This is a note to let you know that I've just added the patch titled

netlink: add a start callback for starting a netlink dump

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: netlink-add-a-start-callback-for-starting-a-netlink-dump.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From fc9e50f5a5a4e1fa9ba2756f745a13e693cf6a06 Mon Sep 17 00:00:00 2001

From: Tom Herbert tom@herbertland.com Date: Tue, 15 Dec 2015 15:41:37 -0800 Subject: netlink: add a start callback for starting a netlink dump

From: Tom Herbert tom@herbertland.com

commit fc9e50f5a5a4e1fa9ba2756f745a13e693cf6a06 upstream.

The start callback allows the caller to set up a context for the dump callbacks. Presumably, the context can then be destroyed in the done callback.

Signed-off-by: Tom Herbert tom@herbertland.com Signed-off-by: David S. Miller davem@davemloft.net Cc: Guenter Roeck linux@roeck-us.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- include/linux/netlink.h | 2 ++ include/net/genetlink.h | 2 ++ net/netlink/af_netlink.c | 4 ++++ net/netlink/genetlink.c | 16 ++++++++++++++++ 4 files changed, 24 insertions(+)

--- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -131,6 +131,7 @@ netlink_skb_clone(struct sk_buff *skb, g 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); @@ -153,6 +154,7 @@ 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; --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -114,6 +114,7 @@ static inline void genl_info_net_set(str * @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 @@ -122,6 +123,7 @@ 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); --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2203,6 +2203,7 @@ int __netlink_dump_start(struct sock *ss

cb = &nlk->cb; memset(cb, 0, sizeof(*cb)); + cb->start = control->start; cb->dump = control->dump; cb->done = control->done; cb->nlh = nlh; @@ -2216,6 +2217,9 @@ int __netlink_dump_start(struct sock *ss

mutex_unlock(nlk->cb_mutex);

+ if (cb->start) + cb->start(cb); + ret = netlink_dump(sk); sock_put(sk);

--- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -513,6 +513,20 @@ void *genlmsg_put(struct sk_buff *skb, u } 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) { /* our ops are always const - netlink API doesn't propagate that */ @@ -577,6 +591,7 @@ static int genl_family_rcv_msg(struct ge .module = family->module, /* we have const, but the netlink API doesn't */ .data = (void *)ops, + .start = genl_lock_start, .dump = genl_lock_dumpit, .done = genl_lock_done, }; @@ -588,6 +603,7 @@ static int genl_family_rcv_msg(struct ge } else { struct netlink_dump_control c = { .module = family->module, + .start = ops->start, .dump = ops->dumpit, .done = ops->done, };

Patches currently in stable-queue which might be from tom@herbertland.com are

queue-4.4/netlink-add-a-start-callback-for-starting-a-netlink-dump.patch