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 1.33 2007/02/03 17:05:57 corecode 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>
38 #include <sys/fcntl.h>
39 #include <sys/select.h>
40 #include <sys/queue.h>
41 #include <sys/event.h>
42 #include <sys/eventvar.h>
44 #include <sys/protosw.h>
45 #include <sys/socket.h>
46 #include <sys/socketvar.h>
48 #include <sys/sysctl.h>
49 #include <sys/sysproto.h>
51 #include <sys/signalvar.h>
52 #include <sys/filio.h>
54 #include <sys/thread2.h>
55 #include <sys/file2.h>
56 #include <sys/mplock2.h>
58 #include <vm/vm_zone.h>
60 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
62 static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count,
63 struct timespec *tsp, int *errorp);
64 static int kqueue_read(struct file *fp, struct uio *uio,
65 struct ucred *cred, int flags);
66 static int kqueue_write(struct file *fp, struct uio *uio,
67 struct ucred *cred, int flags);
68 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
69 struct ucred *cred, struct sysmsg *msg);
70 static int kqueue_poll(struct file *fp, int events, struct ucred *cred);
71 static int kqueue_kqfilter(struct file *fp, struct knote *kn);
72 static int kqueue_stat(struct file *fp, struct stat *st,
74 static int kqueue_close(struct file *fp);
75 static void kqueue_wakeup(struct kqueue *kq);
80 static struct fileops kqueueops = {
81 .fo_read = kqueue_read,
82 .fo_write = kqueue_write,
83 .fo_ioctl = kqueue_ioctl,
84 .fo_poll = kqueue_poll,
85 .fo_kqfilter = kqueue_kqfilter,
86 .fo_stat = kqueue_stat,
87 .fo_close = kqueue_close,
88 .fo_shutdown = nofo_shutdown
91 static void knote_attach(struct knote *kn);
92 static void knote_drop(struct knote *kn);
93 static void knote_enqueue(struct knote *kn);
94 static void knote_dequeue(struct knote *kn);
95 static void knote_init(void);
96 static struct knote *knote_alloc(void);
97 static void knote_free(struct knote *kn);
99 static void filt_kqdetach(struct knote *kn);
100 static int filt_kqueue(struct knote *kn, long hint);
101 static int filt_procattach(struct knote *kn);
102 static void filt_procdetach(struct knote *kn);
103 static int filt_proc(struct knote *kn, long hint);
104 static int filt_fileattach(struct knote *kn);
105 static void filt_timerexpire(void *knx);
106 static int filt_timerattach(struct knote *kn);
107 static void filt_timerdetach(struct knote *kn);
108 static int filt_timer(struct knote *kn, long hint);
110 static struct filterops file_filtops =
111 { 1, filt_fileattach, NULL, NULL };
112 static struct filterops kqread_filtops =
113 { 1, NULL, filt_kqdetach, filt_kqueue };
114 static struct filterops proc_filtops =
115 { 0, filt_procattach, filt_procdetach, filt_proc };
116 static struct filterops timer_filtops =
117 { 0, filt_timerattach, filt_timerdetach, filt_timer };
119 static vm_zone_t knote_zone;
120 static int kq_ncallouts = 0;
121 static int kq_calloutmax = (4 * 1024);
122 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW,
123 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue");
125 #define KNOTE_ACTIVATE(kn) do { \
126 kn->kn_status |= KN_ACTIVE; \
127 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \
131 #define KN_HASHSIZE 64 /* XXX should be tunable */
132 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
134 extern struct filterops aio_filtops;
135 extern struct filterops sig_filtops;
138 * Table for for all system-defined filters.
140 static struct filterops *sysfilt_ops[] = {
141 &file_filtops, /* EVFILT_READ */
142 &file_filtops, /* EVFILT_WRITE */
143 &aio_filtops, /* EVFILT_AIO */
144 &file_filtops, /* EVFILT_VNODE */
145 &proc_filtops, /* EVFILT_PROC */
146 &sig_filtops, /* EVFILT_SIGNAL */
147 &timer_filtops, /* EVFILT_TIMER */
151 filt_fileattach(struct knote *kn)
153 return (fo_kqfilter(kn->kn_fp, kn));
157 * MPALMOSTSAFE - acquires mplock
160 kqueue_kqfilter(struct file *fp, struct knote *kn)
162 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
165 if (kn->kn_filter != EVFILT_READ) {
170 kn->kn_fop = &kqread_filtops;
171 SLIST_INSERT_HEAD(&kq->kq_sel.si_note, kn, kn_selnext);
177 filt_kqdetach(struct knote *kn)
179 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
181 SLIST_REMOVE(&kq->kq_sel.si_note, kn, knote, kn_selnext);
186 filt_kqueue(struct knote *kn, long hint)
188 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
190 kn->kn_data = kq->kq_count;
191 return (kn->kn_data > 0);
195 filt_procattach(struct knote *kn)
201 p = pfind(kn->kn_id);
202 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) {
203 p = zpfind(kn->kn_id);
208 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred))
211 kn->kn_ptr.p_proc = p;
212 kn->kn_flags |= EV_CLEAR; /* automatically set */
215 * internal flag indicating registration done by kernel
217 if (kn->kn_flags & EV_FLAG1) {
218 kn->kn_data = kn->kn_sdata; /* ppid */
219 kn->kn_fflags = NOTE_CHILD;
220 kn->kn_flags &= ~EV_FLAG1;
223 /* XXX lock the proc here while adding to the list? */
224 SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext);
227 * Immediately activate any exit notes if the target process is a
228 * zombie. This is necessary to handle the case where the target
229 * process, e.g. a child, dies before the kevent is registered.
231 if (immediate && filt_proc(kn, NOTE_EXIT))
238 * The knote may be attached to a different process, which may exit,
239 * leaving nothing for the knote to be attached to. So when the process
240 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so
241 * it will be deleted when read out. However, as part of the knote deletion,
242 * this routine is called, so a check is needed to avoid actually performing
243 * a detach, because the original process does not exist any more.
246 filt_procdetach(struct knote *kn)
250 if (kn->kn_status & KN_DETACHED)
252 /* XXX locking? this might modify another process. */
253 p = kn->kn_ptr.p_proc;
254 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
258 filt_proc(struct knote *kn, long hint)
263 * mask off extra data
265 event = (u_int)hint & NOTE_PCTRLMASK;
268 * if the user is interested in this event, record it.
270 if (kn->kn_sfflags & event)
271 kn->kn_fflags |= event;
274 * Process is gone, so flag the event as finished. Detach the
275 * knote from the process now because the process will be poof,
278 if (event == NOTE_EXIT) {
279 struct proc *p = kn->kn_ptr.p_proc;
280 if ((kn->kn_status & KN_DETACHED) == 0) {
281 SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext);
282 kn->kn_status |= KN_DETACHED;
283 kn->kn_data = p->p_xstat;
284 kn->kn_ptr.p_proc = NULL;
286 kn->kn_flags |= (EV_EOF | EV_ONESHOT);
291 * process forked, and user wants to track the new process,
292 * so attach a new knote to it, and immediately report an
293 * event with the parent's pid.
295 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) {
300 * register knote with new process.
302 kev.ident = hint & NOTE_PDATAMASK; /* pid */
303 kev.filter = kn->kn_filter;
304 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;
305 kev.fflags = kn->kn_sfflags;
306 kev.data = kn->kn_id; /* parent */
307 kev.udata = kn->kn_kevent.udata; /* preserve udata */
308 error = kqueue_register(kn->kn_kq, &kev);
310 kn->kn_fflags |= NOTE_TRACKERR;
313 return (kn->kn_fflags != 0);
317 filt_timerexpire(void *knx)
319 struct knote *kn = knx;
320 struct callout *calloutp;
327 if ((kn->kn_flags & EV_ONESHOT) == 0) {
328 tv.tv_sec = kn->kn_sdata / 1000;
329 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
330 tticks = tvtohz_high(&tv);
331 calloutp = (struct callout *)kn->kn_hook;
332 callout_reset(calloutp, tticks, filt_timerexpire, kn);
337 * data contains amount of time to sleep, in milliseconds
340 filt_timerattach(struct knote *kn)
342 struct callout *calloutp;
346 if (kq_ncallouts >= kq_calloutmax)
350 tv.tv_sec = kn->kn_sdata / 1000;
351 tv.tv_usec = (kn->kn_sdata % 1000) * 1000;
352 tticks = tvtohz_high(&tv);
354 kn->kn_flags |= EV_CLEAR; /* automatically set */
355 MALLOC(calloutp, struct callout *, sizeof(*calloutp),
357 callout_init(calloutp);
358 kn->kn_hook = (caddr_t)calloutp;
359 callout_reset(calloutp, tticks, filt_timerexpire, kn);
365 filt_timerdetach(struct knote *kn)
367 struct callout *calloutp;
369 calloutp = (struct callout *)kn->kn_hook;
370 callout_stop(calloutp);
371 FREE(calloutp, M_KQUEUE);
376 filt_timer(struct knote *kn, long hint)
379 return (kn->kn_data != 0);
383 * Initialize a kqueue.
385 * NOTE: The lwp/proc code initializes a kqueue for select/poll ops.
390 kqueue_init(struct kqueue *kq, struct filedesc *fdp)
392 TAILQ_INIT(&kq->kq_knpend);
393 TAILQ_INIT(&kq->kq_knlist);
398 * Terminate a kqueue. Freeing the actual kq itself is left up to the
399 * caller (it might be embedded in a lwp so we don't do it here).
402 kqueue_terminate(struct kqueue *kq)
408 while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) {
409 kn->kn_fop->f_detach(kn);
410 if (kn->kn_fop->f_isfd) {
411 list = &kn->kn_fp->f_klist;
412 SLIST_REMOVE(list, kn, knote, kn_link);
416 hv = KN_HASH(kn->kn_id, kq->kq_knhashmask);
417 list = &kq->kq_knhash[hv];
418 SLIST_REMOVE(list, kn, knote, kn_link);
420 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink);
421 if (kn->kn_status & KN_QUEUED)
427 kfree(kq->kq_knhash, M_KQUEUE);
428 kq->kq_knhash = NULL;
429 kq->kq_knhashmask = 0;
437 sys_kqueue(struct kqueue_args *uap)
439 struct thread *td = curthread;
444 error = falloc(td->td_lwp, &fp, &fd);
447 fp->f_flag = FREAD | FWRITE;
448 fp->f_type = DTYPE_KQUEUE;
449 fp->f_ops = &kqueueops;
451 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO);
452 kqueue_init(kq, td->td_proc->p_fd);
455 fsetfd(kq->kq_fdp, fp, fd);
456 uap->sysmsg_result = fd;
465 sys_kevent(struct kevent_args *uap)
467 struct thread *td = curthread;
468 struct proc *p = td->td_proc;
471 struct file *fp = NULL;
473 struct timespec *tsp;
474 int i, n, total, nerrors, error;
475 struct kevent kev[KQ_NEVENTS];
477 fp = holdfp(p->p_fd, uap->fd, -1);
480 if (fp->f_type != DTYPE_KQUEUE) {
486 error = copyin(uap->timeout, &ts, sizeof(ts));
494 kq = (struct kqueue *)fp->f_data;
498 while (uap->nchanges > 0) {
499 n = uap->nchanges > KQ_NEVENTS ? KQ_NEVENTS : uap->nchanges;
500 error = copyin(uap->changelist, kev, n * sizeof(struct kevent));
503 for (i = 0; i < n; i++) {
505 kevp->flags &= ~EV_SYSFLAGS;
506 error = kqueue_register(kq, kevp);
508 if (uap->nevents != 0) {
509 kevp->flags = EV_ERROR;
511 copyout(kevp, uap->eventlist,
522 uap->changelist += n;
525 uap->sysmsg_result = nerrors;
531 * Acquire/wait for events - setup timeout
536 if (tsp->tv_sec || tsp->tv_nsec) {
538 timespecadd(tsp, &ats); /* tsp = target time */
545 * Collect as many events as we can. The timeout on successive
546 * loops is disabled (kqueue_scan() becomes non-blocking).
550 while ((n = uap->nevents - total) > 0) {
553 i = kqueue_scan(kq, kev, n, tsp, &error);
556 error = copyout(kev, uap->eventlist + total,
557 (size_t)i * sizeof(struct kevent));
561 tsp = &ts; /* successive loops non-blocking */
565 uap->sysmsg_result = total;
574 kqueue_register(struct kqueue *kq, struct kevent *kev)
576 struct filedesc *fdp = kq->kq_fdp;
577 struct filterops *fops;
578 struct file *fp = NULL;
579 struct knote *kn = NULL;
582 if (kev->filter < 0) {
583 if (kev->filter + EVFILT_SYSCOUNT < 0)
585 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
589 * filter attach routine is responsible for insuring that
590 * the identifier can be attached to it.
592 kprintf("unknown filter: %d\n", kev->filter);
597 /* validate descriptor */
598 fp = holdfp(fdp, kev->ident, -1);
602 SLIST_FOREACH(kn, &fp->f_klist, kn_link) {
603 if (kn->kn_kq == kq &&
604 kn->kn_filter == kev->filter &&
605 kn->kn_id == kev->ident) {
610 if (kq->kq_knhashmask) {
613 list = &kq->kq_knhash[
614 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)];
615 SLIST_FOREACH(kn, list, kn_link) {
616 if (kn->kn_id == kev->ident &&
617 kn->kn_filter == kev->filter)
623 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) {
629 * kn now contains the matching knote, or NULL if no match
631 if (kev->flags & EV_ADD) {
643 * apply reference count to knote structure, and
644 * do not release it at the end of this routine.
648 kn->kn_sfflags = kev->fflags;
649 kn->kn_sdata = kev->data;
652 kn->kn_kevent = *kev;
655 if ((error = fops->f_attach(kn)) != 0) {
661 * The user may change some filter values after the
662 * initial EV_ADD, but doing so will not reset any
663 * filter which have already been triggered.
665 kn->kn_sfflags = kev->fflags;
666 kn->kn_sdata = kev->data;
667 kn->kn_kevent.udata = kev->udata;
671 if (kn->kn_fop->f_event(kn, 0))
674 } else if (kev->flags & EV_DELETE) {
675 kn->kn_fop->f_detach(kn);
680 if ((kev->flags & EV_DISABLE) &&
681 ((kn->kn_status & KN_DISABLED) == 0)) {
683 kn->kn_status |= KN_DISABLED;
687 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
689 kn->kn_status &= ~KN_DISABLED;
690 if ((kn->kn_status & KN_ACTIVE) &&
691 ((kn->kn_status & KN_QUEUED) == 0))
703 * Scan the kqueue, blocking if necessary until the target time is reached.
704 * If tsp is NULL we block indefinitely. If tsp->ts_secs/nsecs are both
705 * 0 we do not block at all.
708 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count,
709 struct timespec *tsp, int *errorp)
711 struct knote *kn, marker;
717 if (kq->kq_count == 0) {
719 kq->kq_state |= KQ_SLEEP;
720 *errorp = tsleep(kq, PCATCH, "kqread", 0);
721 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) {
722 *errorp = EWOULDBLOCK;
725 struct timespec atx = *tsp;
729 timespecsub(&atx, &ats);
730 if (ats.tv_sec < 0) {
731 *errorp = EWOULDBLOCK;
733 timeout = atx.tv_sec > 24 * 60 * 60 ?
734 24 * 60 * 60 * hz : tstohz_high(&atx);
735 kq->kq_state |= KQ_SLEEP;
736 *errorp = tsleep(kq, PCATCH, "kqread", timeout);
742 /* don't restart after signals... */
743 if (*errorp == ERESTART)
745 else if (*errorp == EWOULDBLOCK)
751 * Collect events. Continuous mode events may get recycled
752 * past the marker so we stop when we hit it unless no events
753 * have been collected.
755 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe);
757 kn = TAILQ_FIRST(&kq->kq_knpend);
760 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe);
761 if (kn->kn_status & KN_DISABLED) {
762 kn->kn_status &= ~KN_QUEUED;
766 if ((kn->kn_flags & EV_ONESHOT) == 0 &&
767 kn->kn_fop->f_event(kn, 0) == 0) {
768 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
772 *kevp++ = kn->kn_kevent;
777 * Post-event action on the note
779 if (kn->kn_flags & EV_ONESHOT) {
780 kn->kn_status &= ~KN_QUEUED;
783 kn->kn_fop->f_detach(kn);
786 } else if (kn->kn_flags & EV_CLEAR) {
789 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE);
792 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe);
795 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe);
805 * This could be expanded to call kqueue_scan, if desired.
810 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
819 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags)
828 kqueue_ioctl(struct file *fp, u_long com, caddr_t data,
829 struct ucred *cred, struct sysmsg *msg)
835 kq = (struct kqueue *)fp->f_data;
840 kq->kq_state |= KQ_ASYNC;
842 kq->kq_state &= ~KQ_ASYNC;
846 error = fsetown(*(int *)data, &kq->kq_sigio);
857 * MPALMOSTSAFE - acquires mplock
860 kqueue_poll(struct file *fp, int events, struct ucred *cred)
862 struct kqueue *kq = (struct kqueue *)fp->f_data;
867 if (events & (POLLIN | POLLRDNORM)) {
869 revents |= events & (POLLIN | POLLRDNORM);
871 selrecord(curthread, &kq->kq_sel);
872 kq->kq_state |= KQ_SEL;
884 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred)
886 struct kqueue *kq = (struct kqueue *)fp->f_data;
888 bzero((void *)st, sizeof(*st));
889 st->st_size = kq->kq_count;
890 st->st_blksize = sizeof(struct kevent);
891 st->st_mode = S_IFIFO;
896 * MPALMOSTSAFE - acquires mplock
899 kqueue_close(struct file *fp)
901 struct kqueue *kq = (struct kqueue *)fp->f_data;
905 kqueue_terminate(kq);
908 funsetown(kq->kq_sigio);
916 kqueue_wakeup(struct kqueue *kq)
918 if (kq->kq_state & KQ_SLEEP) {
919 kq->kq_state &= ~KQ_SLEEP;
922 if (kq->kq_state & KQ_SEL) {
923 kq->kq_state &= ~KQ_SEL;
924 selwakeup(&kq->kq_sel);
926 KNOTE(&kq->kq_sel.si_note, 0);
930 * walk down a list of knotes, activating them if their event has triggered.
933 knote(struct klist *list, long hint)
937 SLIST_FOREACH(kn, list, kn_selnext)
938 if (kn->kn_fop->f_event(kn, hint))
943 * remove all knotes from a specified klist
946 knote_remove(struct klist *list)
950 while ((kn = SLIST_FIRST(list)) != NULL) {
951 kn->kn_fop->f_detach(kn);
957 * remove all knotes referencing a specified fd
960 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd)
965 SLIST_FOREACH(kn, &fp->f_klist, kn_link) {
966 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) {
967 kn->kn_fop->f_detach(kn);
975 knote_attach(struct knote *kn)
978 struct kqueue *kq = kn->kn_kq;
980 if (kn->kn_fop->f_isfd) {
982 list = &kn->kn_fp->f_klist;
984 if (kq->kq_knhashmask == 0)
985 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE,
987 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
989 SLIST_INSERT_HEAD(list, kn, kn_link);
990 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink);
995 * should be called outside of a critical section, since we don't want to
996 * hold a critical section while calling fdrop and free.
999 knote_drop(struct knote *kn)
1006 if (kn->kn_fop->f_isfd)
1007 list = &kn->kn_fp->f_klist;
1009 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)];
1011 SLIST_REMOVE(list, kn, knote, kn_link);
1012 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink);
1013 if (kn->kn_status & KN_QUEUED)
1015 if (kn->kn_fop->f_isfd)
1022 knote_enqueue(struct knote *kn)
1024 struct kqueue *kq = kn->kn_kq;
1027 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued"));
1029 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe);
1030 kn->kn_status |= KN_QUEUED;
1034 * Send SIGIO on request (typically set up as a mailbox signal)
1036 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1)
1037 pgsigio(kq->kq_sigio, SIGIO, 0);
1043 knote_dequeue(struct knote *kn)
1045 struct kqueue *kq = kn->kn_kq;
1047 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued"));
1050 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe);
1051 kn->kn_status &= ~KN_QUEUED;
1059 knote_zone = zinit("KNOTE", sizeof(struct knote), 0, 0, 1);
1061 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL)
1063 static struct knote *
1066 return ((struct knote *)zalloc(knote_zone));
1070 knote_free(struct knote *kn)
1072 zfree(knote_zone, kn);