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* [PATCH] Remove useless memory barrier.
@ 2006-12-08  0:41 Ralf Baechle
  0 siblings, 0 replies; only message in thread
From: Ralf Baechle @ 2006-12-08  0:41 UTC (permalink / raw)
  To: linux-kernel

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>

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 603b9ad..8df7ff3 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -1151,7 +1151,6 @@ static int copy_from_read_buf(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);

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2006-12-08  0:41 [PATCH] Remove useless memory barrier Ralf Baechle

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