Re: [PATCH 25/35] tty: remove tty_operations::chars_in_buffer for non-buffering

Jiri Slaby <jirislaby@xxxxxxxxxx> · Thu, 6 May 2021 07:47:04 +0200

On 05. 05. 21, 11:19, Jiri Slaby wrote:
The only user of tty_ops::chars_in_buffer is tty_chars_in_buffer. And it
considers tty_ops::chars_in_buffer optional. In case it's NULL, zero is
returned. So remove all those chars_in_buffer from tty_ops which return
zero. (Zero means such driver doesn't buffer.)

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>


c: Richard Henderson <rth@xxxxxxxxxxx>

Uh, "C" is a fugitive. Wanted dead or alive.

So should I send a v2 with:
Cc: Richard Henderson <rth@xxxxxxxxxxx>
?

Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
  arch/alpha/kernel/srmcons.c         |  7 -------
  arch/parisc/kernel/pdc_cons.c       |  6 ------
  arch/xtensa/platforms/iss/console.c |  7 -------
  drivers/s390/char/tty3270.c         | 12 ------------
  drivers/tty/pty.c                   | 17 -----------------
  drivers/tty/vt/vt.c                 |  6 ------
  6 files changed, 55 deletions(-)

diff --git a/arch/alpha/kernel/srmcons.c b/arch/alpha/kernel/srmcons.c
index 2110b7e7f988..fc03471a0b0f 100644
--- a/arch/alpha/kernel/srmcons.c
+++ b/arch/alpha/kernel/srmcons.c
@@ -148,12 +148,6 @@ srmcons_write_room(struct tty_struct *tty)
  	return 512;
  }
  
-static int
-srmcons_chars_in_buffer(struct tty_struct *tty)
-{
-	return 0;
-}
-
  static int
  srmcons_open(struct tty_struct *tty, struct file *filp)
  {
@@ -200,7 +194,6 @@ static const struct tty_operations srmcons_ops = {
  	.close		= srmcons_close,
  	.write		= srmcons_write,
  	.write_room	= srmcons_write_room,
-	.chars_in_buffer= srmcons_chars_in_buffer,
  };
  
  static int __init
diff --git a/arch/parisc/kernel/pdc_cons.c b/arch/parisc/kernel/pdc_cons.c
index fe2ed0bbd07e..39ccad063533 100644
--- a/arch/parisc/kernel/pdc_cons.c
+++ b/arch/parisc/kernel/pdc_cons.c
@@ -108,17 +108,11 @@ static unsigned int pdc_console_tty_write_room(struct tty_struct *tty)
  	return 32768; /* no limit, no buffer used */
  }
  
-static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
-{
-	return 0; /* no buffer */
-}
-
  static const struct tty_operations pdc_console_tty_ops = {
  	.open = pdc_console_tty_open,
  	.close = pdc_console_tty_close,
  	.write = pdc_console_tty_write,
  	.write_room = pdc_console_tty_write_room,
-	.chars_in_buffer = pdc_console_tty_chars_in_buffer,
  };
  
  static void pdc_console_poll(struct timer_list *unused)
diff --git a/arch/xtensa/platforms/iss/console.c b/arch/xtensa/platforms/iss/console.c
index 98ac3a7fdb0a..21184488c277 100644
--- a/arch/xtensa/platforms/iss/console.c
+++ b/arch/xtensa/platforms/iss/console.c
@@ -106,12 +106,6 @@ static unsigned int rs_write_room(struct tty_struct *tty)
  	return 2 * 1024;
  }
  
-static int rs_chars_in_buffer(struct tty_struct *tty)
-{
-	/* the iss doesn't buffer characters */
-	return 0;
-}
-
  static void rs_hangup(struct tty_struct *tty)
  {
  	/* Stub, once again.. */
@@ -135,7 +129,6 @@ static const struct tty_operations serial_ops = {
  	.put_char = rs_put_char,
  	.flush_chars = rs_flush_chars,
  	.write_room = rs_write_room,
-	.chars_in_buffer = rs_chars_in_buffer,
  	.hangup = rs_hangup,
  	.wait_until_sent = rs_wait_until_sent,
  	.proc_show = rs_proc_show,
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index 82d4c961ed06..ba1fbce63fee 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -1756,17 +1756,6 @@ tty3270_flush_chars(struct tty_struct *tty)
  	}
  }
  
-/*
- * Returns the number of characters in the output buffer. This is
- * used in tty_wait_until_sent to wait until all characters have
- * appeared on the screen.
- */
-static int
-tty3270_chars_in_buffer(struct tty_struct *tty)
-{
-	return 0;
-}
-
  static void
  tty3270_flush_buffer(struct tty_struct *tty)
  {
@@ -1892,7 +1881,6 @@ static const struct tty_operations tty3270_ops = {
  	.put_char = tty3270_put_char,
  	.flush_chars = tty3270_flush_chars,
  	.write_room = tty3270_write_room,
-	.chars_in_buffer = tty3270_chars_in_buffer,
  	.flush_buffer = tty3270_flush_buffer,
  	.throttle = tty3270_throttle,
  	.unthrottle = tty3270_unthrottle,
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index eb8556b19592..5ada7e9381eb 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -143,19 +143,6 @@ static unsigned int pty_write_room(struct tty_struct *tty)
  	return tty_buffer_space_avail(tty->link->port);
  }
  
-/**
- *	pty_chars_in_buffer	-	characters currently in our tx queue
- *	@tty: our tty
- *
- *	Report how much we have in the transmit queue. As everything is
- *	instantly at the other end this is easy to implement.
- */
-
-static int pty_chars_in_buffer(struct tty_struct *tty)
-{
-	return 0;
-}
-
  /* Set the lock flag on a pty */
  static int pty_set_lock(struct tty_struct *tty, int __user *arg)
  {
@@ -525,7 +512,6 @@ static const struct tty_operations master_pty_ops_bsd = {
  	.write = pty_write,
  	.write_room = pty_write_room,
  	.flush_buffer = pty_flush_buffer,
-	.chars_in_buffer = pty_chars_in_buffer,
  	.unthrottle = pty_unthrottle,
  	.ioctl = pty_bsd_ioctl,
  	.compat_ioctl = pty_bsd_compat_ioctl,
@@ -541,7 +527,6 @@ static const struct tty_operations slave_pty_ops_bsd = {
  	.write = pty_write,
  	.write_room = pty_write_room,
  	.flush_buffer = pty_flush_buffer,
-	.chars_in_buffer = pty_chars_in_buffer,
  	.unthrottle = pty_unthrottle,
  	.set_termios = pty_set_termios,
  	.cleanup = pty_cleanup,
@@ -776,7 +761,6 @@ static const struct tty_operations ptm_unix98_ops = {
  	.write = pty_write,
  	.write_room = pty_write_room,
  	.flush_buffer = pty_flush_buffer,
-	.chars_in_buffer = pty_chars_in_buffer,
  	.unthrottle = pty_unthrottle,
  	.ioctl = pty_unix98_ioctl,
  	.compat_ioctl = pty_unix98_compat_ioctl,
@@ -794,7 +778,6 @@ static const struct tty_operations pty_unix98_ops = {
  	.write = pty_write,
  	.write_room = pty_write_room,
  	.flush_buffer = pty_flush_buffer,
-	.chars_in_buffer = pty_chars_in_buffer,
  	.unthrottle = pty_unthrottle,
  	.set_termios = pty_set_termios,
  	.start = pty_start,
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 96c130714930..b838f656f4cd 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3270,11 +3270,6 @@ static unsigned int con_write_room(struct tty_struct *tty)
  	return 32768;		/* No limit, really; we're not buffering */
  }
  
-static int con_chars_in_buffer(struct tty_struct *tty)
-{
-	return 0;		/* we're not buffering */
-}
-
  /*
   * con_throttle and con_unthrottle are only used for
   * paste_selection(), which has to stuff in a large number of
@@ -3521,7 +3516,6 @@ static const struct tty_operations con_ops = {
  	.write_room = con_write_room,
  	.put_char = con_put_char,
  	.flush_chars = con_flush_chars,
-	.chars_in_buffer = con_chars_in_buffer,
  	.ioctl = vt_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl = vt_compat_ioctl,



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