[PATCH] tty: remove useless memory barrier

I don't see why there is a memory barrier in copy_from_read_buf() at all.
Even if it was useful spin_unlock_irqrestore implies a barrier.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index e96a00f..2bdb014 100644 (file)
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -1151,7 +1151,6 @@ static int copy_from_read_buf(struct tty_struct *tty,
        n = min(*nr, n);
        spin_unlock_irqrestore(&tty->read_lock, flags);
        if (n) {
-               mb();
                retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n);
                n -= retval;
                spin_lock_irqsave(&tty->read_lock, flags);