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    Subject[take35 2/10] kevent: Core files.
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    Core files.

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

    Some bits of documentation can be found on project's homepage (and links from there):
    http://tservice.net.ru/~s0mbre/old/?section=projects&item=kevent

    Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

    diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
    index 2697e92..9b4cbf1 100644
    --- a/arch/i386/kernel/syscall_table.S
    +++ b/arch/i386/kernel/syscall_table.S
    @@ -319,3 +319,10 @@ ENTRY(sys_call_table)
    .long sys_move_pages
    .long sys_getcpu
    .long sys_epoll_pwait
    + .long sys_kevent_get_events
    + .long sys_kevent_ctl /* 320 */
    + .long sys_kevent_wait
    + .long sys_kevent_commit
    + .long sys_kevent_init
    + .long sys_aio_sendfile
    + .long sys_aio_sendfile_path
    diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
    index b4aa875..df87cde 100644
    --- a/arch/x86_64/ia32/ia32entry.S
    +++ b/arch/x86_64/ia32/ia32entry.S
    @@ -714,8 +714,15 @@ ia32_sys_call_table:
    .quad compat_sys_get_robust_list
    .quad sys_splice
    .quad sys_sync_file_range
    - .quad sys_tee
    + .quad sys_tee /* 315 */
    .quad compat_sys_vmsplice
    .quad compat_sys_move_pages
    .quad sys_getcpu
    + .quad sys_kevent_get_events
    + .quad sys_kevent_ctl /* 320 */
    + .quad sys_kevent_wait
    + .quad sys_kevent_commit
    + .quad sys_kevent_init
    + .quad sys_aio_sendfile
    + .quad sys_aio_sendfile_path
    ia32_syscall_end:
    diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
    index 833fa17..5800a2e 100644
    --- a/include/asm-i386/unistd.h
    +++ b/include/asm-i386/unistd.h
    @@ -325,10 +325,17 @@
    #define __NR_move_pages 317
    #define __NR_getcpu 318
    #define __NR_epoll_pwait 319
    +#define __NR_kevent_get_events 320
    +#define __NR_kevent_ctl 321
    +#define __NR_kevent_wait 322
    +#define __NR_kevent_commit 323
    +#define __NR_kevent_init 324
    +#define __NR_aio_sendfile 325
    +#define __NR_aio_sendfile_path 326

    #ifdef __KERNEL__

    -#define NR_syscalls 320
    +#define NR_syscalls 327

    #define __ARCH_WANT_IPC_PARSE_VERSION
    #define __ARCH_WANT_OLD_READDIR
    diff --git a/include/asm-x86_64/unistd.h b/include/asm-x86_64/unistd.h
    index c5f596e..6984f7c 100644
    --- a/include/asm-x86_64/unistd.h
    +++ b/include/asm-x86_64/unistd.h
    @@ -619,8 +619,22 @@ __SYSCALL(__NR_sync_file_range, sys_sync_file_range)
    __SYSCALL(__NR_vmsplice, sys_vmsplice)
    #define __NR_move_pages 279
    __SYSCALL(__NR_move_pages, sys_move_pages)
    -
    -#define __NR_syscall_max __NR_move_pages
    +#define __NR_kevent_get_events 280
    +__SYSCALL(__NR_kevent_get_events, sys_kevent_get_events)
    +#define __NR_kevent_ctl 281
    +__SYSCALL(__NR_kevent_ctl, sys_kevent_ctl)
    +#define __NR_kevent_wait 282
    +__SYSCALL(__NR_kevent_wait, sys_kevent_wait)
    +#define __NR_kevent_commit 283
    +__SYSCALL(__NR_kevent_commit, sys_kevent_commit)
    +#define __NR_kevent_init 284
    +__SYSCALL(__NR_kevent_init, sys_kevent_init)
    +#define __NR_aio_sendfile 285
    +__SYSCALL(__NR_aio_sendfile, sys_aio_sendfile)
    +#define __NR_aio_sendfile_path 286
    +__SYSCALL(__NR_aio_sendfile_path, sys_aio_sendfile_path)
    +
    +#define __NR_syscall_max __NR_aio_sendfile_path

    #ifndef __NO_STUBS
    #define __ARCH_WANT_OLD_READDIR
    diff --git a/include/linux/kevent.h b/include/linux/kevent.h
    new file mode 100644
    index 0000000..3040d01
    --- /dev/null
    +++ b/include/linux/kevent.h
    @@ -0,0 +1,268 @@
    +/*
    + * 2006 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
    + * 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
    +#include <linux/types.h>
    +#include <linux/list.h>
    +#include <linux/rbtree.h>
    +#include <linux/spinlock.h>
    +#include <linux/mutex.h>
    +#include <linux/wait.h>
    +#include <linux/net.h>
    +#include <linux/rcupdate.h>
    +#include <linux/fs.h>
    +#include <linux/sched.h>
    +#include <linux/hrtimer.h>
    +#include <linux/kevent_storage.h>
    +#include <linux/ukevent.h>
    +
    +#define KEVENT_MIN_BUFFS_ALLOC 3
    +
    +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. */
    +/* @flags - flags for given set of callbacks. */
    +
    +struct kevent_callbacks {
    + kevent_callback_t callback, enqueue, dequeue;
    + unsigned int flags;
    +};
    +
    +#define KEVENT_CALLBACKS_KERNELONLY 0x1
    +
    +int kevent_event_is_allowed(struct ukevent *e);
    +
    +#define KEVENT_READY 0x1
    +#define KEVENT_STORAGE 0x2
    +#define KEVENT_USER 0x4
    +
    +struct kevent
    +{
    + /* Used for kevent freeing.*/
    + struct rcu_head rcu_head;
    + struct ukevent event;
    + /* This lock protects ukevent manipulations, e.g. ret_flags changes. */
    + spinlock_t ulock;
    +
    + /* Entry of user's tree. */
    + struct rb_node kevent_node;
    + /* Entry of origin's queue. */
    + struct list_head storage_entry;
    + /* Entry of user's ready. */
    + struct list_head ready_entry;
    +
    + u32 flags;
    +
    + /* User who requested this kevent. */
    + struct kevent_user *user;
    + /* Kevent container. */
    + struct kevent_storage *st;
    +
    + struct kevent_callbacks callbacks;
    +
    + /* Private data for different storages.
    + * poll()/select storage has a list of wait_queue_t containers
    + * for each ->poll() { poll_wait()' } here.
    + */
    + void *priv;
    +};
    +
    +struct kevent_user
    +{
    + struct rb_root kevent_root;
    + spinlock_t kevent_lock;
    + /* Number of queued kevents. */
    + unsigned int kevent_num;
    +
    + /* List of ready kevents. */
    + struct list_head ready_list;
    + /* Number of ready kevents. */
    + unsigned int ready_num;
    + /* Protects all manipulations with ready queue. */
    + spinlock_t ready_lock;
    +
    + /* Protects against simultaneous kevent_user control manipulations. */
    + struct mutex ctl_mutex;
    + /* Wait until some events are ready. */
    + wait_queue_head_t wait;
    + /* Exit from syscall if someone wants us to do it */
    + int need_exit;
    +
    + /* Reference counter, increased for each new kevent. */
    + atomic_t refcnt;
    +
    + /* Mutex protecting userspace ring buffer. */
    + struct mutex ring_lock;
    + /* Kernel index and size of the userspace ring buffer. */
    + unsigned int kidx, uidx, ring_size, ring_over, full;
    + /* Pointer to userspace ring buffer. */
    + struct kevent_ring __user *pring;
    +
    + /* Is used for absolute waiting times. */
    + struct hrtimer timer;
    +
    + /* Used for userspace private notifications. */
    + struct kevent_storage st;
    +
    +#ifdef CONFIG_KEVENT_USER_STAT
    + unsigned long im_num;
    + unsigned long wait_num, ring_num;
    + unsigned long total;
    +#endif
    +};
    +
    +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);
    +
    +int kevent_add_callbacks(const struct kevent_callbacks *cb, int pos);
    +
    +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);
    +
    +void kevent_ready(struct kevent *k, int ret);
    +
    +int kevent_user_add_ukevent(struct ukevent *uk, struct kevent_user *u);
    +
    +#ifdef CONFIG_KEVENT_POLL
    +void kevent_poll_reinit(struct file *file);
    +#else
    +static inline void kevent_poll_reinit(struct file *file)
    +{
    +}
    +#endif
    +
    +#ifdef CONFIG_KEVENT_USER_STAT
    +static inline void kevent_stat_init(struct kevent_user *u)
    +{
    + u->wait_num = u->im_num = u->total = u->ring_num = 0;
    +}
    +static inline void kevent_stat_print(struct kevent_user *u)
    +{
    + printk(KERN_INFO "%s: u: %p, wait: %lu, ring: %lu, immediately: %lu, total: %lu.\n",
    + __func__, u, u->wait_num, u->ring_num, u->im_num, u->total);
    +}
    +static inline void kevent_stat_im(struct kevent_user *u)
    +{
    + u->im_num++;
    +}
    +static inline void kevent_stat_ring(struct kevent_user *u)
    +{
    + u->ring_num++;
    +}
    +static inline void kevent_stat_wait(struct kevent_user *u)
    +{
    + u->wait_num++;
    +}
    +static inline void kevent_stat_total(struct kevent_user *u)
    +{
    + u->total++;
    +}
    +#else
    +#define kevent_stat_print(u) ({ (void) u;})
    +#define kevent_stat_init(u) ({ (void) u;})
    +#define kevent_stat_im(u) ({ (void) u;})
    +#define kevent_stat_wait(u) ({ (void) u;})
    +#define kevent_stat_ring(u) ({ (void) u;})
    +#define kevent_stat_total(u) ({ (void) u;})
    +#endif
    +
    +void kevent_user_free(struct kevent_user *u);
    +
    +/*
    + * Kevent userspace control block reference counting.
    + * Set to 1 at creation time, when appropriate kevent file descriptor
    + * is closed, that reference counter is decreased.
    + * When counter hits zero block is freed.
    + */
    +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_free(u);
    +
    + }
    +}
    +
    +#ifdef CONFIG_LOCKDEP
    +void kevent_socket_reinit(struct socket *sock);
    +void kevent_sk_reinit(struct sock *sk);
    +#else
    +static inline void kevent_socket_reinit(struct socket *sock)
    +{
    +}
    +static inline void kevent_sk_reinit(struct sock *sk)
    +{
    +}
    +#endif
    +#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_POLL
    +static inline void kevent_init_file(struct file *file)
    +{
    + kevent_storage_init(file, &file->st);
    +}
    +
    +static inline void kevent_cleanup_file(struct file *file)
    +{
    + kevent_storage_fini(&file->st);
    +}
    +#else
    +static inline void kevent_init_file(struct file *file) {}
    +static inline void kevent_cleanup_file(struct file *file) {}
    +#endif
    +
    +#ifdef CONFIG_KEVENT_PIPE
    +extern void kevent_pipe_notify(struct inode *inode, u32 events);
    +#else
    +static inline void kevent_pipe_notify(struct inode *inode, u32 events) {}
    +#endif
    +
    +#ifdef CONFIG_KEVENT_SIGNAL
    +extern int kevent_signal_notify(struct task_struct *tsk, int sig);
    +#else
    +static inline int kevent_signal_notify(struct task_struct *tsk, int sig) {return 0;}
    +#endif
    +
    +#endif /* __KEVENT_H */
    diff --git a/include/linux/kevent_storage.h b/include/linux/kevent_storage.h
    new file mode 100644
    index 0000000..a38575d
    --- /dev/null
    +++ b/include/linux/kevent_storage.h
    @@ -0,0 +1,11 @@
    +#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. */
    + spinlock_t lock; /* Protects users queue. */
    +};
    +
    +#endif /* __KEVENT_STORAGE_H */
    diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
    index 1912c6c..3dc47a3 100644
    --- a/include/linux/syscalls.h
    +++ b/include/linux/syscalls.h
    @@ -54,6 +54,8 @@ struct compat_stat;
    struct compat_timeval;
    struct robust_list_head;
    struct getcpu_cache;
    +struct ukevent;
    +struct kevent_ring;

    #include <linux/types.h>
    #include <linux/aio_abi.h>
    @@ -603,6 +605,19 @@ asmlinkage long sys_set_robust_list(struct robust_list_head __user *head,
    size_t len);
    asmlinkage long sys_getcpu(unsigned __user *cpu, unsigned __user *node, struct getcpu_cache __user *cache);

    +asmlinkage long sys_kevent_get_events(int ctl_fd, unsigned int min, unsigned int max,
    + struct timespec timeout, struct ukevent __user *buf, unsigned flags);
    +asmlinkage long sys_kevent_ctl(int ctl_fd, unsigned int cmd, unsigned int num, struct ukevent __user *buf);
    +asmlinkage long sys_kevent_wait(int ctl_fd, unsigned int num, unsigned int old_uidx,
    + struct timespec timeout, unsigned int flags);
    +asmlinkage long sys_kevent_commit(int ctl_fd, unsigned int new_uidx, unsigned int over);
    +asmlinkage long sys_kevent_init(struct kevent_ring __user *ring, unsigned int num, unsigned int flags);
    +
    int kernel_execve(const char *filename, char *const argv[], char *const envp[]);

    +asmlinkage long sys_aio_sendfile(int kevent_fd, int sock_fd, int in_fd, off_t offset, size_t count);
    +asmlinkage long sys_aio_sendfile_path(int kevent_fd, int sock_fd,
    + void __user *header, size_t header_size,
    + char __user *filename, off_t offset, size_t count);
    +
    #endif
    diff --git a/include/linux/ukevent.h b/include/linux/ukevent.h
    new file mode 100644
    index 0000000..d975407
    --- /dev/null
    +++ b/include/linux/ukevent.h
    @@ -0,0 +1,191 @@
    +/*
    + * 2006 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
    + * 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 __UKEVENT_H
    +#define __UKEVENT_H
    +
    +#include <linux/types.h>
    +
    +/*
    + * Kevent request flags.
    + */
    +
    +/* Process this event only once and then remove it. */
    +#define KEVENT_REQ_ONESHOT 0x1
    +/* Kevent wakes up only first thread interested in given event,
    + * or all threads if this flag is set.
    + */
    +#define KEVENT_REQ_WAKEUP_ALL 0x2
    +/* Edge Triggered behaviour. */
    +#define KEVENT_REQ_ET 0x4
    +/* Perform the last check on kevent (call appropriate callback) when
    + * kevent is marked as ready and has been removed from ready queue.
    + * If it will be confirmed that kevent is ready
    + * (k->callbacks.callback(k) returns true) then kevent will be copied
    + * to userspace, otherwise it will be requeued back to storage.
    + * Second (checking) call is performed with this bit _cleared_ so
    + * callback can detect when it was called from
    + * kevent_storage_ready() - bit is set, or
    + * kevent_dequeue_ready() - bit is cleared.
    + * If kevent will be requeued, bit will be set again. */
    +#define KEVENT_REQ_LAST_CHECK 0x8
    +/*
    + * Always queue kevent even if it is immediately ready.
    + */
    +#define KEVENT_REQ_ALWAYS_QUEUE 0x10
    +/*
    + * Mark event as ready immediately on enqueueing time.
    + */
    +#define KEVENT_REQ_READY 0x20
    +
    +/*
    + * Kevent return flags.
    + */
    +/* Kevent is broken. */
    +#define KEVENT_RET_BROKEN 0x1
    +/* Kevent processing was finished successfully. */
    +#define KEVENT_RET_DONE 0x2
    +/* Kevent was not copied into ring buffer due to some error conditions. */
    +#define KEVENT_RET_COPY_FAILED 0x4
    +
    +/*
    + * 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_PIPE 6
    +#define KEVENT_SIGNAL 7
    +#define KEVENT_POSIX_TIMER 8
    +#define KEVENT_UNOTIFY 9
    +
    +/* Used as array size, so must be equal to the last KEVENT type + 1 */
    +#define KEVENT_MAX 10
    +
    +/*
    + * 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 and PIPE 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
    +#define KEVENT_POLL_POLLRDHUP 0x2000
    +
    +/*
    + * Asynchronous IO events.
    + */
    +#define KEVENT_AIO_BIO 0x1
    +
    +/*
    + * Signal events.
    + */
    +#define KEVENT_SIGNAL_DELIVERY 0x1
    +
    +/* If set in raw64, then given signals will not be delivered
    + * in a usual way through sigmask update and signal callback
    + * invocation. */
    +#define KEVENT_SIGNAL_NOMASK 0x8000000000000000ULL
    +
    +/* Mask of all possible event values. */
    +#define KEVENT_MASK_ALL 0xffffffff
    +/* Empty mask of ready events. */
    +#define KEVENT_MASK_EMPTY 0x0
    +
    +struct kevent_id
    +{
    + union {
    + __u32 raw[2];
    + __u64 raw_u64 __attribute__((aligned(8)));
    + };
    +};
    +
    +struct ukevent
    +{
    + /* Id of this request, e.g. socket number, file descriptor and so on... */
    + struct kevent_id id;
    + /* Event type, e.g. KEVENT_SOCK, KEVENT_INODE, KEVENT_TIMER and so on... */
    + __u32 type;
    + /* Event itself, e.g. SOCK_ACCEPT, INODE_CREATED, TIMER_FIRED... */
    + __u32 event;
    + /* Per-event request flags */
    + __u32 req_flags;
    + /* Per-event return flags */
    + __u32 ret_flags;
    + /* Event return data. Event originator fills it with anything it likes. */
    + __u32 ret_data[2];
    + /* User's data. It is not used, just copied to/from user.
    + * The whole structure is aligned to 8 bytes already, so the last union
    + * is aligned properly.
    + */
    + union {
    + __u32 user[2];
    + void *ptr;
    + };
    +};
    +
    +struct kevent_ring
    +{
    + unsigned int ring_kidx, ring_over;
    + struct ukevent event[0];
    +};
    +
    +#define KEVENT_CTL_ADD 0
    +#define KEVENT_CTL_REMOVE 1
    +#define KEVENT_CTL_MODIFY 2
    +#define KEVENT_CTL_READY 3
    +
    +/* Provided timespec parameter uses absolute time, i.e. 'wait until Aug 27, 2194' */
    +#define KEVENT_FLAGS_ABSTIME 1
    +
    +#endif /* __UKEVENT_H */
    diff --git a/init/Kconfig b/init/Kconfig
    index a3f83e2..561a0fa 100644
    --- a/init/Kconfig
    +++ b/init/Kconfig
    @@ -219,6 +219,8 @@ config AUDITSYSCALL
    such as SELinux. To use audit's filesystem watch feature, please
    ensure that INOTIFY is configured.

    +source "kernel/kevent/Kconfig"
    +
    config IKCONFIG
    tristate "Kernel .config support"
    ---help---
    diff --git a/kernel/Makefile b/kernel/Makefile
    index 14f4d45..6bccdbb 100644
    --- a/kernel/Makefile
    +++ b/kernel/Makefile
    @@ -46,6 +46,7 @@ obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
    obj-$(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-$(CONFIG_UTS_NS) += utsname.o
    obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
    diff --git a/kernel/kevent/Kconfig b/kernel/kevent/Kconfig
    new file mode 100644
    index 0000000..a23e84f
    --- /dev/null
    +++ b/kernel/kevent/Kconfig
    @@ -0,0 +1,82 @@
    +config KEVENT
    + bool "Kernel event notification mechanism" if EMBEDDED
    + default y
    + 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
    + 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_TIMER
    + bool "Kernel event notifications for timers"
    + depends on KEVENT
    + default y
    + help
    + This option allows to use timers through KEVENT subsystem.
    +
    +config KEVENT_POLL
    + bool "Kernel event notifications for poll()/select()"
    + depends on KEVENT
    + default y
    + help
    + This option allows to use kevent subsystem for poll()/select()
    + notifications.
    +
    +config KEVENT_SOCKET
    + bool "Kernel event notifications for sockets"
    + depends on NET && KEVENT
    + default y
    + 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_PIPE
    + bool "Kernel event notifications for pipes"
    + depends on KEVENT
    + default y
    + help
    + This option enables notifications through KEVENT subsystem of
    + pipe read/write operations.
    +
    +config KEVENT_SIGNAL
    + bool "Kernel event notifications for signals"
    + depends on KEVENT
    + default y
    + help
    + This option enables signal delivery through KEVENT subsystem.
    + Signals which were requested to be delivered through kevent
    + subsystem must be registered through usual signal() and others
    + syscalls, this option allows alternative delivery.
    + With KEVENT_SIGNAL_NOMASK flag being set in kevent for set of
    + signals, they will not be delivered in a usual way.
    + Kevents for appropriate signals are not copied when process forks,
    + new process must add new kevents after fork(). Mask of signals
    + is copied as before.
    +
    +config KEVENT_UNOTIFY
    + bool "Private userspace notifications over kevent"
    + depends on KEVENT
    + default y
    + help
    + This option enable possibility to insert private userspace events,
    + which can be marked as ready on demand using kevent_ctl(KEVENT_CTL_READY)
    + command.
    +
    +config KEVENT_AIO
    + bool "Kevent based AIO"
    + depends on KEVENT && NET
    + default y
    + help
    + This option allows to work with kevent based AIO state machine.
    + Among others this allows to implement aio_sendfile() syscall.
    diff --git a/kernel/kevent/Makefile b/kernel/kevent/Makefile
    new file mode 100644
    index 0000000..a179bea
    --- /dev/null
    +++ b/kernel/kevent/Makefile
    @@ -0,0 +1,8 @@
    +obj-y := kevent.o kevent_user.o
    +obj-$(CONFIG_KEVENT_TIMER) += kevent_timer.o
    +obj-$(CONFIG_KEVENT_POLL) += kevent_poll.o epoll.o
    +obj-$(CONFIG_KEVENT_SOCKET) += kevent_socket.o
    +obj-$(CONFIG_KEVENT_PIPE) += kevent_pipe.o
    +obj-$(CONFIG_KEVENT_SIGNAL) += kevent_signal.o
    +obj-$(CONFIG_KEVENT_UNOTIFY) += kevent_unotify.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..743cd0c
    --- /dev/null
    +++ b/kernel/kevent/kevent.c
    @@ -0,0 +1,267 @@
    +/*
    + * 2006 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
    + * 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>
    +
    +/*
    + * 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)
    +{
    + 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)
    +{
    + return k->callbacks.dequeue(k);
    +}
    +
    +/*
    + * Mark kevent as broken.
    + */
    +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 -EINVAL;
    +}
    +
    +static struct kevent_callbacks kevent_registered_callbacks[KEVENT_MAX] __read_mostly;
    +
    +int kevent_event_is_allowed(struct ukevent *e)
    +{
    + if (unlikely(e->type >= KEVENT_MAX))
    + return 0;
    +
    + if (!kevent_registered_callbacks[e->type].callback)
    + return 0;
    +
    + if (unlikely(kevent_registered_callbacks[e->type].callback == kevent_break))
    + return 0;
    +
    + if (kevent_registered_callbacks[e->type].flags & KEVENT_CALLBACKS_KERNELONLY)
    + return 0;
    +
    + return 1;
    +}
    +
    +int kevent_add_callbacks(const struct kevent_callbacks *cb, int pos)
    +{
    + struct kevent_callbacks *p;
    +
    + if (pos >= KEVENT_MAX)
    + return -EINVAL;
    +
    + p = &kevent_registered_callbacks[pos];
    +
    + p->enqueue = (cb->enqueue) ? cb->enqueue : kevent_break;
    + p->dequeue = (cb->dequeue) ? cb->dequeue : kevent_break;
    + p->callback = (cb->callback) ? cb->callback : kevent_break;
    + p->flags = cb->flags;
    +
    + printk(KERN_INFO "KEVENT: Added callbacks for type %d.\n", pos);
    + return 0;
    +}
    +
    +/*
    + * 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->flags = 0;
    +
    + if (unlikely(k->event.type >= KEVENT_MAX)) {
    + kevent_break(k);
    + return -ENOSYS;
    + }
    +
    + if (!kevent_registered_callbacks[k->event.type].callback) {
    + kevent_break(k);
    + return -ENOSYS;
    + }
    +
    + k->callbacks = kevent_registered_callbacks[k->event.type];
    + if (unlikely(k->callbacks.callback == kevent_break)) {
    + kevent_break(k);
    + return -ENOSYS;
    + }
    +
    + 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_rcu(&k->storage_entry, &st->list);
    + k->flags |= KEVENT_STORAGE;
    + if (k->event.req_flags & KEVENT_REQ_READY)
    + kevent_ready(k, 1);
    + 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->flags & KEVENT_STORAGE) {
    + list_del_rcu(&k->storage_entry);
    + k->flags &= ~KEVENT_STORAGE;
    + }
    + spin_unlock_irqrestore(&st->lock, flags);
    +}
    +
    +void kevent_ready(struct kevent *k, int ret)
    +{
    + unsigned long flags;
    + int rem;
    +
    + spin_lock_irqsave(&k->ulock, flags);
    + if (ret > 0)
    + k->event.ret_flags |= KEVENT_RET_DONE;
    + else if (ret < 0)
    + k->event.ret_flags |= (KEVENT_RET_BROKEN | KEVENT_RET_DONE);
    + else
    + ret = (k->event.ret_flags & (KEVENT_RET_BROKEN|KEVENT_RET_DONE));
    + rem = (k->event.req_flags & KEVENT_REQ_ONESHOT);
    + spin_unlock_irqrestore(&k->ulock, flags);
    +
    + if (ret) {
    + if ((rem || ret < 0) && (k->flags & KEVENT_STORAGE)) {
    + list_del_rcu(&k->storage_entry);
    + k->flags &= ~KEVENT_STORAGE;
    + }
    +
    + spin_lock_irqsave(&k->user->ready_lock, flags);
    + if (!(k->flags & KEVENT_READY)) {
    + list_add_tail(&k->ready_entry, &k->user->ready_list);
    + k->flags |= KEVENT_READY;
    + k->user->ready_num++;
    + }
    + spin_unlock_irqrestore(&k->user->ready_lock, flags);
    + wake_up(&k->user->wait);
    + }
    +}
    +
    +/*
    + * Call kevent ready callback and queue it into ready queue if needed.
    + * If kevent is marked as one-shot, then remove it from storage queue.
    + */
    +static int __kevent_requeue(struct kevent *k, u32 event)
    +{
    + int ret;
    +
    + ret = k->callbacks.callback(k);
    +
    + kevent_ready(k, ret);
    +
    + return ret;
    +}
    +
    +/*
    + * Check if kevent is ready (by invoking it's callback) and requeue/remove
    + * if needed.
    + */
    +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;
    + int wake_num = 0;
    +
    + rcu_read_lock();
    + if (unlikely(ready_callback))
    + list_for_each_entry_rcu(k, &st->list, storage_entry)
    + (*ready_callback)(k);
    +
    + list_for_each_entry_rcu(k, &st->list, storage_entry) {
    + if (event & k->event.event)
    + if ((k->event.req_flags & KEVENT_REQ_WAKEUP_ALL) || wake_num == 0)
    + if (__kevent_requeue(k, event))
    + wake_num++;
    + }
    + rcu_read_unlock();
    +}
    +
    +int kevent_storage_init(void *origin, struct kevent_storage *st)
    +{
    + spin_lock_init(&st->lock);
    + st->origin = origin;
    + INIT_LIST_HEAD(&st->list);
    + return 0;
    +}
    +
    +/*
    + * Mark all events as broken, that will remove them from storage,
    + * so storage origin (inode, socket and so on) can be safely removed.
    + * No new entries are allowed to be added into the storage at this point.
    + * (Socket is removed from file table at this point for example).
    + */
    +void kevent_storage_fini(struct kevent_storage *st)
    +{
    + kevent_storage_ready(st, kevent_break, KEVENT_MASK_ALL);
    +}
    diff --git a/kernel/kevent/kevent_user.c b/kernel/kevent/kevent_user.c
    new file mode 100644
    index 0000000..f25d696
    --- /dev/null
    +++ b/kernel/kevent/kevent_user.c
    @@ -0,0 +1,1360 @@
    +/*
    + * 2006 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
    + * 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/miscdevice.h>
    +#include <asm/io.h>
    +
    +static struct kmem_cache *kevent_cache __read_mostly;
    +static struct kmem_cache *kevent_user_cache __read_mostly;
    +
    +static int kevent_debug_abstime;
    +
    +/*
    + * kevents are pollable, return POLLIN and POLLRDNORM
    + * when there is at least one ready kevent.
    + */
    +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 || u->need_exit)
    + mask |= POLLIN | POLLRDNORM;
    + u->need_exit = 0;
    +
    + return mask;
    +}
    +
    +static inline unsigned int kevent_ring_space(struct kevent_user *u)
    +{
    + if (!u->pring)
    + return 1;
    +
    + if (u->full)
    + return 0;
    +
    + return (u->uidx > u->kidx)?
    + (u->uidx - u->kidx):
    + (u->ring_size - (u->kidx - u->uidx));
    +}
    +
    +static inline int kevent_ring_index_inc(unsigned int *pidx, unsigned int size)
    +{
    + unsigned int idx = *pidx;
    +
    + if (++idx >= size)
    + idx = 0;
    + *pidx = idx;
    + return (idx == 0);
    +}
    +
    +/*
    + * Copies kevent into userspace ring buffer if it was initialized.
    + * Returns
    + * 0 on success or if ring buffer is not used
    + * -EAGAIN if there were no place for that kevent
    + * -EFAULT if copy_to_user() failed.
    + *
    + * Must be called under kevent_user->ring_lock locked.
    + */
    +static int kevent_copy_ring_buffer(struct kevent *k)
    +{
    + struct kevent_ring __user *ring;
    + struct kevent_user *u = k->user;
    + unsigned long flags;
    + int err;
    +
    + ring = u->pring;
    + if (!ring)
    + return 0;
    +
    + if (!kevent_ring_space(u))
    + return -EAGAIN;
    +
    + if (copy_to_user(&ring->event[u->kidx], &k->event, sizeof(struct ukevent))) {
    + err = -EFAULT;
    + goto err_out_exit;
    + }
    +
    + kevent_ring_index_inc(&u->kidx, u->ring_size);
    +
    + if (u->kidx == u->uidx)
    + u->full = 1;
    +
    + if (put_user(u->kidx, &ring->ring_kidx)) {
    + err = -EFAULT;
    + goto err_out_exit;
    + }
    +
    + return 0;
    +
    +err_out_exit:
    + spin_lock_irqsave(&k->ulock, flags);
    + k->event.ret_flags |= KEVENT_RET_COPY_FAILED;
    + spin_unlock_irqrestore(&k->ulock, flags);
    + return err;
    +}
    +
    +static struct kevent_user *kevent_user_alloc(struct kevent_ring __user *ring, unsigned int num)
    +{
    + struct kevent_user *u;
    +
    + u = kmem_cache_zalloc(kevent_user_cache, GFP_KERNEL);
    + if (!u)
    + return NULL;
    +
    + INIT_LIST_HEAD(&u->ready_list);
    + spin_lock_init(&u->ready_lock);
    + kevent_stat_init(u);
    + spin_lock_init(&u->kevent_lock);
    + u->kevent_root = RB_ROOT;
    +
    + mutex_init(&u->ctl_mutex);
    + init_waitqueue_head(&u->wait);
    + u->need_exit = 0;
    +
    + atomic_set(&u->refcnt, 1);
    +
    + mutex_init(&u->ring_lock);
    + u->kidx = u->uidx = u->ring_over = u->full = 0;
    +
    + u->pring = ring;
    + u->ring_size = num;
    +
    + hrtimer_init(&u->timer, CLOCK_REALTIME, HRTIMER_ABS);
    +
    + kevent_storage_init(u, &u->st);
    +
    + return u;
    +}
    +
    +void kevent_user_free(struct kevent_user *u)
    +{
    + kevent_stat_print(u);
    + hrtimer_cancel(&u->timer);
    + kmem_cache_free(kevent_user_cache, u);
    +}
    +
    +static inline int kevent_compare_id(struct kevent_id *left, struct kevent_id *right,
    + __u32 type_left, __u32 type_right)
    +{
    + if (left->raw_u64 > right->raw_u64)
    + return -1;
    +
    + if (right->raw_u64 > left->raw_u64)
    + return 1;
    +
    + if (type_left > type_right)
    + return -1;
    +
    + if (type_left < type_right)
    + return 1;
    +
    + return 0;
    +}
    +
    +/*
    + * RCU protects storage list (kevent->storage_entry).
    + * Free entry in RCU callback, it is dequeued from all lists at
    + * this point.
    + */
    +
    +static void kevent_free_rcu(struct rcu_head *rcu)
    +{
    + struct kevent *kevent = container_of(rcu, struct kevent, rcu_head);
    + kmem_cache_free(kevent_cache, kevent);
    +}
    +
    +/*
    + * Must be called under u->ready_lock.
    + * This function unlinks kevent from ready queue.
    + */
    +static inline void kevent_unlink_ready(struct kevent *k)
    +{
    + list_del(&k->ready_entry);
    + k->flags &= ~KEVENT_READY;
    + k->user->ready_num--;
    +}
    +
    +static void kevent_remove_ready(struct kevent *k)
    +{
    + struct kevent_user *u = k->user;
    + unsigned long flags;
    +
    + spin_lock_irqsave(&u->ready_lock, flags);
    + if (k->flags & KEVENT_READY)
    + kevent_unlink_ready(k);
    + spin_unlock_irqrestore(&u->ready_lock, flags);
    +}
    +
    +/*
    + * Complete kevent removing - it dequeues kevent from storage list
    + * if it is requested, removes kevent from ready list, drops userspace
    + * control block reference counter and schedules kevent freeing through RCU.
    + */
    +static void kevent_finish_user_complete(struct kevent *k, int deq)
    +{
    + if (deq)
    + kevent_dequeue(k);
    +
    + kevent_remove_ready(k);
    +
    + kevent_user_put(k->user);
    + call_rcu(&k->rcu_head, kevent_free_rcu);
    +}
    +
    +/*
    + * Remove from all lists and free kevent.
    + * Must be called under kevent_user->kevent_lock to protect
    + * kevent->kevent_entry removing.
    + */
    +static void __kevent_finish_user(struct kevent *k, int deq)
    +{
    + struct kevent_user *u = k->user;
    +
    + rb_erase(&k->kevent_node, &u->kevent_root);
    + k->flags &= ~KEVENT_USER;
    + 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);
    + rb_erase(&k->kevent_node, &u->kevent_root);
    + k->flags &= ~KEVENT_USER;
    + u->kevent_num--;
    + spin_unlock_irqrestore(&u->kevent_lock, flags);
    + kevent_finish_user_complete(k, deq);
    +}
    +
    +static struct kevent *__kevent_dequeue_ready_one(struct kevent_user *u)
    +{
    + unsigned long flags;
    + struct kevent *k = NULL;
    +
    + if (u->ready_num) {
    + 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);
    + kevent_unlink_ready(k);
    + }
    + spin_unlock_irqrestore(&u->ready_lock, flags);
    + }
    +
    + return k;
    +}
    +
    +static struct kevent *kevent_dequeue_ready_one(struct kevent_user *u)
    +{
    + struct kevent *k = NULL;
    +
    + while (u->ready_num && !k) {
    + k = __kevent_dequeue_ready_one(u);
    +
    + if (k && (k->event.req_flags & KEVENT_REQ_LAST_CHECK)) {
    + unsigned long flags;
    +
    + spin_lock_irqsave(&k->ulock, flags);
    + k->event.req_flags &= ~KEVENT_REQ_LAST_CHECK;
    + spin_unlock_irqrestore(&k->ulock, flags);
    +
    + if (!k->callbacks.callback(k)) {
    + spin_lock_irqsave(&k->ulock, flags);
    + k->event.req_flags |= KEVENT_REQ_LAST_CHECK;
    + k->event.ret_flags = 0;
    + k->event.ret_data[0] = k->event.ret_data[1] = 0;
    + spin_unlock_irqrestore(&k->ulock, flags);
    + k = NULL;
    + }
    + } else
    + break;
    + }
    +
    + return k;
    +}
    +
    +static inline void kevent_copy_ring(struct kevent *k)
    +{
    + unsigned long flags;
    +
    + if (!k)
    + return;
    +
    + if (kevent_copy_ring_buffer(k)) {
    + spin_lock_irqsave(&k->ulock, flags);
    + k->event.ret_flags |= KEVENT_RET_COPY_FAILED;
    + spin_unlock_irqrestore(&k->ulock, flags);
    + }
    +}
    +
    +/*
    + * Dequeue one entry from user's ready queue.
    + */
    +static struct kevent *kevent_dequeue_ready(struct kevent_user *u)
    +{
    + struct kevent *k;
    +
    + mutex_lock(&u->ring_lock);
    + k = kevent_dequeue_ready_one(u);
    + kevent_copy_ring(k);
    + mutex_unlock(&u->ring_lock);
    +
    + return k;
    +}
    +
    +/*
    + * Dequeue one entry from user's ready queue if there is space in ring buffer.
    + */
    +static struct kevent *kevent_dequeue_ready_ring(struct kevent_user *u)
    +{
    + struct kevent *k = NULL;
    +
    + mutex_lock(&u->ring_lock);
    + if (kevent_ring_space(u)) {
    + k = kevent_dequeue_ready_one(u);
    + kevent_copy_ring(k);
    + }
    + mutex_unlock(&u->ring_lock);
    +
    + return k;
    +}
    +
    +static void kevent_complete_ready(struct kevent *k)
    +{
    + if (k->event.req_flags & KEVENT_REQ_ONESHOT)
    + /*
    + * If it is one-shot kevent, it has been removed already from
    + * origin's queue, so we can easily free it here.
    + */
    + kevent_finish_user(k, 1);
    + else if (k->event.req_flags & KEVENT_REQ_ET) {
    + unsigned long flags;
    +
    + /*
    + * Edge-triggered behaviour: mark event as clear new one.
    + */
    +
    + spin_lock_irqsave(&k->ulock, flags);
    + k->event.ret_flags = 0;
    + k->event.ret_data[0] = k->event.ret_data[1] = 0;
    + spin_unlock_irqrestore(&k->ulock, flags);
    + }
    +}
    +
    +/*
    + * Search a kevent inside kevent tree for given ukevent.
    + */
    +static struct kevent *__kevent_search(struct kevent_id *id, __u32 type, struct kevent_user *u)
    +{
    + struct kevent *k, *ret = NULL;
    + struct rb_node *n = u->kevent_root.rb_node;
    + int cmp;
    +
    + while (n) {
    + k = rb_entry(n, struct kevent, kevent_node);
    + cmp = kevent_compare_id(&k->event.id, id, k->event.type, type);
    +
    + if (cmp > 0)
    + n = n->rb_right;
    + else if (cmp < 0)
    + n = n->rb_left;
    + else {
    + ret = k;
    + break;
    + }
    + }
    +
    + return ret;
    +}
    +
    +/*
    + * Search and modify kevent according to provided ukevent.
    + */
    +static int kevent_modify(struct ukevent *uk, struct kevent_user *u)
    +{
    + struct kevent *k;
    + int err = -ENODEV;
    + unsigned long flags;
    +
    + spin_lock_irqsave(&u->kevent_lock, flags);
    + k = __kevent_search(&uk->id, uk->type, 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;
    +}
    +
    +/*
    + * Remove kevent which matches provided ukevent.
    + */
    +static int kevent_remove(struct ukevent *uk, struct kevent_user *u)
    +{
    + int err = -ENODEV;
    + struct kevent *k;
    + unsigned long flags;
    +
    + spin_lock_irqsave(&u->kevent_lock, flags);
    + k = __kevent_search(&uk->id, uk->type, u);
    + if (k) {
    + __kevent_finish_user(k, 1);
    + err = 0;
    + }
    + spin_unlock_irqrestore(&u->kevent_lock, flags);
    +
    + return err;
    +}
    +
    +/*
    + * Detaches userspace control block from file descriptor
    + * and decrease it's reference counter.
    + * No new kevents can be added or removed from any list at this point.
    + */
    +static int kevent_user_release(struct inode *inode, struct file *file)
    +{
    + struct kevent_user *u = file->private_data;
    + struct kevent *k;
    + struct rb_node *n;
    +
    + for (n = rb_first(&u->kevent_root); n; n = rb_next(n)) {
    + k = rb_entry(n, struct kevent, kevent_node);
    + kevent_finish_user(k, 1);
    + }
    +
    + kevent_user_put(u);
    + file->private_data = NULL;
    +
    + return 0;
    +}
    +
    +/*
    + * Read requested number of ukevents in one shot.
    + */
    +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(ukev, arg, sizeof(struct ukevent) * num)) {
    + kfree(ukev);
    + return NULL;
    + }
    +
    + return ukev;
    +}
    +
    +static int kevent_mark_ready(struct ukevent *uk, struct kevent_user *u)
    +{
    + struct kevent *k;
    + int err = -ENODEV;
    + unsigned long flags;
    +
    + spin_lock_irqsave(&u->kevent_lock, flags);
    + k = __kevent_search(&uk->id, uk->type, u);
    + if (k) {
    + spin_lock(&k->st->lock);
    + kevent_ready(k, 1);
    + spin_unlock(&k->st->lock);
    + err = 0;
    + }
    + spin_unlock_irqrestore(&u->kevent_lock, flags);
    +
    + return err;
    +}
    +
    +/*
    + * Mark appropriate kevents as ready.
    + * If number of events is zero just wake up one listener.
    + */
    +static int kevent_user_ctl_ready(struct kevent_user *u, unsigned int num, void __user *arg)
    +{
    + int err = -EINVAL, cerr = 0, rnum = 0, i;
    + void __user *orig = arg;
    + struct ukevent uk;
    +
    + if (num > u->kevent_num)
    + return err;
    +
    + if (!num) {
    + u->need_exit = 1;
    + wake_up(&u->wait);
    + return 0;
    + }
    +
    + 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) {
    + err = kevent_mark_ready(&ukev[i], u);
    + if (err) {
    + if (i != rnum)
    + memcpy(&ukev[rnum], &ukev[i], sizeof(struct ukevent));
    + rnum++;
    + }
    + }
    + if (copy_to_user(orig, ukev, rnum*sizeof(struct ukevent)))
    + cerr = -EFAULT;
    + kfree(ukev);
    + goto out_setup;
    + }
    + }
    +
    + for (i = 0; i < num; ++i) {
    + if (copy_from_user(&uk, arg, sizeof(struct ukevent))) {
    + cerr = -EFAULT;
    + break;
    + }
    + arg += sizeof(struct ukevent);
    +
    + err = kevent_mark_ready(&uk, u);
    + if (err) {
    + if (copy_to_user(orig, &uk, sizeof(struct ukevent))) {
    + cerr = -EFAULT;
    + break;
    + }
    + orig += sizeof(struct ukevent);
    + rnum++;
    + }
    + }
    +
    +out_setup:
    + if (cerr < 0) {
    + err = cerr;
    + goto out_remove;
    + }
    +
    + err = num - rnum;
    +out_remove:
    + mutex_unlock(&u->ctl_mutex);
    +
    + return err;
    +}
    +
    +/*
    + * Read from userspace all ukevents and modify appropriate kevents.
    + * If provided number of ukevents is more that threshold, it is faster
    + * to allocate a room for them and copy in one shot instead of copy
    + * one-by-one and then process them.
    + */
    +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 > u->kevent_num) {
    + err = -EINVAL;
    + goto out;
    + }
    +
    + 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 = -EFAULT;
    + kfree(ukev);
    + goto out;
    + }
    + }
    +
    + for (i = 0; i < num; ++i) {
    + if (copy_from_user(&uk, arg, sizeof(struct ukevent))) {
    + err = -EFAULT;
    + 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 = -EFAULT;
    + break;
    + }
    +
    + arg += sizeof(struct ukevent);
    + }
    +out:
    + mutex_unlock(&u->ctl_mutex);
    +
    + return err;
    +}
    +
    +/*
    + * Read from userspace all ukevents and remove appropriate kevents.
    + * If provided number of ukevents is more that threshold, it is faster
    + * to allocate a room for them and copy in one shot instead of copy
    + * one-by-one and then process them.
    + */
    +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 > u->kevent_num) {
    + err = -EINVAL;
    + goto out;
    + }
    +
    + 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 = -EFAULT;
    + kfree(ukev);
    + goto out;
    + }
    + }
    +
    + for (i = 0; i < num; ++i) {
    + if (copy_from_user(&uk, arg, sizeof(struct ukevent))) {
    + err = -EFAULT;
    + 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 = -EFAULT;
    + break;
    + }
    +
    + arg += sizeof(struct ukevent);
    + }
    +out:
    + mutex_unlock(&u->ctl_mutex);
    +
    + return err;
    +}
    +
    +/*
    + * Queue kevent into userspace control block and increase
    + * it's reference counter.
    + */
    +static int kevent_user_enqueue(struct kevent_user *u, struct kevent *new)
    +{
    + unsigned long flags;
    + struct rb_node **p = &u->kevent_root.rb_node, *parent = NULL;
    + struct kevent *k;
    + int err = 0, cmp;
    +
    + spin_lock_irqsave(&u->kevent_lock, flags);
    + while (*p) {
    + parent = *p;
    + k = rb_entry(parent, struct kevent, kevent_node);
    +
    + cmp = kevent_compare_id(&k->event.id, &new->event.id,
    + k->event.type, new->event.type);
    + if (cmp > 0)
    + p = &parent->rb_right;
    + else if (cmp < 0)
    + p = &parent->rb_left;
    + else {
    + err = -EEXIST;
    + break;
    + }
    + }
    + if (likely(!err)) {
    + rb_link_node(&new->kevent_node, parent, p);
    + rb_insert_color(&new->kevent_node, &u->kevent_root);
    + new->flags |= KEVENT_USER;
    + u->kevent_num++;
    + kevent_user_get(u);
    + }
    + spin_unlock_irqrestore(&u->kevent_lock, flags);
    +
    + return err;
    +}
    +
    +/*
    + * Add kevent from both kernel and userspace users.
    + * This function allocates and queues kevent, returns negative value
    + * on error, positive if kevent is ready immediately and zero
    + * if kevent has been queued.
    + */
    +int kevent_user_add_ukevent(struct ukevent *uk, struct kevent_user *u)
    +{
    + struct kevent *k;
    + int err;
    +
    + k = kmem_cache_alloc(kevent_cache, GFP_KERNEL);
    + if (!k) {
    + err = -ENOMEM;
    + goto err_out_exit;
    + }
    +
    + memcpy(&k->event, uk, sizeof(struct ukevent));
    + INIT_RCU_HEAD(&k->rcu_head);
    +
    + k->event.ret_flags = 0;
    +
    + err = kevent_init(k);
    + if (err) {
    + kmem_cache_free(kevent_cache, k);
    + goto err_out_exit;
    + }
    + k->user = u;
    + kevent_stat_total(u);
    + err = kevent_user_enqueue(u, k);
    + if (err) {
    + kmem_cache_free(kevent_cache, k);
    + goto err_out_exit;
    + }
    +
    + err = kevent_enqueue(k);
    + if (err) {
    + memcpy(uk, &k->event, sizeof(struct ukevent));
    + kevent_finish_user(k, 0);
    + goto err_out_exit;
    + }
    +
    + return 0;
    +
    +err_out_exit:
    + if (err < 0) {
    + uk->ret_flags |= KEVENT_RET_BROKEN | KEVENT_RET_DONE;
    + uk->ret_data[1] = err;
    + } else if (err > 0)
    + uk->ret_flags |= KEVENT_RET_DONE;
    + 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...
    + * Ready events will replace ones provided by used and number
    + * of ready events is returned.
    + * User must 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, rnum = 0, i;
    + void __user *orig = arg;
    + struct ukevent uk;
    +
    + mutex_lock(&u->ctl_mutex);
    +
    + err = -EINVAL;
    + 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_event_is_allowed(&ukev[i])) {
    + if (i != rnum)
    + memcpy(&ukev[rnum],
    + &ukev[i],
    + sizeof(struct ukevent));
    + rnum++;
    + } else {
    + err = kevent_user_add_ukevent(&ukev[i], u);
    + if (err) {
    + kevent_stat_im(u);
    + if (i != rnum)
    + memcpy(&ukev[rnum],
    + &ukev[i],
    + sizeof(struct ukevent));
    + rnum++;
    + }
    + }
    + }
    + if (copy_to_user(orig, ukev, rnum*sizeof(struct ukevent)))
    + cerr = -EFAULT;
    + kfree(ukev);
    + goto out_setup;
    + }
    + }
    +
    + for (i = 0; i < num; ++i) {
    + if (copy_from_user(&uk, arg, sizeof(struct ukevent))) {
    + cerr = -EFAULT;
    + break;
    + }
    + arg += sizeof(struct ukevent);
    +
    + if (!kevent_event_is_allowed(&uk)) {
    + err = 1;
    + } else {
    + err = kevent_user_add_ukevent(&uk, u);
    + if (err)
    + kevent_stat_im(u);
    + }
    + if (err) {
    + if (copy_to_user(orig, &uk, sizeof(struct ukevent))) {
    + cerr = -EFAULT;
    + break;
    + }
    + orig += sizeof(struct ukevent);
    + rnum++;
    + }
    + }
    +
    +out_setup:
    + if (cerr < 0) {
    + err = cerr;
    + goto out_remove;
    + }
    +
    + err = rnum;
    +out_remove:
    + mutex_unlock(&u->ctl_mutex);
    +
    + return err;
    +}
    +
    +/* Used to wakeup waiting syscalls in case high-resolution timer is used. */
    +static int kevent_user_wake(struct hrtimer *timer)
    +{
    + struct kevent_user *u = container_of(timer, struct kevent_user, timer);
    +
    + u->need_exit = 1;
    + wake_up(&u->wait);
    +
    + return HRTIMER_NORESTART;
    +}
    +
    +
    +/*
    + * 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.
    + */
    +static int kevent_user_wait(struct file *file, struct kevent_user *u,
    + unsigned int min_nr, unsigned int max_nr, struct timespec timeout,
    + void __user *buf, unsigned int flags)
    +{
    + struct kevent *k;
    + int num = 0;
    + long tm = MAX_SCHEDULE_TIMEOUT;
    +
    + if (!(file->f_flags & O_NONBLOCK)) {
    + if (!timespec_valid(&timeout))
    + return -EINVAL;
    +
    + if (flags & KEVENT_FLAGS_ABSTIME) {
    + hrtimer_cancel(&u->timer);
    + hrtimer_init(&u->timer, CLOCK_REALTIME, HRTIMER_ABS);
    + u->timer.expires = ktime_set(timeout.tv_sec, timeout.tv_nsec);
    + u->timer.function = &kevent_user_wake;
    + hrtimer_start(&u->timer, u->timer.expires, HRTIMER_ABS);
    + if (unlikely(kevent_debug_abstime == 0)) {
    + printk(KERN_INFO "kevent: author was wrong, "
    + "someone uses absolute time in %s, "
    + "please report to remove this warning.\n", __func__);
    + kevent_debug_abstime = 1;
    + }
    + } else {
    + tm = timespec_to_jiffies(&timeout);
    + }
    +
    + wait_event_interruptible_timeout(u->wait,
    + ((u->ready_num >= 1) && kevent_ring_space(u)) || u->need_exit, tm);
    + }
    + u->need_exit = 0;
    +
    + while (num < max_nr && ((k = kevent_dequeue_ready(u)) != NULL)) {
    + if (copy_to_user(buf + num*sizeof(struct ukevent),
    + &k->event, sizeof(struct ukevent))) {
    + if (num == 0)
    + num = -EFAULT;
    + break;
    + }
    + kevent_complete_ready(k);
    + ++num;
    + kevent_stat_wait(u);
    + }
    +
    + return num;
    +}
    +
    +struct file_operations kevent_user_fops = {
    + .release = kevent_user_release,
    + .poll = kevent_user_poll,
    + .owner = THIS_MODULE,
    +};
    +
    +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;
    +
    + 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;
    + case KEVENT_CTL_READY:
    + err = kevent_user_ctl_ready(u, num, arg);
    + break;
    + default:
    + err = -EINVAL;
    + break;
    + }
    +
    + return err;
    +}
    +
    +/*
    + * Used to get ready kevents from queue.
    + * @ctl_fd - kevent control descriptor which must be obtained through kevent_ctl(KEVENT_CTL_INIT).
    + * @min_nr - minimum number of ready kevents.
    + * @max_nr - maximum number of ready kevents.
    + * @timeout - time to wait until some events are ready.
    + * @buf - buffer to place ready events.
    + * @flags - various flags (see include/linux/ukevent.h KEVENT_FLAGS_*).
    + */
    +asmlinkage long sys_kevent_get_events(int ctl_fd, unsigned int min_nr, unsigned int max_nr,
    + struct timespec timeout, struct ukevent __user *buf, unsigned flags)
    +{
    + int err = -EINVAL;
    + struct file *file;
    + struct kevent_user *u;
    +
    + file = fget(ctl_fd);
    + if (!file)
    + return -EBADF;
    +
    + 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, flags);
    +out_fput:
    + fput(file);
    + return err;
    +}
    +
    +static struct vfsmount *kevent_mnt __read_mostly;
    +
    +static int kevent_get_sb(struct file_system_type *fs_type, int flags,
    + const char *dev_name, void *data, struct vfsmount *mnt)
    +{
    + return get_sb_pseudo(fs_type, "kevent", NULL, 0xaabbccdd, mnt);
    +}
    +
    +static struct file_system_type kevent_fs_type = {
    + .name = "keventfs",
    + .get_sb = kevent_get_sb,
    + .kill_sb = kill_anon_super,
    +};
    +
    +static int keventfs_delete_dentry(struct dentry *dentry)
    +{
    + return 1;
    +}
    +
    +static struct dentry_operations keventfs_dentry_operations = {
    + .d_delete = keventfs_delete_dentry,
    +};
    +
    +asmlinkage long sys_kevent_init(struct kevent_ring __user *ring, unsigned int num, unsigned int flags)
    +{
    + struct qstr this;
    + char name[32];
    + struct dentry *dentry;
    + struct inode *inode;
    + struct file *file;
    + int err = -ENFILE, fd;
    + struct kevent_user *u;
    +
    + if ((ring && !num) || (!ring && num) || (num == 1))
    + return -EINVAL;
    +
    + file = get_empty_filp();
    + if (!file)
    + goto err_out_exit;
    +
    + inode = new_inode(kevent_mnt->mnt_sb);
    + if (!inode)
    + goto err_out_fput;
    +
    + inode->i_fop = &kevent_user_fops;
    +
    + inode->i_state = I_DIRTY;
    + inode->i_mode = S_IRUSR | S_IWUSR;
    + inode->i_uid = current->fsuid;
    + inode->i_gid = current->fsgid;
    + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
    +
    + err = get_unused_fd();
    + if (err < 0)
    + goto err_out_iput;
    + fd = err;
    +
    + err = -ENOMEM;
    + u = kevent_user_alloc(ring, num);
    + if (!u)
    + goto err_out_put_fd;
    +
    + sprintf(name, "[%lu]", inode->i_ino);
    + this.name = name;
    + this.len = strlen(name);
    + this.hash = inode->i_ino;
    + dentry = d_alloc(kevent_mnt->mnt_sb->s_root, &this);
    + if (!dentry)
    + goto err_out_free;
    + dentry->d_op = &keventfs_dentry_operations;
    + d_add(dentry, inode);
    + file->f_vfsmnt = mntget(kevent_mnt);
    + file->f_dentry = dentry;
    + file->f_mapping = inode->i_mapping;
    + file->f_pos = 0;
    + file->f_flags = O_RDONLY;
    + file->f_op = &kevent_user_fops;
    + file->f_mode = FMODE_READ;
    + file->f_version = 0;
    + file->private_data = u;
    +
    + fd_install(fd, file);
    +
    + return fd;
    +
    +err_out_free:
    + kmem_cache_free(kevent_user_cache, u);
    +err_out_put_fd:
    + put_unused_fd(fd);
    +err_out_iput:
    + iput(inode);
    +err_out_fput:
    + put_filp(file);
    +err_out_exit:
    + return err;
    +}
    +
    +/*
    + * Commits user's index (consumer index).
    + * Must be called under u->ring_lock mutex held.
    + */
    +static int __kevent_user_commit(struct kevent_user *u, unsigned int new_uidx, unsigned int over)
    +{
    + int err = -EOVERFLOW, comm = 0;
    + struct kevent_ring __user *ring = u->pring;
    +
    + if (!ring) {
    + err = 0;
    + goto err_out_exit;
    + }
    +
    + if (new_uidx >= u->ring_size) {
    + err = -EINVAL;
    + goto err_out_exit;
    + }
    +
    + if ((over != u->ring_over - 1) && (over != u->ring_over))
    + goto err_out_exit;
    +
    + if (u->uidx < u->kidx && new_uidx > u->kidx) {
    + err = -EINVAL;
    + goto err_out_exit;
    + }
    +
    + if (new_uidx > u->uidx) {
    + if (over != u->ring_over)
    + goto err_out_exit;
    +
    + comm = new_uidx - u->uidx;
    + u->uidx = new_uidx;
    + u->full = 0;
    + } else if (new_uidx < u->uidx) {
    + comm = u->ring_size - (u->uidx - new_uidx);
    + u->uidx = new_uidx;
    + u->full = 0;
    + u->ring_over++;
    +
    + if (put_user(u->ring_over, &ring->ring_over)) {
    + err = -EFAULT;
    + goto err_out_exit;
    + }
    + }
    +
    + return comm;
    +
    +err_out_exit:
    + return err;
    +}
    +
    +/*
    + * This syscall is used to perform waiting until there is free space in the ring
    + * buffer, in that case some events will be copied there.
    + * Function returns number of actually copied ready events in ring buffer.
    + * After this function is completed userspace ring->ring_kidx will be updated.
    + *
    + * @ctl_fd - kevent file descriptor.
    + * @num - number of kevents to process.
    + * @old_uidx - the last index user is aware of.
    + * @timeout - time to wait until there is free space in kevent queue.
    + * @flags - various flags (see include/linux/ukevent.h KEVENT_FLAGS_*).
    + *
    + * When we need to commit @num events, it means we should just remove first @num
    + * kevents from ready queue and copy them into the buffer.
    + * Kevents will be copied into ring buffer in order they were placed into ready queue.
    + * One-shot kevents will be removed here, since there is no way they can be reused.
    + * Edge-triggered events will be requeued here for better performance.
    + */
    +asmlinkage long sys_kevent_wait(int ctl_fd, unsigned int num, unsigned int old_uidx,
    + struct timespec timeout, unsigned int flags)
    +{
    + int err = -EINVAL, copied = 0;
    + struct file *file;
    + struct kevent_user *u;
    + struct kevent *k;
    + struct kevent_ring __user *ring;
    + long tm = MAX_SCHEDULE_TIMEOUT;
    + unsigned int i;
    +
    + file = fget(ctl_fd);
    + if (!file)
    + return -EBADF;
    +
    + if (file->f_op != &kevent_user_fops)
    + goto out_fput;
    + u = file->private_data;
    +
    + ring = u->pring;
    + if (!ring || num > u->ring_size)
    + goto out_fput;
    +#if 0
    + /*
    + * Allow to immediately update ring index, but it is not supported,
    + * since syscall() has limited number of arguments which is actually
    + * a good idea - use kevent_commit() instead.
    + */
    + if ((u->uidx != new_uidx) && (new_uidx != 0xffffffff)) {
    + mutex_lock(&u->ring_lock);
    + __kevent_user_commit(u, new_uidx, over);
    + mutex_unlock(&u->ring_lock);
    + }
    +#endif
    +
    + if (!(file->f_flags & O_NONBLOCK)) {
    + if (!timespec_valid(&timeout))
    + goto out_fput;
    +
    + if (flags & KEVENT_FLAGS_ABSTIME) {
    + hrtimer_cancel(&u->timer);
    + hrtimer_init(&u->timer, CLOCK_REALTIME, HRTIMER_ABS);
    + u->timer.expires = ktime_set(timeout.tv_sec, timeout.tv_nsec);
    + u->timer.function = &kevent_user_wake;
    + hrtimer_start(&u->timer, u->timer.expires, HRTIMER_ABS);
    + if (unlikely(kevent_debug_abstime == 0)) {
    + printk(KERN_INFO "kevent: author was wrong, "
    + "someone uses absolute time in %s, "
    + "please report to remove this warning.\n", __func__);
    + kevent_debug_abstime = 1;
    + }
    + } else {
    + tm = timespec_to_jiffies(&timeout);
    + }
    +
    + wait_event_interruptible_timeout(u->wait,
    + ((u->ready_num >= 1) && kevent_ring_space(u)) ||
    + u->need_exit || old_uidx != u->uidx,
    + tm);
    + }
    + u->need_exit = 0;
    +
    + for (i=0; i<num; ++i) {
    + k = kevent_dequeue_ready_ring(u);
    + if (!k)
    + break;
    + kevent_complete_ready(k);
    +
    + if (k->event.ret_flags & KEVENT_RET_COPY_FAILED)
    + break;
    + kevent_stat_ring(u);
    + copied++;
    + }
    +
    + fput(file);
    +
    + return copied;
    +out_fput:
    + fput(file);
    + return err;
    +}
    +
    +/*
    + * This syscall is used to commit events in ring buffer, i.e. mark appropriate
    + * entries as unused by userspace so subsequent kevent_wait() could overwrite them.
    + * This fucntion returns actual number of kevents which were committed.
    + * After this function is completed userspace ring->ring_over can be updated.
    + *
    + * @ctl_fd - kevent file descriptor.
    + * @new_uidx - the last committed kevent.
    + * @over - number of overflows given queue had.
    + */
    +asmlinkage long sys_kevent_commit(int ctl_fd, unsigned int new_uidx, unsigned int over)
    +{
    + int err = -EINVAL, comm = 0;
    + struct file *file;
    + struct kevent_user *u;
    +
    + file = fget(ctl_fd);
    + if (!file)
    + return -EBADF;
    +
    + if (file->f_op != &kevent_user_fops)
    + goto out_fput;
    + u = file->private_data;
    +
    + mutex_lock(&u->ring_lock);
    + err = __kevent_user_commit(u, new_uidx, over);
    + if (err < 0)
    + goto err_out_unlock;
    + comm = err;
    + mutex_unlock(&u->ring_lock);
    +
    + fput(file);
    +
    + return comm;
    +
    +err_out_unlock:
    + mutex_unlock(&u->ring_lock);
    +out_fput:
    + fput(file);
    + return err;
    +}
    +
    +/*
    + * This syscall is used to perform various control operations
    + * on given kevent queue, which is obtained through kevent file descriptor @fd.
    + * @cmd - type of operation.
    + * @num - number of kevents to be processed.
    + * @arg - pointer to array of struct ukevent.
    + */
    +asmlinkage long sys_kevent_ctl(int fd, unsigned int cmd, unsigned int num, struct ukevent __user *arg)
    +{
    + int err = -EINVAL;
    + struct file *file;
    +
    + file = fget(fd);
    + if (!file)
    + return -EBADF;
    +
    + if (file->f_op != &kevent_user_fops)
    + goto out_fput;
    +
    + err = kevent_ctl_process(file, cmd, num, arg);
    +
    +out_fput:
    + fput(file);
    + return err;
    +}
    +
    +/*
    + * Kevent subsystem initialization - create caches and register
    + * filesystem to get control file descriptors from.
    + */
    +static int __init kevent_user_init(void)
    +{
    + int err = 0;
    +
    + kevent_cache = kmem_cache_create("kevent_cache",
    + sizeof(struct kevent), 0, SLAB_PANIC, NULL, NULL);
    +
    + kevent_user_cache = kmem_cache_create("kevent_user_cache",
    + sizeof(struct kevent_user), 0, SLAB_PANIC, NULL, NULL);
    +
    + err = register_filesystem(&kevent_fs_type);
    + if (err)
    + goto err_out_exit;
    +
    + kevent_mnt = kern_mount(&kevent_fs_type);
    + err = PTR_ERR(kevent_mnt);
    + if (IS_ERR(kevent_mnt))
    + goto err_out_unreg;
    +
    + printk(KERN_INFO "KEVENT subsystem has been successfully registered.\n");
    +
    + return 0;
    +
    +err_out_unreg:
    + unregister_filesystem(&kevent_fs_type);
    +err_out_exit:
    + kmem_cache_destroy(kevent_cache);
    + return err;
    +}
    +
    +module_init(kevent_user_init);
    diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
    index d7306d0..22a775a 100644
    --- a/kernel/sys_ni.c
    +++ b/kernel/sys_ni.c
    @@ -123,6 +123,15 @@ cond_syscall(ppc_rtas);
    cond_syscall(sys_spu_run);
    cond_syscall(sys_spu_create);

    +cond_syscall(sys_kevent_get_events);
    +cond_syscall(sys_kevent_ctl);
    +cond_syscall(sys_kevent_wait);
    +cond_syscall(sys_kevent_commit);
    +cond_syscall(sys_kevent_init);
    +
    +cond_syscall(sys_aio_sendfile);
    +cond_syscall(sys_aio_sendfile_path);
    +
    /* mmu depending weak syscall entries */
    cond_syscall(sys_mprotect);
    cond_syscall(sys_msync);
    -
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      Last update: 2007-02-01 11:19    [W:0.163 / U:1.828 seconds]
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