tty: add throttle/unthrottle helpers

Something Arjan suggested which allows us to clean up the code nicely

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index a6c2619..e5cd856 100644 (file)
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -370,9 +370,7 @@ static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *f
        hu->hdev->stat.byte_rx += count;
        spin_unlock(&hu->rx_lock);
 
-       if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
-                                       tty->ops->unthrottle)
-               tty->ops->unthrottle(tty);
+       tty_unthrottle(tty);
 }
 
 static int hci_uart_register_dev(struct hci_uart *hu)

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index abc93a9..19105ec 100644 (file)
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -147,10 +147,8 @@ static void put_tty_queue(unsigned char c, struct tty_struct *tty)
 
 static void check_unthrottle(struct tty_struct *tty)
 {
-       if (tty->count &&
-           test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
-           tty->ops->unthrottle)
-               tty->ops->unthrottle(tty);
+       if (tty->count)
+               tty_unthrottle(tty);
 }
 
 /**
@@ -982,12 +980,8 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
         * mode.  We don't want to throttle the driver if we're in
         * canonical mode and don't have a newline yet!
         */
-       if (tty->receive_room < TTY_THRESHOLD_THROTTLE) {
-               /* check TTY_THROTTLED first so it indicates our state */
-               if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
-                   tty->ops->throttle)
-                       tty->ops->throttle(tty);
-       }
+       if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
+               tty_throttle(tty);
 }
 
 int is_ignored(int sig)

diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index c10d40c..b1a757a 100644 (file)
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -67,6 +67,22 @@ void tty_driver_flush_buffer(struct tty_struct *tty)
 
 EXPORT_SYMBOL(tty_driver_flush_buffer);
 
+void tty_throttle(struct tty_struct *tty)
+{
+       /* check TTY_THROTTLED first so it indicates our state */
+       if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
+           tty->ops->throttle)
+               tty->ops->throttle(tty);
+}
+EXPORT_SYMBOL(tty_throttle);
+
+void tty_unthrottle(struct tty_struct *tty)
+{
+       if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
+           tty->ops->unthrottle)
+               tty->ops->unthrottle(tty);
+}
+EXPORT_SYMBOL(tty_unthrottle);
 
 /**
  *     tty_wait_until_sent     -       wait for I/O to finish

diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
index 82a3626..9d57212 100644 (file)
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -491,9 +491,7 @@ static void sixpack_receive_buf(struct tty_struct *tty,
        sixpack_decode(sp, buf, count1);
 
        sp_put(sp);
-       if (test_and_clear_bit(TTY_THROTTLED, &tty->flags)
-           && tty->ops->unthrottle)
-               tty->ops->unthrottle(tty);
+       tty_unthrottle(tty);
 }
 
 /*

diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index ebcc5ad..6516603 100644 (file)
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -936,9 +936,7 @@ static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp,
        }
 
        mkiss_put(ax);
-       if (test_and_clear_bit(TTY_THROTTLED, &tty->flags)
-           && tty->ops->unthrottle)
-               tty->ops->unthrottle(tty);
+       tty_unthrottle(tty);
 }
 
 /*

diff --git a/drivers/net/ppp_async.c b/drivers/net/ppp_async.c
index 1c4b7e3..f1a52de 100644 (file)
--- a/drivers/net/ppp_async.c
+++ b/drivers/net/ppp_async.c
@@ -361,9 +361,7 @@ ppp_asynctty_receive(struct tty_struct *tty, const unsigned char *buf,
        if (!skb_queue_empty(&ap->rqueue))
                tasklet_schedule(&ap->tsk);
        ap_put(ap);
-       if (test_and_clear_bit(TTY_THROTTLED, &tty->flags)
-           && tty->ops->unthrottle)
-               tty->ops->unthrottle(tty);
+       tty_unthrottle(tty);
 }
 
 static void

diff --git a/drivers/net/ppp_synctty.c b/drivers/net/ppp_synctty.c
index 48ed5fd..b8f0369 100644 (file)
--- a/drivers/net/ppp_synctty.c
+++ b/drivers/net/ppp_synctty.c
@@ -401,9 +401,7 @@ ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf,
        if (!skb_queue_empty(&ap->rqueue))
                tasklet_schedule(&ap->tsk);
        sp_put(ap);
-       if (test_and_clear_bit(TTY_THROTTLED, &tty->flags)
-           && tty->ops->unthrottle)
-               tty->ops->unthrottle(tty);
+       tty_unthrottle(tty);
 }
 
 static void

diff --git a/include/linux/tty.h b/include/linux/tty.h
index c36a76d..7f7121f 100644 (file)
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -303,6 +303,8 @@ extern int tty_put_char(struct tty_struct *tty, unsigned char c);
 extern int tty_chars_in_buffer(struct tty_struct *tty);
 extern int tty_write_room(struct tty_struct *tty);
 extern void tty_driver_flush_buffer(struct tty_struct *tty);
+extern void tty_throttle(struct tty_struct *tty);
+extern void tty_unthrottle(struct tty_struct *tty);
 
 extern int is_current_pgrp_orphaned(void);
 extern struct pid *tty_get_pgrp(struct tty_struct *tty);

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index f80d73b..59f1c0b 100644 (file)
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -100,6 +100,8 @@
  *     This routine notifies the tty driver that input buffers for
  *     the line discipline are close to full, and it should somehow
  *     signal that no more characters should be sent to the tty.
+ *
+ *     Optional: Always invoke via tty_throttle();
  * 
  * void (*unthrottle)(struct tty_struct * tty);
  *
@@ -107,6 +109,8 @@
  *     that characters can now be sent to the tty without fear of
  *     overrunning the input buffers of the line disciplines.
  * 
+ *     Optional: Always invoke via tty_unthrottle();
+ *
  * void (*stop)(struct tty_struct *tty);
  *
  *     This routine notifies the tty driver that it should stop