xref: /openbmc/linux/drivers/s390/scsi/zfcp_aux.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
1 /*
2  * zfcp device driver
3  *
4  * Module interface and handling of zfcp data structures.
5  *
6  * Copyright IBM Corporation 2002, 2009
7  */
8 
9 /*
10  * Driver authors:
11  *            Martin Peschke (originator of the driver)
12  *            Raimund Schroeder
13  *            Aron Zeh
14  *            Wolfgang Taphorn
15  *            Stefan Bader
16  *            Heiko Carstens (kernel 2.6 port of the driver)
17  *            Andreas Herrmann
18  *            Maxim Shchetynin
19  *            Volker Sameske
20  *            Ralph Wuerthner
21  *            Michael Loehr
22  *            Swen Schillig
23  *            Christof Schmitt
24  *            Martin Petermann
25  *            Sven Schuetz
26  */
27 
28 #define KMSG_COMPONENT "zfcp"
29 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
30 
31 #include <linux/miscdevice.h>
32 #include <linux/seq_file.h>
33 #include "zfcp_ext.h"
34 
35 #define ZFCP_BUS_ID_SIZE	20
36 
37 MODULE_AUTHOR("IBM Deutschland Entwicklung GmbH - linux390@de.ibm.com");
38 MODULE_DESCRIPTION("FCP HBA driver");
39 MODULE_LICENSE("GPL");
40 
41 static char *init_device;
42 module_param_named(device, init_device, charp, 0400);
43 MODULE_PARM_DESC(device, "specify initial device");
44 
45 static int zfcp_reqlist_alloc(struct zfcp_adapter *adapter)
46 {
47 	int idx;
48 
49 	adapter->req_list = kcalloc(REQUEST_LIST_SIZE, sizeof(struct list_head),
50 				    GFP_KERNEL);
51 	if (!adapter->req_list)
52 		return -ENOMEM;
53 
54 	for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
55 		INIT_LIST_HEAD(&adapter->req_list[idx]);
56 	return 0;
57 }
58 
59 /**
60  * zfcp_reqlist_isempty - is the request list empty
61  * @adapter: pointer to struct zfcp_adapter
62  *
63  * Returns: true if list is empty, false otherwise
64  */
65 int zfcp_reqlist_isempty(struct zfcp_adapter *adapter)
66 {
67 	unsigned int idx;
68 
69 	for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
70 		if (!list_empty(&adapter->req_list[idx]))
71 			return 0;
72 	return 1;
73 }
74 
75 static void __init zfcp_init_device_configure(char *busid, u64 wwpn, u64 lun)
76 {
77 	struct zfcp_adapter *adapter;
78 	struct zfcp_port *port;
79 	struct zfcp_unit *unit;
80 
81 	down(&zfcp_data.config_sema);
82 	read_lock_irq(&zfcp_data.config_lock);
83 	adapter = zfcp_get_adapter_by_busid(busid);
84 	if (adapter)
85 		zfcp_adapter_get(adapter);
86 	read_unlock_irq(&zfcp_data.config_lock);
87 
88 	if (!adapter)
89 		goto out_adapter;
90 	port = zfcp_port_enqueue(adapter, wwpn, 0, 0);
91 	if (IS_ERR(port))
92 		goto out_port;
93 	unit = zfcp_unit_enqueue(port, lun);
94 	if (IS_ERR(unit))
95 		goto out_unit;
96 	up(&zfcp_data.config_sema);
97 	ccw_device_set_online(adapter->ccw_device);
98 
99 	zfcp_erp_wait(adapter);
100 	wait_event(adapter->erp_done_wqh,
101 		   !(atomic_read(&unit->status) &
102 				ZFCP_STATUS_UNIT_SCSI_WORK_PENDING));
103 
104 	down(&zfcp_data.config_sema);
105 	zfcp_unit_put(unit);
106 out_unit:
107 	zfcp_port_put(port);
108 out_port:
109 	zfcp_adapter_put(adapter);
110 out_adapter:
111 	up(&zfcp_data.config_sema);
112 	return;
113 }
114 
115 static struct kmem_cache *zfcp_cache_create(int size, char *name)
116 {
117 	int align = 1;
118 	while ((size - align) > 0)
119 		align <<= 1;
120 	return kmem_cache_create(name , size, align, 0, NULL);
121 }
122 
123 static void __init zfcp_init_device_setup(char *devstr)
124 {
125 	char *token;
126 	char *str;
127 	char busid[ZFCP_BUS_ID_SIZE];
128 	u64 wwpn, lun;
129 
130 	/* duplicate devstr and keep the original for sysfs presentation*/
131 	str = kmalloc(strlen(devstr) + 1, GFP_KERNEL);
132 	if (!str)
133 		return;
134 
135 	strcpy(str, devstr);
136 
137 	token = strsep(&str, ",");
138 	if (!token || strlen(token) >= ZFCP_BUS_ID_SIZE)
139 		goto err_out;
140 	strncpy(busid, token, ZFCP_BUS_ID_SIZE);
141 
142 	token = strsep(&str, ",");
143 	if (!token || strict_strtoull(token, 0, (unsigned long long *) &wwpn))
144 		goto err_out;
145 
146 	token = strsep(&str, ",");
147 	if (!token || strict_strtoull(token, 0, (unsigned long long *) &lun))
148 		goto err_out;
149 
150 	kfree(str);
151 	zfcp_init_device_configure(busid, wwpn, lun);
152 	return;
153 
154  err_out:
155 	kfree(str);
156 	pr_err("%s is not a valid SCSI device\n", devstr);
157 }
158 
159 static int __init zfcp_module_init(void)
160 {
161 	int retval = -ENOMEM;
162 
163 	zfcp_data.fsf_req_qtcb_cache = zfcp_cache_create(
164 			sizeof(struct zfcp_fsf_req_qtcb), "zfcp_fsf");
165 	if (!zfcp_data.fsf_req_qtcb_cache)
166 		goto out;
167 
168 	zfcp_data.sr_buffer_cache = zfcp_cache_create(
169 			sizeof(struct fsf_status_read_buffer), "zfcp_sr");
170 	if (!zfcp_data.sr_buffer_cache)
171 		goto out_sr_cache;
172 
173 	zfcp_data.gid_pn_cache = zfcp_cache_create(
174 			sizeof(struct zfcp_gid_pn_data), "zfcp_gid");
175 	if (!zfcp_data.gid_pn_cache)
176 		goto out_gid_cache;
177 
178 	zfcp_data.work_queue = create_singlethread_workqueue("zfcp_wq");
179 
180 	sema_init(&zfcp_data.config_sema, 1);
181 	rwlock_init(&zfcp_data.config_lock);
182 
183 	zfcp_data.scsi_transport_template =
184 		fc_attach_transport(&zfcp_transport_functions);
185 	if (!zfcp_data.scsi_transport_template)
186 		goto out_transport;
187 
188 	retval = misc_register(&zfcp_cfdc_misc);
189 	if (retval) {
190 		pr_err("Registering the misc device zfcp_cfdc failed\n");
191 		goto out_misc;
192 	}
193 
194 	retval = zfcp_ccw_register();
195 	if (retval) {
196 		pr_err("The zfcp device driver could not register with "
197 		       "the common I/O layer\n");
198 		goto out_ccw_register;
199 	}
200 
201 	if (init_device)
202 		zfcp_init_device_setup(init_device);
203 	return 0;
204 
205 out_ccw_register:
206 	misc_deregister(&zfcp_cfdc_misc);
207 out_misc:
208 	fc_release_transport(zfcp_data.scsi_transport_template);
209 out_transport:
210 	kmem_cache_destroy(zfcp_data.gid_pn_cache);
211 out_gid_cache:
212 	kmem_cache_destroy(zfcp_data.sr_buffer_cache);
213 out_sr_cache:
214 	kmem_cache_destroy(zfcp_data.fsf_req_qtcb_cache);
215 out:
216 	return retval;
217 }
218 
219 module_init(zfcp_module_init);
220 
221 /**
222  * zfcp_get_unit_by_lun - find unit in unit list of port by FCP LUN
223  * @port: pointer to port to search for unit
224  * @fcp_lun: FCP LUN to search for
225  *
226  * Returns: pointer to zfcp_unit or NULL
227  */
228 struct zfcp_unit *zfcp_get_unit_by_lun(struct zfcp_port *port, u64 fcp_lun)
229 {
230 	struct zfcp_unit *unit;
231 
232 	list_for_each_entry(unit, &port->unit_list_head, list)
233 		if ((unit->fcp_lun == fcp_lun) &&
234 		    !(atomic_read(&unit->status) & ZFCP_STATUS_COMMON_REMOVE))
235 		    return unit;
236 	return NULL;
237 }
238 
239 /**
240  * zfcp_get_port_by_wwpn - find port in port list of adapter by wwpn
241  * @adapter: pointer to adapter to search for port
242  * @wwpn: wwpn to search for
243  *
244  * Returns: pointer to zfcp_port or NULL
245  */
246 struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *adapter,
247 					u64 wwpn)
248 {
249 	struct zfcp_port *port;
250 
251 	list_for_each_entry(port, &adapter->port_list_head, list)
252 		if ((port->wwpn == wwpn) &&
253 		    !(atomic_read(&port->status) & ZFCP_STATUS_COMMON_REMOVE))
254 			return port;
255 	return NULL;
256 }
257 
258 static void zfcp_sysfs_unit_release(struct device *dev)
259 {
260 	kfree(container_of(dev, struct zfcp_unit, sysfs_device));
261 }
262 
263 /**
264  * zfcp_unit_enqueue - enqueue unit to unit list of a port.
265  * @port: pointer to port where unit is added
266  * @fcp_lun: FCP LUN of unit to be enqueued
267  * Returns: pointer to enqueued unit on success, ERR_PTR on error
268  * Locks: config_sema must be held to serialize changes to the unit list
269  *
270  * Sets up some unit internal structures and creates sysfs entry.
271  */
272 struct zfcp_unit *zfcp_unit_enqueue(struct zfcp_port *port, u64 fcp_lun)
273 {
274 	struct zfcp_unit *unit;
275 
276 	unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
277 	if (!unit)
278 		return ERR_PTR(-ENOMEM);
279 
280 	atomic_set(&unit->refcount, 0);
281 	init_waitqueue_head(&unit->remove_wq);
282 
283 	unit->port = port;
284 	unit->fcp_lun = fcp_lun;
285 
286 	dev_set_name(&unit->sysfs_device, "0x%016llx",
287 		     (unsigned long long) fcp_lun);
288 	unit->sysfs_device.parent = &port->sysfs_device;
289 	unit->sysfs_device.release = zfcp_sysfs_unit_release;
290 	dev_set_drvdata(&unit->sysfs_device, unit);
291 
292 	/* mark unit unusable as long as sysfs registration is not complete */
293 	atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
294 
295 	spin_lock_init(&unit->latencies.lock);
296 	unit->latencies.write.channel.min = 0xFFFFFFFF;
297 	unit->latencies.write.fabric.min = 0xFFFFFFFF;
298 	unit->latencies.read.channel.min = 0xFFFFFFFF;
299 	unit->latencies.read.fabric.min = 0xFFFFFFFF;
300 	unit->latencies.cmd.channel.min = 0xFFFFFFFF;
301 	unit->latencies.cmd.fabric.min = 0xFFFFFFFF;
302 
303 	read_lock_irq(&zfcp_data.config_lock);
304 	if (zfcp_get_unit_by_lun(port, fcp_lun)) {
305 		read_unlock_irq(&zfcp_data.config_lock);
306 		goto err_out_free;
307 	}
308 	read_unlock_irq(&zfcp_data.config_lock);
309 
310 	if (device_register(&unit->sysfs_device))
311 		goto err_out_free;
312 
313 	if (sysfs_create_group(&unit->sysfs_device.kobj,
314 			       &zfcp_sysfs_unit_attrs)) {
315 		device_unregister(&unit->sysfs_device);
316 		return ERR_PTR(-EIO);
317 	}
318 
319 	zfcp_unit_get(unit);
320 
321 	write_lock_irq(&zfcp_data.config_lock);
322 	list_add_tail(&unit->list, &port->unit_list_head);
323 	atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
324 	atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &unit->status);
325 
326 	write_unlock_irq(&zfcp_data.config_lock);
327 
328 	zfcp_port_get(port);
329 
330 	return unit;
331 
332 err_out_free:
333 	kfree(unit);
334 	return ERR_PTR(-EINVAL);
335 }
336 
337 /**
338  * zfcp_unit_dequeue - dequeue unit
339  * @unit: pointer to zfcp_unit
340  *
341  * waits until all work is done on unit and removes it then from the unit->list
342  * of the associated port.
343  */
344 void zfcp_unit_dequeue(struct zfcp_unit *unit)
345 {
346 	wait_event(unit->remove_wq, atomic_read(&unit->refcount) == 0);
347 	write_lock_irq(&zfcp_data.config_lock);
348 	list_del(&unit->list);
349 	write_unlock_irq(&zfcp_data.config_lock);
350 	zfcp_port_put(unit->port);
351 	sysfs_remove_group(&unit->sysfs_device.kobj, &zfcp_sysfs_unit_attrs);
352 	device_unregister(&unit->sysfs_device);
353 }
354 
355 static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
356 {
357 	/* must only be called with zfcp_data.config_sema taken */
358 	adapter->pool.fsf_req_erp =
359 		mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
360 	if (!adapter->pool.fsf_req_erp)
361 		return -ENOMEM;
362 
363 	adapter->pool.fsf_req_scsi =
364 		mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
365 	if (!adapter->pool.fsf_req_scsi)
366 		return -ENOMEM;
367 
368 	adapter->pool.fsf_req_abort =
369 		mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
370 	if (!adapter->pool.fsf_req_abort)
371 		return -ENOMEM;
372 
373 	adapter->pool.fsf_req_status_read =
374 		mempool_create_kmalloc_pool(FSF_STATUS_READS_RECOM,
375 					    sizeof(struct zfcp_fsf_req));
376 	if (!adapter->pool.fsf_req_status_read)
377 		return -ENOMEM;
378 
379 	adapter->pool.data_status_read =
380 		mempool_create_slab_pool(FSF_STATUS_READS_RECOM,
381 					 zfcp_data.sr_buffer_cache);
382 	if (!adapter->pool.data_status_read)
383 		return -ENOMEM;
384 
385 	adapter->pool.data_gid_pn =
386 		mempool_create_slab_pool(1, zfcp_data.gid_pn_cache);
387 	if (!adapter->pool.data_gid_pn)
388 		return -ENOMEM;
389 
390 	return 0;
391 }
392 
393 static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
394 {
395 	/* zfcp_data.config_sema must be held */
396 	if (adapter->pool.fsf_req_erp)
397 		mempool_destroy(adapter->pool.fsf_req_erp);
398 	if (adapter->pool.fsf_req_scsi)
399 		mempool_destroy(adapter->pool.fsf_req_scsi);
400 	if (adapter->pool.fsf_req_abort)
401 		mempool_destroy(adapter->pool.fsf_req_abort);
402 	if (adapter->pool.fsf_req_status_read)
403 		mempool_destroy(adapter->pool.fsf_req_status_read);
404 	if (adapter->pool.data_status_read)
405 		mempool_destroy(adapter->pool.data_status_read);
406 	if (adapter->pool.data_gid_pn)
407 		mempool_destroy(adapter->pool.data_gid_pn);
408 }
409 
410 /**
411  * zfcp_status_read_refill - refill the long running status_read_requests
412  * @adapter: ptr to struct zfcp_adapter for which the buffers should be refilled
413  *
414  * Returns: 0 on success, 1 otherwise
415  *
416  * if there are 16 or more status_read requests missing an adapter_reopen
417  * is triggered
418  */
419 int zfcp_status_read_refill(struct zfcp_adapter *adapter)
420 {
421 	while (atomic_read(&adapter->stat_miss) > 0)
422 		if (zfcp_fsf_status_read(adapter)) {
423 			if (atomic_read(&adapter->stat_miss) >= 16) {
424 				zfcp_erp_adapter_reopen(adapter, 0, "axsref1",
425 							NULL);
426 				return 1;
427 			}
428 			break;
429 		} else
430 			atomic_dec(&adapter->stat_miss);
431 	return 0;
432 }
433 
434 static void _zfcp_status_read_scheduler(struct work_struct *work)
435 {
436 	zfcp_status_read_refill(container_of(work, struct zfcp_adapter,
437 					     stat_work));
438 }
439 
440 static void zfcp_print_sl(struct seq_file *m, struct service_level *sl)
441 {
442 	struct zfcp_adapter *adapter =
443 		container_of(sl, struct zfcp_adapter, service_level);
444 
445 	seq_printf(m, "zfcp: %s microcode level %x\n",
446 		   dev_name(&adapter->ccw_device->dev),
447 		   adapter->fsf_lic_version);
448 }
449 
450 /**
451  * zfcp_adapter_enqueue - enqueue a new adapter to the list
452  * @ccw_device: pointer to the struct cc_device
453  *
454  * Returns:	0             if a new adapter was successfully enqueued
455  *		-ENOMEM       if alloc failed
456  * Enqueues an adapter at the end of the adapter list in the driver data.
457  * All adapter internal structures are set up.
458  * Proc-fs entries are also created.
459  * locks:	config_sema must be held to serialise changes to the adapter list
460  */
461 int zfcp_adapter_enqueue(struct ccw_device *ccw_device)
462 {
463 	struct zfcp_adapter *adapter;
464 
465 	/*
466 	 * Note: It is safe to release the list_lock, as any list changes
467 	 * are protected by the config_sema, which must be held to get here
468 	 */
469 
470 	adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
471 	if (!adapter)
472 		return -ENOMEM;
473 
474 	ccw_device->handler = NULL;
475 	adapter->ccw_device = ccw_device;
476 	atomic_set(&adapter->refcount, 0);
477 
478 	if (zfcp_qdio_allocate(adapter))
479 		goto qdio_allocate_failed;
480 
481 	if (zfcp_allocate_low_mem_buffers(adapter))
482 		goto failed_low_mem_buffers;
483 
484 	if (zfcp_reqlist_alloc(adapter))
485 		goto failed_low_mem_buffers;
486 
487 	if (zfcp_adapter_debug_register(adapter))
488 		goto debug_register_failed;
489 
490 	init_waitqueue_head(&adapter->remove_wq);
491 	init_waitqueue_head(&adapter->erp_thread_wqh);
492 	init_waitqueue_head(&adapter->erp_done_wqh);
493 
494 	INIT_LIST_HEAD(&adapter->port_list_head);
495 	INIT_LIST_HEAD(&adapter->erp_ready_head);
496 	INIT_LIST_HEAD(&adapter->erp_running_head);
497 
498 	spin_lock_init(&adapter->req_list_lock);
499 
500 	spin_lock_init(&adapter->hba_dbf_lock);
501 	spin_lock_init(&adapter->san_dbf_lock);
502 	spin_lock_init(&adapter->scsi_dbf_lock);
503 	spin_lock_init(&adapter->rec_dbf_lock);
504 	spin_lock_init(&adapter->req_q_lock);
505 	spin_lock_init(&adapter->qdio_stat_lock);
506 
507 	rwlock_init(&adapter->erp_lock);
508 	rwlock_init(&adapter->abort_lock);
509 
510 	sema_init(&adapter->erp_ready_sem, 0);
511 
512 	INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
513 	INIT_WORK(&adapter->scan_work, _zfcp_scan_ports_later);
514 
515 	adapter->service_level.seq_print = zfcp_print_sl;
516 
517 	/* mark adapter unusable as long as sysfs registration is not complete */
518 	atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
519 
520 	dev_set_drvdata(&ccw_device->dev, adapter);
521 
522 	if (sysfs_create_group(&ccw_device->dev.kobj,
523 			       &zfcp_sysfs_adapter_attrs))
524 		goto sysfs_failed;
525 
526 	atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
527 
528 	if (!zfcp_adapter_scsi_register(adapter))
529 		return 0;
530 
531 sysfs_failed:
532 	zfcp_adapter_debug_unregister(adapter);
533 debug_register_failed:
534 	dev_set_drvdata(&ccw_device->dev, NULL);
535 	kfree(adapter->req_list);
536 failed_low_mem_buffers:
537 	zfcp_free_low_mem_buffers(adapter);
538 qdio_allocate_failed:
539 	zfcp_qdio_free(adapter);
540 	kfree(adapter);
541 	return -ENOMEM;
542 }
543 
544 /**
545  * zfcp_adapter_dequeue - remove the adapter from the resource list
546  * @adapter: pointer to struct zfcp_adapter which should be removed
547  * locks:	adapter list write lock is assumed to be held by caller
548  */
549 void zfcp_adapter_dequeue(struct zfcp_adapter *adapter)
550 {
551 	int retval = 0;
552 	unsigned long flags;
553 
554 	cancel_work_sync(&adapter->scan_work);
555 	cancel_work_sync(&adapter->stat_work);
556 	cancel_delayed_work_sync(&adapter->nsp.work);
557 	zfcp_adapter_scsi_unregister(adapter);
558 	sysfs_remove_group(&adapter->ccw_device->dev.kobj,
559 			   &zfcp_sysfs_adapter_attrs);
560 	dev_set_drvdata(&adapter->ccw_device->dev, NULL);
561 	/* sanity check: no pending FSF requests */
562 	spin_lock_irqsave(&adapter->req_list_lock, flags);
563 	retval = zfcp_reqlist_isempty(adapter);
564 	spin_unlock_irqrestore(&adapter->req_list_lock, flags);
565 	if (!retval)
566 		return;
567 
568 	zfcp_adapter_debug_unregister(adapter);
569 	zfcp_qdio_free(adapter);
570 	zfcp_free_low_mem_buffers(adapter);
571 	kfree(adapter->req_list);
572 	kfree(adapter->fc_stats);
573 	kfree(adapter->stats_reset_data);
574 	kfree(adapter);
575 }
576 
577 static void zfcp_sysfs_port_release(struct device *dev)
578 {
579 	kfree(container_of(dev, struct zfcp_port, sysfs_device));
580 }
581 
582 /**
583  * zfcp_port_enqueue - enqueue port to port list of adapter
584  * @adapter: adapter where remote port is added
585  * @wwpn: WWPN of the remote port to be enqueued
586  * @status: initial status for the port
587  * @d_id: destination id of the remote port to be enqueued
588  * Returns: pointer to enqueued port on success, ERR_PTR on error
589  * Locks: config_sema must be held to serialize changes to the port list
590  *
591  * All port internal structures are set up and the sysfs entry is generated.
592  * d_id is used to enqueue ports with a well known address like the Directory
593  * Service for nameserver lookup.
594  */
595 struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
596 				     u32 status, u32 d_id)
597 {
598 	struct zfcp_port *port;
599 	int retval;
600 
601 	port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
602 	if (!port)
603 		return ERR_PTR(-ENOMEM);
604 
605 	init_waitqueue_head(&port->remove_wq);
606 	INIT_LIST_HEAD(&port->unit_list_head);
607 	INIT_WORK(&port->gid_pn_work, zfcp_erp_port_strategy_open_lookup);
608 	INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
609 	INIT_WORK(&port->rport_work, zfcp_scsi_rport_work);
610 
611 	port->adapter = adapter;
612 	port->d_id = d_id;
613 	port->wwpn = wwpn;
614 	port->rport_task = RPORT_NONE;
615 
616 	/* mark port unusable as long as sysfs registration is not complete */
617 	atomic_set_mask(status | ZFCP_STATUS_COMMON_REMOVE, &port->status);
618 	atomic_set(&port->refcount, 0);
619 
620 	dev_set_name(&port->sysfs_device, "0x%016llx",
621 		     (unsigned long long)wwpn);
622 	port->sysfs_device.parent = &adapter->ccw_device->dev;
623 
624 	port->sysfs_device.release = zfcp_sysfs_port_release;
625 	dev_set_drvdata(&port->sysfs_device, port);
626 
627 	read_lock_irq(&zfcp_data.config_lock);
628 	if (zfcp_get_port_by_wwpn(adapter, wwpn)) {
629 		read_unlock_irq(&zfcp_data.config_lock);
630 		goto err_out_free;
631 	}
632 	read_unlock_irq(&zfcp_data.config_lock);
633 
634 	if (device_register(&port->sysfs_device))
635 		goto err_out_free;
636 
637 	retval = sysfs_create_group(&port->sysfs_device.kobj,
638 				    &zfcp_sysfs_port_attrs);
639 
640 	if (retval) {
641 		device_unregister(&port->sysfs_device);
642 		goto err_out;
643 	}
644 
645 	zfcp_port_get(port);
646 
647 	write_lock_irq(&zfcp_data.config_lock);
648 	list_add_tail(&port->list, &adapter->port_list_head);
649 	atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &port->status);
650 	atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &port->status);
651 
652 	write_unlock_irq(&zfcp_data.config_lock);
653 
654 	zfcp_adapter_get(adapter);
655 	return port;
656 
657 err_out_free:
658 	kfree(port);
659 err_out:
660 	return ERR_PTR(-EINVAL);
661 }
662 
663 /**
664  * zfcp_port_dequeue - dequeues a port from the port list of the adapter
665  * @port: pointer to struct zfcp_port which should be removed
666  */
667 void zfcp_port_dequeue(struct zfcp_port *port)
668 {
669 	wait_event(port->remove_wq, atomic_read(&port->refcount) == 0);
670 	write_lock_irq(&zfcp_data.config_lock);
671 	list_del(&port->list);
672 	write_unlock_irq(&zfcp_data.config_lock);
673 	if (port->rport)
674 		fc_remote_port_delete(port->rport);
675 	port->rport = NULL;
676 	zfcp_adapter_put(port->adapter);
677 	sysfs_remove_group(&port->sysfs_device.kobj, &zfcp_sysfs_port_attrs);
678 	device_unregister(&port->sysfs_device);
679 }
680 
681 /**
682  * zfcp_sg_free_table - free memory used by scatterlists
683  * @sg: pointer to scatterlist
684  * @count: number of scatterlist which are to be free'ed
685  * the scatterlist are expected to reference pages always
686  */
687 void zfcp_sg_free_table(struct scatterlist *sg, int count)
688 {
689 	int i;
690 
691 	for (i = 0; i < count; i++, sg++)
692 		if (sg)
693 			free_page((unsigned long) sg_virt(sg));
694 		else
695 			break;
696 }
697 
698 /**
699  * zfcp_sg_setup_table - init scatterlist and allocate, assign buffers
700  * @sg: pointer to struct scatterlist
701  * @count: number of scatterlists which should be assigned with buffers
702  * of size page
703  *
704  * Returns: 0 on success, -ENOMEM otherwise
705  */
706 int zfcp_sg_setup_table(struct scatterlist *sg, int count)
707 {
708 	void *addr;
709 	int i;
710 
711 	sg_init_table(sg, count);
712 	for (i = 0; i < count; i++, sg++) {
713 		addr = (void *) get_zeroed_page(GFP_KERNEL);
714 		if (!addr) {
715 			zfcp_sg_free_table(sg, i);
716 			return -ENOMEM;
717 		}
718 		sg_set_buf(sg, addr, PAGE_SIZE);
719 	}
720 	return 0;
721 }
722