[src/jmcneill-audiomp3]: src/sys/dev more steps towards making this work:

[mrg <mrg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/81126668aab7
branches:  jmcneill-audiomp3
changeset: 771399:81126668aab7
user:      mrg <mrg%NetBSD.org@localhost>
date:      Tue Nov 22 11:50:02 2011 +0000

description:
more steps towards making this work:
- avoid using uninitialised memory to get a pointer, this fixes
  hangs in sequencerwrite() and general mayhem when it corrupts
  random other memory.
- re-take sc->lock in sequencewrite() when continuing from the
  main loop.

diffstat:

 sys/dev/sequencer.c |  28 ++++++++++++++++++----------
 1 files changed, 18 insertions(+), 10 deletions(-)

diffs (128 lines):

diff -r 1224c2822228 -r 81126668aab7 sys/dev/sequencer.c
--- a/sys/dev/sequencer.c       Tue Nov 22 08:58:48 2011 +0000
+++ b/sys/dev/sequencer.c       Tue Nov 22 11:50:02 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sequencer.c,v 1.52.14.3 2011/11/22 07:57:23 mrg Exp $  */
+/*     $NetBSD: sequencer.c,v 1.52.14.4 2011/11/22 11:50:02 mrg Exp $  */
 
 /*
  * Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
@@ -55,7 +55,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sequencer.c,v 1.52.14.3 2011/11/22 07:57:23 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sequencer.c,v 1.52.14.4 2011/11/22 11:50:02 mrg Exp $");
 
 #include "sequencer.h"
 
@@ -240,7 +240,7 @@
 
        if ((error = sequencer_enter(dev, &sc)) != 0)
                return error;
-       sc = &seqdevs[unit];
+       KASSERT(sc == &seqdevs[unit]);
        if (sc->isopen != 0) {
                sequencer_exit(sc);
                return EBUSY;
@@ -296,7 +296,7 @@
        seq_reset(sc);
        sequencer_exit(sc);
 
-       DPRINTF(("sequenceropen: mode=%d, nmidi=%d\n", sc->mode, sc->nmidi));
+       DPRINTF(("%s: mode=%d, nmidi=%d\n", __func__, sc->mode, sc->nmidi));
        return 0;
 }
 
@@ -310,7 +310,7 @@
        DPRINTFN(3, ("seq_drain: %p, len=%d\n", sc, SEQ_QLEN(&sc->outq)));
        seq_startoutput(sc);
        error = 0;
-       while(!SEQ_QEMPTY(&sc->outq) && !error)
+       while (!SEQ_QEMPTY(&sc->outq) && !error)
                error = cv_timedwait_sig(&sc->wchan, &sc->lock, 60*hz);
        return (error);
 }
@@ -357,7 +357,7 @@
        if (sc->timeout)
                return;
        DPRINTFN(4, ("seq_startoutput: %p, len=%d\n", sc, SEQ_QLEN(q)));
-       while(!SEQ_QEMPTY(q) && !sc->timeout) {
+       while (!SEQ_QEMPTY(q) && !sc->timeout) {
                SEQ_QGET(q, cmd);
                seq_do_command(sc, &cmd);
        }
@@ -410,7 +410,6 @@
 seq_input_event(struct sequencer_softc *sc, seq_event_t *cmd)
 {
        struct sequencer_queue *q;
-       proc_t *p;
 
        KASSERT(mutex_owned(&sc->lock));
 
@@ -427,6 +426,8 @@
        cv_broadcast(&sc->rchan);
        selnotify(&sc->rsel, 0, NOTE_SUBMIT);
        if (sc->async != 0) {
+               proc_t *p;
+
                mutex_enter(proc_lock);
                if ((p = proc_find(sc->async)) != NULL)
                        psignal(p, SIGIO);
@@ -448,6 +449,7 @@
        sc = addr;
 
        mutex_enter(&sc->lock);
+
        qi.qi_ptr = pcq_get(sc->pcq);
        if (qi.qi_ptr == NULL) {
                mutex_exit(&sc->lock);
@@ -516,9 +518,10 @@
        DPRINTFN(20, ("sequencerread: %"PRIx64", count=%d, ioflag=%x\n",
           dev, (int)uio->uio_resid, ioflag));
 
-       q = &sc->inq;
        if ((error = sequencer_enter(dev, &sc)) != 0)
                return error;
+       q = &sc->inq;
+
        if (sc->mode == SEQ_OLD) {
                sequencer_exit(sc);
                DPRINTFN(-1,("sequencerread: old read\n"));
@@ -563,22 +566,24 @@
        DPRINTFN(2, ("sequencerwrite: %"PRIx64", count=%d\n", dev,
            (int)uio->uio_resid));
 
+       if ((error = sequencer_enter(dev, &sc)) != 0)
+               return error;
        q = &sc->outq;
 
-       if ((error = sequencer_enter(dev, &sc)) != 0)
-               return error;
        size = sc->mode == SEQ_NEW ? sizeof cmdbuf : SEQOLD_CMDSIZE;
        while (uio->uio_resid >= size && error == 0) {
                mutex_exit(&sc->lock);
                error = uiomove(&cmdbuf, size, uio);
                if (error == 0) {
                        if (sc->mode == SEQ_OLD && seq_to_new(&cmdbuf, uio)) {
+                               mutex_enter(&sc->lock);
                                continue;
                        }
                        if (cmdbuf.tag == SEQ_FULLSIZE) {
                                /* We do it like OSS does, asynchronously */
                                error = seq_do_fullsize(sc, &cmdbuf, uio);
                                if (error == 0) {
+                                       mutex_enter(&sc->lock);
                                        continue;
                                }
                        }
@@ -1297,6 +1302,9 @@
        struct sequencer_softc *sc;
        sequencer_pcqitem_t qi;
 
+       DPRINTFN(2, ("midiseq_in: %p %02x %02x %02x\n",
+                    md, msg[0], msg[1], msg[2]));
+
        sc = md->seq;
 
        qi.qi_msg[0] = msg[0];