[PATCH] n_tty: Ensure reader restarts worker for next reader

From: Peter Hurley
Date: Thu Nov 07 2013 - 14:22:33 EST


A departing reader must restart a flush_to_ldisc() worker _before_
the next reader enters the read loop; this is to avoid the new reader
concluding no more i/o is available and prematurely exiting, when the
old reader simply hasn't re-started the worker yet.

Cc: stable@xxxxxxxxxx # 3.12
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/n_tty.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 7a744b6..ce11cd5 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2250,6 +2250,9 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (time)
timeout = time;
}
+ n_tty_set_room(tty);
+ up_read(&tty->termios_rwsem);
+
mutex_unlock(&ldata->atomic_read_lock);
remove_wait_queue(&tty->read_wait, &wait);

@@ -2260,8 +2263,6 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (b - buf)
retval = b - buf;

- n_tty_set_room(tty);
- up_read(&tty->termios_rwsem);
return retval;
}

--
1.8.1.2

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