[SCSI] zfcp: Add support for unchained FSF requests

Add the support to send CT and ELS requests as unchained FSF requests. This is
required for older hardware and was somehow omitted during the cleanup of the
FSF layer. The req_count and resp_count attributes are unused, so remove them
instead of adding a special case for setting them. Also add debug data and a
warning, when the ct request hits a limit.

Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Acked-by: Martin Petermann <martin@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c
index 217c3b0..eabdfe2 100644
--- a/drivers/s390/scsi/zfcp_fc.c
+++ b/drivers/s390/scsi/zfcp_fc.c
@@ -40,9 +40,12 @@
 	u64 wwpn;
 } __attribute__ ((packed));
 
-#define ZFCP_GPN_FT_ENTRIES ((PAGE_SIZE - sizeof(struct ct_hdr)) \
-				/ sizeof(struct gpn_ft_resp_acc))
+#define ZFCP_CT_SIZE_ONE_PAGE	(PAGE_SIZE - sizeof(struct ct_hdr))
+#define ZFCP_GPN_FT_ENTRIES	(ZFCP_CT_SIZE_ONE_PAGE \
+					/ sizeof(struct gpn_ft_resp_acc))
 #define ZFCP_GPN_FT_BUFFERS 4
+#define ZFCP_GPN_FT_MAX_SIZE (ZFCP_GPN_FT_BUFFERS * PAGE_SIZE \
+				- sizeof(struct ct_hdr))
 #define ZFCP_GPN_FT_MAX_ENTRIES ZFCP_GPN_FT_BUFFERS * (ZFCP_GPN_FT_ENTRIES + 1)
 
 struct ct_iu_gpn_ft_resp {
@@ -282,8 +285,6 @@
 	gid_pn->ct.timeout = ZFCP_NS_GID_PN_TIMEOUT;
 	gid_pn->ct.req = &gid_pn->req;
 	gid_pn->ct.resp = &gid_pn->resp;
-	gid_pn->ct.req_count = 1;
-	gid_pn->ct.resp_count = 1;
 	sg_init_one(&gid_pn->req, &gid_pn->ct_iu_req,
 		    sizeof(struct ct_iu_gid_pn_req));
 	sg_init_one(&gid_pn->resp, &gid_pn->ct_iu_resp,
@@ -295,7 +296,7 @@
 	gid_pn->ct_iu_req.header.gs_subtype = ZFCP_CT_NAME_SERVER;
 	gid_pn->ct_iu_req.header.options = ZFCP_CT_SYNCHRONOUS;
 	gid_pn->ct_iu_req.header.cmd_rsp_code = ZFCP_CT_GID_PN;
-	gid_pn->ct_iu_req.header.max_res_size = ZFCP_CT_MAX_SIZE;
+	gid_pn->ct_iu_req.header.max_res_size = ZFCP_CT_SIZE_ONE_PAGE / 4;
 	gid_pn->ct_iu_req.wwpn = erp_action->port->wwpn;
 
 	init_completion(&compl_rec.done);
@@ -405,8 +406,6 @@
 	sg_init_one(adisc->els.resp, &adisc->ls_adisc_acc,
 		    sizeof(struct zfcp_ls_adisc));
 
-	adisc->els.req_count = 1;
-	adisc->els.resp_count = 1;
 	adisc->els.adapter = adapter;
 	adisc->els.port = port;
 	adisc->els.d_id = port->d_id;
@@ -446,17 +445,17 @@
 		zfcp_erp_port_forced_reopen(port, 0, 65, NULL);
 }
 
-static void zfcp_free_sg_env(struct zfcp_gpn_ft *gpn_ft)
+static void zfcp_free_sg_env(struct zfcp_gpn_ft *gpn_ft, int buf_num)
 {
 	struct scatterlist *sg = &gpn_ft->sg_req;
 
 	kfree(sg_virt(sg)); /* free request buffer */
-	zfcp_sg_free_table(gpn_ft->sg_resp, ZFCP_GPN_FT_BUFFERS);
+	zfcp_sg_free_table(gpn_ft->sg_resp, buf_num);
 
 	kfree(gpn_ft);
 }
 
-static struct zfcp_gpn_ft *zfcp_alloc_sg_env(void)
+static struct zfcp_gpn_ft *zfcp_alloc_sg_env(int buf_num)
 {
 	struct zfcp_gpn_ft *gpn_ft;
 	struct ct_iu_gpn_ft_req *req;
@@ -473,8 +472,8 @@
 	}
 	sg_init_one(&gpn_ft->sg_req, req, sizeof(*req));
 
-	if (zfcp_sg_setup_table(gpn_ft->sg_resp, ZFCP_GPN_FT_BUFFERS)) {
-		zfcp_free_sg_env(gpn_ft);
+	if (zfcp_sg_setup_table(gpn_ft->sg_resp, buf_num)) {
+		zfcp_free_sg_env(gpn_ft, buf_num);
 		gpn_ft = NULL;
 	}
 out:
@@ -483,7 +482,8 @@
 
 
 static int zfcp_scan_issue_gpn_ft(struct zfcp_gpn_ft *gpn_ft,
-				  struct zfcp_adapter *adapter)
+				  struct zfcp_adapter *adapter,
+				  int max_bytes)
 {
 	struct zfcp_send_ct *ct = &gpn_ft->ct;
 	struct ct_iu_gpn_ft_req *req = sg_virt(&gpn_ft->sg_req);
@@ -496,8 +496,7 @@
 	req->header.gs_subtype = ZFCP_CT_NAME_SERVER;
 	req->header.options = ZFCP_CT_SYNCHRONOUS;
 	req->header.cmd_rsp_code = ZFCP_CT_GPN_FT;
-	req->header.max_res_size = (sizeof(struct gpn_ft_resp_acc) *
-					(ZFCP_GPN_FT_MAX_ENTRIES - 1)) >> 2;
+	req->header.max_res_size = max_bytes / 4;
 	req->flags = 0;
 	req->domain_id_scope = 0;
 	req->area_id_scope = 0;
@@ -510,8 +509,6 @@
 	ct->timeout = 10;
 	ct->req = &gpn_ft->sg_req;
 	ct->resp = gpn_ft->sg_resp;
-	ct->req_count = 1;
-	ct->resp_count = ZFCP_GPN_FT_BUFFERS;
 
 	init_completion(&compl_rec.done);
 	compl_rec.handler = NULL;
@@ -538,7 +535,7 @@
 	zfcp_port_dequeue(port);
 }
 
-static int zfcp_scan_eval_gpn_ft(struct zfcp_gpn_ft *gpn_ft)
+static int zfcp_scan_eval_gpn_ft(struct zfcp_gpn_ft *gpn_ft, int max_entries)
 {
 	struct zfcp_send_ct *ct = &gpn_ft->ct;
 	struct scatterlist *sg = gpn_ft->sg_resp;
@@ -558,13 +555,17 @@
 		return -EIO;
 	}
 
-	if (hdr->max_res_size)
+	if (hdr->max_res_size) {
+		dev_warn(&adapter->ccw_device->dev,
+			 "The name server reported %d words residual data\n",
+			 hdr->max_res_size);
 		return -E2BIG;
+	}
 
 	down(&zfcp_data.config_sema);
 
 	/* first entry is the header */
-	for (x = 1; x < ZFCP_GPN_FT_MAX_ENTRIES && !last; x++) {
+	for (x = 1; x < max_entries && !last; x++) {
 		if (x % (ZFCP_GPN_FT_ENTRIES + 1))
 			acc++;
 		else
@@ -609,6 +610,12 @@
 {
 	int ret, i;
 	struct zfcp_gpn_ft *gpn_ft;
+	int chain, max_entries, buf_num, max_bytes;
+
+	chain = adapter->adapter_features & FSF_FEATURE_ELS_CT_CHAINED_SBALS;
+	buf_num = chain ? ZFCP_GPN_FT_BUFFERS : 1;
+	max_entries = chain ? ZFCP_GPN_FT_MAX_ENTRIES : ZFCP_GPN_FT_ENTRIES;
+	max_bytes = chain ? ZFCP_GPN_FT_MAX_SIZE : ZFCP_CT_SIZE_ONE_PAGE;
 
 	if (fc_host_port_type(adapter->scsi_host) != FC_PORTTYPE_NPORT)
 		return 0;
@@ -617,23 +624,23 @@
 	if (ret)
 		return ret;
 
-	gpn_ft = zfcp_alloc_sg_env();
+	gpn_ft = zfcp_alloc_sg_env(buf_num);
 	if (!gpn_ft) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
 	for (i = 0; i < 3; i++) {
-		ret = zfcp_scan_issue_gpn_ft(gpn_ft, adapter);
+		ret = zfcp_scan_issue_gpn_ft(gpn_ft, adapter, max_bytes);
 		if (!ret) {
-			ret = zfcp_scan_eval_gpn_ft(gpn_ft);
+			ret = zfcp_scan_eval_gpn_ft(gpn_ft, max_entries);
 			if (ret == -EAGAIN)
 				ssleep(1);
 			else
 				break;
 		}
 	}
-	zfcp_free_sg_env(gpn_ft);
+	zfcp_free_sg_env(gpn_ft, buf_num);
 out:
 	zfcp_wka_port_put(&adapter->nsp);
 	return ret;