Use newly-introduced tty->flow_lock to serialize updates to
tty->flow_stopped (via tcflow()) and with concurrent tty flow
control changes from other sources.
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/tty_ioctl.c | 8 ++++++--
include/linux/tty.h | 2 +-
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 6fd60fe..ffed466 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -1177,16 +1177,20 @@ int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
return retval;
switch (arg) {
case TCOOFF:
+ spin_lock_irq(&tty->flow_lock);
if (!tty->flow_stopped) {
tty->flow_stopped = 1;
- stop_tty(tty);
+ __stop_tty(tty);
}
+ spin_unlock_irq(&tty->flow_lock);
break;
case TCOON:
+ spin_lock_irq(&tty->flow_lock);
if (tty->flow_stopped) {
tty->flow_stopped = 0;
- start_tty(tty);
+ __start_tty(tty);
}
+ spin_unlock_irq(&tty->flow_lock);
break;
case TCIOFF:
if (STOP_CHAR(tty) != __DISABLED_CHAR)
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 19ce455..0a457c9 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -264,7 +264,7 @@ struct tty_struct {
struct winsize winsize; /* winsize_mutex */
bool stopped; /* flow_lock */
bool hw_stopped;
- bool flow_stopped;
+ bool flow_stopped; /* flow_lock */
bool packet;
unsigned char ctrl_status; /* ctrl_lock */
unsigned int receive_room; /* Bytes free for queue */
--
2.1.0
--
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