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Commit 1075a6e2 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
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n_tty: Fix apparent order of echoed output 



With block processing of echoed output, observed output order is still
required. Push completed echoes and echo commands prior to output.

Introduce echo_mark echo buffer index, which tracks completed echo
commands; ie., those submitted via commit_echoes but which may not
have been committed. Ensure that completed echoes are output prior
to subsequent terminal writes in process_echoes().

Fixes newline/prompt output order in cooked mode shell.

Cc: <stable@vger.kernel.org> # 3.12.x : 39434abd n_tty: Fix missing newline echo
Reported-by: default avatarKarl Dahlke <eklhad@comcast.net>
Reported-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Tested-by: default avatarKarl Dahlke <eklhad@comcast.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d24c195f

drivers/tty/n_tty.c

+6 −1
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ struct n_tty_data { 
	size_t canon_head;

	size_t echo_head;

	size_t echo_commit;

	size_t echo_mark;

	DECLARE_BITMAP(char_map, 256);



	/* private to n_tty_receive_overrun (single-threaded) */
@@ -336,6 +337,7 @@ static void reset_buffer_flags(struct n_tty_data *ldata) 
{

	ldata->read_head = ldata->canon_head = ldata->read_tail = 0;

	ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0;

	ldata->echo_mark = 0;

	ldata->line_start = 0;



	ldata->erasing = 0;
@@ -787,6 +789,7 @@ static void commit_echoes(struct tty_struct *tty) 
	size_t head;



	head = ldata->echo_head;

	ldata->echo_mark = head;

	old = ldata->echo_commit - ldata->echo_tail;



	/* Process committed echoes if the accumulated # of bytes
@@ -811,10 +814,11 @@ static void process_echoes(struct tty_struct *tty) 
	size_t echoed;



	if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||

	    ldata->echo_commit == ldata->echo_tail)

	    ldata->echo_mark == ldata->echo_tail)

		return;



	mutex_lock(&ldata->output_lock);

	ldata->echo_commit = ldata->echo_mark;

	echoed = __process_echoes(tty);

	mutex_unlock(&ldata->output_lock);
@@ -822,6 +826,7 @@ static void process_echoes(struct tty_struct *tty) 
		tty->ops->flush_chars(tty);

}



/* NB: echo_mark and echo_head should be equivalent here */

static void flush_echoes(struct tty_struct *tty)

{

	struct n_tty_data *ldata = tty->disc_data;