From: Patrick McHardy <[EMAIL PROTECTED]> Date: Thu, 12 Jul 2007 20:13:40 +0200 (MEST)
> [NET]: Add net_device change_rx_mode callback > > Currently the set_multicast_list (and set_rx_mode) callbacks are > responsible for configuring the device according to the IFF_PROMISC, > IFF_MULTICAST and IFF_ALLMULTI flags and the mc_list (and uc_list in > case of set_rx_mode). > > These callbacks can be invoked from BH context without the rtnl_mutex > by dev_mc_add/dev_mc_delete, which makes reading the device flags and > promiscous/allmulti count racy. For real hardware drivers that just > commit all changes to the hardware this is not a real problem since > the stack guarantees to call them for every change, so at least the > final call will not race and commit the correct configuration to the > hardware. > > For software devices that want to synchronize promiscous and multicast > state to an underlying device however this can cause corruption of the > underlying device's flags or promisc/allmulti counts. > > When the software device is concurrently put in promiscous or allmulti > mode while set_multicast_list is invoked from bottem half context, the > device might synchronize the change to the underlying device without > holding the rtnl_mutex, which races with concurrent changes to the > underlying device. > > Add a dev->change_rx_flags hook that is invoked when any of the flags > that affect rx filtering change (under the rtnl_mutex), which allows > drivers to perform synchronization immediately and only synchronize > the address lists in set_multicast_list/set_rx_mode. > > Signed-off-by: Patrick McHardy <[EMAIL PROTECTED]> Applied, thanks Patrick. - 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
