+ tty-flush-flip-buffer-on-ldisc-input-queue-flush.patch added to -mm tree

[akpm@xxxxxxxxxxxxxxxxxxxx]

The patch titled
     tty: flush flip buffer on ldisc input queue flush
has been added to the -mm tree.  Its filename is
     tty-flush-flip-buffer-on-ldisc-input-queue-flush.patch

*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

------------------------------------------------------
Subject: tty: flush flip buffer on ldisc input queue flush
From: Paul Fulghum <paulkf@xxxxxxxxxxxxx>

Flush the tty flip buffer when the line discipline input queue is flushed,
including the user call tcflush(TCIFLUSH/TCIOFLUSH).  This prevents
unexpected stale data after a user application calls tcflush().

Cc: Alan Cox <alan@xxxxxxxxxxxxxx>
Cc: Antonino Ingargiola <tritemio@xxxxxxxxx>
Signed-off-by: Paul Fulghum <paulkf@xxxxxxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 drivers/char/tty_io.c |   33 +++++++++++++++++++++++++++++++++
 1 files changed, 33 insertions(+)

diff -puN drivers/char/tty_io.c~tty-flush-flip-buffer-on-ldisc-input-queue-flush drivers/char/tty_io.c
--- a/drivers/char/tty_io.c~tty-flush-flip-buffer-on-ldisc-input-queue-flush
+++ a/drivers/char/tty_io.c
@@ -363,6 +363,29 @@ static void tty_buffer_free(struct tty_s
 }
 
 /**
+ *	tty_buffer_flush		-	flush full tty buffers
+ *	@tty: tty to flush
+ *
+ *	flush all the buffers containing receive data
+ *
+ *	Locking: none
+ */
+
+static void tty_buffer_flush(struct tty_struct *tty)
+{
+	struct tty_buffer *thead;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tty->buf.lock, flags);
+	while((thead = tty->buf.head) != NULL) {
+		tty->buf.head = thead->next;
+		tty_buffer_free(tty, thead);
+	}
+	tty->buf.tail = NULL;
+	spin_unlock_irqrestore(&tty->buf.lock, flags);
+}
+
+/**
  *	tty_buffer_find		-	find a free tty buffer
  *	@tty: tty owning the buffer
  *	@size: characters wanted
@@ -1238,6 +1261,7 @@ void tty_ldisc_flush(struct tty_struct *
 			ld->flush_buffer(tty);
 		tty_ldisc_deref(ld);
 	}
+	tty_buffer_flush(tty);
 }
 
 EXPORT_SYMBOL_GPL(tty_ldisc_flush);
@@ -3340,6 +3364,15 @@ int tty_ioctl(struct inode * inode, stru
 		case TIOCMBIC:
 		case TIOCMBIS:
 			return tty_tiocmset(tty, file, cmd, p);
+		case TCFLSH:
+			switch (arg) {
+			case TCIFLUSH:
+			case TCIOFLUSH:
+				/* flush tty buffer and allow ldisc to process ioctl */
+				tty_buffer_flush(tty);
+				break;
+			}
+			break;
 	}
 	if (tty->driver->ioctl) {
 		retval = (tty->driver->ioctl)(tty, file, cmd, arg);
_

Patches currently in -mm which might be from paulkf@xxxxxxxxxxxxx are

drivers-char-synclinkc-check-kmalloc-return-value.patch
synclink_gt-use-dynamic-tty-device-registration.patch
tty_set_ldisc-receive_room-fix.patch
tty-flush-flip-buffer-on-ldisc-input-queue-flush.patch
tty-add-compat_ioctl.patch
tty-add-compat_ioctl-fix.patch

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