[PATCH v2 3/3] nvmet: add set feature tracing support

[Hou Pu]

A nvme connect command produces following trace from the target side.

Before:
    kworker/0:1H-56      [000] ....  9012.155139: nvmet_req_init: nvmet1: qid=0, cmdid=16, nsid=0, flags=0x40, meta=0x0, cmd=(nvme_admin_set_features, cdw10=07 00 00 00 07 00 07 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00)
    kworker/0:1H-56      [000] ....  9012.872272: nvmet_req_init: nvmet1: qid=0, cmdid=13, nsid=0, flags=0x40, meta=0x0, cmd=(nvme_admin_set_features, cdw10=0b 00 00 00 00 09 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00)

After:
    kworker/0:1H-56      [000] ....    97.207441: nvmet_req_init: nvmet1: qid=0, cmdid=6, nsid=0, flags=0x40, meta=0x0, cmd=(nvme_admin_set_features, fid=0x7, sv=0x0, cdw11=07 00 07 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00)
    kworker/0:1H-56      [000] ....    97.925443: nvmet_req_init: nvmet1: qid=0, cmdid=7, nsid=0, flags=0x40, meta=0x0, cmd=(nvme_admin_set_features, fid=0xb, sv=0x0, cdw11=00 09 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00)

Signed-off-by: Hou Pu <houpu.main at gmail.com>
---
 drivers/nvme/target/trace.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/nvme/target/trace.c b/drivers/nvme/target/trace.c
index 902500a57185..a1200837646a 100644
--- a/drivers/nvme/target/trace.c
+++ b/drivers/nvme/target/trace.c
@@ -19,6 +19,20 @@ static const char *nvmet_trace_admin_identify(struct trace_seq *p, u8 *cdw10)
 	return ret;
 }
 
+static const char *nvmet_trace_admin_set_features(struct trace_seq *p,
+						 u8 *cdw10)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+	u8 fid = cdw10[0];
+	u8 sv = cdw10[3] & 0x8;
+
+	trace_seq_printf(p, "fid=0x%x, sv=0x%x, ", fid, sv);
+	trace_seq_printf(p, "cdw11=%*ph", 20, cdw10 + 4);
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+
 static const char *nvmet_trace_admin_get_features(struct trace_seq *p,
 						 u8 *cdw10)
 {
@@ -96,6 +110,8 @@ const char *nvmet_trace_parse_admin_cmd(struct trace_seq *p,
 	switch (opcode) {
 	case nvme_admin_identify:
 		return nvmet_trace_admin_identify(p, cdw10);
+	case nvme_admin_set_features:
+		return nvmet_trace_admin_set_features(p, cdw10);
 	case nvme_admin_get_features:
 		return nvmet_trace_admin_get_features(p, cdw10);
 	case nvme_admin_get_lba_status:
-- 
2.28.0