IB/core, cma: Nice log-friendly string helpers

Some of us keep revisiting the code to decode enumerations that
appear in out logs. Let's borrow the nice logging helpers that
exists in xprtrdma and rds for CMA events, IB events and WC statuses.

Reviewd-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

include/rdma/ib_verbs.h

@@ -412,6 +412,8 @@ enum ib_event_type {
 	IB_EVENT_GID_CHANGE,
 };
 
+__attribute_const__ const char *ib_event_msg(enum ib_event_type event);
+
 struct ib_event {
 	struct ib_device	*device;
 	union {
@@ -663,6 +665,8 @@ enum ib_wc_status {
 	IB_WC_GENERAL_ERR
 };
 
+__attribute_const__ const char *ib_wc_status_msg(enum ib_wc_status status);
+
 enum ib_wc_opcode {
 	IB_WC_SEND,
 	IB_WC_RDMA_WRITE,

include/rdma/rdma_cm.h

@@ -62,6 +62,8 @@ enum rdma_cm_event_type {
 	RDMA_CM_EVENT_TIMEWAIT_EXIT
 };
 
+__attribute_const__ const char *rdma_event_msg(enum rdma_cm_event_type event);
+
 enum rdma_port_space {
 	RDMA_PS_SDP   = 0x0001,
 	RDMA_PS_IPOIB = 0x0002,