[PATCH] powerpc: ibmveth: Harden driver initilisation for kexec

[Randy.Dunlap]

On Fri, 3 Mar 2006 11:22:45 +1100 Michael Ellerman wrote:

> Hi Jeff,
> 
> I realise it's late, but it'd be really good if you could send this up for 
> 2.6.16, we're hosed without it.

I'm wondering if this means that for every virtual/hypervisor
situation, we have to modify any $interested_drivers.
Why wouldn't we come up with a cleaner solution (in the long term)?

E.g., could the hypervisor know when one of it's virtual OSes
dies or reboots and release its resources then?

This patch just looks like a short-term solution to me.


> cheers
> 
> On Fri, 3 Mar 2006 06:40, Santiago Leon wrote:
> > From: Michael Ellerman <michael at ellerman.id.au>
> >
> > After a kexec the veth driver will fail when trying to register with the
> > Hypervisor because the previous kernel has not unregistered.
> >
> > So if the registration fails, we unregister and then try again.
> >
> > Signed-off-by: Michael Ellerman <michael at ellerman.id.au>
> > Acked-by: Anton Blanchard <anton at samba.org>
> > Signed-off-by: Santiago Leon <santil at us.ibm.com>
> > ---
> >
> >   drivers/net/ibmveth.c |   32 ++++++++++++++++++++++++++------
> >   1 files changed, 26 insertions(+), 6 deletions(-)
> >
> > Looks good to me, and has been around for a couple of months.
> >
> > Index: kexec/drivers/net/ibmveth.c
> > ===================================================================
> > --- kexec.orig/drivers/net/ibmveth.c
> > +++ kexec/drivers/net/ibmveth.c
> > @@ -436,6 +436,31 @@ static void ibmveth_cleanup(struct ibmve
> >   		ibmveth_free_buffer_pool(adapter, &adapter->rx_buff_pool[i]);
> >   }
> >
> > +static int ibmveth_register_logical_lan(struct ibmveth_adapter *adapter,
> > +		union ibmveth_buf_desc rxq_desc, u64 mac_address)
> > +{
> > +	int rc, try_again = 1;
> > +
> > +	/* After a kexec the adapter will still be open, so our attempt to
> > +	 * open it will fail. So if we get a failure we free the adapter and
> > +	 * try again, but only once. */
> > +retry:
> > +	rc = h_register_logical_lan(adapter->vdev->unit_address,
> > +			adapter->buffer_list_dma, rxq_desc.desc,
> > +			adapter->filter_list_dma, mac_address);
> > +
> > +	if (rc != H_Success && try_again) {
> > +		do {
> > +			rc = h_free_logical_lan(adapter->vdev->unit_address);
> > +		} while (H_isLongBusy(rc) || (rc == H_Busy));
> > +
> > +		try_again = 0;
> > +		goto retry;
> > +	}
> > +
> > +	return rc;
> > +}
> > +
> >   static int ibmveth_open(struct net_device *netdev)
> >   {
> >   	struct ibmveth_adapter *adapter = netdev->priv;
> > @@ -504,12 +529,7 @@ static int ibmveth_open(struct net_devic
> >   	ibmveth_debug_printk("filter list @ 0x%p\n", adapter->filter_list_addr);
> >   	ibmveth_debug_printk("receive q   @ 0x%p\n",
> > adapter->rx_queue.queue_addr);
> >
> > -
> > -	lpar_rc = h_register_logical_lan(adapter->vdev->unit_address,
> > -					 adapter->buffer_list_dma,
> > -					 rxq_desc.desc,
> > -					 adapter->filter_list_dma,
> > -					 mac_address);
> > +	lpar_rc = ibmveth_register_logical_lan(adapter, rxq_desc, mac_address);
> >
> >   	if(lpar_rc != H_Success) {
> >   		ibmveth_error_printk("h_register_logical_lan failed with %ld\n",
> > lpar_rc);
> >
> >
> >
> > _______________________________________________
> > Linuxppc64-dev mailing list
> > Linuxppc64-dev at ozlabs.org
> > https://ozlabs.org/mailman/listinfo/linuxppc64-dev
> 
> -- 
> Michael Ellerman
> IBM OzLabs

---
~Randy