diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 9516dad45109..b3c6501ae3d2 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -103,6 +103,7 @@ int netlink_sendskb(struct sock *sk, struct sk_buff *skb); struct netlink_callback { struct sk_buff *skb; const struct nlmsghdr *nlh; + int (*start)(struct netlink_callback *); int (*dump)(struct sk_buff * skb, struct netlink_callback *cb); int (*done)(struct netlink_callback *cb); @@ -125,6 +126,7 @@ struct nlmsghdr * __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags); struct netlink_dump_control { + int (*start)(struct netlink_callback *); int (*dump)(struct sk_buff *skb, struct netlink_callback *); int (*done)(struct netlink_callback *); void *data; diff --git a/include/net/genetlink.h b/include/net/genetlink.h index 8e0b6c856a13..d0c5bb84a257 100644 --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -105,6 +105,7 @@ static inline void genl_info_net_set(struct genl_info *info, struct net *net) * @flags: flags * @policy: attribute validation policy * @doit: standard command callback + * @start: start callback for dumps * @dumpit: callback for dumpers * @done: completion callback for dumps * @ops_list: operations list @@ -116,6 +117,7 @@ struct genl_ops { const struct nla_policy *policy; int (*doit)(struct sk_buff *skb, struct genl_info *info); + int (*start)(struct netlink_callback *cb); int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb); int (*done)(struct netlink_callback *cb); diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 881b04b13980..410f83227338 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2572,6 +2572,7 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, cb = &nlk->cb; memset(cb, 0, sizeof(*cb)); + cb->start = control->start; cb->dump = control->dump; cb->done = control->done; cb->nlh = nlh; @@ -2584,6 +2585,9 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, mutex_unlock(nlk->cb_mutex); + if (cb->start) + cb->start(cb); + ret = netlink_dump(sk); sock_put(sk); diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index b6f12ed3a7ed..cb8621c574e1 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -544,6 +544,20 @@ void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, } EXPORT_SYMBOL(genlmsg_put); +static int genl_lock_start(struct netlink_callback *cb) +{ + /* our ops are always const - netlink API doesn't propagate that */ + const struct genl_ops *ops = cb->data; + int rc = 0; + + if (ops->start) { + genl_lock(); + rc = ops->start(cb); + genl_unlock(); + } + return rc; +} + static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) { struct genl_ops *ops = cb->data; @@ -605,6 +619,7 @@ static int genl_family_rcv_msg(struct genl_family *family, struct netlink_dump_control c = { .module = family->module, .data = ops, + .start = genl_lock_start, .dump = genl_lock_dumpit, .done = genl_lock_done, }; @@ -616,6 +631,7 @@ static int genl_family_rcv_msg(struct genl_family *family, } else { struct netlink_dump_control c = { .module = family->module, + .start = genl_lock_start, .dump = ops->dumpit, .done = ops->done, };