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 1.2.2.10 2004/04/04 07:03:14 cperciva Exp $
27 * $DragonFly: src/sys/kern/kern_event.c,v 1.12 2004/05/13 23:49:23 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,
58 struct proc *p, int *res);
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 = {
84 static void knote_attach(struct knote *kn, struct filedesc *fdp);
85 static void knote_drop(struct knote *kn, struct thread *td);
86 static void knote_enqueue(struct knote *kn);
87 static void knote_dequeue(struct knote *kn);
88 static void knote_init(void);
89 static struct knote *knote_alloc(void);
90 static void knote_free(struct knote *kn);
92 static void filt_kqdetach(struct knote *kn);
93 static int filt_kqueue(struct knote *kn, long hint);
94 static int filt_procattach(struct knote *kn);
95 static void filt_procdetach(struct knote *kn);
96 static int filt_proc(struct knote *kn, long hint);
97 static int filt_fileattach(struct knote *kn);
98 static void filt_timerexpire(void *knx);
99 static int filt_timerattach(struct knote *kn);
100 static void filt_timerdetach(struct knote *kn);
101 static int filt_timer(struct knote *kn, long hint);
103 static struct filterops file_filtops =
104 { 1, filt_fileattach, NULL, NULL };
105 static struct filterops kqread_filtops =
106 { 1, NULL, filt_kqdetach, filt_kqueue };
107 static struct filterops proc_filtops =
108 { 0, filt_procattach, filt_procdetach, filt_proc };
109 static struct filterops timer_filtops =
110 { 0, filt_timerattach, filt_timerdetach, filt_timer };
112 static vm_zone_t knote_zone;
113 static int kq_ncallouts = 0;
114 static int kq_calloutmax = (4 * 1024);
115 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
116 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
118 #define KNOTE_ACTIVATE(kn) do { \
119 kn->kn_status |= KN_ACTIVE; \
120 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
124 #define KN_HASHSIZE 64 /* XXX should be tunable */
125 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
127 extern struct filterops aio_filtops;
128 extern struct filterops sig_filtops;
131 * Table for for all system-defined filters.
133 static struct filterops *sysfilt_ops[] = {
134 &file_filtops, /* EVFILT_READ */
135 &file_filtops, /* EVFILT_WRITE */
136 &aio_filtops, /* EVFILT_AIO */
137 &file_filtops, /* EVFILT_VNODE */
138 &proc_filtops, /* EVFILT_PROC */
139 &sig_filtops, /* EVFILT_SIGNAL */
140 &timer_filtops, /* EVFILT_TIMER */
144 filt_fileattach(struct knote *kn)
146 return (fo_kqfilter(kn->kn_fp, kn));
151 kqueue_kqfilter(struct file *fp, struct knote *kn)
153 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
155 if (kn->kn_filter != EVFILT_READ)
158 kn->kn_fop = &kqread_filtops;
159 SLIST_INSERT_HEAD(&kq->kq_sel.si_note, kn, kn_selnext);
164 filt_kqdetach(struct knote *kn)
166 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
168 SLIST_REMOVE(&kq->kq_sel.si_note, kn, knote, kn_selnext);
173 filt_kqueue(struct knote *kn, long hint)
175 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
177 kn->kn_data = kq->kq_count;
178 return (kn->kn_data > 0);
182 filt_procattach(struct knote *kn)
188 p = pfind(kn->kn_id);
189 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
190 p = zpfind(kn->kn_id);
195 if (! PRISON_CHECK(curproc->p_ucred, p->p_ucred))
198 kn->kn_ptr.p_proc = p;
199 kn->kn_flags |= EV_CLEAR; /* automatically set */
202 * internal flag indicating registration done by kernel
204 if (kn->kn_flags & EV_FLAG1) {
205 kn->kn_data = kn->kn_sdata; /* ppid */
206 kn->kn_fflags = NOTE_CHILD;
207 kn->kn_flags &= ~EV_FLAG1;
210 /* XXX lock the proc here while adding to the list? */
211 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
214 * Immediately activate any exit notes if the target process is a
215 * zombie. This is necessary to handle the case where the target
216 * process, e.g. a child, dies before the kevent is registered.
218 if (immediate && filt_proc(kn, NOTE_EXIT))
225 * The knote may be attached to a different process, which may exit,
226 * leaving nothing for the knote to be attached to. So when the process
227 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
228 * it will be deleted when read out. However, as part of the knote deletion,
229 * this routine is called, so a check is needed to avoid actually performing
230 * a detach, because the original process does not exist any more.
233 filt_procdetach(struct knote *kn)
235 struct proc *p = kn->kn_ptr.p_proc;
237 if (kn->kn_status & KN_DETACHED)
240 /* XXX locking? this might modify another process. */
241 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
245 filt_proc(struct knote *kn, long hint)
250 * mask off extra data
252 event = (u_int)hint & NOTE_PCTRLMASK;
255 * if the user is interested in this event, record it.
257 if (kn->kn_sfflags & event)
258 kn->kn_fflags |= event;
261 * process is gone, so flag the event as finished.
263 if (event == NOTE_EXIT) {
264 kn->kn_status |= KN_DETACHED;
265 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
270 * process forked, and user wants to track the new process,
271 * so attach a new knote to it, and immediately report an
272 * event with the parent's pid.
274 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
279 * register knote with new process.
281 kev.ident = hint & NOTE_PDATAMASK; /* pid */
282 kev.filter = kn->kn_filter;
283 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
284 kev.fflags = kn->kn_sfflags;
285 kev.data = kn->kn_id; /* parent */
286 kev.udata = kn->kn_kevent.udata; /* preserve udata */
287 error = kqueue_register(kn->kn_kq, &kev, NULL);
289 kn->kn_fflags |= NOTE_TRACKERR;
292 return (kn->kn_fflags != 0);
296 filt_timerexpire(void *knx)
298 struct knote *kn = knx;
299 struct callout *calloutp;
306 if ((kn->kn_flags & EV_ONESHOT) == 0) {
307 tv.tv_sec = kn->kn_sdata / 1000;
308 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
309 tticks = tvtohz_high(&tv);
310 calloutp = (struct callout *)kn->kn_hook;
311 callout_reset(calloutp, tticks, filt_timerexpire, kn);
316 * data contains amount of time to sleep, in milliseconds
319 filt_timerattach(struct knote *kn)
321 struct callout *calloutp;
325 if (kq_ncallouts >= kq_calloutmax)
329 tv.tv_sec = kn->kn_sdata / 1000;
330 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
331 tticks = tvtohz_high(&tv);
333 kn->kn_flags |= EV_CLEAR; /* automatically set */
334 MALLOC(calloutp, struct callout *, sizeof(*calloutp),
336 callout_init(calloutp);
337 kn->kn_hook = (caddr_t)calloutp;
338 callout_reset(calloutp, tticks, filt_timerexpire, kn);
344 filt_timerdetach(struct knote *kn)
346 struct callout *calloutp;
348 calloutp = (struct callout *)kn->kn_hook;
349 callout_stop(calloutp);
350 FREE(calloutp, M_KQUEUE);
355 filt_timer(struct knote *kn, long hint)
358 return (kn->kn_data != 0);
362 kqueue(struct kqueue_args *uap)
364 struct proc *p = curproc;
365 struct filedesc *fdp = p->p_fd;
370 error = falloc(p, &fp, &fd);
373 fp->f_flag = FREAD | FWRITE;
374 fp->f_type = DTYPE_KQUEUE;
375 fp->f_ops = &kqueueops;
376 kq = malloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
377 TAILQ_INIT(&kq->kq_head);
378 fp->f_data = (caddr_t)kq;
379 uap->sysmsg_result = fd;
380 if (fdp->fd_knlistsize < 0)
381 fdp->fd_knlistsize = 0; /* this process has a kq */
387 kevent(struct kevent_args *uap)
389 struct thread *td = curthread;
390 struct proc *p = td->td_proc;
391 struct filedesc *fdp;
394 struct file *fp = NULL;
396 int i, n, nerrors, error;
401 if (((u_int)uap->fd) >= fdp->fd_nfiles ||
402 (fp = fdp->fd_ofiles[uap->fd]) == NULL ||
403 (fp->f_type != DTYPE_KQUEUE))
408 if (uap->timeout != NULL) {
409 error = copyin(uap->timeout, &ts, sizeof(ts));
415 kq = (struct kqueue *)fp->f_data;
418 while (uap->nchanges > 0) {
419 n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
420 error = copyin(uap->changelist, kq->kq_kev,
421 n * sizeof(struct kevent));
424 for (i = 0; i < n; i++) {
425 kevp = &kq->kq_kev[i];
426 kevp->flags &= ~EV_SYSFLAGS;
427 error = kqueue_register(kq, kevp, td);
429 if (uap->nevents != 0) {
430 kevp->flags = EV_ERROR;
432 (void) copyout((caddr_t)kevp,
433 (caddr_t)uap->eventlist,
444 uap->changelist += n;
447 uap->sysmsg_result = nerrors;
452 error = kqueue_scan(fp, uap->nevents, uap->eventlist, uap->timeout, p, &uap->sysmsg_result);
455 fdrop(fp, p->p_thread);
460 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td)
462 struct filedesc *fdp = kq->kq_fdp;
463 struct filterops *fops;
464 struct file *fp = NULL;
465 struct knote *kn = NULL;
468 if (kev->filter < 0) {
469 if (kev->filter + EVFILT_SYSCOUNT < 0)
471 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
475 * filter attach routine is responsible for insuring that
476 * the identifier can be attached to it.
478 printf("unknown filter: %d\n", kev->filter);
483 /* validate descriptor */
484 if ((u_int)kev->ident >= fdp->fd_nfiles ||
485 (fp = fdp->fd_ofiles[kev->ident]) == NULL)
489 if (kev->ident < fdp->fd_knlistsize) {
490 SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
491 if (kq == kn->kn_kq &&
492 kev->filter == kn->kn_filter)
496 if (fdp->fd_knhashmask != 0) {
499 list = &fdp->fd_knhash[
500 KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
501 SLIST_FOREACH(kn, list, kn_link)
502 if (kev->ident == kn->kn_id &&
504 kev->filter == kn->kn_filter)
509 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
515 * kn now contains the matching knote, or NULL if no match
517 if (kev->flags & EV_ADD) {
530 * apply reference count to knote structure, and
531 * do not release it at the end of this routine.
535 kn->kn_sfflags = kev->fflags;
536 kn->kn_sdata = kev->data;
539 kn->kn_kevent = *kev;
541 knote_attach(kn, fdp);
542 if ((error = fops->f_attach(kn)) != 0) {
548 * The user may change some filter values after the
549 * initial EV_ADD, but doing so will not reset any
550 * filter which have already been triggered.
552 kn->kn_sfflags = kev->fflags;
553 kn->kn_sdata = kev->data;
554 kn->kn_kevent.udata = kev->udata;
558 if (kn->kn_fop->f_event(kn, 0))
562 } else if (kev->flags & EV_DELETE) {
563 kn->kn_fop->f_detach(kn);
568 if ((kev->flags & EV_DISABLE) &&
569 ((kn->kn_status & KN_DISABLED) == 0)) {
571 kn->kn_status |= KN_DISABLED;
575 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
577 kn->kn_status &= ~KN_DISABLED;
578 if ((kn->kn_status & KN_ACTIVE) &&
579 ((kn->kn_status & KN_QUEUED) == 0))
591 kqueue_scan(struct file *fp, int maxevents, struct kevent *ulistp,
592 const struct timespec *tsp, struct proc *p, int *res)
594 struct thread *td = p->p_thread;
595 struct kqueue *kq = (struct kqueue *)fp->f_data;
597 struct timeval atv, rtv, ttv;
598 struct knote *kn, marker;
599 int s, count, timeout, nkev = 0, error = 0;
606 TIMESPEC_TO_TIMEVAL(&atv, tsp);
607 if (itimerfix(&atv)) {
611 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
614 timeout = atv.tv_sec > 24 * 60 * 60 ?
615 24 * 60 * 60 * hz : tvtohz_high(&atv);
616 getmicrouptime(&rtv);
617 timevaladd(&atv, &rtv);
626 if (atv.tv_sec || atv.tv_usec) {
627 getmicrouptime(&rtv);
628 if (timevalcmp(&rtv, &atv, >=))
631 timevalsub(&ttv, &rtv);
632 timeout = ttv.tv_sec > 24 * 60 * 60 ?
633 24 * 60 * 60 * hz : tvtohz_high(&ttv);
639 if (kq->kq_count == 0) {
643 kq->kq_state |= KQ_SLEEP;
644 error = tsleep(kq, PCATCH, "kqread", timeout);
649 /* don't restart after signals... */
650 if (error == ERESTART)
652 else if (error == EWOULDBLOCK)
657 TAILQ_INSERT_TAIL(&kq->kq_head, &marker, kn_tqe);
659 kn = TAILQ_FIRST(&kq->kq_head);
660 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
663 if (count == maxevents)
667 if (kn->kn_status & KN_DISABLED) {
668 kn->kn_status &= ~KN_QUEUED;
672 if ((kn->kn_flags & EV_ONESHOT) == 0 &&
673 kn->kn_fop->f_event(kn, 0) == 0) {
674 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
678 *kevp = kn->kn_kevent;
681 if (kn->kn_flags & EV_ONESHOT) {
682 kn->kn_status &= ~KN_QUEUED;
685 kn->kn_fop->f_detach(kn);
688 } else if (kn->kn_flags & EV_CLEAR) {
691 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
694 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
697 if (nkev == KQ_NEVENTS) {
699 error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
700 sizeof(struct kevent) * nkev);
709 TAILQ_REMOVE(&kq->kq_head, &marker, kn_tqe);
713 error = copyout((caddr_t)&kq->kq_kev, (caddr_t)ulistp,
714 sizeof(struct kevent) * nkev);
715 *res = maxevents - count;
721 * This could be expanded to call kqueue_scan, if desired.
725 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred,
726 int flags, struct thread *td)
733 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred,
734 int flags, struct thread *td)
741 kqueue_ioctl(struct file *fp, u_long com, caddr_t data, struct thread *td)
748 kqueue_poll(struct file *fp, int events, struct ucred *cred, struct thread *td)
750 struct kqueue *kq = (struct kqueue *)fp->f_data;
754 if (events & (POLLIN | POLLRDNORM)) {
756 revents |= events & (POLLIN | POLLRDNORM);
758 selrecord(td, &kq->kq_sel);
759 kq->kq_state |= KQ_SEL;
768 kqueue_stat(struct file *fp, struct stat *st, struct thread *td)
770 struct kqueue *kq = (struct kqueue *)fp->f_data;
772 bzero((void *)st, sizeof(*st));
773 st->st_size = kq->kq_count;
774 st->st_blksize = sizeof(struct kevent);
775 st->st_mode = S_IFIFO;
781 kqueue_close(struct file *fp, struct thread *td)
783 struct proc *p = td->td_proc;
784 struct kqueue *kq = (struct kqueue *)fp->f_data;
785 struct filedesc *fdp;
786 struct knote **knp, *kn, *kn0;
791 for (i = 0; i < fdp->fd_knlistsize; i++) {
792 knp = &SLIST_FIRST(&fdp->fd_knlist[i]);
795 kn0 = SLIST_NEXT(kn, kn_link);
796 if (kq == kn->kn_kq) {
797 kn->kn_fop->f_detach(kn);
798 fdrop(kn->kn_fp, td);
802 knp = &SLIST_NEXT(kn, kn_link);
807 if (fdp->fd_knhashmask != 0) {
808 for (i = 0; i < fdp->fd_knhashmask + 1; i++) {
809 knp = &SLIST_FIRST(&fdp->fd_knhash[i]);
812 kn0 = SLIST_NEXT(kn, kn_link);
813 if (kq == kn->kn_kq) {
814 kn->kn_fop->f_detach(kn);
815 /* XXX non-fd release of kn->kn_ptr */
819 knp = &SLIST_NEXT(kn, kn_link);
832 kqueue_wakeup(struct kqueue *kq)
835 if (kq->kq_state & KQ_SLEEP) {
836 kq->kq_state &= ~KQ_SLEEP;
839 if (kq->kq_state & KQ_SEL) {
840 kq->kq_state &= ~KQ_SEL;
841 selwakeup(&kq->kq_sel);
843 KNOTE(&kq->kq_sel.si_note, 0);
847 * walk down a list of knotes, activating them if their event has triggered.
850 knote(struct klist *list, long hint)
854 SLIST_FOREACH(kn, list, kn_selnext)
855 if (kn->kn_fop->f_event(kn, hint))
860 * remove all knotes from a specified klist
863 knote_remove(struct thread *td, struct klist *list)
867 while ((kn = SLIST_FIRST(list)) != NULL) {
868 kn->kn_fop->f_detach(kn);
874 * remove all knotes referencing a specified fd
877 knote_fdclose(struct proc *p, int fd)
879 struct filedesc *fdp = p->p_fd;
880 struct klist *list = &fdp->fd_knlist[fd];
882 knote_remove(p->p_thread, list);
886 knote_attach(struct knote *kn, struct filedesc *fdp)
891 if (! kn->kn_fop->f_isfd) {
892 if (fdp->fd_knhashmask == 0)
893 fdp->fd_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
894 &fdp->fd_knhashmask);
895 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
899 if (fdp->fd_knlistsize <= kn->kn_id) {
900 size = fdp->fd_knlistsize;
901 while (size <= kn->kn_id)
903 MALLOC(list, struct klist *,
904 size * sizeof(struct klist *), M_KQUEUE, M_WAITOK);
905 bcopy((caddr_t)fdp->fd_knlist, (caddr_t)list,
906 fdp->fd_knlistsize * sizeof(struct klist *));
907 bzero((caddr_t)list +
908 fdp->fd_knlistsize * sizeof(struct klist *),
909 (size - fdp->fd_knlistsize) * sizeof(struct klist *));
910 if (fdp->fd_knlist != NULL)
911 FREE(fdp->fd_knlist, M_KQUEUE);
912 fdp->fd_knlistsize = size;
913 fdp->fd_knlist = list;
915 list = &fdp->fd_knlist[kn->kn_id];
917 SLIST_INSERT_HEAD(list, kn, kn_link);
922 * should be called at spl == 0, since we don't want to hold spl
923 * while calling fdrop and free.
926 knote_drop(struct knote *kn, struct thread *td)
928 struct filedesc *fdp;
931 KKASSERT(td->td_proc);
932 fdp = td->td_proc->p_fd;
933 if (kn->kn_fop->f_isfd)
934 list = &fdp->fd_knlist[kn->kn_id];
936 list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
938 SLIST_REMOVE(list, kn, knote, kn_link);
939 if (kn->kn_status & KN_QUEUED)
941 if (kn->kn_fop->f_isfd)
942 fdrop(kn->kn_fp, td);
948 knote_enqueue(struct knote *kn)
950 struct kqueue *kq = kn->kn_kq;
953 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
955 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe);
956 kn->kn_status |= KN_QUEUED;
963 knote_dequeue(struct knote *kn)
965 struct kqueue *kq = kn->kn_kq;
968 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
970 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
971 kn->kn_status &= ~KN_QUEUED;
979 knote_zone = zinit("KNOTE", sizeof(struct knote), 0, 0, 1);
981 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL)
983 static struct knote *
986 return ((struct knote *)zalloc(knote_zone));
990 knote_free(struct knote *kn)
992 zfree(knote_zone, kn);