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convert cardslot event thread from wakeup/tsleep to mutex/condvar. 

this avoids a strange hang at reboot i am seeing on an old pentium4-m
laptop, that was introduced with kern_mutex.c 1.91/92, though i can
not really explain why that matters (in the waiting thread, a pointer
that should be NULL remains non NULL.)  thanks to jmcneill@ for some
helpful review commentary here.

don't panic() if either "cardbus" or "pcmcia" didn't attach and a
card is inserted.  this can happen for various reasons, including
some regression in netbsd (-current, and -9, at least) that suggests
using PCI_BUS_FIXUP (though it still fails to attach the card i have.)

both found with GCC 10 testing, though both also occur with GCC 7 in
the netbsd-9 tree as well.
This commit is contained in:
mrg 2021-04-17 01:19:48 +00:00
parent 0e59457009
commit 856324edf9
2 changed files with 43 additions and 24 deletions
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61
sys/dev/cardbus/cardslot.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: cardslot.c,v 1.57 2020/10/04 06:15:54 nat Exp $ */
/* $NetBSD: cardslot.c,v 1.58 2021/04/17 01:19:48 mrg Exp $ */
/*
* Copyright (c) 1999 and 2000
@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cardslot.c,v 1.57 2020/10/04 06:15:54 nat Exp $");
__KERNEL_RCSID(0, "$NetBSD: cardslot.c,v 1.58 2021/04/17 01:19:48 mrg Exp $");
#include "opt_cardslot.h"
@ -129,6 +129,8 @@ cardslotattach(device_t parent, device_t self, void *aux)
sc->sc_16_softc = NULL;
SIMPLEQ_INIT(&sc->sc_events);
sc->sc_th_enable = 0;
mutex_init(&sc->sc_event_lock, MUTEX_DEFAULT, IPL_TTY);
cv_init(&sc->sc_event_cv, "evexit");
aprint_naive("\n");
aprint_normal("\n");
@ -192,14 +194,24 @@ cardslotdetach(device_t self, int flags)
if ((rc = config_detach_children(self, flags)) != 0)
return rc;
sc->sc_th_enable = 0;
wakeup(&sc->sc_events);
while (sc->sc_event_thread != NULL)
(void)tsleep(sc, PWAIT, "cardslotthd", 0);
mutex_enter(&sc->sc_event_lock);
if (sc->sc_event_thread != NULL) {
sc->sc_th_enable = 0;
cv_signal(&sc->sc_event_cv);
while (sc->sc_event_thread != NULL) {
cv_wait(&sc->sc_event_cv, &sc->sc_event_lock);
}
}
if (!SIMPLEQ_EMPTY(&sc->sc_events))
aprint_error_dev(self, "events outstanding");
mutex_exit(&sc->sc_event_lock);
mutex_destroy(&sc->sc_event_lock);
cv_destroy(&sc->sc_event_cv);
pmf_device_deregister(self);
return 0;
}
@ -272,13 +284,11 @@ cardslot_event_throw(struct cardslot_softc *sc, int ev)
ce->ce_type = ev;
{
int s = spltty();
SIMPLEQ_INSERT_TAIL(&sc->sc_events, ce, ce_q);
splx(s);
}
mutex_enter(&sc->sc_event_lock);
SIMPLEQ_INSERT_TAIL(&sc->sc_events, ce, ce_q);
mutex_exit(&sc->sc_event_lock);
wakeup(&sc->sc_events);
cv_signal(&sc->sc_event_cv);
return;
}
@ -296,29 +306,28 @@ cardslot_event_thread(void *arg)
{
struct cardslot_softc *sc = arg;
struct cardslot_event *ce;
int s, first = 1;
int first = 1;
static int antonym_ev[4] = {
CARDSLOT_EVENT_REMOVAL_16, CARDSLOT_EVENT_INSERTION_16,
CARDSLOT_EVENT_REMOVAL_CB, CARDSLOT_EVENT_INSERTION_CB
};
mutex_enter(&sc->sc_event_lock);
while (sc->sc_th_enable) {
s = spltty();
if ((ce = SIMPLEQ_FIRST(&sc->sc_events)) == NULL) {
splx(s);
if (first) {
first = 0;
mutex_exit(&sc->sc_event_lock);
config_pending_decr(sc->sc_dev);
mutex_enter(&sc->sc_event_lock);
}
(void) tsleep(&sc->sc_events, PWAIT, "cardslotev", 0);
cv_wait(&sc->sc_event_cv, &sc->sc_event_lock);
continue;
}
SIMPLEQ_REMOVE_HEAD(&sc->sc_events, ce_q);
splx(s);
if (IS_CARDSLOT_INSERT_REMOVE_EV(ce->ce_type)) {
/* Chattering suppression */
s = spltty();
while (1) {
struct cardslot_event *ce1, *ce2;
@ -340,8 +349,8 @@ cardslot_event_thread(void *arg)
free(ce2, M_TEMP);
}
}
splx(s);
}
mutex_exit(&sc->sc_event_lock);
switch (ce->ce_type) {
case CARDSLOT_EVENT_INSERTION_CB:
@ -371,8 +380,10 @@ cardslot_event_thread(void *arg)
CARDSLOT_STATUS_NOTWORK);
}
} else {
panic("no cardbus on %s",
printf("%s: no cardbus on %s\n", __func__,
device_xname(sc->sc_dev));
CARDSLOT_SET_WORK(sc->sc_status,
CARDSLOT_STATUS_NOTWORK);
}
break;
@ -400,8 +411,10 @@ cardslot_event_thread(void *arg)
CARDSLOT_STATUS_WORKING);
}
} else {
panic("no 16-bit pcmcia on %s",
printf("%s: no 16-bit pcmcia on %s\n", __func__,
device_xname(sc->sc_dev));
CARDSLOT_SET_WORK(sc->sc_status,
CARDSLOT_STATUS_NOTWORK);
}
break;
@ -451,12 +464,14 @@ cardslot_event_thread(void *arg)
panic("cardslot_event_thread: unknown event %d", ce->ce_type);
}
free(ce, M_TEMP);
mutex_enter(&sc->sc_event_lock);
}
/* The parent device is waiting for us to exit. */
sc->sc_event_thread = NULL;
/* In case the parent device is waiting for us to exit. */
wakeup(sc);
cv_signal(&sc->sc_event_cv);
mutex_exit(&sc->sc_event_lock);
kthread_exit(0);
}

6
sys/dev/cardbus/cardslotvar.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: cardslotvar.h,v 1.16 2009/12/15 22:17:12 snj Exp $ */
/* $NetBSD: cardslotvar.h,v 1.17 2021/04/17 01:19:48 mrg Exp $ */
/*
* Copyright (c) 1999
@ -65,6 +65,10 @@ struct cardslot_softc {
/* An event queue for the thread which processes slot state events. */
SIMPLEQ_HEAD(, cardslot_event) sc_events;
/* Safely handle detach. */
kmutex_t sc_event_lock;
kcondvar_t sc_event_cv;
};
#define CARDSLOT_STATUS_CARD_MASK 0x07