From: Ilya Zykov <ilya@ilyx.ru>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Cox <alan@linux.intel.com>,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..).
Date: Wed, 16 Jan 2013 13:07:50 +0400 [thread overview]
Message-ID: <50F66DE6.6080101@ilyx.ru> (raw)
In-Reply-To: <20121127193208.331673ae@pyramind.ukuu.org.uk>
Regression 'tty: fix "IRQ45: nobody cared"'
Regression commit 7b292b4bf9a9d6098440d85616d6ca4c608b8304
Function reset_buffer_flags() also invoked during the ioctl(...,TCFLSH,..).
At the time of request we can have full buffers and throttled driver too.
If we don't unthrottle driver, we can get forever throttled driver, because,
after request, we will have empty buffers and throttled driver and
there is no place to unthrottle driver.
It simple reproduce with "pty" pair then one side sleep on tty->write_wait,
and other side do ioctl(...,TCFLSH,..). Then there is no place to do writers wake up.
Signed-off-by: Ilya Zykov <ilya@ilyx.ru>
---
drivers/tty/tty_ioctl.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 8481b29..cc0fc52 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -1096,12 +1096,16 @@ int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
ld = tty_ldisc_ref_wait(tty);
switch (arg) {
case TCIFLUSH:
- if (ld && ld->ops->flush_buffer)
+ if (ld && ld->ops->flush_buffer) {
ld->ops->flush_buffer(tty);
+ tty_unthrottle(tty);
+ }
break;
case TCIOFLUSH:
- if (ld && ld->ops->flush_buffer)
+ if (ld && ld->ops->flush_buffer) {
ld->ops->flush_buffer(tty);
+ tty_unthrottle(tty);
+ }
/* fall through */
case TCOFLUSH:
tty_driver_flush_buffer(tty);
next prev parent reply other threads:[~2013-01-16 9:08 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-27 6:14 [PATCH v4] tty: Add driver unthrottle in ioctl(...,TCFLSH,..) Ilya Zykov
2012-11-27 17:24 ` Greg Kroah-Hartman
2012-11-27 18:46 ` Ilya Zykov
2012-11-27 19:32 ` Alan Cox
2013-01-16 9:07 ` Ilya Zykov [this message]
-- strict thread matches above, loose matches on Subject: below --
2012-11-21 21:12 [PATCH] " Ilya Zykov
2012-11-21 21:30 ` Alan Cox
2012-11-21 21:39 ` Ilya Zykov
2012-11-22 0:47 ` andrew mcgregor
2012-11-22 4:29 ` Ilya Zykov
2012-11-22 5:25 ` andrew mcgregor
2012-11-22 6:35 ` Ilya Zykov
2012-11-22 6:03 ` Ilya Zykov
2012-11-22 6:16 ` Ilya Zykov
2012-11-21 21:55 ` Ilya Zykov
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