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path: root/drivers/tty/pty.c
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-rw-r--r--drivers/tty/pty.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 9bbdb1de12e2..7c4447a5c0f4 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -24,6 +24,7 @@
#include <linux/devpts_fs.h>
#include <linux/slab.h>
#include <linux/mutex.h>
+#include <linux/poll.h>
#ifdef CONFIG_UNIX98_PTYS
@@ -313,6 +314,42 @@ done:
}
/**
+ * pty_start - start() handler
+ * pty_stop - stop() handler
+ * @tty: tty being flow-controlled
+ *
+ * Propagates the TIOCPKT status to the master pty.
+ *
+ * NB: only the master pty can be in packet mode so only the slave
+ * needs start()/stop() handlers
+ */
+static void pty_start(struct tty_struct *tty)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&tty->ctrl_lock, flags);
+ if (tty->link && tty->link->packet) {
+ tty->ctrl_status &= ~TIOCPKT_STOP;
+ tty->ctrl_status |= TIOCPKT_START;
+ wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
+ }
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+}
+
+static void pty_stop(struct tty_struct *tty)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&tty->ctrl_lock, flags);
+ if (tty->link && tty->link->packet) {
+ tty->ctrl_status &= ~TIOCPKT_START;
+ tty->ctrl_status |= TIOCPKT_STOP;
+ wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
+ }
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+}
+
+/**
* pty_common_install - set up the pty pair
* @driver: the pty driver
* @tty: the tty being instantiated
@@ -471,6 +508,8 @@ static const struct tty_operations slave_pty_ops_bsd = {
.set_termios = pty_set_termios,
.cleanup = pty_cleanup,
.resize = pty_resize,
+ .start = pty_start,
+ .stop = pty_stop,
.remove = pty_remove
};
@@ -646,6 +685,8 @@ static const struct tty_operations pty_unix98_ops = {
.chars_in_buffer = pty_chars_in_buffer,
.unthrottle = pty_unthrottle,
.set_termios = pty_set_termios,
+ .start = pty_start,
+ .stop = pty_stop,
.shutdown = pty_unix98_shutdown,
.cleanup = pty_cleanup,
};