[NETLINK]: Switch cb_lock spinlock to mutex and allow to override it

Switch cb_lock to mutex and allow netlink kernel users to override it
with a subsystem specific mutex for consistent locking in dump callbacks.
All netlink_dump_start users have been audited not to rely on any
side-effects of the previously used spinlock.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 0d11f6a7389c..f41688f56632 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -157,7 +157,10 @@ struct netlink_skb_parms
 #define NETLINK_CREDS(skb)      (&NETLINK_CB((skb)).creds)
 
 
-extern struct sock *netlink_kernel_create(int unit, unsigned int groups, void (*input)(struct sock *sk, int len), struct module *module);
+extern struct sock *netlink_kernel_create(int unit, unsigned int groups,
+                                          void (*input)(struct sock *sk, int len),
+                                          struct mutex *cb_mutex,
+                                          struct module *module);
 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
 extern int netlink_has_listeners(struct sock *sk, unsigned int group);
 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);