On Wed, Jul 03, 2019 at 03:33:52PM +0200, Jiri Pirko wrote: > >+/* notifications */ > >+ > >+typedef void (*ethnl_notify_handler_t)(struct net_device *dev, > >+ struct netlink_ext_ack *extack, > >+ unsigned int cmd, u32 req_mask, > >+ const void *data); > >+ > >+static const ethnl_notify_handler_t ethnl_notify_handlers[] = { > >+}; > >+ > >+void ethtool_notify(struct net_device *dev, struct netlink_ext_ack *extack, > >+ unsigned int cmd, u32 req_mask, const void *data) > > What's "req_mask" ?
It's infomask to interpret the same way as if it came from request header (the notification triggered by a SET request or its ioctl equivalent uses the same format as corresponding GET_REPLY message and is created by the same code). But it could be called infomask, I have no strong opinion about that. > >+{ > >+ if (unlikely(!ethnl_ok)) > >+ return; > >+ ASSERT_RTNL(); > >+ > >+ if (likely(cmd < ARRAY_SIZE(ethnl_notify_handlers) && > >+ ethnl_notify_handlers[cmd])) > > How it could be null? Notification message types share the enum with other kernel messages: /* message types - kernel to userspace */ enum { ETHTOOL_MSG_KERNEL_NONE, ETHTOOL_MSG_STRSET_GET_REPLY, ETHTOOL_MSG_SETTINGS_GET_REPLY, ETHTOOL_MSG_SETTINGS_NTF, ETHTOOL_MSG_SETTINGS_SET_REPLY, ETHTOOL_MSG_INFO_GET_REPLY, ETHTOOL_MSG_PARAMS_GET_REPLY, ETHTOOL_MSG_PARAMS_NTF, ETHTOOL_MSG_NWAYRST_NTF, ETHTOOL_MSG_PHYSID_NTF, ETHTOOL_MSG_RESET_NTF, ETHTOOL_MSG_RESET_ACT_REPLY, ETHTOOL_MSG_RXFLOW_GET_REPLY, ETHTOOL_MSG_RXFLOW_NTF, ETHTOOL_MSG_RXFLOW_SET_REPLY, /* add new constants above here */ __ETHTOOL_MSG_KERNEL_CNT, ETHTOOL_MSG_KERNEL_MAX = (__ETHTOOL_MSG_KERNEL_CNT - 1) }; Only entries for *_NTF types are non-null in ethnl_notify_handlers[]: static const ethnl_notify_handler_t ethnl_notify_handlers[] = { [ETHTOOL_MSG_SETTINGS_NTF] = ethnl_std_notify, [ETHTOOL_MSG_PARAMS_NTF] = ethnl_std_notify, [ETHTOOL_MSG_NWAYRST_NTF] = ethnl_nwayrst_notify, [ETHTOOL_MSG_PHYSID_NTF] = ethnl_physid_notify, [ETHTOOL_MSG_RESET_NTF] = ethnl_reset_notify, [ETHTOOL_MSG_RXFLOW_NTF] = ethnl_rxflow_notify, }; If the check above fails, it means that kernel code tried to send a notification with type which does not exist or is not a notification, i.e. a bug in kernel; that's why the WARN_ONCE. Michal > >+ ethnl_notify_handlers[cmd](dev, extack, cmd, req_mask, data); > >+ else > >+ WARN_ONCE(1, "notification %u not implemented (dev=%s, > >req_mask=0x%x)\n", > >+ cmd, netdev_name(dev), req_mask); > >+} > >+EXPORT_SYMBOL(ethtool_notify);