net/smc: Introduce tracepoint for fallback
This introduces tracepoint for smc fallback to TCP, so that we can track
which connection and why it fallbacks, and map the clcsocks' pointer with
/proc/net/tcp to find more details about TCP connections. Compared with
kprobe or other dynamic tracing, tracepoints are stable and easy to use.
Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 8dc3438..0cf7ed2 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;
