RDMA/cma: Add multicast communication support
Extend rdma_cm to support multicast communication. Multicast support
is added to the existing RDMA_PS_UDP port space, as well as a new
RDMA_PS_IPOIB port space. The latter port space allows joining the
multicast groups used by IPoIB, which enables offloading IPoIB traffic
to a separate QP. The port space determines the signature used in the
MGID when joining the group. The newly added RDMA_PS_IPOIB also
allows for unicast operations, similar to RDMA_PS_UDP.
Supporting the RDMA_PS_IPOIB requires changing how UD QPs are initialized,
since we can no longer assume that the qkey is constant. This requires
saving the Q_Key to use when attaching to a device, so that it is
available when creating the QP. The Q_Key information is exported to
the user through the existing rdma_init_qp_attr() interface.
Multicast support is also exported to userspace through the rdma_ucm.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/include/rdma/rdma_cm_ib.h b/include/rdma/rdma_cm_ib.h
index 9b176df..950424b 100644
--- a/include/rdma/rdma_cm_ib.h
+++ b/include/rdma/rdma_cm_ib.h
@@ -44,7 +44,7 @@
int rdma_set_ib_paths(struct rdma_cm_id *id,
struct ib_sa_path_rec *path_rec, int num_paths);
-/* Global qkey for UD QPs and multicast groups. */
-#define RDMA_UD_QKEY 0x01234567
+/* Global qkey for UDP QPs and multicast groups. */
+#define RDMA_UDP_QKEY 0x01234567
#endif /* RDMA_CM_IB_H */