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.
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