On Thu, Jun 28, 2012 at 05:24:52PM +0200, Eric Dumazet wrote:
> On Thu, 2012-06-28 at 16:10 +0200, Jiri Pirko wrote:
> > Introduce IFF_LIFE_ADDR_CHANGE priv_flag and use it to disable
> > netif_running() check in eth_mac_addr()
> >
> > Signed-off-by: Jiri Pirko <jpirko@xxxxxxxxxx>
> > ---
> > include/linux/if.h | 2 ++
> > net/ethernet/eth.c | 2 +-
> > 2 files changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/if.h b/include/linux/if.h
> > index f995c66..fd9ee7c 100644
> > --- a/include/linux/if.h
> > +++ b/include/linux/if.h
> > @@ -81,6 +81,8 @@
> > #define IFF_UNICAST_FLT 0x20000 /* Supports unicast filtering */
> > #define IFF_TEAM_PORT 0x40000 /* device used as team port */
> > #define IFF_SUPP_NOFCS 0x80000 /* device supports sending custom FCS */
> > +#define IFF_LIFE_ADDR_CHANGE 0x100000 /* device supports hardware address
> > + * change when it's running */
> >
> >
> > #define IF_GET_IFACE 0x0001 /* for querying only */
> > diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
> > index 36e5880..8f8ded4 100644
> > --- a/net/ethernet/eth.c
> > +++ b/net/ethernet/eth.c
> > @@ -283,7 +283,7 @@ int eth_mac_addr(struct net_device *dev, void *p)
> > {
> > struct sockaddr *addr = p;
> >
> > - if (netif_running(dev))
> > + if (!(dev->priv_flags & IFF_LIFE_ADDR_CHANGE) && netif_running(dev))
> > return -EBUSY;
> > if (!is_valid_ether_addr(addr->sa_data))
> > return -EADDRNOTAVAIL;
>
> Since the memcpy() is not atomic, there is a small window where a reader
> could get a half-changed mac address. I guess its a detail.
>
At least for virtio nothing changes - we had this bug forever.
How'd you fix this?
--
MST
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