[PATCH] remove TTY_DONT_FLIP

Remove TTY_DONT_FLIP tty flag.  This flag was introduced in 2.1.X kernels
to prevent the N_TTY line discipline functions read_chan() and
n_tty_receive_buf() from running at the same time.  2.2.15 introduced
tty->read_lock to protect access to the N_TTY read buffer, which is the
only state requiring protection between these two functions.

The current TTY_DONT_FLIP implementation is broken for SMP, and is not
universally honored by drivers that send data directly to the line
discipline receive_buf function.

Because TTY_DONT_FLIP is not necessary, is broken in implementation, and is
not universally honored, it is removed.

Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 6 deletions

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index 74368f79ee5d..b81fad893328 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -480,12 +480,8 @@ static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb)
 
         BT_DBG("dlc %p tty %p len %d", dlc, tty, skb->len);
 
-        if (test_bit(TTY_DONT_FLIP, &tty->flags)) {
-                tty_buffer_request_room(tty, skb->len);
-                tty_insert_flip_string(tty, skb->data, skb->len);
-                tty_flip_buffer_push(tty);
-        } else
-                tty->ldisc.receive_buf(tty, skb->data, NULL, skb->len);
+        tty_insert_flip_string(tty, skb->data, skb->len);
+        tty_flip_buffer_push(tty);
 
         kfree_skb(skb);
 }