On Wed, 13 Sep 2006 21:04:02 -0500 Larry Finger <[EMAIL PROTECTED]> wrote:
> Stephen Hemminger wrote: > > On Wed, 13 Sep 2006 15:49:23 +0200 > > Michael Buesch <[EMAIL PROTECTED]> wrote: > >> Simple. Reading the code of synchronize_net() and > >> netif_stop_queue() and thinking about why it breaks, instead > >> of committing bugfixes that only substitute one bug by another. ;) > >> I'll take a look, too. > > > > Why are you doing the synchronize_net()? it is meant for RCU. > > We know and it no longer is in the code. We have known for a couple of days > that > it was the synchronize_net() step that led to the netdev timeouts, but we > were > afraid that a bare netif_stop_queue would not be SMP safe. The current > structure has > > mutex_lock > netif_tx_disable(dev) (equivalent to netif_tx_lock_bh(dev); > netif_stop_queue(dev); > netif_tx_unlock_bh(dev); > spin_lock_irqsafe > > I see you listed as a maintainer in several network-related parts of the > system, > so AFAIK, you are a network guru. Do you think this will work? I have tested > code with just a netif_stop_queue (without the lock_bh/unlock_bh parts) on a > UP > system and have gotten no errors, but I do not have access to SMP hardware. > > Thanks, > I haven't done a careful review of the broadcom driver. What you are proposing looks fine. But most network devices just use spin_lock's rather than mutexs because there is little need for holding the lock for a long length of time. > - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
