1 files changed, 79 insertions, 106 deletions

diff --git a/drivers/accessibility/speakup/spk_ttyio.c b/drivers/accessibility/speakup/spk_ttyio.c
index 835d17455fcd..9af1d4c124d3 100644
--- a/drivers/accessibility/speakup/spk_ttyio.c
+++ b/drivers/accessibility/speakup/spk_ttyio.c
@@ -12,14 +12,15 @@ struct spk_ldisc_data {
 	char buf;
 	struct completion completion;
 	bool buf_free;
+	struct spk_synth *synth;
 };
 
-static struct spk_synth *spk_ttyio_synth;
-static struct tty_struct *speakup_tty;
-/* mutex to protect against speakup_tty disappearing from underneath us while
- * we are using it. this can happen when the device physically unplugged,
- * while in use. it also serialises access to speakup_tty.
+/*
+ * This allows to catch within spk_ttyio_ldisc_open whether it is getting set
+ * on for a speakup-driven device.
  */
+static struct tty_struct *speakup_tty;
+/* This mutex serializes the use of such global speakup_tty variable */
 static DEFINE_MUTEX(speakup_tty_mutex);
 
 static int ser_to_dev(int ser, dev_t *dev_no)
@@ -67,22 +68,20 @@ static int spk_ttyio_ldisc_open(struct tty_struct *tty)
 
 static void spk_ttyio_ldisc_close(struct tty_struct *tty)
 {
-	mutex_lock(&speakup_tty_mutex);
-	kfree(speakup_tty->disc_data);
-	speakup_tty = NULL;
-	mutex_unlock(&speakup_tty_mutex);
+	kfree(tty->disc_data);
 }
 
 static int spk_ttyio_receive_buf2(struct tty_struct *tty,
 				  const unsigned char *cp, char *fp, int count)
 {
 	struct spk_ldisc_data *ldisc_data = tty->disc_data;
+	struct spk_synth *synth = ldisc_data->synth;
 
-	if (spk_ttyio_synth->read_buff_add) {
+	if (synth->read_buff_add) {
 		int i;
 
 		for (i = 0; i < count; i++)
-			spk_ttyio_synth->read_buff_add(cp[i]);
+			synth->read_buff_add(cp[i]);
 
 		return count;
 	}
@@ -114,11 +113,11 @@ static struct tty_ldisc_ops spk_ttyio_ldisc_ops = {
 
 static int spk_ttyio_out(struct spk_synth *in_synth, const char ch);
 static int spk_ttyio_out_unicode(struct spk_synth *in_synth, u16 ch);
-static void spk_ttyio_send_xchar(char ch);
-static void spk_ttyio_tiocmset(unsigned int set, unsigned int clear);
-static unsigned char spk_ttyio_in(void);
-static unsigned char spk_ttyio_in_nowait(void);
-static void spk_ttyio_flush_buffer(void);
+static void spk_ttyio_send_xchar(struct spk_synth *in_synth, char ch);
+static void spk_ttyio_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear);
+static unsigned char spk_ttyio_in(struct spk_synth *in_synth);
+static unsigned char spk_ttyio_in_nowait(struct spk_synth *in_synth);
+static void spk_ttyio_flush_buffer(struct spk_synth *in_synth);
 static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth);
 
 struct spk_io_ops spk_ttyio_ops = {
@@ -187,13 +186,17 @@ static int spk_ttyio_initialise_ldisc(struct spk_synth *synth)
 	mutex_lock(&speakup_tty_mutex);
 	speakup_tty = tty;
 	ret = tty_set_ldisc(tty, N_SPEAKUP);
-	if (ret)
-		speakup_tty = NULL;
+	speakup_tty = NULL;
 	mutex_unlock(&speakup_tty_mutex);
 
-	if (!ret)
+	if (!ret) {
 		/* Success */
+		struct spk_ldisc_data *ldisc_data = tty->disc_data;
+
+		ldisc_data->synth = synth;
+		synth->dev = tty;
 		return 0;
+	}
 
 	pr_err("speakup: Failed to set N_SPEAKUP on tty\n");
 
@@ -221,29 +224,30 @@ void spk_ttyio_unregister_ldisc(void)
 
 static int spk_ttyio_out(struct spk_synth *in_synth, const char ch)
 {
-	mutex_lock(&speakup_tty_mutex);
-	if (in_synth->alive && speakup_tty && speakup_tty->ops->write) {
-		int ret = speakup_tty->ops->write(speakup_tty, &ch, 1);
-
-		mutex_unlock(&speakup_tty_mutex);
-		if (ret == 0)
-			/* No room */
-			return 0;
-		if (ret < 0) {
-			pr_warn("%s: I/O error, deactivating speakup\n",
-				in_synth->long_name);
-			/* No synth any more, so nobody will restart TTYs,
-			 * and we thus need to do it ourselves.  Now that there
-			 * is no synth we can let application flood anyway
-			 */
-			in_synth->alive = 0;
-			speakup_start_ttys();
-			return 0;
-		}
+	struct tty_struct *tty = in_synth->dev;
+	int ret;
+
+	if (!in_synth->alive || !tty->ops->write)
+		return 0;
+
+	ret = tty->ops->write(tty, &ch, 1);
+
+	if (ret == 0)
+		/* No room */
+		return 0;
+
+	if (ret > 0)
+		/* Success */
 		return 1;
-	}
 
-	mutex_unlock(&speakup_tty_mutex);
+	pr_warn("%s: I/O error, deactivating speakup\n",
+		in_synth->long_name);
+	/* No synth any more, so nobody will restart TTYs,
+	 * and we thus need to do it ourselves.  Now that there
+	 * is no synth we can let application flood anyway
+	 */
+	in_synth->alive = 0;
+	speakup_start_ttys();
 	return 0;
 }
 
@@ -264,47 +268,20 @@ static int spk_ttyio_out_unicode(struct spk_synth *in_synth, u16 ch)
 	return ret;
 }
 
-static int check_tty(struct tty_struct *tty)
-{
-	if (!tty) {
-		pr_warn("%s: I/O error, deactivating speakup\n",
-			spk_ttyio_synth->long_name);
-		/* No synth any more, so nobody will restart TTYs, and we thus
-		 * need to do it ourselves.  Now that there is no synth we can
-		 * let application flood anyway
-		 */
-		spk_ttyio_synth->alive = 0;
-		speakup_start_ttys();
-		return 1;
-	}
-
-	return 0;
-}
-
-static void spk_ttyio_send_xchar(char ch)
+static void spk_ttyio_send_xchar(struct spk_synth *in_synth, char ch)
 {
-	mutex_lock(&speakup_tty_mutex);
-	if (check_tty(speakup_tty)) {
-		mutex_unlock(&speakup_tty_mutex);
-		return;
-	}
+	struct tty_struct *tty = in_synth->dev;
 
-	if (speakup_tty->ops->send_xchar)
-		speakup_tty->ops->send_xchar(speakup_tty, ch);
-	mutex_unlock(&speakup_tty_mutex);
+	if (tty->ops->send_xchar)
+		tty->ops->send_xchar(tty, ch);
 }
 
-static void spk_ttyio_tiocmset(unsigned int set, unsigned int clear)
+static void spk_ttyio_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear)
 {
-	mutex_lock(&speakup_tty_mutex);
-	if (check_tty(speakup_tty)) {
-		mutex_unlock(&speakup_tty_mutex);
-		return;
-	}
+	struct tty_struct *tty = in_synth->dev;
 
-	if (speakup_tty->ops->tiocmset)
-		speakup_tty->ops->tiocmset(speakup_tty, set, clear);
-	mutex_unlock(&speakup_tty_mutex);
+	if (tty->ops->tiocmset)
+		tty->ops->tiocmset(tty, set, clear);
 }
 
 static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth)
@@ -312,9 +289,10 @@ static int spk_ttyio_wait_for_xmitr(struct spk_synth *in_synth)
 	return 1;
 }
 
-static unsigned char ttyio_in(int timeout)
+static unsigned char ttyio_in(struct spk_synth *in_synth, int timeout)
 {
-	struct spk_ldisc_data *ldisc_data = speakup_tty->disc_data;
+	struct tty_struct *tty = in_synth->dev;
+	struct spk_ldisc_data *ldisc_data = tty->disc_data;
 	char rv;
 
 	if (!timeout) {
@@ -334,35 +312,29 @@ static unsigned char ttyio_in(int timeout)
 	mb();
 	ldisc_data->buf_free = true;
 	/* Let TTY push more characters */
-	tty_schedule_flip(speakup_tty->port);
+	tty_schedule_flip(tty->port);
 
 	return rv;
 }
 
-static unsigned char spk_ttyio_in(void)
+static unsigned char spk_ttyio_in(struct spk_synth *in_synth)
 {
-	return ttyio_in(SPK_SYNTH_TIMEOUT);
+	return ttyio_in(in_synth, SPK_SYNTH_TIMEOUT);
 }
 
-static unsigned char spk_ttyio_in_nowait(void)
+static unsigned char spk_ttyio_in_nowait(struct spk_synth *in_synth)
 {
-	u8 rv = ttyio_in(0);
+	u8 rv = ttyio_in(in_synth, 0);
 
 	return (rv == 0xff) ? 0 : rv;
 }
 
-static void spk_ttyio_flush_buffer(void)
+static void spk_ttyio_flush_buffer(struct spk_synth *in_synth)
 {
-	mutex_lock(&speakup_tty_mutex);
-	if (check_tty(speakup_tty)) {
-		mutex_unlock(&speakup_tty_mutex);
-		return;
-	}
+	struct tty_struct *tty = in_synth->dev;
 
-	if (speakup_tty->ops->flush_buffer)
-		speakup_tty->ops->flush_buffer(speakup_tty);
-
-	mutex_unlock(&speakup_tty_mutex);
+	if (tty->ops->flush_buffer)
+		tty->ops->flush_buffer(tty);
 }
 
 int spk_ttyio_synth_probe(struct spk_synth *synth)
@@ -373,37 +345,38 @@ int spk_ttyio_synth_probe(struct spk_synth *synth)
 		return rv;
 
 	synth->alive = 1;
-	spk_ttyio_synth = synth;
 
 	return 0;
 }
 EXPORT_SYMBOL_GPL(spk_ttyio_synth_probe);
 
-void spk_ttyio_release(void)
+void spk_ttyio_release(struct spk_synth *in_synth)
 {
-	if (!speakup_tty)
-		return;
+	struct tty_struct *tty = in_synth->dev;
 
-	tty_lock(speakup_tty);
+	tty_lock(tty);
 
-	if (speakup_tty->ops->close)
-		speakup_tty->ops->close(speakup_tty, NULL);
+	if (tty->ops->close)
+		tty->ops->close(tty, NULL);
+
+	tty_ldisc_flush(tty);
+	tty_unlock(tty);
+	tty_kclose(tty);
 
-	tty_ldisc_flush(speakup_tty);
-	tty_unlock(speakup_tty);
-	tty_kclose(speakup_tty);
+	in_synth->dev = NULL;
 }
 EXPORT_SYMBOL_GPL(spk_ttyio_release);
 
-const char *spk_ttyio_synth_immediate(struct spk_synth *synth, const char *buff)
+const char *spk_ttyio_synth_immediate(struct spk_synth *in_synth, const char *buff)
 {
+	struct tty_struct *tty = in_synth->dev;
 	u_char ch;
 
 	while ((ch = *buff)) {
 		if (ch == '\n')
-			ch = synth->procspeech;
-		if (tty_write_room(speakup_tty) < 1 ||
-		    !synth->io_ops->synth_out(synth, ch))
+			ch = in_synth->procspeech;
+		if (tty_write_room(tty) < 1 ||
+		    !in_synth->io_ops->synth_out(in_synth, ch))
 			return buff;
 		buff++;
 	}