RDMA/rtrs-srv: Add event tracing support

Add event tracing mechanism for following routines:
- send_io_resp_imm()

How to use:
1. Load the rtrs_server module
2. cd /sys/kernel/debug/tracing
3. If all the events need to be enabled:
        echo 1 > events/rtrs_srv/enable
4. OR only speific routine/event needs to be enabled e.g.
        echo 1 > events/rtrs_srv/send_io_resp_imm/enable
5. cat trace
6. Run some I/O workload which can trigger send_io_resp_imm()

Link: https://lore.kernel.org/r/20220818105240.110234-3-haris.iqbal@ionos.com
Signed-off-by: Santosh Pradhan <santosh.pradhan@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/ulp/rtrs/Makefile

@@ -7,9 +7,12 @@ rtrs-client-y := rtrs-clt.o \
 		  rtrs-clt-sysfs.o \
 		  rtrs-clt-trace.o
 
+CFLAGS_rtrs-srv-trace.o = -I$(src)
+
 rtrs-server-y := rtrs-srv.o \
 		  rtrs-srv-stats.o \
-		  rtrs-srv-sysfs.o
+		  rtrs-srv-sysfs.o \
+		  rtrs-srv-trace.o
 
 rtrs-core-y := rtrs.o
 

drivers/infiniband/ulp/rtrs/rtrs-srv-trace.c

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * RDMA Network Block Driver
+ *
+ * Copyright (c) 2022 1&1 IONOS SE. All rights reserved.
+ */
+#include "rtrs.h"
+#include "rtrs-pri.h"
+#include "rtrs-srv.h"
+
+/*
+ * We include this last to have the helpers above available for the trace
+ * event implementations.
+ */
+#define CREATE_TRACE_POINTS
+#include "rtrs-srv-trace.h"

drivers/infiniband/ulp/rtrs/rtrs-srv-trace.h

@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * RDMA Network Block Driver
+ *
+ * Copyright (c) 2022 1&1 IONOS SE. All rights reserved.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rtrs_srv
+
+#if !defined(_TRACE_RTRS_SRV_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_RTRS_SRV_H
+
+#include <linux/tracepoint.h>
+
+struct rtrs_srv_op;
+struct rtrs_srv_con;
+struct rtrs_srv_path;
+
+TRACE_DEFINE_ENUM(RTRS_SRV_CONNECTING);
+TRACE_DEFINE_ENUM(RTRS_SRV_CONNECTED);
+TRACE_DEFINE_ENUM(RTRS_SRV_CLOSING);
+TRACE_DEFINE_ENUM(RTRS_SRV_CLOSED);
+
+#define show_rtrs_srv_state(x) \
+	__print_symbolic(x, \
+		{ RTRS_SRV_CONNECTING,	"CONNECTING" }, \
+		{ RTRS_SRV_CONNECTED,	"CONNECTED" }, \
+		{ RTRS_SRV_CLOSING,	"CLOSING" }, \
+		{ RTRS_SRV_CLOSED,	"CLOSED" })
+
+TRACE_EVENT(send_io_resp_imm,
+	TP_PROTO(struct rtrs_srv_op *id,
+		 bool need_inval,
+		 bool always_invalidate,
+		 int errno),
+
+	TP_ARGS(id, need_inval, always_invalidate, errno),
+
+	TP_STRUCT__entry(
+		__field(u8, dir)
+		__field(bool, need_inval)
+		__field(bool, always_invalidate)
+		__field(u32, msg_id)
+		__field(int, wr_cnt)
+		__field(u32, signal_interval)
+		__field(int, state)
+		__field(int, errno)
+		__array(char, sessname, NAME_MAX)
+	),
+
+	TP_fast_assign(
+		struct rtrs_srv_con *con = id->con;
+		struct rtrs_path *s = con->c.path;
+		struct rtrs_srv_path *srv_path = to_srv_path(s);
+
+		__entry->dir = id->dir;
+		__entry->state = srv_path->state;
+		__entry->errno = errno;
+		__entry->need_inval = need_inval;
+		__entry->always_invalidate = always_invalidate;
+		__entry->msg_id = id->msg_id;
+		__entry->wr_cnt = atomic_read(&con->c.wr_cnt);
+		__entry->signal_interval = s->signal_interval;
+		memcpy(__entry->sessname, kobject_name(&srv_path->kobj), NAME_MAX);
+	),
+
+	TP_printk("sess='%s' state='%s' dir=%s err='%d' inval='%d' glob-inval='%d' msgid='%u' wrcnt='%d' sig-interval='%u'",
+		   __entry->sessname,
+		   show_rtrs_srv_state(__entry->state),
+		   __print_symbolic(__entry->dir,
+			 { READ,  "READ" },
+			 { WRITE, "WRITE" }),
+		   __entry->errno,
+		   __entry->need_inval,
+		   __entry->always_invalidate,
+		   __entry->msg_id,
+		   __entry->wr_cnt,
+		   __entry->signal_interval
+	)
+);
+
+#endif /* _TRACE_RTRS_SRV_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE rtrs-srv-trace
+#include <trace/define_trace.h>
+

drivers/infiniband/ulp/rtrs/rtrs-srv.c

@@ -16,6 +16,7 @@
 #include "rtrs-log.h"
 #include <rdma/ib_cm.h>
 #include <rdma/ib_verbs.h>
+#include "rtrs-srv-trace.h"
 
 MODULE_DESCRIPTION("RDMA Transport Server");
 MODULE_LICENSE("GPL");
@@ -57,11 +58,6 @@ static inline struct rtrs_srv_con *to_srv_con(struct rtrs_con *c)
 	return container_of(c, struct rtrs_srv_con, c);
 }
 
-static inline struct rtrs_srv_path *to_srv_path(struct rtrs_path *s)
-{
-	return container_of(s, struct rtrs_srv_path, s);
-}
-
 static bool rtrs_srv_change_state(struct rtrs_srv_path *srv_path,
 				  enum rtrs_srv_state new_state)
 {
@@ -375,6 +371,8 @@ static int send_io_resp_imm(struct rtrs_srv_con *con, struct rtrs_srv_op *id,
 		}
 	}
 
+	trace_send_io_resp_imm(id, need_inval, always_invalidate, errno);
+
 	if (need_inval && always_invalidate) {
 		wr = &inv_wr;
 		inv_wr.next = &rwr.wr;

drivers/infiniband/ulp/rtrs/rtrs-srv.h

@@ -91,6 +91,11 @@ struct rtrs_srv_path {
 	struct rtrs_srv_stats	*stats;
 };
 
+static inline struct rtrs_srv_path *to_srv_path(struct rtrs_path *s)
+{
+	return container_of(s, struct rtrs_srv_path, s);
+}
+
 struct rtrs_srv_sess {
 	struct list_head	paths_list;
 	int			paths_up;