+
+	pidx = idx/KEVENTS_ON_PAGE;
+	off = idx%KEVENTS_ON_PAGE;
+
+	if (pidx == 0)
+		ukev = (struct ukevent *)(k->user->pring[pidx] + sizeof(unsigned int));
+	else
+		ukev = (struct ukevent *)(k->user->pring[pidx]);
+
+	memcpy(&ukev[off], &k->event, sizeof(struct ukevent));
+
+	idx++;
+	if (idx >= KEVENT_MAX_EVENTS)
+		idx = 0;
+
+	idx_ptr[0] = idx;
+}
+
+static int kevent_user_ring_init(struct kevent_user *u)
+{
+	int i, pnum;
+
+	pnum = ALIGN(KEVENT_MAX_EVENTS*sizeof(struct ukevent) + sizeof(unsigned int), PAGE_SIZE)/PAGE_SIZE;
+
+	u->pring = kmalloc(pnum * sizeof(unsigned long), GFP_KERNEL);
+	if (!u->pring)
+		return -ENOMEM;
+
+	for (i=0; i<pnum; ++i) {
+		u->pring[i] = __get_free_page(GFP_KERNEL);
+		if (!u->pring)
+			break;
+	}
+
+	if (i != pnum) {
+		pnum = i;
+		goto err_out_free;
+	}
+
+	kevent_user_ring_set(u, 0);
+
+	return 0;
+
+err_out_free:
+	for (i=0; i<pnum; ++i)
+		free_page(u->pring[i]);
+
+	kfree(u->pring);
+
+	return -ENOMEM;
+}
+
+static void kevent_user_ring_fini(struct kevent_user *u)
+{
+	int i, pnum;
+
+	pnum = ALIGN(KEVENT_MAX_EVENTS*sizeof(struct ukevent) + sizeof(unsigned int), PAGE_SIZE)/PAGE_SIZE;
+	
+	for (i=0; i<pnum; ++i)
+		free_page(u->pring[i]);
+
+	kfree(u->pring);
+}
+
+static struct kevent_user *kevent_user_alloc(void)
+{
+	struct kevent_user *u;
+	int i;
+
+	u = kzalloc(sizeof(struct kevent_user), GFP_KERNEL);
+	if (!u)
+		return NULL;
+
+	INIT_LIST_HEAD(&u->ready_list);
+	spin_lock_init(&u->ready_lock);
+	u->ready_num = 0;
+	kevent_user_stat_init(u);
+	spin_lock_init(&u->kevent_lock);
+	for (i=0; i<ARRAY_SIZE(u->kevent_list); ++i)
+		INIT_LIST_HEAD(&u->kevent_list[i]);
+	u->kevent_num = 0;
+	
+	mutex_init(&u->ctl_mutex);
+	mutex_init(&u->wait_mutex);
+	init_waitqueue_head(&u->wait);
+	u->max_ready_num = 0;
+
+	atomic_set(&u->refcnt, 1);
+
+	if (kevent_user_ring_init(u)) {
+		kfree(u);
+		u = NULL;
+	}
+
+	return u;
+}
+
+static int kevent_user_open(struct inode *inode, struct file *file)
+{
+	struct kevent_user *u = kevent_user_alloc();
+	
+	if (!u)
+		return -ENOMEM;
+
+	file->private_data = u;
+	
+	return 0;
+}
+
+static inline void kevent_user_get(struct kevent_user *u)
+{
+	atomic_inc(&u->refcnt);
+}
+
+static inline void kevent_user_put(struct kevent_user *u)
+{
+	if (atomic_dec_and_test(&u->refcnt)) {
+		kevent_user_stat_print(u);
+		kevent_user_ring_fini(u);
+		kfree(u);
+	}
+}
+
+static int kevnet_user_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	size_t size = vma->vm_end - vma->vm_start, psize;
+	int pnum = size/PAGE_SIZE, i;
+	unsigned long start = vma->vm_start;
+	struct kevent_user *u = file->private_data;
+
+	psize = ALIGN(KEVENT_MAX_EVENTS*sizeof(struct ukevent) + sizeof(unsigned int), PAGE_SIZE);
+
+	if (size + vma->vm_pgoff*PAGE_SIZE != psize)
+		return -EINVAL;
+
+	if (vma->vm_flags & VM_WRITE)
+		return -EPERM;
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	for (i=0; i<pnum; ++i) {
+		if (remap_pfn_range(vma, start, virt_to_phys((void *)u->pring[i+vma->vm_pgoff]), PAGE_SIZE,
+					vma->vm_page_prot))
+			return -EAGAIN;
+		start += PAGE_SIZE;
+	}
+
+	return 0;
+}
+
+#if 0
+static inline unsigned int kevent_user_hash(struct ukevent *uk)
+{
+	unsigned int h = (uk->user[0] ^ uk->user[1]) ^ (uk->id.raw[0] ^ uk->id.raw[1]);
+	
+	h = (((h >> 16) & 0xffff) ^ (h & 0xffff)) & 0xffff;
+	h = (((h >> 8) & 0xff) ^ (h & 0xff)) & KEVENT_HASH_MASK;
+
+	return h;
+}
+#else
+static inline unsigned int kevent_user_hash(struct ukevent *uk)
+{
+	return jhash_1word(uk->id.raw[0], 0) & KEVENT_HASH_MASK;
+}
+#endif
+
+static void kevent_finish_user_complete(struct kevent *k, int deq)
+{
+	struct kevent_user *u = k->user;
+	unsigned long flags;
+
+	if (deq)
+		kevent_dequeue(k);
+
+	spin_lock_irqsave(&u->ready_lock, flags);
+	if (k->ready_entry.next != LIST_POISON1) {
+		list_del(&k->ready_entry);
+		u->ready_num--;
+	}
+	spin_unlock_irqrestore(&u->ready_lock, flags);
+
+	kevent_user_put(u);
+	kevent_free(k);
+}
+
+static void __kevent_finish_user(struct kevent *k, int deq)
+{
+	struct kevent_user *u = k->user;
+
+	list_del(&k->kevent_entry);
+	u->kevent_num--;
+	kevent_finish_user_complete(k, deq);
+}
+
+/*
+ * Remove kevent from user's list of all events, 
+ * dequeue it from storage and decrease user's reference counter,
+ * since this kevent does not exist anymore. That is why it is freed here.
+ */
+static void kevent_finish_user(struct kevent *k, int deq)
+{
+	struct kevent_user *u = k->user;
+	unsigned long flags;
+
+	spin_lock_irqsave(&u->kevent_lock, flags);
+	list_del(&k->kevent_entry);
+	u->kevent_num--;
+	spin_unlock_irqrestore(&u->kevent_lock, flags);
+	kevent_finish_user_complete(k, deq);
+}
+
+/*
+ * Dequeue one entry from user's ready queue.
+ */
+
+static struct kevent *kqueue_dequeue_ready(struct kevent_user *u)
+{
+	unsigned long flags;
+	struct kevent *k = NULL;
+
+	spin_lock_irqsave(&u->ready_lock, flags);
+	if (u->ready_num && !list_empty(&u->ready_list)) {
+		k = list_entry(u->ready_list.next, struct kevent, ready_entry);
+		list_del(&k->ready_entry);
+		u->ready_num--;
+	}
+	spin_unlock_irqrestore(&u->ready_lock, flags);
+
+	return k;
+}
+
+static struct kevent *__kevent_search(struct list_head *head, struct ukevent *uk, 
+		struct kevent_user *u)
+{
+	struct kevent *k;
+	int found = 0;
+	
+	list_for_each_entry(k, head, kevent_entry) {
+		spin_lock(&k->ulock);
+		if (k->event.user[0] == uk->user[0] && k->event.user[1] == uk->user[1] &&
+				k->event.id.raw[0] == uk->id.raw[0] && 
+				k->event.id.raw[1] == uk->id.raw[1]) {
+			found = 1;
+			spin_unlock(&k->ulock);
+			break;
+		}
+		spin_unlock(&k->ulock);
+	}
+
+	return (found)?k:NULL;
+}
+
+static int kevent_modify(struct ukevent *uk, struct kevent_user *u)
+{
+	struct kevent *k;
+	unsigned int hash = kevent_user_hash(uk);
+	int err = -ENODEV;
+	unsigned long flags;
+	
+	spin_lock_irqsave(&u->kevent_lock, flags);
+	k = __kevent_search(&u->kevent_list[hash], uk, u);
+	if (k) {
+		spin_lock(&k->ulock);
+		k->event.event = uk->event;
+		k->event.req_flags = uk->req_flags;
+		k->event.ret_flags = 0;
+		spin_unlock(&k->ulock);
+		kevent_requeue(k);
+		err = 0;
+	}
+	spin_unlock_irqrestore(&u->kevent_lock, flags);
+	
+	return err;
+}
+
+static int kevent_remove(struct ukevent *uk, struct kevent_user *u)
+{
+	int err = -ENODEV;
+	struct kevent *k;
+	unsigned int hash = kevent_user_hash(uk);
+	unsigned long flags;
+
+	spin_lock_irqsave(&u->kevent_lock, flags);
+	k = __kevent_search(&u->kevent_list[hash], uk, u);
+	if (k) {
+		__kevent_finish_user(k, 1);
+		err = 0;
+	}
+	spin_unlock_irqrestore(&u->kevent_lock, flags);
+
+	return err;
+}
+
+/*
+ * No new entry can be added or removed from any list at this point.
+ * It is not permitted to call ->ioctl() and ->release() in parallel.
+ */
+static int kevent_user_release(struct inode *inode, struct file *file)
+{
+	struct kevent_user *u = file->private_data;
+	struct kevent *k, *n;
+	int i;
+
+	for (i=0; i<KEVENT_HASH_MASK+1; ++i) {
+		list_for_each_entry_safe(k, n, &u->kevent_list[i], kevent_entry)
+			kevent_finish_user(k, 1);
+	}
+
+	kevent_user_put(u);
+	file->private_data = NULL;
+
+	return 0;
+}
+
+static struct ukevent *kevent_get_user(unsigned int num, void __user *arg)
+{
+	struct ukevent *ukev;
+
+	ukev = kmalloc(sizeof(struct ukevent) * num, GFP_KERNEL);
+	if (!ukev)
+		return NULL;
+
+	if (copy_from_user(arg, ukev, sizeof(struct ukevent) * num)) {
+		kfree(ukev);
+		return NULL;
+	}
+
+	return ukev;
+}
+
+static int kevent_user_ctl_modify(struct kevent_user *u, unsigned int num, void __user *arg)
+{
+	int err = 0, i;
+	struct ukevent uk;
+
+	mutex_lock(&u->ctl_mutex);
+	
+	if (num > KEVENT_MIN_BUFFS_ALLOC) {
+		struct ukevent *ukev;
+
+		ukev = kevent_get_user(num, arg);
+		if (ukev) {
+			for (i=0; i<num; ++i) {
+				if (kevent_modify(&ukev[i], u))
+					ukev[i].ret_flags |= KEVENT_RET_BROKEN;
+				ukev[i].ret_flags |= KEVENT_RET_DONE;
+			}
+			if (copy_to_user(arg, ukev, num*sizeof(struct ukevent)))
+				err = -EINVAL;
+			kfree(ukev);
+			goto out;
+		}
+	}
+
+	for (i=0; i<num; ++i) {
+		if (copy_from_user(&uk, arg, sizeof(struct ukevent))) {
+			err = -EINVAL;
+			break;
+		}
+
+		if (kevent_modify(&uk, u))
+			uk.ret_flags |= KEVENT_RET_BROKEN;
+		uk.ret_flags |= KEVENT_RET_DONE;
+
+		if (copy_to_user(arg, &uk, sizeof(struct ukevent))) {
+			err = -EINVAL;
+			break;
+		}
+
+		arg += sizeof(struct ukevent);
+	}
+out:
+	mutex_unlock(&u->ctl_mutex);
+
+	return err;
+}
+
+static int kevent_user_ctl_remove(struct kevent_user *u, unsigned int num, void __user *arg)
+{
+	int err = 0, i;
+	struct ukevent uk;
+
+	mutex_lock(&u->ctl_mutex);
+	
+	if (num > KEVENT_MIN_BUFFS_ALLOC) {
+		struct ukevent *ukev;
+
+		ukev = kevent_get_user(num, arg);
+		if (ukev) {
+			for (i=0; i<num; ++i) {
+				if (kevent_remove(&ukev[i], u))
+					ukev[i].ret_flags |= KEVENT_RET_BROKEN;
+				ukev[i].ret_flags |= KEVENT_RET_DONE;
+			}
+			if (copy_to_user(arg, ukev, num*sizeof(struct ukevent)))
+				err = -EINVAL;
+			kfree(ukev);
+			goto out;
+		}
+	}
+
+	for (i=0; i<num; ++i) {
+		if (copy_from_user(&uk, arg, sizeof(struct ukevent))) {
+			err = -EINVAL;
+			break;
+		}
+
+		if (kevent_remove(&uk, u))
+			uk.ret_flags |= KEVENT_RET_BROKEN;
+
+		uk.ret_flags |= KEVENT_RET_DONE;
+
+		if (copy_to_user(arg, &uk, sizeof(struct ukevent))) {
+			err = -EINVAL;
+			break;
+		}
+
+		arg += sizeof(struct ukevent);
+	}
+out:
+	mutex_unlock(&u->ctl_mutex);
+
+	return err;
+}
+
+static void kevent_user_enqueue(struct kevent_user *u, struct kevent *k)
+{
+	unsigned long flags;
+	unsigned int hash = kevent_user_hash(&k->event);
+
+	spin_lock_irqsave(&u->kevent_lock, flags);
+	list_add_tail(&k->kevent_entry, &u->kevent_list[hash]);
+	u->kevent_num++;
+	kevent_user_get(u);
+	spin_unlock_irqrestore(&u->kevent_lock, flags);
+}
+
+int kevent_user_add_ukevent(struct ukevent *uk, struct kevent_user *u)
+{
+	struct kevent *k;
+	int err;
+
+	k = kevent_alloc(GFP_KERNEL);
+	if (!k) {
+		err = -ENOMEM;
+		goto err_out_exit;
+	}
+
+	memcpy(&k->event, uk, sizeof(struct ukevent));
+
+	k->event.ret_flags = 0;
+
+	err = kevent_init(k);
+	if (err) {
+		kevent_free(k);
+		goto err_out_exit;
+	}
+	k->user = u;
+	kevent_user_stat_increase_total(u);
+	kevent_user_enqueue(u, k);
+
+	err = kevent_enqueue(k);
+	if (err) {
+		memcpy(uk, &k->event, sizeof(struct ukevent));
+		if (err < 0)
+			uk->ret_flags |= KEVENT_RET_BROKEN;
+		uk->ret_flags |= KEVENT_RET_DONE;
+		kevent_finish_user(k, 0);
+	} 
+
+err_out_exit:
+	return err;
+}
+
+/*
+ * Copy all ukevents from userspace, allocate kevent for each one 
+ * and add them into appropriate kevent_storages, 
+ * e.g. sockets, inodes and so on...
+ * If something goes wrong, all events will be dequeued and 
+ * negative error will be returned. 
+ * On success number of finished events is returned and 
+ * Array of finished events (struct ukevent) will be placed behind 
+ * kevent_user_control structure. User must run through that array and check 
+ * ret_flags field of each ukevent structure to determine if it is fired or failed event.
+ */
+static int kevent_user_ctl_add(struct kevent_user *u, unsigned int num, void __user *arg)
+{
+	int err, cerr = 0, knum = 0, rnum = 0, i;
+	void __user *orig = arg;
+	struct ukevent uk;
+
+	mutex_lock(&u->ctl_mutex);
+
+	err = -ENFILE;
+	if (u->kevent_num + num >= KEVENT_MAX_EVENTS)
+		goto out_remove;
+
+	if (num > KEVENT_MIN_BUFFS_ALLOC) {
+		struct ukevent *ukev;
+
+		ukev = kevent_get_user(num, arg);
+		if (ukev) {
+			for (i=0; i<num; ++i) {
+				err = kevent_user_add_ukevent(&ukev[i], u);
+				if (err) {
+					kevent_user_stat_increase_im(u);
+					if (i != rnum)
+						memcpy(&ukev[rnum], &ukev[i], sizeof(struct ukevent));
+					rnum++;
+				} else
+					knum++;
+			}
+			if (copy_to_user(orig, ukev, rnum*sizeof(struct ukevent)))
+				cerr = -EINVAL;
+			kfree(ukev);
+			goto out_setup;
+		}
+	}
+
+	for (i=0; i<num; ++i) {
+		if (copy_from_user(&uk, arg, sizeof(struct ukevent))) {
+			cerr = -EINVAL;
+			break;
+		}
+		arg += sizeof(struct ukevent);
+
+		err = kevent_user_add_ukevent(&uk, u);
+		if (err) {
+			kevent_user_stat_increase_im(u);
+			if (copy_to_user(orig, &uk, sizeof(struct ukevent))) {
+				cerr = -EINVAL;
+				break;
+			}
+			orig += sizeof(struct ukevent);
+			rnum++;
+		} else
+			knum++;
+	}
+
+out_setup:
+	if (cerr < 0) {
+		err = cerr;
+		goto out_remove;
+	}
+
+	err = rnum;
+out_remove:
+	mutex_unlock(&u->ctl_mutex);
+
+	return err;
+}
+
+/*
+ * In nonblocking mode it returns as many events as possible, but not more than @max_nr.
+ * In blocking mode it waits until timeout or if at least @min_nr events are ready,
+ * if timeout is zero, than it waits no more than 1 second or if at least one event
+ * is ready.
+ */
+static int kevent_user_wait(struct file *file, struct kevent_user *u, 
+		unsigned int min_nr, unsigned int max_nr, unsigned int timeout, 
+		void __user *buf)
+{
+	struct kevent *k;
+	int cerr = 0, num = 0;
+
+	if (!(file->f_flags & O_NONBLOCK)) {
+		if (timeout)
+			wait_event_interruptible_timeout(u->wait, 
+				u->ready_num >= min_nr, msecs_to_jiffies(timeout));
+		else
+			wait_event_interruptible_timeout(u->wait, 
+					u->ready_num > 0, msecs_to_jiffies(1000));
+	}
+	
+	mutex_lock(&u->ctl_mutex);
+	while (num < max_nr && ((k = kqueue_dequeue_ready(u)) != NULL)) {
+		if (copy_to_user(buf + num*sizeof(struct ukevent), 
+					&k->event, sizeof(struct ukevent))) {
+			cerr = -EINVAL;
+			break;
+		}
+
+		/*
+		 * If it is one-shot kevent, it has been removed already from
+		 * origin's queue, so we can easily free it here.
+		 */
+		if (k->event.req_flags & KEVENT_REQ_ONESHOT)
+			kevent_finish_user(k, 1);
+		++num;
+		kevent_user_stat_increase_wait(u);
+	}
+	mutex_unlock(&u->ctl_mutex);
+
+	return (cerr)?cerr:num;
+}
+
+static int kevent_ctl_init(void)
+{
+	struct kevent_user *u;
+	struct file *file;
+	int fd, ret;
+
+	fd = get_unused_fd();
+	if (fd < 0)
+		return fd;
+
+	file = get_empty_filp();
+	if (!file) {
+		ret = -ENFILE;
+		goto out_put_fd;
+	}
+
+	u = kevent_user_alloc();
+	if (unlikely(!u)) {
+		ret = -ENOMEM;
+		goto out_put_file;
+	}
+
+	file->f_op = &kevent_user_fops;
+	file->f_vfsmnt = mntget(kevent_mnt);
+	file->f_dentry = dget(kevent_mnt->mnt_root);
+	file->f_mapping = file->f_dentry->d_inode->i_mapping;
+	file->f_mode = FMODE_READ;
+	file->f_flags = O_RDONLY;
+	file->private_data = u;
+	
+	fd_install(fd, file);
+
+	return fd;
+
+out_put_file:
+	put_filp(file);
+out_put_fd:
+	put_unused_fd(fd);
+	return ret;
+}
+
+static int kevent_ctl_process(struct file *file, unsigned int cmd, unsigned int num, void __user *arg)
+{
+	int err;
+	struct kevent_user *u = file->private_data;
+
+	if (!u)
+		return -EINVAL;
+
+	switch (cmd) {
+	case KEVENT_CTL_ADD:
+		err = kevent_user_ctl_add(u, num, arg);
+		break;
+	case KEVENT_CTL_REMOVE:
+		err = kevent_user_ctl_remove(u, num, arg);
+		break;
+	case KEVENT_CTL_MODIFY:
+		err = kevent_user_ctl_modify(u, num, arg);
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+asmlinkage long sys_kevent_get_events(int ctl_fd, unsigned int min_nr, unsigned int max_nr,
+		unsigned int timeout, void __user *buf, unsigned flags)
+{
+	int err = -EINVAL, fput_needed;
+	struct file *file;
+	struct kevent_user *u;
+
+	file = fget_light(ctl_fd, &fput_needed);
+	if (!file)
+		return -ENODEV;
+
+	if (file->f_op != &kevent_user_fops)
+		goto out_fput;
+	u = file->private_data;
+
+	err = kevent_user_wait(file, u, min_nr, max_nr, timeout, buf);
+out_fput:
+	fput_light(file, fput_needed);
+	return err;
+}
+
+asmlinkage long sys_kevent_ctl(int fd, unsigned int cmd, unsigned int num, void __user *arg)
+{
+	int err = -EINVAL, fput_needed;
+	struct file *file;
+
+	if (cmd == KEVENT_CTL_INIT)
+		return kevent_ctl_init();
+
+	file = fget_light(fd, &fput_needed);
+	if (!file)
+		return -ENODEV;
+
+	if (file->f_op != &kevent_user_fops)
+		goto out_fput;
+
+	err = kevent_ctl_process(file, cmd, num, arg);
+
+out_fput:
+	fput_light(file, fput_needed);
+	return err;
+}
+
+static int __devinit kevent_user_init(void)
+{
+	struct class_device *dev;
+	int err = 0;
+	
+	err = register_filesystem(&kevent_fs_type);
+	if (err)
+		panic("%s: failed to register filesystem: err=%d.\n",
+			       kevent_name, err);
+
+	kevent_mnt = kern_mount(&kevent_fs_type);
+	if (IS_ERR(kevent_mnt))
+		panic("%s: failed to mount silesystem: err=%ld.\n", 
+				kevent_name, PTR_ERR(kevent_mnt));
+	
+	kevent_user_major = register_chrdev(0, kevent_name, &kevent_user_fops);
+	if (kevent_user_major < 0) {
+		printk(KERN_ERR "Failed to register \"%s\" char device: err=%d.\n", 
+				kevent_name, kevent_user_major);
+		return -ENODEV;
+	}
+
+	kevent_user_class = class_create(THIS_MODULE, "kevent");
+	if (IS_ERR(kevent_user_class)) {
+		printk(KERN_ERR "Failed to register \"%s\" class: err=%ld.\n", 
+				kevent_name, PTR_ERR(kevent_user_class));
+		err = PTR_ERR(kevent_user_class);
+		goto err_out_unregister;
+	}
+
+	dev = class_device_create(kevent_user_class, NULL, 
+			MKDEV(kevent_user_major, 0), NULL, kevent_name);
+	if (IS_ERR(dev)) {
+		printk(KERN_ERR "Failed to create %d.%d class device in \"%s\" class: err=%ld.\n", 
+				kevent_user_major, 0, kevent_name, PTR_ERR(dev));
+		err = PTR_ERR(dev);
+		goto err_out_class_destroy;
+	}
+
+	printk("KEVENT subsystem: chardev helper: major=%d.\n", kevent_user_major);
+
+	return 0;
+
+err_out_class_destroy:
+	class_destroy(kevent_user_class);
+err_out_unregister:
+	unregister_chrdev(kevent_user_major, kevent_name);
+
+	return err;
+}
+
+static void __devexit kevent_user_fini(void)
+{
+	class_device_destroy(kevent_user_class, MKDEV(kevent_user_major, 0));
+	class_destroy(kevent_user_class);
+	unregister_chrdev(kevent_user_major, kevent_name);
+	mntput(kevent_mnt);
+	unregister_filesystem(&kevent_fs_type);
+}
+
+module_init(kevent_user_init);
+module_exit(kevent_user_fini);
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 6991bec..8843cca 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -122,6 +122,11 @@ cond_syscall(ppc_rtas);
 cond_syscall(sys_spu_run);
 cond_syscall(sys_spu_create);
 
+cond_syscall(sys_aio_recv);
+cond_syscall(sys_aio_send);
+cond_syscall(sys_kevent_get_events);
+cond_syscall(sys_kevent_ctl);
+
 /* mmu depending weak syscall entries */
 cond_syscall(sys_mprotect);
 cond_syscall(sys_msync);