Differential D24459 Diff 147476 sys/kern/kern_cons.c

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sys/kern/kern_cons.c

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	* Redirect console output to a tty.			* Redirect console output to a tty.
	*/			*/
	int			int
	constty_set(struct tty *tp)			constty_set(struct tty *tp)
	{			{
	int size = consmsgbuf_size;			int size = consmsgbuf_size;
	void *buf = NULL;			void *buf = NULL;

	tty_assert_locked(tp);			ttydisc_assert_locked(tp);
	if (constty == tp)			if (constty == tp)
	return (0);			return (0);
	if (constty != NULL)			if (constty != NULL)
	return (EBUSY);			return (EBUSY);

	if (consbuf == NULL) {			if (consbuf == NULL) {
	tty_unlock(tp);			ttydisc_unlock(tp);
	buf = malloc(size, M_TTYCONS, M_WAITOK);			buf = malloc(size, M_TTYCONS, M_WAITOK);
	tty_lock(tp);			ttydisc_lock(tp);
				impUnsubmitted Not Done Inline Actions I thought that ttydisc is a sx lock, so this shouldn't be needed.... Or is that a 'future thing after these patches'? imp: I thought that ttydisc is a sx lock, so this shouldn't be needed.... Or is that a 'future thing…
				kevansAuthorUnsubmitted Done Inline Actions The ttydisc lock is separated out, so it's effectively the discipline + driver lock while the historical tty lock is just for the tty itself. kevans: The ttydisc lock is separated out, so it's effectively the discipline + driver lock while the…
				impUnsubmitted Not Done Inline Actions I thought wrong, it's still mtx. imp: I thought wrong, it's still mtx.
	}			}
	mtx_lock(&constty_mtx);			mtx_lock(&constty_mtx);
	if (constty != NULL) {			if (constty != NULL) {
	mtx_unlock(&constty_mtx);			mtx_unlock(&constty_mtx);
	free(buf, M_TTYCONS);			free(buf, M_TTYCONS);
	return (EBUSY);			return (EBUSY);
	}			}
	if (consbuf == NULL) {			if (consbuf == NULL) {
	consbuf = buf;			consbuf = buf;
	msgbuf_init(&consmsgbuf, buf, size);			msgbuf_init(&consmsgbuf, buf, size);
	} else			} else
	free(buf, M_TTYCONS);			free(buf, M_TTYCONS);
	constty = tp;			constty = tp;
	mtx_unlock(&constty_mtx);			mtx_unlock(&constty_mtx);

	callout_init_mtx(&conscallout, tty_getlock(tp), 0);			callout_init_mtx(&conscallout, ttydisc_getlock(tp), 0);
	constty_timeout(tp);			constty_timeout(tp);
	return (0);			return (0);
	}			}

	/*			/*
	* Disable console redirection to a tty.			* Disable console redirection to a tty.
	*/			*/
	int			int
	constty_clear(struct tty *tp)			constty_clear(struct tty *tp)
	{			{
	int c;			int c;

	tty_assert_locked(tp);			ttydisc_assert_locked(tp);
	if (constty != tp)			if (constty != tp)
	return (ENXIO);			return (ENXIO);
	callout_stop(&conscallout);			callout_stop(&conscallout);
	mtx_lock(&constty_mtx);			mtx_lock(&constty_mtx);
	constty = NULL;			constty = NULL;
	mtx_unlock(&constty_mtx);			mtx_unlock(&constty_mtx);
	while ((c = msgbuf_getchar(&consmsgbuf)) != -1)			while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
	cnputc(c);			cnputc(c);
	/* We never free consbuf because it can still be in use. */			/* We never free consbuf because it can still be in use. */
	return (0);			return (0);
	}			}

	/* Times per second to check for pending console tty messages. */			/* Times per second to check for pending console tty messages. */
	static int constty_wakeups_per_second = 15;			static int constty_wakeups_per_second = 15;
	SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,			SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
	&constty_wakeups_per_second, 0,			&constty_wakeups_per_second, 0,
	"Times per second to check for pending console tty messages");			"Times per second to check for pending console tty messages");

	static void			static void
	constty_timeout(void *arg)			constty_timeout(void *arg)
	{			{
	struct tty *tp = arg;			struct tty *tp = arg;
	int c;			int c;

	tty_assert_locked(tp);			ttydisc_assert_locked(tp);
	while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {			while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
	if (tty_putchar(tp, c) < 0) {			if (tty_putchar(tp, c) < 0) {
	constty_clear(tp);			constty_clear(tp);
	return;			return;
	}			}
	}			}
	callout_reset_sbt(&conscallout, SBT_1S / constty_wakeups_per_second,			callout_reset_sbt(&conscallout, SBT_1S / constty_wakeups_per_second,
	0, constty_timeout, tp, C_PREL(1));			0, constty_timeout, tp, C_PREL(1));
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