linux-kernel - [PATCH v2 06/18] n_tty: Split n_tty_chars_in

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1364384648-6636-7-git-send-email-peter@hurleysoftware.com>
Date:	Wed, 27 Mar 2013 07:43:56 -0400
From:	Peter Hurley <peter@...leysoftware.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.cz>
Cc:	linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
	Min Zhang <mzhang@...sta.com>, Ilya Zykov <linux@...k.ru>,
	Peter Hurley <peter@...leysoftware.com>
Subject: [PATCH v2 06/18] 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 <peter@...leysoftware.com>
---
 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 2cc3be0..51b08d9 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -299,7 +299,7 @@ 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;
@@ -317,6 +317,11 @@ 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
@@ -2030,7 +2035,7 @@ 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,
@@ -2038,7 +2043,7 @@ 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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/