svcrdma: Record send_ctxt completion ID in trace_svcrdma_post_send()

First, refactor: Dereference the svc_rdma_send_ctxt inside
svc_rdma_send() instead of at every call site.

Then, it can be passed into trace_svcrdma_post_send() to get the
proper completion ID.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

include/linux/sunrpc/svc_rdma.h

@@ -196,7 +196,8 @@ extern struct svc_rdma_send_ctxt *
 		svc_rdma_send_ctxt_get(struct svcxprt_rdma *rdma);
 extern void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
 				   struct svc_rdma_send_ctxt *ctxt);
-extern int svc_rdma_send(struct svcxprt_rdma *rdma, struct ib_send_wr *wr);
+extern int svc_rdma_send(struct svcxprt_rdma *rdma,
+			 struct svc_rdma_send_ctxt *ctxt);
 extern int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
 				  struct svc_rdma_send_ctxt *sctxt,
 				  const struct svc_rdma_recv_ctxt *rctxt,

include/trace/events/rpcrdma.h

@@ -1839,27 +1839,31 @@ DECLARE_EVENT_CLASS(svcrdma_sendcomp_event,
 
 TRACE_EVENT(svcrdma_post_send,
 	TP_PROTO(
-		const struct ib_send_wr *wr
+		const struct svc_rdma_send_ctxt *ctxt
 	),
 
-	TP_ARGS(wr),
+	TP_ARGS(ctxt),
 
 	TP_STRUCT__entry(
-		__field(const void *, cqe)
+		__field(u32, cq_id)
+		__field(int, completion_id)
 		__field(unsigned int, num_sge)
 		__field(u32, inv_rkey)
 	),
 
 	TP_fast_assign(
-		__entry->cqe = wr->wr_cqe;
+		const struct ib_send_wr *wr = &ctxt->sc_send_wr;
+
+		__entry->cq_id = ctxt->sc_cid.ci_queue_id;
+		__entry->completion_id = ctxt->sc_cid.ci_completion_id;
 		__entry->num_sge = wr->num_sge;
 		__entry->inv_rkey = (wr->opcode == IB_WR_SEND_WITH_INV) ?
 					wr->ex.invalidate_rkey : 0;
 	),
 
-	TP_printk("cqe=%p num_sge=%u inv_rkey=0x%08x",
-		__entry->cqe, __entry->num_sge,
-		__entry->inv_rkey
+	TP_printk("cq_id=%u cid=%d num_sge=%u inv_rkey=0x%08x",
+		__entry->cq_id, __entry->completion_id,
+		__entry->num_sge, __entry->inv_rkey
 	)
 );
 

net/sunrpc/xprtrdma/svc_rdma_backchannel.c

@@ -87,7 +87,7 @@ static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
 	 */
 	get_page(virt_to_page(rqst->rq_buffer));
 	ctxt->sc_send_wr.opcode = IB_WR_SEND;
-	return svc_rdma_send(rdma, &ctxt->sc_send_wr);
+	return svc_rdma_send(rdma, ctxt);
 }
 
 /* Server-side transport endpoint wants a whole page for its send

net/sunrpc/xprtrdma/svc_rdma_sendto.c

@@ -298,13 +298,14 @@ static void svc_rdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
 /**
  * svc_rdma_send - Post a single Send WR
  * @rdma: transport on which to post the WR
- * @wr: prepared Send WR to post
+ * @ctxt: send ctxt with a Send WR ready to post
  *
  * Returns zero the Send WR was posted successfully. Otherwise, a
  * negative errno is returned.
  */
-int svc_rdma_send(struct svcxprt_rdma *rdma, struct ib_send_wr *wr)
+int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt)
 {
+	struct ib_send_wr *wr = &ctxt->sc_send_wr;
 	int ret;
 
 	might_sleep();
@@ -330,7 +331,7 @@ int svc_rdma_send(struct svcxprt_rdma *rdma, struct ib_send_wr *wr)
 		}
 
 		svc_xprt_get(&rdma->sc_xprt);
-		trace_svcrdma_post_send(wr);
+		trace_svcrdma_post_send(ctxt);
 		ret = ib_post_send(rdma->sc_qp, wr, NULL);
 		if (ret)
 			break;
@@ -805,7 +806,7 @@ static int svc_rdma_send_reply_msg(struct svcxprt_rdma *rdma,
 	} else {
 		sctxt->sc_send_wr.opcode = IB_WR_SEND;
 	}
-	return svc_rdma_send(rdma, &sctxt->sc_send_wr);
+	return svc_rdma_send(rdma, sctxt);
 }
 
 /**
@@ -869,7 +870,7 @@ void svc_rdma_send_error_msg(struct svcxprt_rdma *rdma,
 	sctxt->sc_send_wr.num_sge = 1;
 	sctxt->sc_send_wr.opcode = IB_WR_SEND;
 	sctxt->sc_sges[0].length = sctxt->sc_hdrbuf.len;
-	if (svc_rdma_send(rdma, &sctxt->sc_send_wr))
+	if (svc_rdma_send(rdma, sctxt))
 		goto put_ctxt;
 	return;