xref: /openbmc/linux/drivers/s390/scsi/zfcp_fc.c (revision b627b4ed)
1 /*
2  * zfcp device driver
3  *
4  * Fibre Channel related functions for the zfcp device driver.
5  *
6  * Copyright IBM Corporation 2008, 2009
7  */
8 
9 #define KMSG_COMPONENT "zfcp"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11 
12 #include "zfcp_ext.h"
13 
14 enum rscn_address_format {
15 	RSCN_PORT_ADDRESS	= 0x0,
16 	RSCN_AREA_ADDRESS	= 0x1,
17 	RSCN_DOMAIN_ADDRESS	= 0x2,
18 	RSCN_FABRIC_ADDRESS	= 0x3,
19 };
20 
21 static u32 rscn_range_mask[] = {
22 	[RSCN_PORT_ADDRESS]		= 0xFFFFFF,
23 	[RSCN_AREA_ADDRESS]		= 0xFFFF00,
24 	[RSCN_DOMAIN_ADDRESS]		= 0xFF0000,
25 	[RSCN_FABRIC_ADDRESS]		= 0x000000,
26 };
27 
28 struct ct_iu_gpn_ft_req {
29 	struct ct_hdr header;
30 	u8 flags;
31 	u8 domain_id_scope;
32 	u8 area_id_scope;
33 	u8 fc4_type;
34 } __attribute__ ((packed));
35 
36 struct gpn_ft_resp_acc {
37 	u8 control;
38 	u8 port_id[3];
39 	u8 reserved[4];
40 	u64 wwpn;
41 } __attribute__ ((packed));
42 
43 #define ZFCP_CT_SIZE_ONE_PAGE	(PAGE_SIZE - sizeof(struct ct_hdr))
44 #define ZFCP_GPN_FT_ENTRIES	(ZFCP_CT_SIZE_ONE_PAGE \
45 					/ sizeof(struct gpn_ft_resp_acc))
46 #define ZFCP_GPN_FT_BUFFERS 4
47 #define ZFCP_GPN_FT_MAX_SIZE (ZFCP_GPN_FT_BUFFERS * PAGE_SIZE \
48 				- sizeof(struct ct_hdr))
49 #define ZFCP_GPN_FT_MAX_ENTRIES ZFCP_GPN_FT_BUFFERS * (ZFCP_GPN_FT_ENTRIES + 1)
50 
51 struct ct_iu_gpn_ft_resp {
52 	struct ct_hdr header;
53 	struct gpn_ft_resp_acc accept[ZFCP_GPN_FT_ENTRIES];
54 } __attribute__ ((packed));
55 
56 struct zfcp_gpn_ft {
57 	struct zfcp_send_ct ct;
58 	struct scatterlist sg_req;
59 	struct scatterlist sg_resp[ZFCP_GPN_FT_BUFFERS];
60 };
61 
62 struct zfcp_fc_ns_handler_data {
63 	struct completion done;
64 	void (*handler)(unsigned long);
65 	unsigned long handler_data;
66 };
67 
68 static int zfcp_wka_port_get(struct zfcp_wka_port *wka_port)
69 {
70 	if (mutex_lock_interruptible(&wka_port->mutex))
71 		return -ERESTARTSYS;
72 
73 	if (wka_port->status == ZFCP_WKA_PORT_OFFLINE ||
74 	    wka_port->status == ZFCP_WKA_PORT_CLOSING) {
75 		wka_port->status = ZFCP_WKA_PORT_OPENING;
76 		if (zfcp_fsf_open_wka_port(wka_port))
77 			wka_port->status = ZFCP_WKA_PORT_OFFLINE;
78 	}
79 
80 	mutex_unlock(&wka_port->mutex);
81 
82 	wait_event_timeout(
83 		wka_port->completion_wq,
84 		wka_port->status == ZFCP_WKA_PORT_ONLINE ||
85 		wka_port->status == ZFCP_WKA_PORT_OFFLINE,
86 		HZ >> 1);
87 
88 	if (wka_port->status == ZFCP_WKA_PORT_ONLINE) {
89 		atomic_inc(&wka_port->refcount);
90 		return 0;
91 	}
92 	return -EIO;
93 }
94 
95 static void zfcp_wka_port_offline(struct work_struct *work)
96 {
97 	struct delayed_work *dw = to_delayed_work(work);
98 	struct zfcp_wka_port *wka_port =
99 			container_of(dw, struct zfcp_wka_port, work);
100 
101 	/* Don't wait forvever. If the wka_port is too busy take it offline
102 	   through a new call later */
103 	if (!wait_event_timeout(wka_port->completion_wq,
104 				atomic_read(&wka_port->refcount) == 0,
105 				HZ >> 1))
106 		return;
107 
108 	mutex_lock(&wka_port->mutex);
109 	if ((atomic_read(&wka_port->refcount) != 0) ||
110 	    (wka_port->status != ZFCP_WKA_PORT_ONLINE))
111 		goto out;
112 
113 	wka_port->status = ZFCP_WKA_PORT_CLOSING;
114 	if (zfcp_fsf_close_wka_port(wka_port)) {
115 		wka_port->status = ZFCP_WKA_PORT_OFFLINE;
116 		wake_up(&wka_port->completion_wq);
117 	}
118 out:
119 	mutex_unlock(&wka_port->mutex);
120 }
121 
122 static void zfcp_wka_port_put(struct zfcp_wka_port *wka_port)
123 {
124 	if (atomic_dec_return(&wka_port->refcount) != 0)
125 		return;
126 	/* wait 10 miliseconds, other reqs might pop in */
127 	schedule_delayed_work(&wka_port->work, HZ / 100);
128 }
129 
130 void zfcp_fc_nameserver_init(struct zfcp_adapter *adapter)
131 {
132 	struct zfcp_wka_port *wka_port = &adapter->nsp;
133 
134 	init_waitqueue_head(&wka_port->completion_wq);
135 
136 	wka_port->adapter = adapter;
137 	wka_port->d_id = ZFCP_DID_DIRECTORY_SERVICE;
138 
139 	wka_port->status = ZFCP_WKA_PORT_OFFLINE;
140 	atomic_set(&wka_port->refcount, 0);
141 	mutex_init(&wka_port->mutex);
142 	INIT_DELAYED_WORK(&wka_port->work, zfcp_wka_port_offline);
143 }
144 
145 static void _zfcp_fc_incoming_rscn(struct zfcp_fsf_req *fsf_req, u32 range,
146 				   struct fcp_rscn_element *elem)
147 {
148 	unsigned long flags;
149 	struct zfcp_port *port;
150 
151 	read_lock_irqsave(&zfcp_data.config_lock, flags);
152 	list_for_each_entry(port, &fsf_req->adapter->port_list_head, list)
153 		if ((port->d_id & range) == (elem->nport_did & range))
154 			zfcp_test_link(port);
155 
156 	read_unlock_irqrestore(&zfcp_data.config_lock, flags);
157 }
158 
159 static void zfcp_fc_incoming_rscn(struct zfcp_fsf_req *fsf_req)
160 {
161 	struct fsf_status_read_buffer *status_buffer = (void *)fsf_req->data;
162 	struct fcp_rscn_head *fcp_rscn_head;
163 	struct fcp_rscn_element *fcp_rscn_element;
164 	u16 i;
165 	u16 no_entries;
166 	u32 range_mask;
167 
168 	fcp_rscn_head = (struct fcp_rscn_head *) status_buffer->payload.data;
169 	fcp_rscn_element = (struct fcp_rscn_element *) fcp_rscn_head;
170 
171 	/* see FC-FS */
172 	no_entries = fcp_rscn_head->payload_len /
173 			sizeof(struct fcp_rscn_element);
174 
175 	for (i = 1; i < no_entries; i++) {
176 		/* skip head and start with 1st element */
177 		fcp_rscn_element++;
178 		range_mask = rscn_range_mask[fcp_rscn_element->addr_format];
179 		_zfcp_fc_incoming_rscn(fsf_req, range_mask, fcp_rscn_element);
180 	}
181 	schedule_work(&fsf_req->adapter->scan_work);
182 }
183 
184 static void zfcp_fc_incoming_wwpn(struct zfcp_fsf_req *req, u64 wwpn)
185 {
186 	struct zfcp_adapter *adapter = req->adapter;
187 	struct zfcp_port *port;
188 	unsigned long flags;
189 
190 	read_lock_irqsave(&zfcp_data.config_lock, flags);
191 	list_for_each_entry(port, &adapter->port_list_head, list)
192 		if (port->wwpn == wwpn)
193 			break;
194 	read_unlock_irqrestore(&zfcp_data.config_lock, flags);
195 
196 	if (port && (port->wwpn == wwpn))
197 		zfcp_erp_port_forced_reopen(port, 0, "fciwwp1", req);
198 }
199 
200 static void zfcp_fc_incoming_plogi(struct zfcp_fsf_req *req)
201 {
202 	struct fsf_status_read_buffer *status_buffer =
203 		(struct fsf_status_read_buffer *)req->data;
204 	struct fsf_plogi *els_plogi =
205 		(struct fsf_plogi *) status_buffer->payload.data;
206 
207 	zfcp_fc_incoming_wwpn(req, els_plogi->serv_param.wwpn);
208 }
209 
210 static void zfcp_fc_incoming_logo(struct zfcp_fsf_req *req)
211 {
212 	struct fsf_status_read_buffer *status_buffer =
213 		(struct fsf_status_read_buffer *)req->data;
214 	struct fcp_logo *els_logo =
215 		(struct fcp_logo *) status_buffer->payload.data;
216 
217 	zfcp_fc_incoming_wwpn(req, els_logo->nport_wwpn);
218 }
219 
220 /**
221  * zfcp_fc_incoming_els - handle incoming ELS
222  * @fsf_req - request which contains incoming ELS
223  */
224 void zfcp_fc_incoming_els(struct zfcp_fsf_req *fsf_req)
225 {
226 	struct fsf_status_read_buffer *status_buffer =
227 		(struct fsf_status_read_buffer *) fsf_req->data;
228 	unsigned int els_type = status_buffer->payload.data[0];
229 
230 	zfcp_san_dbf_event_incoming_els(fsf_req);
231 	if (els_type == LS_PLOGI)
232 		zfcp_fc_incoming_plogi(fsf_req);
233 	else if (els_type == LS_LOGO)
234 		zfcp_fc_incoming_logo(fsf_req);
235 	else if (els_type == LS_RSCN)
236 		zfcp_fc_incoming_rscn(fsf_req);
237 }
238 
239 static void zfcp_fc_ns_handler(unsigned long data)
240 {
241 	struct zfcp_fc_ns_handler_data *compl_rec =
242 			(struct zfcp_fc_ns_handler_data *) data;
243 
244 	if (compl_rec->handler)
245 		compl_rec->handler(compl_rec->handler_data);
246 
247 	complete(&compl_rec->done);
248 }
249 
250 static void zfcp_fc_ns_gid_pn_eval(unsigned long data)
251 {
252 	struct zfcp_gid_pn_data *gid_pn = (struct zfcp_gid_pn_data *) data;
253 	struct zfcp_send_ct *ct = &gid_pn->ct;
254 	struct ct_iu_gid_pn_req *ct_iu_req = sg_virt(ct->req);
255 	struct ct_iu_gid_pn_resp *ct_iu_resp = sg_virt(ct->resp);
256 	struct zfcp_port *port = gid_pn->port;
257 
258 	if (ct->status)
259 		return;
260 	if (ct_iu_resp->header.cmd_rsp_code != ZFCP_CT_ACCEPT)
261 		return;
262 
263 	/* paranoia */
264 	if (ct_iu_req->wwpn != port->wwpn)
265 		return;
266 	/* looks like a valid d_id */
267 	port->d_id = ct_iu_resp->d_id & ZFCP_DID_MASK;
268 }
269 
270 int static zfcp_fc_ns_gid_pn_request(struct zfcp_erp_action *erp_action,
271 				     struct zfcp_gid_pn_data *gid_pn)
272 {
273 	struct zfcp_adapter *adapter = erp_action->adapter;
274 	struct zfcp_fc_ns_handler_data compl_rec;
275 	int ret;
276 
277 	/* setup parameters for send generic command */
278 	gid_pn->port = erp_action->port;
279 	gid_pn->ct.wka_port = &adapter->nsp;
280 	gid_pn->ct.handler = zfcp_fc_ns_handler;
281 	gid_pn->ct.handler_data = (unsigned long) &compl_rec;
282 	gid_pn->ct.timeout = ZFCP_NS_GID_PN_TIMEOUT;
283 	gid_pn->ct.req = &gid_pn->req;
284 	gid_pn->ct.resp = &gid_pn->resp;
285 	sg_init_one(&gid_pn->req, &gid_pn->ct_iu_req,
286 		    sizeof(struct ct_iu_gid_pn_req));
287 	sg_init_one(&gid_pn->resp, &gid_pn->ct_iu_resp,
288 		    sizeof(struct ct_iu_gid_pn_resp));
289 
290 	/* setup nameserver request */
291 	gid_pn->ct_iu_req.header.revision = ZFCP_CT_REVISION;
292 	gid_pn->ct_iu_req.header.gs_type = ZFCP_CT_DIRECTORY_SERVICE;
293 	gid_pn->ct_iu_req.header.gs_subtype = ZFCP_CT_NAME_SERVER;
294 	gid_pn->ct_iu_req.header.options = ZFCP_CT_SYNCHRONOUS;
295 	gid_pn->ct_iu_req.header.cmd_rsp_code = ZFCP_CT_GID_PN;
296 	gid_pn->ct_iu_req.header.max_res_size = ZFCP_CT_SIZE_ONE_PAGE / 4;
297 	gid_pn->ct_iu_req.wwpn = erp_action->port->wwpn;
298 
299 	init_completion(&compl_rec.done);
300 	compl_rec.handler = zfcp_fc_ns_gid_pn_eval;
301 	compl_rec.handler_data = (unsigned long) gid_pn;
302 	ret = zfcp_fsf_send_ct(&gid_pn->ct, adapter->pool.fsf_req_erp,
303 			       erp_action);
304 	if (!ret)
305 		wait_for_completion(&compl_rec.done);
306 	return ret;
307 }
308 
309 /**
310  * zfcp_fc_ns_gid_pn_request - initiate GID_PN nameserver request
311  * @erp_action: pointer to zfcp_erp_action where GID_PN request is needed
312  * return: -ENOMEM on error, 0 otherwise
313  */
314 int zfcp_fc_ns_gid_pn(struct zfcp_erp_action *erp_action)
315 {
316 	int ret;
317 	struct zfcp_gid_pn_data *gid_pn;
318 	struct zfcp_adapter *adapter = erp_action->adapter;
319 
320 	gid_pn = mempool_alloc(adapter->pool.data_gid_pn, GFP_ATOMIC);
321 	if (!gid_pn)
322 		return -ENOMEM;
323 
324 	memset(gid_pn, 0, sizeof(*gid_pn));
325 
326 	ret = zfcp_wka_port_get(&adapter->nsp);
327 	if (ret)
328 		goto out;
329 
330 	ret = zfcp_fc_ns_gid_pn_request(erp_action, gid_pn);
331 
332 	zfcp_wka_port_put(&adapter->nsp);
333 out:
334 	mempool_free(gid_pn, adapter->pool.data_gid_pn);
335 	return ret;
336 }
337 
338 /**
339  * zfcp_fc_plogi_evaluate - evaluate PLOGI playload
340  * @port: zfcp_port structure
341  * @plogi: plogi payload
342  *
343  * Evaluate PLOGI playload and copy important fields into zfcp_port structure
344  */
345 void zfcp_fc_plogi_evaluate(struct zfcp_port *port, struct fsf_plogi *plogi)
346 {
347 	port->maxframe_size = plogi->serv_param.common_serv_param[7] |
348 		((plogi->serv_param.common_serv_param[6] & 0x0F) << 8);
349 	if (plogi->serv_param.class1_serv_param[0] & 0x80)
350 		port->supported_classes |= FC_COS_CLASS1;
351 	if (plogi->serv_param.class2_serv_param[0] & 0x80)
352 		port->supported_classes |= FC_COS_CLASS2;
353 	if (plogi->serv_param.class3_serv_param[0] & 0x80)
354 		port->supported_classes |= FC_COS_CLASS3;
355 	if (plogi->serv_param.class4_serv_param[0] & 0x80)
356 		port->supported_classes |= FC_COS_CLASS4;
357 }
358 
359 struct zfcp_els_adisc {
360 	struct zfcp_send_els els;
361 	struct scatterlist req;
362 	struct scatterlist resp;
363 	struct zfcp_ls_adisc ls_adisc;
364 	struct zfcp_ls_adisc ls_adisc_acc;
365 };
366 
367 static void zfcp_fc_adisc_handler(unsigned long data)
368 {
369 	struct zfcp_els_adisc *adisc = (struct zfcp_els_adisc *) data;
370 	struct zfcp_port *port = adisc->els.port;
371 	struct zfcp_ls_adisc *ls_adisc = &adisc->ls_adisc_acc;
372 
373 	if (adisc->els.status) {
374 		/* request rejected or timed out */
375 		zfcp_erp_port_forced_reopen(port, 0, "fcadh_1", NULL);
376 		goto out;
377 	}
378 
379 	if (!port->wwnn)
380 		port->wwnn = ls_adisc->wwnn;
381 
382 	if ((port->wwpn != ls_adisc->wwpn) ||
383 	    !(atomic_read(&port->status) & ZFCP_STATUS_COMMON_OPEN)) {
384 		zfcp_erp_port_reopen(port, ZFCP_STATUS_COMMON_ERP_FAILED,
385 				     "fcadh_2", NULL);
386 		goto out;
387 	}
388 
389 	/* port is good, unblock rport without going through erp */
390 	zfcp_scsi_schedule_rport_register(port);
391  out:
392 	zfcp_port_put(port);
393 	kfree(adisc);
394 }
395 
396 static int zfcp_fc_adisc(struct zfcp_port *port)
397 {
398 	struct zfcp_els_adisc *adisc;
399 	struct zfcp_adapter *adapter = port->adapter;
400 
401 	adisc = kzalloc(sizeof(struct zfcp_els_adisc), GFP_ATOMIC);
402 	if (!adisc)
403 		return -ENOMEM;
404 
405 	adisc->els.req = &adisc->req;
406 	adisc->els.resp = &adisc->resp;
407 	sg_init_one(adisc->els.req, &adisc->ls_adisc,
408 		    sizeof(struct zfcp_ls_adisc));
409 	sg_init_one(adisc->els.resp, &adisc->ls_adisc_acc,
410 		    sizeof(struct zfcp_ls_adisc));
411 
412 	adisc->els.adapter = adapter;
413 	adisc->els.port = port;
414 	adisc->els.d_id = port->d_id;
415 	adisc->els.handler = zfcp_fc_adisc_handler;
416 	adisc->els.handler_data = (unsigned long) adisc;
417 	adisc->els.ls_code = adisc->ls_adisc.code = ZFCP_LS_ADISC;
418 
419 	/* acc. to FC-FS, hard_nport_id in ADISC should not be set for ports
420 	   without FC-AL-2 capability, so we don't set it */
421 	adisc->ls_adisc.wwpn = fc_host_port_name(adapter->scsi_host);
422 	adisc->ls_adisc.wwnn = fc_host_node_name(adapter->scsi_host);
423 	adisc->ls_adisc.nport_id = fc_host_port_id(adapter->scsi_host);
424 
425 	return zfcp_fsf_send_els(&adisc->els);
426 }
427 
428 void zfcp_fc_link_test_work(struct work_struct *work)
429 {
430 	struct zfcp_port *port =
431 		container_of(work, struct zfcp_port, test_link_work);
432 	int retval;
433 
434 	if (!(atomic_read(&port->status) & ZFCP_STATUS_COMMON_UNBLOCKED)) {
435 		zfcp_port_put(port);
436 		return; /* port erp is running and will update rport status */
437 	}
438 
439 	zfcp_port_get(port);
440 	port->rport_task = RPORT_DEL;
441 	zfcp_scsi_rport_work(&port->rport_work);
442 
443 	retval = zfcp_fc_adisc(port);
444 	if (retval == 0)
445 		return;
446 
447 	/* send of ADISC was not possible */
448 	zfcp_erp_port_forced_reopen(port, 0, "fcltwk1", NULL);
449 
450 	zfcp_port_put(port);
451 }
452 
453 /**
454  * zfcp_test_link - lightweight link test procedure
455  * @port: port to be tested
456  *
457  * Test status of a link to a remote port using the ELS command ADISC.
458  * If there is a problem with the remote port, error recovery steps
459  * will be triggered.
460  */
461 void zfcp_test_link(struct zfcp_port *port)
462 {
463 	zfcp_port_get(port);
464 	if (!queue_work(zfcp_data.work_queue, &port->test_link_work))
465 		zfcp_port_put(port);
466 }
467 
468 static void zfcp_free_sg_env(struct zfcp_gpn_ft *gpn_ft, int buf_num)
469 {
470 	struct scatterlist *sg = &gpn_ft->sg_req;
471 
472 	kfree(sg_virt(sg)); /* free request buffer */
473 	zfcp_sg_free_table(gpn_ft->sg_resp, buf_num);
474 
475 	kfree(gpn_ft);
476 }
477 
478 static struct zfcp_gpn_ft *zfcp_alloc_sg_env(int buf_num)
479 {
480 	struct zfcp_gpn_ft *gpn_ft;
481 	struct ct_iu_gpn_ft_req *req;
482 
483 	gpn_ft = kzalloc(sizeof(*gpn_ft), GFP_KERNEL);
484 	if (!gpn_ft)
485 		return NULL;
486 
487 	req = kzalloc(sizeof(struct ct_iu_gpn_ft_req), GFP_KERNEL);
488 	if (!req) {
489 		kfree(gpn_ft);
490 		gpn_ft = NULL;
491 		goto out;
492 	}
493 	sg_init_one(&gpn_ft->sg_req, req, sizeof(*req));
494 
495 	if (zfcp_sg_setup_table(gpn_ft->sg_resp, buf_num)) {
496 		zfcp_free_sg_env(gpn_ft, buf_num);
497 		gpn_ft = NULL;
498 	}
499 out:
500 	return gpn_ft;
501 }
502 
503 
504 static int zfcp_scan_issue_gpn_ft(struct zfcp_gpn_ft *gpn_ft,
505 				  struct zfcp_adapter *adapter,
506 				  int max_bytes)
507 {
508 	struct zfcp_send_ct *ct = &gpn_ft->ct;
509 	struct ct_iu_gpn_ft_req *req = sg_virt(&gpn_ft->sg_req);
510 	struct zfcp_fc_ns_handler_data compl_rec;
511 	int ret;
512 
513 	/* prepare CT IU for GPN_FT */
514 	req->header.revision = ZFCP_CT_REVISION;
515 	req->header.gs_type = ZFCP_CT_DIRECTORY_SERVICE;
516 	req->header.gs_subtype = ZFCP_CT_NAME_SERVER;
517 	req->header.options = ZFCP_CT_SYNCHRONOUS;
518 	req->header.cmd_rsp_code = ZFCP_CT_GPN_FT;
519 	req->header.max_res_size = max_bytes / 4;
520 	req->flags = 0;
521 	req->domain_id_scope = 0;
522 	req->area_id_scope = 0;
523 	req->fc4_type = ZFCP_CT_SCSI_FCP;
524 
525 	/* prepare zfcp_send_ct */
526 	ct->wka_port = &adapter->nsp;
527 	ct->handler = zfcp_fc_ns_handler;
528 	ct->handler_data = (unsigned long)&compl_rec;
529 	ct->timeout = 10;
530 	ct->req = &gpn_ft->sg_req;
531 	ct->resp = gpn_ft->sg_resp;
532 
533 	init_completion(&compl_rec.done);
534 	compl_rec.handler = NULL;
535 	ret = zfcp_fsf_send_ct(ct, NULL, NULL);
536 	if (!ret)
537 		wait_for_completion(&compl_rec.done);
538 	return ret;
539 }
540 
541 static void zfcp_validate_port(struct zfcp_port *port)
542 {
543 	struct zfcp_adapter *adapter = port->adapter;
544 
545 	atomic_clear_mask(ZFCP_STATUS_COMMON_NOESC, &port->status);
546 
547 	if ((port->supported_classes != 0) ||
548 	    !list_empty(&port->unit_list_head)) {
549 		zfcp_port_put(port);
550 		return;
551 	}
552 	zfcp_erp_port_shutdown(port, 0, "fcpval1", NULL);
553 	zfcp_erp_wait(adapter);
554 	zfcp_port_put(port);
555 	zfcp_port_dequeue(port);
556 }
557 
558 static int zfcp_scan_eval_gpn_ft(struct zfcp_gpn_ft *gpn_ft, int max_entries)
559 {
560 	struct zfcp_send_ct *ct = &gpn_ft->ct;
561 	struct scatterlist *sg = gpn_ft->sg_resp;
562 	struct ct_hdr *hdr = sg_virt(sg);
563 	struct gpn_ft_resp_acc *acc = sg_virt(sg);
564 	struct zfcp_adapter *adapter = ct->wka_port->adapter;
565 	struct zfcp_port *port, *tmp;
566 	u32 d_id;
567 	int ret = 0, x, last = 0;
568 
569 	if (ct->status)
570 		return -EIO;
571 
572 	if (hdr->cmd_rsp_code != ZFCP_CT_ACCEPT) {
573 		if (hdr->reason_code == ZFCP_CT_UNABLE_TO_PERFORM_CMD)
574 			return -EAGAIN; /* might be a temporary condition */
575 		return -EIO;
576 	}
577 
578 	if (hdr->max_res_size) {
579 		dev_warn(&adapter->ccw_device->dev,
580 			 "The name server reported %d words residual data\n",
581 			 hdr->max_res_size);
582 		return -E2BIG;
583 	}
584 
585 	down(&zfcp_data.config_sema);
586 
587 	/* first entry is the header */
588 	for (x = 1; x < max_entries && !last; x++) {
589 		if (x % (ZFCP_GPN_FT_ENTRIES + 1))
590 			acc++;
591 		else
592 			acc = sg_virt(++sg);
593 
594 		last = acc->control & 0x80;
595 		d_id = acc->port_id[0] << 16 | acc->port_id[1] << 8 |
596 		       acc->port_id[2];
597 
598 		/* don't attach ports with a well known address */
599 		if ((d_id & ZFCP_DID_WKA) == ZFCP_DID_WKA)
600 			continue;
601 		/* skip the adapter's port and known remote ports */
602 		if (acc->wwpn == fc_host_port_name(adapter->scsi_host))
603 			continue;
604 		port = zfcp_get_port_by_wwpn(adapter, acc->wwpn);
605 		if (port) {
606 			zfcp_port_get(port);
607 			continue;
608 		}
609 
610 		port = zfcp_port_enqueue(adapter, acc->wwpn,
611 					 ZFCP_STATUS_COMMON_NOESC, d_id);
612 		if (IS_ERR(port))
613 			ret = PTR_ERR(port);
614 		else
615 			zfcp_erp_port_reopen(port, 0, "fcegpf1", NULL);
616 	}
617 
618 	zfcp_erp_wait(adapter);
619 	list_for_each_entry_safe(port, tmp, &adapter->port_list_head, list)
620 		zfcp_validate_port(port);
621 	up(&zfcp_data.config_sema);
622 	return ret;
623 }
624 
625 /**
626  * zfcp_scan_ports - scan remote ports and attach new ports
627  * @adapter: pointer to struct zfcp_adapter
628  */
629 int zfcp_scan_ports(struct zfcp_adapter *adapter)
630 {
631 	int ret, i;
632 	struct zfcp_gpn_ft *gpn_ft;
633 	int chain, max_entries, buf_num, max_bytes;
634 
635 	chain = adapter->adapter_features & FSF_FEATURE_ELS_CT_CHAINED_SBALS;
636 	buf_num = chain ? ZFCP_GPN_FT_BUFFERS : 1;
637 	max_entries = chain ? ZFCP_GPN_FT_MAX_ENTRIES : ZFCP_GPN_FT_ENTRIES;
638 	max_bytes = chain ? ZFCP_GPN_FT_MAX_SIZE : ZFCP_CT_SIZE_ONE_PAGE;
639 
640 	if (fc_host_port_type(adapter->scsi_host) != FC_PORTTYPE_NPORT)
641 		return 0;
642 
643 	ret = zfcp_wka_port_get(&adapter->nsp);
644 	if (ret)
645 		return ret;
646 
647 	gpn_ft = zfcp_alloc_sg_env(buf_num);
648 	if (!gpn_ft) {
649 		ret = -ENOMEM;
650 		goto out;
651 	}
652 
653 	for (i = 0; i < 3; i++) {
654 		ret = zfcp_scan_issue_gpn_ft(gpn_ft, adapter, max_bytes);
655 		if (!ret) {
656 			ret = zfcp_scan_eval_gpn_ft(gpn_ft, max_entries);
657 			if (ret == -EAGAIN)
658 				ssleep(1);
659 			else
660 				break;
661 		}
662 	}
663 	zfcp_free_sg_env(gpn_ft, buf_num);
664 out:
665 	zfcp_wka_port_put(&adapter->nsp);
666 	return ret;
667 }
668 
669 
670 void _zfcp_scan_ports_later(struct work_struct *work)
671 {
672 	zfcp_scan_ports(container_of(work, struct zfcp_adapter, scan_work));
673 }
674