[PATCH 3.16 017/306] zfcp: trace full payload of all SAN records (req,resp,iels)

[Ben Hutchings]

3.16.40-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Steffen Maier <maier@xxxxxxxxxxxxxxxxxx>

commit aceeffbb59bb91404a0bda32a542d7ebf878433a upstream.

This was lost with commit 2c55b750a884b86dea8b4cc5f15e1484cc47a25c
("[SCSI] zfcp: Redesign of the debug tracing for SAN records.")
but is necessary for problem determination, e.g. to see the
currently active zone set during automatic port scan.

For the large GPN_FT response (4 pages), save space by not dumping
any empty residual entries.

Signed-off-by: Steffen Maier <maier@xxxxxxxxxxxxxxxxxx>
Fixes: 2c55b750a884 ("[SCSI] zfcp: Redesign of the debug tracing for SAN records.")
Reviewed-by: Alexey Ishchuk <aishchuk@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Benjamin Block <bblock@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/s390/scsi/zfcp_dbf.c | 116 ++++++++++++++++++++++++++++++++++++++-----
 drivers/s390/scsi/zfcp_dbf.h |   1 +
 2 files changed, 104 insertions(+), 13 deletions(-)

--- a/drivers/s390/scsi/zfcp_dbf.c
+++ b/drivers/s390/scsi/zfcp_dbf.c
@@ -3,7 +3,7 @@
  *
  * Debug traces for zfcp.
  *
- * Copyright IBM Corp. 2002, 2015
+ * Copyright IBM Corp. 2002, 2016
  */
 
 #define KMSG_COMPONENT "zfcp"
@@ -356,12 +356,15 @@ void zfcp_dbf_rec_run_wka(char *tag, str
 }
 
 static inline
-void zfcp_dbf_san(char *tag, struct zfcp_dbf *dbf, void *data, u8 id, u16 len,
-		  u64 req_id, u32 d_id)
+void zfcp_dbf_san(char *tag, struct zfcp_dbf *dbf,
+		  char *paytag, struct scatterlist *sg, u8 id, u16 len,
+		  u64 req_id, u32 d_id, u16 cap_len)
 {
 	struct zfcp_dbf_san *rec = &dbf->san_buf;
 	u16 rec_len;
 	unsigned long flags;
+	struct zfcp_dbf_pay *payload = &dbf->pay_buf;
+	u16 pay_sum = 0;
 
 	spin_lock_irqsave(&dbf->san_lock, flags);
 	memset(rec, 0, sizeof(*rec));
@@ -369,10 +372,41 @@ void zfcp_dbf_san(char *tag, struct zfcp
 	rec->id = id;
 	rec->fsf_req_id = req_id;
 	rec->d_id = d_id;
-	rec_len = min(len, (u16)ZFCP_DBF_SAN_MAX_PAYLOAD);
-	memcpy(rec->payload, data, rec_len);
 	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
+	rec->pl_len = len; /* full length even if we cap pay below */
+	if (!sg)
+		goto out;
+	rec_len = min_t(unsigned int, sg->length, ZFCP_DBF_SAN_MAX_PAYLOAD);
+	memcpy(rec->payload, sg_virt(sg), rec_len); /* part of 1st sg entry */
+	if (len <= rec_len)
+		goto out; /* skip pay record if full content in rec->payload */
+
+	/* if (len > rec_len):
+	 * dump data up to cap_len ignoring small duplicate in rec->payload
+	 */
+	spin_lock_irqsave(&dbf->pay_lock, flags);
+	memset(payload, 0, sizeof(*payload));
+	memcpy(payload->area, paytag, ZFCP_DBF_TAG_LEN);
+	payload->fsf_req_id = req_id;
+	payload->counter = 0;
+	for (; sg && pay_sum < cap_len; sg = sg_next(sg)) {
+		u16 pay_len, offset = 0;
+
+		while (offset < sg->length && pay_sum < cap_len) {
+			pay_len = min((u16)ZFCP_DBF_PAY_MAX_REC,
+				      (u16)(sg->length - offset));
+			/* cap_len <= pay_sum < cap_len+ZFCP_DBF_PAY_MAX_REC */
+			memcpy(payload->data, sg_virt(sg) + offset, pay_len);
+			debug_event(dbf->pay, 1, payload,
+				    zfcp_dbf_plen(pay_len));
+			payload->counter++;
+			offset += pay_len;
+			pay_sum += pay_len;
+		}
+	}
+	spin_unlock(&dbf->pay_lock);
 
+out:
 	debug_event(dbf->san, 1, rec, sizeof(*rec));
 	spin_unlock_irqrestore(&dbf->san_lock, flags);
 }
@@ -389,9 +423,62 @@ void zfcp_dbf_san_req(char *tag, struct
 	struct zfcp_fsf_ct_els *ct_els = fsf->data;
 	u16 length;
 
-	length = (u16)(ct_els->req->length);
-	zfcp_dbf_san(tag, dbf, sg_virt(ct_els->req), ZFCP_DBF_SAN_REQ, length,
-		     fsf->req_id, d_id);
+	length = (u16)zfcp_qdio_real_bytes(ct_els->req);
+	zfcp_dbf_san(tag, dbf, "san_req", ct_els->req, ZFCP_DBF_SAN_REQ,
+		     length, fsf->req_id, d_id, length);
+}
+
+static u16 zfcp_dbf_san_res_cap_len_if_gpn_ft(char *tag,
+					      struct zfcp_fsf_req *fsf,
+					      u16 len)
+{
+	struct zfcp_fsf_ct_els *ct_els = fsf->data;
+	struct fc_ct_hdr *reqh = sg_virt(ct_els->req);
+	struct fc_ns_gid_ft *reqn = (struct fc_ns_gid_ft *)(reqh + 1);
+	struct scatterlist *resp_entry = ct_els->resp;
+	struct fc_gpn_ft_resp *acc;
+	int max_entries, x, last = 0;
+
+	if (!(memcmp(tag, "fsscth2", 7) == 0
+	      && ct_els->d_id == FC_FID_DIR_SERV
+	      && reqh->ct_rev == FC_CT_REV
+	      && reqh->ct_in_id[0] == 0
+	      && reqh->ct_in_id[1] == 0
+	      && reqh->ct_in_id[2] == 0
+	      && reqh->ct_fs_type == FC_FST_DIR
+	      && reqh->ct_fs_subtype == FC_NS_SUBTYPE
+	      && reqh->ct_options == 0
+	      && reqh->_ct_resvd1 == 0
+	      && reqh->ct_cmd == FC_NS_GPN_FT
+	      /* reqh->ct_mr_size can vary so do not match but read below */
+	      && reqh->_ct_resvd2 == 0
+	      && reqh->ct_reason == 0
+	      && reqh->ct_explan == 0
+	      && reqh->ct_vendor == 0
+	      && reqn->fn_resvd == 0
+	      && reqn->fn_domain_id_scope == 0
+	      && reqn->fn_area_id_scope == 0
+	      && reqn->fn_fc4_type == FC_TYPE_FCP))
+		return len; /* not GPN_FT response so do not cap */
+
+	acc = sg_virt(resp_entry);
+	max_entries = (reqh->ct_mr_size * 4 / sizeof(struct fc_gpn_ft_resp))
+		+ 1 /* zfcp_fc_scan_ports: bytes correct, entries off-by-one
+		     * to account for header as 1st pseudo "entry" */;
+
+	/* the basic CT_IU preamble is the same size as one entry in the GPN_FT
+	 * response, allowing us to skip special handling for it - just skip it
+	 */
+	for (x = 1; x < max_entries && !last; x++) {
+		if (x % (ZFCP_FC_GPN_FT_ENT_PAGE + 1))
+			acc++;
+		else
+			acc = sg_virt(++resp_entry);
+
+		last = acc->fp_flags & FC_NS_FID_LAST;
+	}
+	len = min(len, (u16)(x * sizeof(struct fc_gpn_ft_resp)));
+	return len; /* cap after last entry */
 }
 
 /**
@@ -405,9 +492,10 @@ void zfcp_dbf_san_res(char *tag, struct
 	struct zfcp_fsf_ct_els *ct_els = fsf->data;
 	u16 length;
 
-	length = (u16)(ct_els->resp->length);
-	zfcp_dbf_san(tag, dbf, sg_virt(ct_els->resp), ZFCP_DBF_SAN_RES, length,
-		     fsf->req_id, ct_els->d_id);
+	length = (u16)zfcp_qdio_real_bytes(ct_els->resp);
+	zfcp_dbf_san(tag, dbf, "san_res", ct_els->resp, ZFCP_DBF_SAN_RES,
+		     length, fsf->req_id, ct_els->d_id,
+		     zfcp_dbf_san_res_cap_len_if_gpn_ft(tag, fsf, length));
 }
 
 /**
@@ -421,11 +509,13 @@ void zfcp_dbf_san_in_els(char *tag, stru
 	struct fsf_status_read_buffer *srb =
 		(struct fsf_status_read_buffer *) fsf->data;
 	u16 length;
+	struct scatterlist sg;
 
 	length = (u16)(srb->length -
 			offsetof(struct fsf_status_read_buffer, payload));
-	zfcp_dbf_san(tag, dbf, srb->payload.data, ZFCP_DBF_SAN_ELS, length,
-		     fsf->req_id, ntoh24(srb->d_id));
+	sg_init_one(&sg, srb->payload.data, length);
+	zfcp_dbf_san(tag, dbf, "san_els", &sg, ZFCP_DBF_SAN_ELS, length,
+		     fsf->req_id, ntoh24(srb->d_id), length);
 }
 
 /**
--- a/drivers/s390/scsi/zfcp_dbf.h
+++ b/drivers/s390/scsi/zfcp_dbf.h
@@ -115,6 +115,7 @@ struct zfcp_dbf_san {
 	u32 d_id;
 #define ZFCP_DBF_SAN_MAX_PAYLOAD (FC_CT_HDR_LEN + 32)
 	char payload[ZFCP_DBF_SAN_MAX_PAYLOAD];
+	u16 pl_len;
 } __packed;
 
 /**