Replace selwakeup() with KNOTE() in audio(4)

KNOTE() is safe to use at IPL_AUDIO. Remove the now-unnecessary
deferring that uses soft interrupts.

Remove selwakeup() calls from audio_detach() because klist_invalidate()
wakes up any remaining kevent/poll/select waiters.

OK mpi@

diff --git a/sys/dev/audio.c b/sys/dev/audio.c
index 19c7bef..8bb1e36 100644 (file)
--- a/sys/dev/audio.c
+++ b/sys/dev/audio.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: audio.c,v 1.199 2022/07/02 08:50:41 visa Exp $        */
+/*     $OpenBSD: audio.c,v 1.200 2022/07/31 03:31:36 visa Exp $        */
 /*
  * Copyright (c) 2015 Alexandre Ratchov <alex@caoua.org>
  *
@@ -20,6 +20,8 @@
 #include <sys/ioctl.h>
 #include <sys/conf.h>
 #include <sys/kernel.h>
+#include <sys/event.h>
+#include <sys/mutex.h>
 #include <sys/task.h>
 #include <sys/vnode.h>
 #include <sys/malloc.h>
@@ -75,8 +77,7 @@ struct audio_buf {
        size_t used;                    /* bytes used in the FIFO */
        size_t blksz;                   /* DMA block size */
        unsigned int nblks;             /* number of blocks */
-       struct selinfo sel;             /* to record & wakeup poll(2) */
-       void *softintr;                 /* context to call selwakeup() */
+       struct klist klist;             /* list of knotes */
        unsigned int pos;               /* bytes transferred */
        unsigned int xrun;              /* bytes lost by xruns */
        int blocking;                   /* read/write blocking */
@@ -136,10 +137,9 @@ struct audio_softc {
        int mix_nent;                   /* size of mixer state */
        int mix_isopen;                 /* mixer open for reading */
        int mix_blocking;               /* read() blocking */
-       struct selinfo mix_sel;         /* wakeup poll(2) */
+       struct klist mix_klist;         /* list of knotes */
        struct mixer_ev *mix_evbuf;     /* per mixer-control event */
        struct mixer_ev *mix_pending;   /* list of changed controls */
-       void *mix_softintr;             /* context to call selwakeup() */
 #if NWSKBD > 0
        struct wskbd_vol spkr, mic;
        struct task wskbd_task;
@@ -153,6 +153,8 @@ int audio_activate(struct device *, int);
 int audio_detach(struct device *, int);
 void audio_pintr(void *);
 void audio_rintr(void *);
+void audio_buf_wakeup(struct audio_buf *);
+void audio_mixer_wakeup(struct audio_softc *);
 #if NWSKBD > 0
 void wskbd_mixer_init(struct audio_softc *);
 void wskbd_mixer_cb(void *);
@@ -275,53 +277,33 @@ audio_blksz_bytes(int mode,
 }
 
 void
-audio_mixer_wakeup(void *addr)
+audio_mixer_wakeup(struct audio_softc *sc)
 {
-       struct audio_softc *sc = addr;
+       MUTEX_ASSERT_LOCKED(&audio_lock);
 
        if (sc->mix_blocking) {
                wakeup(&sc->mix_blocking);
                sc->mix_blocking = 0;
        }
-       /*
-        * As long as selwakeup() grabs the KERNEL_LOCK() make sure it is
-        * already held here to avoid lock ordering problems with `audio_lock'
-        */
-       KERNEL_ASSERT_LOCKED();
-       mtx_enter(&audio_lock);
-       selwakeup(&sc->mix_sel);
-       mtx_leave(&audio_lock);
+       KNOTE(&sc->mix_klist, 0);
 }
 
 void
-audio_buf_wakeup(void *addr)
+audio_buf_wakeup(struct audio_buf *buf)
 {
-       struct audio_buf *buf = addr;
+       MUTEX_ASSERT_LOCKED(&audio_lock);
 
        if (buf->blocking) {
                wakeup(&buf->blocking);
                buf->blocking = 0;
        }
-       /*
-        * As long as selwakeup() grabs the KERNEL_LOCK() make sure it is
-        * already held here to avoid lock ordering problems with `audio_lock'
-        */
-       KERNEL_ASSERT_LOCKED();
-       mtx_enter(&audio_lock);
-       selwakeup(&buf->sel);
-       mtx_leave(&audio_lock);
+       KNOTE(&buf->klist, 0);
 }
 
 int
 audio_buf_init(struct audio_softc *sc, struct audio_buf *buf, int dir)
 {
-       klist_init_mutex(&buf->sel.si_note, &audio_lock);
-       buf->softintr = softintr_establish(IPL_SOFTAUDIO,
-           audio_buf_wakeup, buf);
-       if (buf->softintr == NULL) {
-               printf("%s: can't establish softintr\n", DEVNAME(sc));
-               goto bad;
-       }
+       klist_init_mutex(&buf->klist, &audio_lock);
        if (sc->ops->round_buffersize) {
                buf->datalen = sc->ops->round_buffersize(sc->arg,
                    dir, AUDIO_BUFSZ);
@@ -333,13 +315,10 @@ audio_buf_init(struct audio_softc *sc, struct audio_buf *buf, int dir)
        } else
                buf->data = malloc(buf->datalen, M_DEVBUF, M_WAITOK);
        if (buf->data == NULL) {
-               softintr_disestablish(buf->softintr);
-               goto bad;
+               klist_free(&buf->klist);
+               return ENOMEM;
        }
        return 0;
-bad:
-       klist_free(&buf->sel.si_note);
-       return ENOMEM;
 }
 
 void
@@ -349,8 +328,7 @@ audio_buf_done(struct audio_softc *sc, struct audio_buf *buf)
                sc->ops->freem(sc->arg, buf->data, M_DEVBUF);
        else
                free(buf->data, M_DEVBUF, buf->datalen);
-       softintr_disestablish(buf->softintr);
-       klist_free(&buf->sel.si_note);
+       klist_free(&buf->klist);
 }
 
 /*
@@ -563,13 +541,7 @@ audio_pintr(void *addr)
        if (sc->play.used < sc->play.len) {
                DPRINTFN(1, "%s: play wakeup, chan = %d\n",
                    DEVNAME(sc), sc->play.blocking);
-               /*
-                * As long as selwakeup() needs to be protected by the
-                * KERNEL_LOCK() we have to delay the wakeup to another
-                * context to keep the interrupt context KERNEL_LOCK()
-                * free.
-                */
-               softintr_schedule(sc->play.softintr);
+               audio_buf_wakeup(&sc->play);
        }
 }
 
@@ -646,13 +618,7 @@ audio_rintr(void *addr)
        if (sc->rec.used > 0) {
                DPRINTFN(1, "%s: rec wakeup, chan = %d\n",
                    DEVNAME(sc), sc->rec.blocking);
-               /*
-                * As long as selwakeup() needs to be protected by the
-                * KERNEL_LOCK() we have to delay the wakeup to another
-                * context to keep the interrupt context KERNEL_LOCK()
-                * free.
-                */
-               softintr_schedule(sc->rec.softintr);
+               audio_buf_wakeup(&sc->rec);
        }
 }
 
@@ -1272,17 +1238,7 @@ audio_attach(struct device *parent, struct device *self, void *aux)
                return;
        }
 
-       klist_init_mutex(&sc->mix_sel.si_note, &audio_lock);
-       sc->mix_softintr = softintr_establish(IPL_SOFTAUDIO,
-           audio_mixer_wakeup, sc);
-       if (sc->mix_softintr == NULL) {
-               klist_free(&sc->mix_sel.si_note);
-               audio_buf_done(sc, &sc->rec);
-               audio_buf_done(sc, &sc->play);
-               sc->ops = 0;
-               printf("%s: can't establish softintr\n", DEVNAME(sc));
-               return;
-       }
+       klist_init_mutex(&sc->mix_klist, &audio_lock);
 
        /* set defaults */
 #if BYTE_ORDER == LITTLE_ENDIAN
@@ -1445,31 +1401,20 @@ audio_detach(struct device *self, int flags)
        if (sc->mode != 0) {
                if (sc->active) {
                        wakeup(&sc->play.blocking);
-                       KERNEL_ASSERT_LOCKED();
-                       mtx_enter(&audio_lock);
                        wakeup(&sc->rec.blocking);
-                       selwakeup(&sc->play.sel);
-                       selwakeup(&sc->rec.sel);
-                       mtx_leave(&audio_lock);
                        audio_stop(sc);
                }
                sc->ops->close(sc->arg);
                sc->mode = 0;
        }
-       if (sc->mix_isopen) {
+       if (sc->mix_isopen)
                wakeup(&sc->mix_blocking);
-               KERNEL_ASSERT_LOCKED();
-               mtx_enter(&audio_lock);
-               selwakeup(&sc->mix_sel);
-               mtx_leave(&audio_lock);
-       }
-       klist_invalidate(&sc->play.sel.si_note);
-       klist_invalidate(&sc->rec.sel.si_note);
-       klist_invalidate(&sc->mix_sel.si_note);
+       klist_invalidate(&sc->play.klist);
+       klist_invalidate(&sc->rec.klist);
+       klist_invalidate(&sc->mix_klist);
 
        /* free resources */
-       softintr_disestablish(sc->mix_softintr);
-       klist_free(&sc->mix_sel.si_note);
+       klist_free(&sc->mix_klist);
        free(sc->mix_evbuf, M_DEVBUF, sc->mix_nent * sizeof(struct mixer_ev));
        free(sc->mix_ents, M_DEVBUF, sc->mix_nent * sizeof(struct mixer_ctrl));
        audio_buf_done(sc, &sc->play);
@@ -1875,7 +1820,7 @@ audio_event(struct audio_softc *sc, int addr)
                        e->next = sc->mix_pending;
                        sc->mix_pending = e;
                }
-               softintr_schedule(sc->mix_softintr);
+               audio_mixer_wakeup(sc);
        }
        mtx_leave(&audio_lock);
 }
@@ -2228,11 +2173,11 @@ audiokqfilter(dev_t dev, struct knote *kn)
        case AUDIO_DEV_AUDIO:
                switch (kn->kn_filter) {
                case EVFILT_READ:
-                       klist = &sc->rec.sel.si_note;
+                       klist = &sc->rec.klist;
                        kn->kn_fop = &audioread_filtops;
                        break;
                case EVFILT_WRITE:
-                       klist = &sc->play.sel.si_note;
+                       klist = &sc->play.klist;
                        kn->kn_fop = &audiowrite_filtops;
                        break;
                default:
@@ -2243,7 +2188,7 @@ audiokqfilter(dev_t dev, struct knote *kn)
        case AUDIO_DEV_AUDIOCTL:
                switch (kn->kn_filter) {
                case EVFILT_READ:
-                       klist = &sc->mix_sel.si_note;
+                       klist = &sc->mix_klist;
                        kn->kn_fop = &audioctlread_filtops;
                        break;
                default:
@@ -2265,7 +2210,7 @@ filt_audiordetach(struct knote *kn)
 {
        struct audio_softc *sc = kn->kn_hook;
 
-       klist_remove(&sc->rec.sel.si_note, kn);
+       klist_remove(&sc->rec.klist, kn);
 }
 
 int
@@ -2283,7 +2228,7 @@ filt_audiowdetach(struct knote *kn)
 {
        struct audio_softc *sc = kn->kn_hook;
 
-       klist_remove(&sc->play.sel.si_note, kn);
+       klist_remove(&sc->play.klist, kn);
 }
 
 int
@@ -2301,7 +2246,7 @@ filt_audioctlrdetach(struct knote *kn)
 {
        struct audio_softc *sc = kn->kn_hook;
 
-       klist_remove(&sc->mix_sel.si_note, kn);
+       klist_remove(&sc->mix_klist, kn);
 }
 
 int