Merge branch 'SMC-tracepoints'

Tony Lu says:

====================
Tracepoints for SMC

This patch set introduces tracepoints for SMC, including the tracepoints
basic code. The tracepoitns would help us to track SMC's behaviors by
automatic tools, or other BPF tools, and zero overhead if not enabled.

Compared with kprobe and other dymatic tools, the tracepoints are
considered as stable API, and less overhead for tracing with easy-to-use
API.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 142 insertions, 2 deletions

diff --git a/net/smc/Makefile b/net/smc/Makefile
index 99a0186cba5be3..196fb6f01b14f3 100644
--- a/net/smc/Makefile
+++ b/net/smc/Makefile
@@ -1,5 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
+ccflags-y += -I$(src)
 obj-$(CONFIG_SMC)	+= smc.o
 obj-$(CONFIG_SMC_DIAG)	+= smc_diag.o
 smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o smc_wr.o smc_llc.o
 smc-y += smc_cdc.o smc_tx.o smc_rx.o smc_close.o smc_ism.o smc_netlink.o smc_stats.o
+smc-y += smc_tracepoint.o
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 8dc34388b2c198..0cf7ed2f5d41b5 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -50,6 +50,7 @@
 #include "smc_rx.h"
 #include "smc_close.h"
 #include "smc_stats.h"
+#include "smc_tracepoint.h"
 
 static DEFINE_MUTEX(smc_server_lgr_pending);	/* serialize link group
 						 * creation on server
@@ -564,6 +565,7 @@ static void smc_switch_to_fallback(struct smc_sock *smc, int reason_code)
 	smc->use_fallback = true;
 	smc->fallback_rsn = reason_code;
 	smc_stat_fallback(smc);
+	trace_smc_switch_to_fallback(smc, reason_code);
 	if (smc->sk.sk_socket && smc->sk.sk_socket->file) {
 		smc->clcsock->file = smc->sk.sk_socket->file;
 		smc->clcsock->file->private_data = smc->clcsock;
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 8e642f8f334f10..49b8ba3bb6835e 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -34,6 +34,7 @@
 #include "smc_ism.h"
 #include "smc_netlink.h"
 #include "smc_stats.h"
+#include "smc_tracepoint.h"
 
 #define SMC_LGR_NUM_INCR		256
 #define SMC_LGR_FREE_DELAY_SERV		(600 * HZ)
@@ -1620,15 +1621,19 @@ static void smcr_link_down(struct smc_link *lnk)
 /* must be called under lgr->llc_conf_mutex lock */
 void smcr_link_down_cond(struct smc_link *lnk)
 {
-	if (smc_link_downing(&lnk->state))
+	if (smc_link_downing(&lnk->state)) {
+		trace_smcr_link_down(lnk, __builtin_return_address(0));
 		smcr_link_down(lnk);
+	}
 }
 
 /* will get the lgr->llc_conf_mutex lock */
 void smcr_link_down_cond_sched(struct smc_link *lnk)
 {
-	if (smc_link_downing(&lnk->state))
+	if (smc_link_downing(&lnk->state)) {
+		trace_smcr_link_down(lnk, __builtin_return_address(0));
 		schedule_work(&lnk->link_down_wrk);
+	}
 }
 
 void smcr_port_err(struct smc_ib_device *smcibdev, u8 ibport)
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index 170b733bc73675..51e8eb2933ff47 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -22,6 +22,7 @@
 #include "smc_tx.h" /* smc_tx_consumer_update() */
 #include "smc_rx.h"
 #include "smc_stats.h"
+#include "smc_tracepoint.h"
 
 /* callback implementation to wakeup consumers blocked with smc_rx_wait().
  * indirectly called by smc_cdc_msg_recv_action().
@@ -438,6 +439,8 @@ copy:
 			if (msg && smc_rx_update_consumer(smc, cons, copylen))
 				goto out;
 		}
+
+		trace_smc_rx_recvmsg(smc, copylen);
 	} while (read_remaining);
 out:
 	return read_done;
diff --git a/net/smc/smc_tracepoint.c b/net/smc/smc_tracepoint.c
new file mode 100644
index 00000000000000..8d47ced5a49236
--- /dev/null
+++ b/net/smc/smc_tracepoint.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define CREATE_TRACE_POINTS
+#include "smc_tracepoint.h"
+
+EXPORT_TRACEPOINT_SYMBOL(smc_switch_to_fallback);
+EXPORT_TRACEPOINT_SYMBOL(smc_tx_sendmsg);
+EXPORT_TRACEPOINT_SYMBOL(smc_rx_recvmsg);
+EXPORT_TRACEPOINT_SYMBOL(smcr_link_down);
diff --git a/net/smc/smc_tracepoint.h b/net/smc/smc_tracepoint.h
new file mode 100644
index 00000000000000..b4c36795a9280f
--- /dev/null
+++ b/net/smc/smc_tracepoint.h
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM smc
+
+#if !defined(_TRACE_SMC_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SMC_H
+
+#include <linux/ipv6.h>
+#include <linux/tcp.h>
+#include <linux/tracepoint.h>
+#include <net/ipv6.h>
+#include "smc.h"
+#include "smc_core.h"
+
+TRACE_EVENT(smc_switch_to_fallback,
+
+	    TP_PROTO(const struct smc_sock *smc, int fallback_rsn),
+
+	    TP_ARGS(smc, fallback_rsn),
+
+	    TP_STRUCT__entry(
+			     __field(const void *, sk)
+			     __field(const void *, clcsk)
+			     __field(int, fallback_rsn)
+	    ),
+
+	    TP_fast_assign(
+			   const struct sock *sk = &smc->sk;
+			   const struct sock *clcsk = smc->clcsock->sk;
+
+			   __entry->sk = sk;
+			   __entry->clcsk = clcsk;
+			   __entry->fallback_rsn = fallback_rsn;
+	    ),
+
+	    TP_printk("sk=%p clcsk=%p fallback_rsn=%d",
+		      __entry->sk, __entry->clcsk, __entry->fallback_rsn)
+);
+
+DECLARE_EVENT_CLASS(smc_msg_event,
+
+		    TP_PROTO(const struct smc_sock *smc, size_t len),
+
+		    TP_ARGS(smc, len),
+
+		    TP_STRUCT__entry(
+				     __field(const void *, smc)
+				     __field(size_t, len)
+				     __string(name, smc->conn.lnk->ibname)
+		    ),
+
+		    TP_fast_assign(
+				   __entry->smc = smc;
+				   __entry->len = len;
+				   __assign_str(name, smc->conn.lnk->ibname);
+		    ),
+
+		    TP_printk("smc=%p len=%zu dev=%s",
+			      __entry->smc, __entry->len,
+			      __get_str(name))
+);
+
+DEFINE_EVENT(smc_msg_event, smc_tx_sendmsg,
+
+	     TP_PROTO(const struct smc_sock *smc, size_t len),
+
+	     TP_ARGS(smc, len)
+);
+
+DEFINE_EVENT(smc_msg_event, smc_rx_recvmsg,
+
+	     TP_PROTO(const struct smc_sock *smc, size_t len),
+
+	     TP_ARGS(smc, len)
+);
+
+TRACE_EVENT(smcr_link_down,
+
+	    TP_PROTO(const struct smc_link *lnk, void *location),
+
+	    TP_ARGS(lnk, location),
+
+	    TP_STRUCT__entry(
+			     __field(const void *, lnk)
+			     __field(const void *, lgr)
+			     __field(int, state)
+			     __string(name, lnk->ibname)
+			     __field(void *, location)
+	    ),
+
+	    TP_fast_assign(
+			   const struct smc_link_group *lgr = lnk->lgr;
+
+			   __entry->lnk = lnk;
+			   __entry->lgr = lgr;
+			   __entry->state = lnk->state;
+			   __assign_str(name, lnk->ibname);
+			   __entry->location = location;
+	    ),
+
+	    TP_printk("lnk=%p lgr=%p state=%d dev=%s location=%p",
+		      __entry->lnk, __entry->lgr,
+		      __entry->state, __get_str(name),
+		      __entry->location)
+);
+
+#endif /* _TRACE_SMC_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE smc_tracepoint
+
+#include <trace/define_trace.h>
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 738a4a99c82797..be241d53020f1e 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -28,6 +28,7 @@
 #include "smc_ism.h"
 #include "smc_tx.h"
 #include "smc_stats.h"
+#include "smc_tracepoint.h"
 
 #define SMC_TX_WORK_DELAY	0
 #define SMC_TX_CORK_DELAY	(HZ >> 2)	/* 250 ms */
@@ -245,6 +246,8 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len)
 					   SMC_TX_CORK_DELAY);
 		else
 			smc_tx_sndbuf_nonempty(conn);
+
+		trace_smc_tx_sendmsg(smc, copylen);
 	} /* while (msg_data_left(msg)) */
 
 	return send_done;