IB/core: Add rdma netlink helper functions

This patch adds a function to check if listeners for a netlink multicast
group are present. It also adds a function to receive netlink response
messages.

Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: John Fleck <john.fleck@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/core/netlink.c b/drivers/infiniband/core/netlink.c
index 23dd5a5c7597122de45eddf8211c736bedae553e..d47df935677966b6b8ceaf3217036ee8a16f4507 100644 (file)
--- a/drivers/infiniband/core/netlink.c
+++ b/drivers/infiniband/core/netlink.c
@@ -49,6 +49,14 @@ static DEFINE_MUTEX(ibnl_mutex);
 static struct sock *nls;
 static LIST_HEAD(client_list);
 
+int ibnl_chk_listeners(unsigned int group)
+{
+       if (netlink_has_listeners(nls, group) == 0)
+               return -1;
+       return 0;
+}
+EXPORT_SYMBOL(ibnl_chk_listeners);
+
 int ibnl_add_client(int index, int nops,
                    const struct ibnl_client_cbs cb_table[])
 {
@@ -151,6 +159,23 @@ static int ibnl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                            !client->cb_table[op].dump)
                                return -EINVAL;
 
+                       /*
+                        * For response or local service set_timeout request,
+                        * there is no need to use netlink_dump_start.
+                        */
+                       if (!(nlh->nlmsg_flags & NLM_F_REQUEST) ||
+                           (index == RDMA_NL_LS &&
+                            op == RDMA_NL_LS_OP_SET_TIMEOUT)) {
+                               struct netlink_callback cb = {
+                                       .skb = skb,
+                                       .nlh = nlh,
+                                       .dump = client->cb_table[op].dump,
+                                       .module = client->cb_table[op].module,
+                               };
+
+                               return cb.dump(skb, &cb);
+                       }
+
                        {
                                struct netlink_dump_control c = {
                                        .dump = client->cb_table[op].dump,
@@ -165,9 +190,39 @@ static int ibnl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
        return -EINVAL;
 }
 
+static void ibnl_rcv_reply_skb(struct sk_buff *skb)
+{
+       struct nlmsghdr *nlh;
+       int msglen;
+
+       /*
+        * Process responses until there is no more message or the first
+        * request. Generally speaking, it is not recommended to mix responses
+        * with requests.
+        */
+       while (skb->len >= nlmsg_total_size(0)) {
+               nlh = nlmsg_hdr(skb);
+
+               if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
+                       return;
+
+               /* Handle response only */
+               if (nlh->nlmsg_flags & NLM_F_REQUEST)
+                       return;
+
+               ibnl_rcv_msg(skb, nlh);
+
+               msglen = NLMSG_ALIGN(nlh->nlmsg_len);
+               if (msglen > skb->len)
+                       msglen = skb->len;
+               skb_pull(skb, msglen);
+       }
+}
+
 static void ibnl_rcv(struct sk_buff *skb)
 {
        mutex_lock(&ibnl_mutex);
+       ibnl_rcv_reply_skb(skb);
        netlink_rcv_skb(skb, &ibnl_rcv_msg);
        mutex_unlock(&ibnl_mutex);
 }

diff --git a/include/rdma/rdma_netlink.h b/include/rdma/rdma_netlink.h
index 0790882e0c9b32443a37c44a26b3357224245d82..5852661443290d52eb8a3e719716452d752b6eaa 100644 (file)
--- a/include/rdma/rdma_netlink.h
+++ b/include/rdma/rdma_netlink.h
@@ -77,4 +77,11 @@ int ibnl_unicast(struct sk_buff *skb, struct nlmsghdr *nlh,
 int ibnl_multicast(struct sk_buff *skb, struct nlmsghdr *nlh,
                        unsigned int group, gfp_t flags);
 
+/**
+ * Check if there are any listeners to the netlink group
+ * @group: the netlink group ID
+ * Returns 0 on success or a negative for no listeners.
+ */
+int ibnl_chk_listeners(unsigned int group);
+
 #endif /* _RDMA_NETLINK_H */