[PATCH] n_hdlc add buffer flushing

Paul Fulghum
2009-06-15T15:26:21Z

Add flush_buffer tty callback to flush rx buffers.
Add TCFLSH ioctl processing to flush tx buffers.
Increase default tx buffers from 1 to 3.
Remove unneeded flush_buffer call in open callback.
Remove vendor specific CVS version string.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>

--- a/drivers/char/n_hdlc.c 2009-06-09 22:05:27.000000000 -0500
+++ b/drivers/char/n_hdlc.c 2009-06-12 13:16:54.000000000 -0500
@@ -10,7 +10,6 @@
* Paul Mackerras <Paul.Mackerras@cs.anu.edu.au>
*
* Original release 01/11/99
- * $Id: n_hdlc.c,v 4.8 2003/05/06 21:18:51 paulkf Exp $
*
* This code is released under the GNU General Public License (GPL)
*
@@ -79,7 +78,6 @@
*/

#define HDLC_MAGIC 0x239e
-#define HDLC_VERSION "$Revision: 4.8 $"

#include <linux/module.h>
#include <linux/init.h>
@@ -114,7 +112,7 @@
#define MAX_HDLC_FRAME_SIZE 65535
#define DEFAULT_RX_BUF_COUNT 10
#define MAX_RX_BUF_COUNT 60
-#define DEFAULT_TX_BUF_COUNT 1
+#define DEFAULT_TX_BUF_COUNT 3

struct n_hdlc_buf {
struct n_hdlc_buf *link;
@@ -199,6 +197,31 @@ static void n_hdlc_tty_wakeup(struct tty
#define tty2n_hdlc(tty) ((struct n_hdlc *) ((tty)->disc_data))
#define n_hdlc2tty(n_hdlc) ((n_hdlc)->tty)

+static void flush_rx_queue(struct tty_struct *tty)
+{
+ struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
+ struct n_hdlc_buf *buf;
+
+ while ((buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)))
+ n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, buf);
+}
+
+static void flush_tx_queue(struct tty_struct *tty)
+{
+ struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
+ struct n_hdlc_buf *buf;
+ unsigned long flags;
+
+ while ((buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list)))
+ n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, buf);
+ spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
+ if (n_hdlc->tbuf) {
+ n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, n_hdlc->tbuf);
+ n_hdlc->tbuf = NULL;
+ }
+ spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
+}
+
static struct tty_ldisc_ops n_hdlc_ldisc = {
.owner = THIS_MODULE,
.magic = TTY_LDISC_MAGIC,
@@ -211,6 +234,7 @@ static struct tty_ldisc_ops n_hdlc_ldisc
.poll = n_hdlc_tty_poll,
.receive_buf = n_hdlc_tty_receive,
.write_wakeup = n_hdlc_tty_wakeup,
+ .flush_buffer = flush_rx_queue,
};

/**
@@ -341,10 +365,7 @@ static int n_hdlc_tty_open (struct tty_s
set_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
#endif

- /* Flush any pending characters in the driver and discipline. */
- if (tty->ldisc.ops->flush_buffer)
- tty->ldisc.ops->flush_buffer(tty);
-
+ /* flush receive data from driver */
tty_driver_flush_buffer(tty);

if (debuglevel >= DEBUG_LEVEL_INFO)
@@ -763,6 +784,14 @@ static int n_hdlc_tty_ioctl(struct tty_s
error = put_user(count, (int __user *)arg);
break;

+ case TCFLSH:
+ switch (arg) {
+ case TCIOFLUSH:
+ case TCOFLUSH:
+ flush_tx_queue(tty);
+ }
+ /* fall through to default */
+
default:
error = n_tty_ioctl_helper(tty, file, cmd, arg);
break;
@@ -919,8 +948,7 @@ static struct n_hdlc_buf* n_hdlc_buf_get
} /* end of n_hdlc_buf_get() */

static char hdlc_banner[] __initdata =
- KERN_INFO "HDLC line discipline: version " HDLC_VERSION
- ", maxframe=%u\n";
+ KERN_INFO "HDLC line discipline maxframe=%u\n";
static char hdlc_register_ok[] __initdata =
KERN_INFO "N_HDLC line discipline registered.\n";
static char hdlc_register_fail[] __initdata =