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n_tty: Only perform wakeups for waiters 

Only wakeup the _waiting_ reader, polls and/or writer(s).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2013-12-02 14:24:46 -05:00 committed by Greg Kroah-Hartman
parent eafbe67f84
commit 6c67716d64
1 changed files with 12 additions and 6 deletions
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18
drivers/tty/n_tty.c
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@ -274,7 +274,8 @@ static void n_tty_check_unthrottle(struct tty_struct *tty)
return; return;
n_tty_set_room(tty); n_tty_set_room(tty);
n_tty_write_wakeup(tty->link); n_tty_write_wakeup(tty->link);
wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT); if (waitqueue_active(&tty->link->write_wait))
wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
return; return;
} }
@ -349,7 +350,8 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty)
spin_lock_irqsave(&tty->ctrl_lock, flags); spin_lock_irqsave(&tty->ctrl_lock, flags);
if (tty->link->packet) { if (tty->link->packet) {
tty->ctrl_status |= TIOCPKT_FLUSHREAD; tty->ctrl_status |= TIOCPKT_FLUSHREAD;
wake_up_interruptible(&tty->link->read_wait); if (waitqueue_active(&tty->link->read_wait))
wake_up_interruptible(&tty->link->read_wait);
} }
spin_unlock_irqrestore(&tty->ctrl_lock, flags); spin_unlock_irqrestore(&tty->ctrl_lock, flags);
} }
@ -1155,7 +1157,8 @@ static void n_tty_receive_break(struct tty_struct *tty)
put_tty_queue('\0', ldata); put_tty_queue('\0', ldata);
} }
put_tty_queue('\0', ldata); put_tty_queue('\0', ldata);
wake_up_interruptible(&tty->read_wait); if (waitqueue_active(&tty->read_wait))
wake_up_interruptible(&tty->read_wait);
} }
/** /**
@ -1213,7 +1216,8 @@ static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
put_tty_queue('\0', ldata); put_tty_queue('\0', ldata);
else else
put_tty_queue(c, ldata); put_tty_queue(c, ldata);
wake_up_interruptible(&tty->read_wait); if (waitqueue_active(&tty->read_wait))
wake_up_interruptible(&tty->read_wait);
} }
static void static void
@ -1802,8 +1806,10 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
start_tty(tty); start_tty(tty);
/* The termios change make the tty ready for I/O */ /* The termios change make the tty ready for I/O */
wake_up_interruptible(&tty->write_wait); if (waitqueue_active(&tty->write_wait))
wake_up_interruptible(&tty->read_wait); wake_up_interruptible(&tty->write_wait);
if (waitqueue_active(&tty->read_wait))
wake_up_interruptible(&tty->read_wait);
} }
/** /**