[PATCH v4 06/24] n_tty: Split n_tty_chars_in_buffer() for reader-only interface
From: Peter Hurley <hidden>
Date: 2013-06-15 13:15:13
Also in:
lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
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 <redacted> --- 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;
--
1.8.1.2