From: Kaike Wan <kaike.wan@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: John Fleck <john.fleck@xxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
drivers/infiniband/core/netlink.c | 55 +++++++++++++++++++++++++++++++++++++
include/rdma/rdma_netlink.h | 7 +++++
2 files changed, 62 insertions(+), 0 deletions(-)
diff --git a/drivers/infiniband/core/netlink.c b/drivers/infiniband/core/netlink.c
index 23dd5a5..d47df93 100644
--- 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 0790882..5852661 100644
--- 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 */
--
1.7.1
--
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