xprtrdma: Add unique trace points for posting Local Invalidate WRs

commit 4b93dab36f upstream.

When adding frwr_unmap_async way back when, I re-used the existing
trace_xprtrdma_post_send() trace point to record the return code
of ib_post_send.

Unfortunately there are some cases where re-using that trace point
causes a crash. Instead, construct a trace point specific to posting
Local Invalidate WRs that will always be safe to use in that context,
and will act as a trace log eye-catcher for Local Invalidation.

Fixes: 847568942f ("xprtrdma: Remove fr_state")
Fixes: d8099feda4 ("xprtrdma: Reduce context switching due ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Bill Baker <bill.baker@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/trace/events/rpcrdma.h

@@ -735,6 +735,31 @@ TRACE_EVENT(xprtrdma_post_recvs,
 	)
 );
 
+TRACE_EVENT(xprtrdma_post_linv,
+	TP_PROTO(
+		const struct rpcrdma_req *req,
+		int status
+	),
+
+	TP_ARGS(req, status),
+
+	TP_STRUCT__entry(
+		__field(const void *, req)
+		__field(int, status)
+		__field(u32, xid)
+	),
+
+	TP_fast_assign(
+		__entry->req = req;
+		__entry->status = status;
+		__entry->xid = be32_to_cpu(req->rl_slot.rq_xid);
+	),
+
+	TP_printk("req=%p xid=0x%08x status=%d",
+		__entry->req, __entry->xid, __entry->status
+	)
+);
+
 /**
  ** Completion events
  **/