Hi.
I think there is a confusion with n_tty_chars_in_buffer(): it
calculates the amount of input chars, but is used as a
.chars_in_buffer member of tty_ldisc_ops, which, AFAIK,
should calculate the amount of _output_ chars buffered.
Here is the patch that changes this.
Since it doesn't fix any problem I can practically observe,
the chances are high that I am missing something obvious.
Can someone please take a look if there is really a bug here?
>From cea19eda592e61db780e3ce1a7bf9a5f0899a0fc Mon Sep 17 00:00:00 2001
From: Stas Sergeev <s...@users.sourceforge.net>
Date: Sat, 18 May 2013 15:06:39 +0400
Subject: [PATCH] n_tty: fix .chars_in_buffer confusion
n_tty_chars_in_buffer() was calculating the amount of input
chars, not output chars. It therefore should not be used as
a .chars_in_buffer member.
This patch removes it from tty_ldisc_ops and renames to
chars_in_input_buffer()
Signed-off-by: Stas Sergeev <s...@users.sourceforge.net>
---
drivers/tty/n_tty.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 3f228c9..0567235 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -253,7 +253,7 @@ static void n_tty_flush_buffer(struct tty_struct *tty)
}
/**
- * n_tty_chars_in_buffer - report available bytes
+ * chars_in_input_buffer - report available bytes
* @tty: tty device
*
* Report the number of characters buffered to be delivered to user
@@ -262,7 +262,7 @@ static void n_tty_flush_buffer(struct tty_struct *tty)
* Locking: read_lock
*/
-static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
+static ssize_t chars_in_input_buffer(struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
unsigned long flags;
@@ -1977,7 +1977,7 @@ do_it_again:
}
/* If there is enough space in the read buffer now, let the
- * low-level driver know. We use n_tty_chars_in_buffer() to
+ * low-level driver know. We use chars_in_input_buffer() to
* check the buffer, as it now knows about canonical mode.
* Otherwise, if the driver is throttled and the line is
* longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
@@ -1985,7 +1985,7 @@ do_it_again:
*/
while (1) {
tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
- if (n_tty_chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
+ if (chars_in_input_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
break;
if (!tty->count)
break;
@@ -2206,7 +2206,6 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = {
.open = n_tty_open,
.close = n_tty_close,
.flush_buffer = n_tty_flush_buffer,
- .chars_in_buffer = n_tty_chars_in_buffer,
.read = n_tty_read,
.write = n_tty_write,
.ioctl = n_tty_ioctl,
--
1.7.11.7
