Message ID | 200809222150.m8MLog27031875@imap1.linux-foundation.org |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
From: akpm@linux-foundation.org Date: Mon, 22 Sep 2008 14:50:42 -0700 > smp_mb is enough for ordering memory operations among processors,and mb is > more expensive than smp_mb for UP machine, so replace it with smp_mb(). > > Signed-off-by: Ming Lei <tom.leiming@gmail.com> > Acked-by: Marcel Holtmann <marcel@holtmann.org> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Since this already ACK'd by Marcel, I've added this to net-next-2.6 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Dave, > > smp_mb is enough for ordering memory operations among processors,and mb is > > more expensive than smp_mb for UP machine, so replace it with smp_mb(). > > > > Signed-off-by: Ming Lei <tom.leiming@gmail.com> > > Acked-by: Marcel Holtmann <marcel@holtmann.org> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > > Since this already ACK'd by Marcel, I've added this to net-next-2.6 that is absolutely fine by me. The hci_usb driver is a dead end and we do have multiple people now looking at and testing btusb. So expect the hci_usb driver to go away soon. Either 2.6.28 or 2.6.29. Regards Marcel -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff -puN drivers/bluetooth/hci_usb.h~hci_usb-replace-mb-with-smp_mb drivers/bluetooth/hci_usb.h --- a/drivers/bluetooth/hci_usb.h~hci_usb-replace-mb-with-smp_mb +++ a/drivers/bluetooth/hci_usb.h @@ -70,8 +70,8 @@ static inline void _urb_queue_head(struc { unsigned long flags; spin_lock_irqsave(&q->lock, flags); - /* _urb_unlink needs to know which spinlock to use, thus mb(). */ - _urb->queue = q; mb(); list_add(&_urb->list, &q->head); + /* _urb_unlink needs to know which spinlock to use, thus smp_mb(). */ + _urb->queue = q; smp_mb(); list_add(&_urb->list, &q->head); spin_unlock_irqrestore(&q->lock, flags); } @@ -79,8 +79,8 @@ static inline void _urb_queue_tail(struc { unsigned long flags; spin_lock_irqsave(&q->lock, flags); - /* _urb_unlink needs to know which spinlock to use, thus mb(). */ - _urb->queue = q; mb(); list_add_tail(&_urb->list, &q->head); + /* _urb_unlink needs to know which spinlock to use, thus smp_mb(). */ + _urb->queue = q; smp_mb(); list_add_tail(&_urb->list, &q->head); spin_unlock_irqrestore(&q->lock, flags); } @@ -89,7 +89,7 @@ static inline void _urb_unlink(struct _u struct _urb_queue *q; unsigned long flags; - mb(); + smp_mb(); q = _urb->queue; /* If q is NULL, it will die at easy-to-debug NULL pointer dereference. No need to BUG(). */