diff options
| -rw-r--r-- | drivers/staging/speakup/spk_ttyio.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/drivers/staging/speakup/spk_ttyio.c b/drivers/staging/speakup/spk_ttyio.c index bcc3873c8c50..f643167921c3 100644 --- a/drivers/staging/speakup/spk_ttyio.c +++ b/drivers/staging/speakup/spk_ttyio.c @@ -15,6 +15,11 @@ struct spk_ldisc_data { 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. + */ +static DEFINE_MUTEX(speakup_tty_mutex); static int ser_to_dev(int ser, dev_t *dev_no) { @@ -60,8 +65,10 @@ 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); } static int spk_ttyio_receive_buf2(struct tty_struct *tty, @@ -189,9 +196,11 @@ 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; @@ -207,17 +216,50 @@ static int spk_ttyio_out(struct spk_synth *in_synth, const char ch) } return 1; } + + mutex_unlock(&speakup_tty_mutex); + return 0; +} + +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) { + mutex_lock(&speakup_tty_mutex); + if (check_tty(speakup_tty)) { + mutex_unlock(&speakup_tty_mutex); + return; + } + speakup_tty->ops->send_xchar(speakup_tty, ch); + mutex_unlock(&speakup_tty_mutex); } static void spk_ttyio_tiocmset(unsigned int set, unsigned int clear) { + mutex_lock(&speakup_tty_mutex); + if (check_tty(speakup_tty)) { + mutex_unlock(&speakup_tty_mutex); + return; + } + speakup_tty->ops->tiocmset(speakup_tty, set, clear); + mutex_unlock(&speakup_tty_mutex); } static unsigned char ttyio_in(int timeout) @@ -257,8 +299,16 @@ static unsigned char spk_ttyio_in_nowait(void) static void spk_ttyio_flush_buffer(void) { + mutex_lock(&speakup_tty_mutex); + if (check_tty(speakup_tty)) { + mutex_unlock(&speakup_tty_mutex); + return; + } + if (speakup_tty->ops->flush_buffer) speakup_tty->ops->flush_buffer(speakup_tty); + + mutex_unlock(&speakup_tty_mutex); } int spk_ttyio_synth_probe(struct spk_synth *synth) |