pps: Move timestamp read into PPS code proper

The PPS (Pulse-Per-Second) line discipline has developed a number of
unhealthy attachments to core tty data and functions, ultimately leading
to its breakage.

The previous patches fixed the crashing.  This one reduces coupling further
by eliminating the timestamp parameter from the dcd_change ldisc method.
This reduces header file linkage and makes the extension more generic,
and the timestamp read is delayed only slightly, from just before the
ldisc->ops->dcd_change method call to just after.

Fix attendant build breakage in
    drivers/tty/n_tty.c
    drivers/tty/tty_buffer.c
    drivers/staging/speakup/selection.c
    drivers/staging/dgrp/dgrp_*.c

Cc: William Hubbs <w.d.hubbs@gmail.com>
Cc: Chris Brannon <chris@the-brannons.com>
Cc: Kirk Reiser <kirk@braille.uwo.ca>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: George Spelvin <linux@horizon.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 4 insertions, 5 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 095072899b5e..05e72bea9b07 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -49,6 +49,7 @@
 #include <linux/file.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>
+#include <linux/ratelimit.h>
 
 
 /* number of characters left in xmit buffer before select has we have room */
@@ -2188,7 +2189,7 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = {
  *      n_tty_inherit_ops       -       inherit N_TTY methods
  *      @ops: struct tty_ldisc_ops where to save N_TTY methods
  *
- *      Used by a generic struct tty_ldisc_ops to easily inherit N_TTY
+ *      Enables a 'subclass' line discipline to 'inherit' N_TTY
  *      methods.
  */
 
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index ca98a3f65fe1..765be520cd2e 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2726,13 +2726,12 @@ void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
         struct uart_state *state = uport->state;
         struct tty_port *port = &state->port;
         struct tty_ldisc *ld = NULL;
-        struct pps_event_time ts;
         struct tty_struct *tty = port->tty;
 
         if (tty)
                 ld = tty_ldisc_ref(tty);
         if (ld && ld->ops->dcd_change)
-                pps_get_ts(&ts);
+                ld->ops->dcd_change(tty, status);
 
         uport->icount.dcd++;
 #ifdef CONFIG_HARD_PPS
@@ -2747,8 +2746,6 @@ void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
                         tty_hangup(tty);
         }
 
-        if (ld && ld->ops->dcd_change)
-                ld->ops->dcd_change(tty, status, &ts);
         if (ld)
                 tty_ldisc_deref(ld);
 }
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 61ec4ddf47e0..bb119934e76c 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -16,6 +16,7 @@
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/ratelimit.h>
 
 /**
  *      tty_buffer_free_all             -       free buffers used by a tty