From a19d0c6a9166fe3d8bb1575b64f28590206148d9 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 15 Jun 2013 09:14:18 -0400 Subject: [PATCH] n_tty: Split n_tty_chars_in_buffer() for reader-only interface N_TTY .chars_in_buffer() method requires serialized access if the current thread is not the single-consumer, n_tty_read(). Separate the internal interface; prepare for lockless read-side. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_tty.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 74dcedd..594a3c1 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -277,7 +277,7 @@ 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_buffer(struct tty_struct *tty) { struct n_tty_data *ldata = tty->disc_data; unsigned long flags; @@ -295,6 +295,11 @@ static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) return n; } +static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) +{ + return chars_in_buffer(tty); +} + /** * is_utf8_continuation - utf8 multibyte check * @c: byte to check @@ -2032,7 +2037,7 @@ 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_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, @@ -2040,7 +2045,7 @@ 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_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) break; if (!tty->count) break; -- 2.7.4