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authorPeter Hurley <peter@hurleysoftware.com>2014-11-05 12:13:09 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-05 18:50:43 -0800
commit86c80a8e2ab443e9c4261b3499de4ce808399104 (patch)
treeaec087bbbc43f28deb617f958007599bce5146fe /drivers/tty/tty_ldisc.c
parent276a661a4d75258b3aa28701b0748f99b773563b (diff)
downloadlinux-86c80a8e2ab443e9c4261b3499de4ce808399104.tar.bz2
tty: Flush ldisc buffer atomically with tty flip buffers
tty_ldisc_flush() first clears the line discipline input buffer, then clears the tty flip buffers. However, this allows for existing data in the tty flip buffers to be added after the ldisc input buffer has been cleared, but before the flip buffers have been cleared. Add an optional ldisc parameter to tty_buffer_flush() to allow tty_ldisc_flush() to pass the ldisc to clear. NB: Initially, the plan was to do this automatically in tty_buffer_flush(). However, an audit of the behavior of existing line disciplines showed that performing a ldisc buffer flush on ioctl(TCFLSH) was not always the outcome. For example, some line disciplines have flush_buffer() methods but not ioctl() methods, so a ->flush_buffer() command would be unexpected. Reviewed-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_ldisc.c')
-rw-r--r--drivers/tty/tty_ldisc.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 6368dd95e137..b66a81d0549e 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -397,19 +397,17 @@ static void __lockfunc tty_ldisc_unlock_pair(struct tty_struct *tty,
* tty_ldisc_flush - flush line discipline queue
* @tty: tty
*
- * Flush the line discipline queue (if any) for this tty. If there
- * is no line discipline active this is a no-op.
+ * Flush the line discipline queue (if any) and the tty flip buffers
+ * for this tty.
*/
void tty_ldisc_flush(struct tty_struct *tty)
{
struct tty_ldisc *ld = tty_ldisc_ref(tty);
- if (ld) {
- if (ld->ops->flush_buffer)
- ld->ops->flush_buffer(tty);
+
+ tty_buffer_flush(tty, ld);
+ if (ld)
tty_ldisc_deref(ld);
- }
- tty_buffer_flush(tty);
}
EXPORT_SYMBOL_GPL(tty_ldisc_flush);