2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/sys/kern/kern_event.c,v 1.2.2.9 2003/05/08 07:47:16 kbyanc Exp $
27 * $DragonFly: src/sys/kern/kern_event.c,v 1.5 2003/07/19 21:14:38 dillon Exp $
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
34 #include <sys/malloc.h>
35 #include <sys/unistd.h>
37 #include <sys/fcntl.h>
38 #include <sys/select.h>
39 #include <sys/queue.h>
40 #include <sys/event.h>
41 #include <sys/eventvar.h>
43 #include <sys/protosw.h>
44 #include <sys/socket.h>
45 #include <sys/socketvar.h>
47 #include <sys/sysctl.h>
48 #include <sys/sysproto.h>
50 #include <sys/file2.h>
52 #include <vm/vm_zone.h>
54 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
56 static int kqueue_scan(struct file *fp, int maxevents,
57 struct kevent *ulistp, const struct timespec *timeout,
59 static int kqueue_read(struct file *fp, struct uio *uio,
60 struct ucred *cred, int flags, struct thread *td);
61 static int kqueue_write(struct file *fp, struct uio *uio,
62 struct ucred *cred, int flags, struct thread *td);
63 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
65 static int kqueue_poll(struct file *fp, int events, struct ucred *cred,
67 static int kqueue_kqfilter(struct file *fp, struct knote *kn);
68 static int kqueue_stat(struct file *fp, struct stat *st, struct thread *td);
69 static int kqueue_close(struct file *fp, struct thread *td);
70 static void kqueue_wakeup(struct kqueue *kq);
72 static struct fileops kqueueops = {
82 static void knote_attach(struct knote *kn, struct filedesc *fdp);
83 static void knote_drop(struct knote *kn, struct thread *td);
84 static void knote_enqueue(struct knote *kn);
85 static void knote_dequeue(struct knote *kn);
86 static void knote_init(void);
87 static struct knote *knote_alloc(void);
88 static void knote_free(struct knote *kn);
90 static void filt_kqdetach(struct knote *kn);
91 static int filt_kqueue(struct knote *kn, long hint);
92 static int filt_procattach(struct knote *kn);
93 static void filt_procdetach(struct knote *kn);
94 static int filt_proc(struct knote *kn, long hint);
95 static int filt_fileattach(struct knote *kn);
96 static void filt_timerexpire(void *knx);
97 static int filt_timerattach(struct knote *kn);
98 static void filt_timerdetach(struct knote *kn);
99 static int filt_timer(struct knote *kn, long hint);
101 static struct filterops file_filtops =
102 { 1, filt_fileattach, NULL, NULL };
103 static struct filterops kqread_filtops =
104 { 1, NULL, filt_kqdetach, filt_kqueue };
105 static struct filterops proc_filtops =
106 { 0, filt_procattach, filt_procdetach, filt_proc };
107 static struct filterops timer_filtops =
108 { 0, filt_timerattach, filt_timerdetach, filt_timer };
110 static vm_zone_t knote_zone;
111 static int kq_ncallouts = 0;
112 static int kq_calloutmax = (4 * 1024);
113 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
114 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
116 #define KNOTE_ACTIVATE(kn) do { \
117 kn->kn_status |= KN_ACTIVE; \
118 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
122 #define KN_HASHSIZE 64 /* XXX should be tunable */
123 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
125 extern struct filterops aio_filtops;
126 extern struct filterops sig_filtops;
129 * Table for for all system-defined filters.
131 static struct filterops *sysfilt_ops[] = {
132 &file_filtops, /* EVFILT_READ */
133 &file_filtops, /* EVFILT_WRITE */
134 &aio_filtops, /* EVFILT_AIO */
135 &file_filtops, /* EVFILT_VNODE */
136 &proc_filtops, /* EVFILT_PROC */
137 &sig_filtops, /* EVFILT_SIGNAL */
138 &timer_filtops, /* EVFILT_TIMER */
142 filt_fileattach(struct knote *kn)
144 return (fo_kqfilter(kn->kn_fp, kn));
149 kqueue_kqfilter(struct file *fp, struct knote *kn)
151 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
153 if (kn->kn_filter != EVFILT_READ)
156 kn->kn_fop = &kqread_filtops;
157 SLIST_INSERT_HEAD(&kq->kq_sel.si_note, kn, kn_selnext);
162 filt_kqdetach(struct knote *kn)
164 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
166 SLIST_REMOVE(&kq->kq_sel.si_note, kn, knote, kn_selnext);
171 filt_kqueue(struct knote *kn, long hint)
173 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
175 kn->kn_data = kq->kq_count;
176 return (kn->kn_data > 0);
180 filt_procattach(struct knote *kn)
186 p = pfind(kn->kn_id);
187 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
188 p = zpfind(kn->kn_id);
193 if (! PRISON_CHECK(curproc->p_ucred, p->p_ucred))
196 kn->kn_ptr.p_proc = p;
197 kn->kn_flags |= EV_CLEAR; /* automatically set */
200 * internal flag indicating registration done by kernel
202 if (kn->kn_flags & EV_FLAG1) {
203 kn->kn_data = kn->kn_sdata; /* ppid */
204 kn->kn_fflags = NOTE_CHILD;
205 kn->kn_flags &= ~EV_FLAG1;
208 /* XXX lock the proc here while adding to the list? */
209 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
212 * Immediately activate any exit notes if the target process is a
213 * zombie. This is necessary to handle the case where the target
214 * process, e.g. a child, dies before the kevent is registered.
216 if (immediate && filt_proc(kn, NOTE_EXIT))
223 * The knote may be attached to a different process, which may exit,
224 * leaving nothing for the knote to be attached to. So when the process
225 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
226 * it will be deleted when read out. However, as part of the knote deletion,
227 * this routine is called, so a check is needed to avoid actually performing
228 * a detach, because the original process does not exist any more.
231 filt_procdetach(struct knote *kn)
233 struct proc *p = kn->kn_ptr.p_proc;
235 if (kn->kn_status & KN_DETACHED)
238 /* XXX locking? this might modify another process. */
239 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
243 filt_proc(struct knote *kn, long hint)
248 * mask off extra data
250 event = (u_int)hint & NOTE_PCTRLMASK;
253 * if the user is interested in this event, record it.
255 if (kn->kn_sfflags & event)
256 kn->kn_fflags |= event;
259 * process is gone, so flag the event as finished.
261 if (event == NOTE_EXIT) {
262 kn->kn_status |= KN_DETACHED;
263 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
268 * process forked, and user wants to track the new process,
269 * so attach a new knote to it, and immediately report an
270 * event with the parent's pid.
272 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
277 * register knote with new process.
279 kev.ident = hint & NOTE_PDATAMASK; /* pid */
280 kev.filter = kn->kn_filter;
281 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
282 kev.fflags = kn->kn_sfflags;
283 kev.data = kn->kn_id; /* parent */
284 kev.udata = kn->kn_kevent.udata; /* preserve udata */
285 error = kqueue_register(kn->kn_kq, &kev, NULL);
287 kn->kn_fflags |= NOTE_TRACKERR;
290 return (kn->kn_fflags != 0);
294 filt_timerexpire(void *knx)
296 struct knote *kn = knx;
297 struct callout *calloutp;
304 if ((kn->kn_flags & EV_ONESHOT) == 0) {
305 tv.tv_sec = kn->kn_sdata / 1000;
306 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
307 tticks = tvtohz(&tv);
308 calloutp = (struct callout *)kn->kn_hook;
309 callout_reset(calloutp, tticks, filt_timerexpire, kn);
314 * data contains amount of time to sleep, in milliseconds
317 filt_timerattach(struct knote *kn)
319 struct callout *calloutp;
323 if (kq_ncallouts >= kq_calloutmax)
327 tv.tv_sec = kn->kn_sdata / 1000;
328 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
329 tticks = tvtohz(&tv);
331 kn->kn_flags |= EV_CLEAR; /* automatically set */
332 MALLOC(calloutp, struct callout *, sizeof(*calloutp),
334 callout_init(calloutp);
335 callout_reset(calloutp, tticks, filt_timerexpire, kn);
336 kn->kn_hook = (caddr_t)calloutp;
342 filt_timerdetach(struct knote *kn)
344 struct callout *calloutp;
346 calloutp = (struct callout *)kn->kn_hook;
347 callout_stop(calloutp);
348 FREE(calloutp, M_KQUEUE);
353 filt_timer(struct knote *kn, long hint)
356 return (kn->kn_data != 0);
360 kqueue(struct kqueue_args *uap)
362 struct proc *p = curproc;
363 struct filedesc *fdp = p->p_fd;
368 error = falloc(p, &fp, &fd);
371 fp->f_flag = FREAD | FWRITE;
372 fp->f_type = DTYPE_KQUEUE;
373 fp->f_ops = &kqueueops;
374 kq = malloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
375 TAILQ_INIT(&kq->kq_head);
376 fp->f_data = (caddr_t)kq;
378 if (fdp->fd_knlistsize < 0)
379 fdp->fd_knlistsize = 0; /* this process has a kq */
384 #ifndef _SYS_SYSPROTO_H_
387 const struct kevent *changelist;
389 struct kevent *eventlist;
391 const struct timespec *timeout;
395 kevent(struct kevent_args *uap)
397 struct thread *td = curthread;
398 struct proc *p = td->td_proc;
399 struct filedesc *fdp;
402 struct file *fp = NULL;
404 int i, n, nerrors, error;
409 if (((u_int)uap->fd) >= fdp->fd_nfiles ||
410 (fp = fdp->fd_ofiles[uap->fd]) == NULL ||
411 (fp->f_type != DTYPE_KQUEUE))
416 if (uap->timeout != NULL) {
417 error = copyin(uap->timeout, &ts, sizeof(ts));
423 kq = (struct kqueue *)fp->f_data;
426 while (uap->nchanges > 0) {
427 n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
428 error = copyin(uap->changelist, kq->kq_kev,
429 n * sizeof(struct kevent));
432 for (i = 0; i < n; i++) {
433 kevp = &kq->kq_kev[i];
434 kevp->flags &= ~EV_SYSFLAGS;
435 error = kqueue_register(kq, kevp, td);
437 if (uap->nevents != 0) {
438 kevp->flags = EV_ERROR;
440 (void) copyout((caddr_t)kevp,
441 (caddr_t)uap->eventlist,
452 uap->changelist += n;
455 p->p_retval[0] = nerrors;
460 error = kqueue_scan(fp, uap->nevents, uap->eventlist, uap->timeout, p);
463 fdrop(fp, p->p_thread);
468 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td)
470 struct filedesc *fdp = kq->kq_fdp;
471 struct filterops *fops;
472 struct file *fp = NULL;
473 struct knote *kn = NULL;
476 if (kev->filter < 0) {
477 if (kev->filter + EVFILT_SYSCOUNT < 0)
479 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
483 * filter attach routine is responsible for insuring that
484 * the identifier can be attached to it.
486 printf("unknown filter: %d\n", kev->filter);
491 /* validate descriptor */
492 if ((u_int)kev->ident >= fdp->fd_nfiles ||
493 (fp = fdp->fd_ofiles[kev->ident]) == NULL)
497 if (kev->ident < fdp->fd_knlistsize) {
498 SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
499 if (kq == kn->kn_kq &&
500 kev->filter == kn->kn_filter)
504 if (fdp->fd_knhashmask != 0) {
507 list = &fdp->fd_knhash[
508 KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
509 SLIST_FOREACH(kn, list, kn_link)
510 if (kev->ident == kn->kn_id &&
512 kev->filter == kn->kn_filter)
517 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
523 * kn now contains the matching knote, or NULL if no match
525 if (kev->flags & EV_ADD) {
538 * apply reference count to knote structure, and
539 * do not release it at the end of this routine.
543 kn->kn_sfflags = kev->fflags;
544 kn->kn_sdata = kev->data;
547 kn->kn_kevent = *kev;
549 knote_attach(kn, fdp);
550 if ((error = fops->f_attach(kn)) != 0) {
556 * The user may change some filter values after the
557 * initial EV_ADD, but doing so will not reset any
558 * filter which have already been triggered.
560 kn->kn_sfflags = kev->fflags;
561 kn->kn_sdata = kev->data;
562 kn->kn_kevent.udata = kev->udata;
566 if (kn->kn_fop->f_event(kn, 0))
570 } else if (kev->flags & EV_DELETE) {
571 kn->kn_fop->f_detach(kn);
576 if ((kev->flags & EV_DISABLE) &&
577 ((kn->kn_status & KN_DISABLED) == 0)) {
579 kn->kn_status |= KN_DISABLED;
583 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
585 kn->kn_status &= ~KN_DISABLED;
586 if ((kn->kn_status & KN_ACTIVE) &&
587 ((kn->kn_status & KN_QUEUED) == 0))
599 kqueue_scan(struct file *fp, int maxevents, struct kevent *ulistp,
600 const struct timespec *tsp, struct proc *p)
602 struct thread *td = p->p_thread;
603 struct kqueue *kq = (struct kqueue *)fp->f_data;
605 struct timeval atv, rtv, ttv;
606 struct knote *kn, marker;
607 int s, count, timeout, nkev = 0, error = 0;
614 TIMESPEC_TO_TIMEVAL(&atv, tsp);
615 if (itimerfix(&atv)) {
619 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
622 timeout = atv.tv_sec > 24 * 60 * 60 ?
623 24 * 60 * 60 * hz : tvtohz(&atv);
624 getmicrouptime(&rtv);
625 timevaladd(&atv, &rtv);
634 if (atv.tv_sec || atv.tv_usec) {
635 getmicrouptime(&rtv);
636 if (timevalcmp(&rtv, &atv, >=))
639 timevalsub(&ttv, &rtv);
640 timeout = ttv.tv_sec > 24 * 60 * 60 ?
641 24 * 60 * 60 * hz : tvtohz(&ttv);
647 if (kq->kq_count == 0) {
651 kq->kq_state |= KQ_SLEEP;
652 error = tsleep(kq, PCATCH, "kqread", timeout);
657 /* don't restart after signals... */
658 if (error == ERESTART)
660 else if (error == EWOULDBLOCK)
665 TAILQ_INSERT_TAIL(&kq->kq_head, &marker, kn_tqe);
667 kn = TAILQ_FIRST(&kq->kq_head);
668 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
671 if (count == maxevents)
675 if (kn->kn_status & KN_DISABLED) {
676 kn->kn_status &= ~KN_QUEUED;
680 if ((kn->kn_flags & EV_ONESHOT) == 0 &&
681 kn->kn_fop->f_event(kn, 0) == 0) {
682 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
686 *kevp = kn->kn_kevent;
689 if (kn->kn_flags & EV_ONESHOT) {
690 kn->kn_status &= ~KN_QUEUED;
693 kn->kn_fop->f_detach(kn);
696 } else if (kn->kn_flags & EV_CLEAR) {
699 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
702 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
705 if (nkev == KQ_NEVENTS) {
707 error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
708 sizeof(struct kevent) * nkev);
717 TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe);
721 error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
722 sizeof(struct kevent) * nkev);
723 p->p_retval[0] = maxevents - count;
729 * This could be expanded to call kqueue_scan, if desired.
733 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred,
734 int flags, struct thread *td)
741 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred,
742 int flags, struct thread *td)
749 kqueue_ioctl(struct file *fp, u_long com, caddr_t data, struct thread *td)
756 kqueue_poll(struct file *fp, int events, struct ucred *cred, struct thread *td)
758 struct kqueue *kq = (struct kqueue *)fp->f_data;
762 if (events & (POLLIN | POLLRDNORM)) {
764 revents |= events & (POLLIN | POLLRDNORM);
766 selrecord(td, &kq->kq_sel);
767 kq->kq_state |= KQ_SEL;
776 kqueue_stat(struct file *fp, struct stat *st, struct thread *td)
778 struct kqueue *kq = (struct kqueue *)fp->f_data;
780 bzero((void *)st, sizeof(*st));
781 st->st_size = kq->kq_count;
782 st->st_blksize = sizeof(struct kevent);
783 st->st_mode = S_IFIFO;
789 kqueue_close(struct file *fp, struct thread *td)
791 struct proc *p = td->td_proc;
792 struct kqueue *kq = (struct kqueue *)fp->f_data;
793 struct filedesc *fdp;
794 struct knote **knp, *kn, *kn0;
799 for (i = 0; i < fdp->fd_knlistsize; i++) {
800 knp = &SLIST_FIRST(&fdp->fd_knlist[i]);
803 kn0 = SLIST_NEXT(kn, kn_link);
804 if (kq == kn->kn_kq) {
805 kn->kn_fop->f_detach(kn);
806 fdrop(kn->kn_fp, td);
810 knp = &SLIST_NEXT(kn, kn_link);
815 if (fdp->fd_knhashmask != 0) {
816 for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
817 knp = &SLIST_FIRST(&fdp->fd_knhash[i]);
820 kn0 = SLIST_NEXT(kn, kn_link);
821 if (kq == kn->kn_kq) {
822 kn->kn_fop->f_detach(kn);
823 /* XXX non-fd release of kn->kn_ptr */
827 knp = &SLIST_NEXT(kn, kn_link);
840 kqueue_wakeup(struct kqueue *kq)
843 if (kq->kq_state & KQ_SLEEP) {
844 kq->kq_state &= ~KQ_SLEEP;
847 if (kq->kq_state & KQ_SEL) {
848 kq->kq_state &= ~KQ_SEL;
849 selwakeup(&kq->kq_sel);
851 KNOTE(&kq->kq_sel.si_note, 0);
855 * walk down a list of knotes, activating them if their event has triggered.
858 knote(struct klist *list, long hint)
862 SLIST_FOREACH(kn, list, kn_selnext)
863 if (kn->kn_fop->f_event(kn, hint))
868 * remove all knotes from a specified klist
871 knote_remove(struct thread *td, struct klist *list)
875 while ((kn = SLIST_FIRST(list)) != NULL) {
876 kn->kn_fop->f_detach(kn);
882 * remove all knotes referencing a specified fd
885 knote_fdclose(struct proc *p, int fd)
887 struct filedesc *fdp = p->p_fd;
888 struct klist *list = &fdp->fd_knlist[fd];
890 knote_remove(p->p_thread, list);
894 knote_attach(struct knote *kn, struct filedesc *fdp)
899 if (! kn->kn_fop->f_isfd) {
900 if (fdp->fd_knhashmask == 0)
901 fdp->fd_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
902 &fdp->fd_knhashmask);
903 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
907 if (fdp->fd_knlistsize <= kn->kn_id) {
908 size = fdp->fd_knlistsize;
909 while (size <= kn->kn_id)
911 MALLOC(list, struct klist *,
912 size * sizeof(struct klist *), M_KQUEUE, M_WAITOK);
913 bcopy((caddr_t)fdp->fd_knlist, (caddr_t)list,
914 fdp->fd_knlistsize * sizeof(struct klist *));
915 bzero((caddr_t)list +
916 fdp->fd_knlistsize * sizeof(struct klist *),
917 (size - fdp->fd_knlistsize) * sizeof(struct klist *));
918 if (fdp->fd_knlist != NULL)
919 FREE(fdp->fd_knlist, M_KQUEUE);
920 fdp->fd_knlistsize = size;
921 fdp->fd_knlist = list;
923 list = &fdp->fd_knlist[kn->kn_id];
925 SLIST_INSERT_HEAD(list, kn, kn_link);
930 * should be called at spl == 0, since we don't want to hold spl
931 * while calling fdrop and free.
934 knote_drop(struct knote *kn, struct thread *td)
936 struct filedesc *fdp;
939 KKASSERT(td->td_proc);
940 fdp = td->td_proc->p_fd;
941 if (kn->kn_fop->f_isfd)
942 list = &fdp->fd_knlist[kn->kn_id];
944 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
946 SLIST_REMOVE(list, kn, knote, kn_link);
947 if (kn->kn_status & KN_QUEUED)
949 if (kn->kn_fop->f_isfd)
950 fdrop(kn->kn_fp, td);
956 knote_enqueue(struct knote *kn)
958 struct kqueue *kq = kn->kn_kq;
961 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
963 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
964 kn->kn_status |= KN_QUEUED;
971 knote_dequeue(struct knote *kn)
973 struct kqueue *kq = kn->kn_kq;
976 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
978 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
979 kn->kn_status &= ~KN_QUEUED;
987 knote_zone = zinit("KNOTE", sizeof(struct knote), 0, 0, 1);
989 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL)
991 static struct knote *
994 return ((struct knote *)zalloc(knote_zone));
998 knote_free(struct knote *kn)
1000 zfree(knote_zone, kn);