lkml.org 
[lkml]   [2013]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH tty-next 6/7] n_tty: Only perform wakeups for waiters
Date
Only wakeup the _waiting_ reader, polls and/or writer(s).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
drivers/tty/n_tty.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 8f2356e..aae28a6 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -275,7 +275,8 @@ static void n_tty_check_unthrottle(struct tty_struct *tty)
return;
n_tty_set_room(tty);
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;
}

@@ -350,7 +351,8 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty)
spin_lock_irqsave(&tty->ctrl_lock, flags);
if (tty->link->packet) {
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);
}
@@ -1156,7 +1158,8 @@ static void n_tty_receive_break(struct tty_struct *tty)
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);
}

/**
@@ -1214,7 +1217,8 @@ static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
put_tty_queue('\0', ldata);
else
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
@@ -1808,8 +1812,10 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
start_tty(tty);

/* The termios change make the tty ready for I/O */
- wake_up_interruptible(&tty->write_wait);
- wake_up_interruptible(&tty->read_wait);
+ if (waitqueue_active(&tty->write_wait))
+ wake_up_interruptible(&tty->write_wait);
+ if (waitqueue_active(&tty->read_wait))
+ wake_up_interruptible(&tty->read_wait);
}

/**
--
1.8.1.2


\
 
 \ /
  Last update: 2013-11-22 17:21    [W:0.194 / U:0.148 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site