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-rw-r--r--drivers/tty/n_gsm.c5
-rw-r--r--drivers/tty/tty_buffer.c14
-rw-r--r--drivers/tty/tty_ldisc.c49
-rw-r--r--drivers/tty/vt/vc_screen.c6
4 files changed, 60 insertions, 14 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 04ef3ef0a422..81b46585edf7 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -716,8 +716,8 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
if (msg->len < 128)
*--dp = (msg->len << 1) | EA;
else {
- *--dp = (msg->len >> 6) | EA;
- *--dp = (msg->len & 127) << 1;
+ *--dp = ((msg->len & 127) << 1) | EA;
+ *--dp = (msg->len >> 6) & 0xfe;
}
}
@@ -2375,6 +2375,7 @@ static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
gsm->mru = c->mru;
gsm->encoding = c->encapsulation;
gsm->adaption = c->adaption;
+ gsm->n2 = c->n2;
if (c->i == 1)
gsm->ftype = UIH;
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index cc1e9850d655..d8210ca00720 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -413,7 +413,8 @@ static void flush_to_ldisc(struct work_struct *work)
spin_lock_irqsave(&tty->buf.lock, flags);
if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
- struct tty_buffer *head;
+ struct tty_buffer *head, *tail = tty->buf.tail;
+ int seen_tail = 0;
while ((head = tty->buf.head) != NULL) {
int count;
char *char_buf;
@@ -423,6 +424,15 @@ static void flush_to_ldisc(struct work_struct *work)
if (!count) {
if (head->next == NULL)
break;
+ /*
+ There's a possibility tty might get new buffer
+ added during the unlock window below. We could
+ end up spinning in here forever hogging the CPU
+ completely. To avoid this let's have a rest each
+ time we processed the tail buffer.
+ */
+ if (tail == head)
+ seen_tail = 1;
tty->buf.head = head->next;
tty_buffer_free(tty, head);
continue;
@@ -432,7 +442,7 @@ static void flush_to_ldisc(struct work_struct *work)
line discipline as we want to empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags))
break;
- if (!tty->receive_room) {
+ if (!tty->receive_room || seen_tail) {
schedule_delayed_work(&tty->buf.work, 1);
break;
}
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 412f9775d19c..d8e96b005023 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -47,6 +47,7 @@
static DEFINE_SPINLOCK(tty_ldisc_lock);
static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);
+static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_idle);
/* Line disc dispatch table */
static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS];
@@ -83,6 +84,7 @@ static void put_ldisc(struct tty_ldisc *ld)
return;
}
local_irq_restore(flags);
+ wake_up(&tty_ldisc_idle);
}
/**
@@ -531,6 +533,23 @@ static int tty_ldisc_halt(struct tty_struct *tty)
}
/**
+ * tty_ldisc_wait_idle - wait for the ldisc to become idle
+ * @tty: tty to wait for
+ *
+ * Wait for the line discipline to become idle. The discipline must
+ * have been halted for this to guarantee it remains idle.
+ */
+static int tty_ldisc_wait_idle(struct tty_struct *tty)
+{
+ int ret;
+ ret = wait_event_interruptible_timeout(tty_ldisc_idle,
+ atomic_read(&tty->ldisc->users) == 1, 5 * HZ);
+ if (ret < 0)
+ return ret;
+ return ret > 0 ? 0 : -EBUSY;
+}
+
+/**
* tty_set_ldisc - set line discipline
* @tty: the terminal to set
* @ldisc: the line discipline
@@ -634,8 +653,17 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
flush_scheduled_work();
+ retval = tty_ldisc_wait_idle(tty);
+
tty_lock();
mutex_lock(&tty->ldisc_mutex);
+
+ /* handle wait idle failure locked */
+ if (retval) {
+ tty_ldisc_put(new_ldisc);
+ goto enable;
+ }
+
if (test_bit(TTY_HUPPED, &tty->flags)) {
/* We were raced by the hangup method. It will have stomped
the ldisc data and closed the ldisc down */
@@ -669,6 +697,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
tty_ldisc_put(o_ldisc);
+enable:
/*
* Allow ldisc referencing to occur again
*/
@@ -714,9 +743,12 @@ static void tty_reset_termios(struct tty_struct *tty)
* state closed
*/
-static void tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
+static int tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
{
- struct tty_ldisc *ld;
+ struct tty_ldisc *ld = tty_ldisc_get(ldisc);
+
+ if (IS_ERR(ld))
+ return -1;
tty_ldisc_close(tty, tty->ldisc);
tty_ldisc_put(tty->ldisc);
@@ -724,10 +756,10 @@ static void tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
/*
* Switch the line discipline back
*/
- ld = tty_ldisc_get(ldisc);
- BUG_ON(IS_ERR(ld));
tty_ldisc_assign(tty, ld);
tty_set_termios_ldisc(tty, ldisc);
+
+ return 0;
}
/**
@@ -802,13 +834,16 @@ void tty_ldisc_hangup(struct tty_struct *tty)
a FIXME */
if (tty->ldisc) { /* Not yet closed */
if (reset == 0) {
- tty_ldisc_reinit(tty, tty->termios->c_line);
- err = tty_ldisc_open(tty, tty->ldisc);
+
+ if (!tty_ldisc_reinit(tty, tty->termios->c_line))
+ err = tty_ldisc_open(tty, tty->ldisc);
+ else
+ err = 1;
}
/* If the re-open fails or we reset then go to N_TTY. The
N_TTY open cannot fail */
if (reset || err) {
- tty_ldisc_reinit(tty, N_TTY);
+ BUG_ON(tty_ldisc_reinit(tty, N_TTY));
WARN_ON(tty_ldisc_open(tty, tty->ldisc));
}
tty_ldisc_enable(tty);
diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
index 273ab44cc91d..eab3a1ff99e4 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -553,12 +553,12 @@ static unsigned int
vcs_poll(struct file *file, poll_table *wait)
{
struct vcs_poll_data *poll = vcs_poll_data_get(file);
- int ret = 0;
+ int ret = DEFAULT_POLLMASK|POLLERR|POLLPRI;
if (poll) {
poll_wait(file, &poll->waitq, wait);
- if (!poll->seen_last_update)
- ret = POLLIN | POLLRDNORM;
+ if (poll->seen_last_update)
+ ret = DEFAULT_POLLMASK;
}
return ret;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-17 04:06:35 +0000