net/smc: Introduce tracepoints for tx and rx msg

This introduce two tracepoints for smc tx and rx msg to help us
diagnosis issues of data path. These two tracepoitns don't cover the
path of CORK or MSG_MORE in tx, just the top half of data path.

Signed-off-by: Tony Lu <[e-mail]>
Reviewed-by: Wen Gu <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/smc/smc_rx.c

···
 #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().
···
 			if (msg && smc_rx_update_consumer(smc, cons, copylen))
 				goto out;
 		}
+
+		trace_smc_rx_recvmsg(smc, copylen);
 	} while (read_remaining);
 out:
 	return read_done;

net/smc/smc_tracepoint.c

···
 #include "smc_tracepoint.h"
 
 EXPORT_TRACEPOINT_SYMBOL(smc_switch_to_fallback);
+EXPORT_TRACEPOINT_SYMBOL(smc_tx_sendmsg);
+EXPORT_TRACEPOINT_SYMBOL(smc_rx_recvmsg);

net/smc/smc_tracepoint.h

···
 		      __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)
+);
+
 #endif /* _TRACE_SMC_H */
 
 #undef TRACE_INCLUDE_PATH

net/smc/smc_tx.c

···
 #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 */
···
 					   SMC_TX_CORK_DELAY);
 		else
 			smc_tx_sndbuf_nonempty(conn);
+
+		trace_smc_tx_sendmsg(smc, copylen);
 	} /* while (msg_data_left(msg)) */
 
 	return send_done;