3b56220fb900291df60b56284191b6e66119a02d
[linux-3.10.git] / drivers / s390 / scsi / zfcp_aux.c
1 /*
2  * zfcp device driver
3  *
4  * Module interface and handling of zfcp data structures.
5  *
6  * Copyright IBM Corporation 2002, 2008
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 #include <linux/miscdevice.h>
29 #include "zfcp_ext.h"
30
31 static char *device;
32
33 MODULE_AUTHOR("IBM Deutschland Entwicklung GmbH - linux390@de.ibm.com");
34 MODULE_DESCRIPTION("FCP HBA driver");
35 MODULE_LICENSE("GPL");
36
37 module_param(device, charp, 0400);
38 MODULE_PARM_DESC(device, "specify initial device");
39
40 static int zfcp_reqlist_alloc(struct zfcp_adapter *adapter)
41 {
42         int idx;
43
44         adapter->req_list = kcalloc(REQUEST_LIST_SIZE, sizeof(struct list_head),
45                                     GFP_KERNEL);
46         if (!adapter->req_list)
47                 return -ENOMEM;
48
49         for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
50                 INIT_LIST_HEAD(&adapter->req_list[idx]);
51         return 0;
52 }
53
54 /**
55  * zfcp_reqlist_isempty - is the request list empty
56  * @adapter: pointer to struct zfcp_adapter
57  *
58  * Returns: true if list is empty, false otherwise
59  */
60 int zfcp_reqlist_isempty(struct zfcp_adapter *adapter)
61 {
62         unsigned int idx;
63
64         for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
65                 if (!list_empty(&adapter->req_list[idx]))
66                         return 0;
67         return 1;
68 }
69
70 static int __init zfcp_device_setup(char *devstr)
71 {
72         char *token;
73         char *str;
74
75         if (!devstr)
76                 return 0;
77
78         /* duplicate devstr and keep the original for sysfs presentation*/
79         str = kmalloc(strlen(devstr) + 1, GFP_KERNEL);
80         if (!str)
81                 return 0;
82
83         strcpy(str, devstr);
84
85         token = strsep(&str, ",");
86         if (!token || strlen(token) >= BUS_ID_SIZE)
87                 goto err_out;
88         strncpy(zfcp_data.init_busid, token, BUS_ID_SIZE);
89
90         token = strsep(&str, ",");
91         if (!token || strict_strtoull(token, 0,
92                                 (unsigned long long *) &zfcp_data.init_wwpn))
93                 goto err_out;
94
95         token = strsep(&str, ",");
96         if (!token || strict_strtoull(token, 0,
97                                 (unsigned long long *) &zfcp_data.init_fcp_lun))
98                 goto err_out;
99
100         kfree(str);
101         return 1;
102
103  err_out:
104         kfree(str);
105         pr_err("zfcp: %s is not a valid SCSI device\n", devstr);
106         return 0;
107 }
108
109 static void __init zfcp_init_device_configure(void)
110 {
111         struct zfcp_adapter *adapter;
112         struct zfcp_port *port;
113         struct zfcp_unit *unit;
114
115         down(&zfcp_data.config_sema);
116         read_lock_irq(&zfcp_data.config_lock);
117         adapter = zfcp_get_adapter_by_busid(zfcp_data.init_busid);
118         if (adapter)
119                 zfcp_adapter_get(adapter);
120         read_unlock_irq(&zfcp_data.config_lock);
121
122         if (!adapter)
123                 goto out_adapter;
124         port = zfcp_port_enqueue(adapter, zfcp_data.init_wwpn, 0, 0);
125         if (IS_ERR(port))
126                 goto out_port;
127         unit = zfcp_unit_enqueue(port, zfcp_data.init_fcp_lun);
128         if (IS_ERR(unit))
129                 goto out_unit;
130         up(&zfcp_data.config_sema);
131         ccw_device_set_online(adapter->ccw_device);
132
133         zfcp_erp_wait(adapter);
134         wait_event(adapter->erp_done_wqh,
135                    !(atomic_read(&unit->status) &
136                                 ZFCP_STATUS_UNIT_SCSI_WORK_PENDING));
137
138         down(&zfcp_data.config_sema);
139         zfcp_unit_put(unit);
140 out_unit:
141         zfcp_port_put(port);
142 out_port:
143         zfcp_adapter_put(adapter);
144 out_adapter:
145         up(&zfcp_data.config_sema);
146         return;
147 }
148
149 static struct kmem_cache *zfcp_cache_create(int size, char *name)
150 {
151         int align = 1;
152         while ((size - align) > 0)
153                 align <<= 1;
154         return kmem_cache_create(name , size, align, 0, NULL);
155 }
156
157 static int __init zfcp_module_init(void)
158 {
159         int retval = -ENOMEM;
160
161         zfcp_data.fsf_req_qtcb_cache = zfcp_cache_create(
162                         sizeof(struct zfcp_fsf_req_qtcb), "zfcp_fsf");
163         if (!zfcp_data.fsf_req_qtcb_cache)
164                 goto out;
165
166         zfcp_data.sr_buffer_cache = zfcp_cache_create(
167                         sizeof(struct fsf_status_read_buffer), "zfcp_sr");
168         if (!zfcp_data.sr_buffer_cache)
169                 goto out_sr_cache;
170
171         zfcp_data.gid_pn_cache = zfcp_cache_create(
172                         sizeof(struct zfcp_gid_pn_data), "zfcp_gid");
173         if (!zfcp_data.gid_pn_cache)
174                 goto out_gid_cache;
175
176         zfcp_data.work_queue = create_singlethread_workqueue("zfcp_wq");
177
178         INIT_LIST_HEAD(&zfcp_data.adapter_list_head);
179         sema_init(&zfcp_data.config_sema, 1);
180         rwlock_init(&zfcp_data.config_lock);
181
182         zfcp_data.scsi_transport_template =
183                 fc_attach_transport(&zfcp_transport_functions);
184         if (!zfcp_data.scsi_transport_template)
185                 goto out_transport;
186
187         retval = misc_register(&zfcp_cfdc_misc);
188         if (retval) {
189                 pr_err("zfcp: Registering the misc device zfcp_cfdc failed\n");
190                 goto out_misc;
191         }
192
193         retval = zfcp_ccw_register();
194         if (retval) {
195                 pr_err("zfcp: The zfcp device driver could not register with "
196                        "the common I/O layer\n");
197                 goto out_ccw_register;
198         }
199
200         if (zfcp_device_setup(device))
201                 zfcp_init_device_configure();
202
203         goto out;
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) && !(atomic_read(&port->status) &
253                       (ZFCP_STATUS_PORT_NO_WWPN | 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, 103, NULL);
425                                 return 1;
426                         }
427                         break;
428                 } else
429                         atomic_dec(&adapter->stat_miss);
430         return 0;
431 }
432
433 static void _zfcp_status_read_scheduler(struct work_struct *work)
434 {
435         zfcp_status_read_refill(container_of(work, struct zfcp_adapter,
436                                              stat_work));
437 }
438
439 /**
440  * zfcp_adapter_enqueue - enqueue a new adapter to the list
441  * @ccw_device: pointer to the struct cc_device
442  *
443  * Returns:     0             if a new adapter was successfully enqueued
444  *              -ENOMEM       if alloc failed
445  * Enqueues an adapter at the end of the adapter list in the driver data.
446  * All adapter internal structures are set up.
447  * Proc-fs entries are also created.
448  * locks:       config_sema must be held to serialise changes to the adapter list
449  */
450 int zfcp_adapter_enqueue(struct ccw_device *ccw_device)
451 {
452         struct zfcp_adapter *adapter;
453
454         /*
455          * Note: It is safe to release the list_lock, as any list changes
456          * are protected by the config_sema, which must be held to get here
457          */
458
459         adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
460         if (!adapter)
461                 return -ENOMEM;
462
463         ccw_device->handler = NULL;
464         adapter->ccw_device = ccw_device;
465         atomic_set(&adapter->refcount, 0);
466
467         if (zfcp_qdio_allocate(adapter))
468                 goto qdio_allocate_failed;
469
470         if (zfcp_allocate_low_mem_buffers(adapter))
471                 goto failed_low_mem_buffers;
472
473         if (zfcp_reqlist_alloc(adapter))
474                 goto failed_low_mem_buffers;
475
476         if (zfcp_adapter_debug_register(adapter))
477                 goto debug_register_failed;
478
479         init_waitqueue_head(&adapter->remove_wq);
480         init_waitqueue_head(&adapter->erp_thread_wqh);
481         init_waitqueue_head(&adapter->erp_done_wqh);
482
483         INIT_LIST_HEAD(&adapter->port_list_head);
484         INIT_LIST_HEAD(&adapter->erp_ready_head);
485         INIT_LIST_HEAD(&adapter->erp_running_head);
486
487         spin_lock_init(&adapter->req_list_lock);
488
489         spin_lock_init(&adapter->hba_dbf_lock);
490         spin_lock_init(&adapter->san_dbf_lock);
491         spin_lock_init(&adapter->scsi_dbf_lock);
492         spin_lock_init(&adapter->rec_dbf_lock);
493         spin_lock_init(&adapter->req_q_lock);
494
495         rwlock_init(&adapter->erp_lock);
496         rwlock_init(&adapter->abort_lock);
497
498         sema_init(&adapter->erp_ready_sem, 0);
499
500         INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
501         INIT_WORK(&adapter->scan_work, _zfcp_scan_ports_later);
502
503         /* mark adapter unusable as long as sysfs registration is not complete */
504         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
505
506         dev_set_drvdata(&ccw_device->dev, adapter);
507
508         if (sysfs_create_group(&ccw_device->dev.kobj,
509                                &zfcp_sysfs_adapter_attrs))
510                 goto sysfs_failed;
511
512         write_lock_irq(&zfcp_data.config_lock);
513         atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
514         list_add_tail(&adapter->list, &zfcp_data.adapter_list_head);
515         write_unlock_irq(&zfcp_data.config_lock);
516
517         zfcp_fc_nameserver_init(adapter);
518
519         return 0;
520
521 sysfs_failed:
522         zfcp_adapter_debug_unregister(adapter);
523 debug_register_failed:
524         dev_set_drvdata(&ccw_device->dev, NULL);
525         kfree(adapter->req_list);
526 failed_low_mem_buffers:
527         zfcp_free_low_mem_buffers(adapter);
528 qdio_allocate_failed:
529         zfcp_qdio_free(adapter);
530         kfree(adapter);
531         return -ENOMEM;
532 }
533
534 /**
535  * zfcp_adapter_dequeue - remove the adapter from the resource list
536  * @adapter: pointer to struct zfcp_adapter which should be removed
537  * locks:       adapter list write lock is assumed to be held by caller
538  */
539 void zfcp_adapter_dequeue(struct zfcp_adapter *adapter)
540 {
541         int retval = 0;
542         unsigned long flags;
543
544         cancel_work_sync(&adapter->scan_work);
545         cancel_work_sync(&adapter->stat_work);
546         zfcp_adapter_scsi_unregister(adapter);
547         sysfs_remove_group(&adapter->ccw_device->dev.kobj,
548                            &zfcp_sysfs_adapter_attrs);
549         dev_set_drvdata(&adapter->ccw_device->dev, NULL);
550         /* sanity check: no pending FSF requests */
551         spin_lock_irqsave(&adapter->req_list_lock, flags);
552         retval = zfcp_reqlist_isempty(adapter);
553         spin_unlock_irqrestore(&adapter->req_list_lock, flags);
554         if (!retval)
555                 return;
556
557         zfcp_adapter_debug_unregister(adapter);
558
559         /* remove specified adapter data structure from list */
560         write_lock_irq(&zfcp_data.config_lock);
561         list_del(&adapter->list);
562         write_unlock_irq(&zfcp_data.config_lock);
563
564         zfcp_qdio_free(adapter);
565
566         zfcp_free_low_mem_buffers(adapter);
567         kfree(adapter->req_list);
568         kfree(adapter->fc_stats);
569         kfree(adapter->stats_reset_data);
570         kfree(adapter);
571 }
572
573 static void zfcp_sysfs_port_release(struct device *dev)
574 {
575         kfree(container_of(dev, struct zfcp_port, sysfs_device));
576 }
577
578 /**
579  * zfcp_port_enqueue - enqueue port to port list of adapter
580  * @adapter: adapter where remote port is added
581  * @wwpn: WWPN of the remote port to be enqueued
582  * @status: initial status for the port
583  * @d_id: destination id of the remote port to be enqueued
584  * Returns: pointer to enqueued port on success, ERR_PTR on error
585  * Locks: config_sema must be held to serialize changes to the port list
586  *
587  * All port internal structures are set up and the sysfs entry is generated.
588  * d_id is used to enqueue ports with a well known address like the Directory
589  * Service for nameserver lookup.
590  */
591 struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
592                                      u32 status, u32 d_id)
593 {
594         struct zfcp_port *port;
595         int retval;
596
597         port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
598         if (!port)
599                 return ERR_PTR(-ENOMEM);
600
601         init_waitqueue_head(&port->remove_wq);
602         INIT_LIST_HEAD(&port->unit_list_head);
603         INIT_WORK(&port->gid_pn_work, zfcp_erp_port_strategy_open_lookup);
604
605         port->adapter = adapter;
606         port->d_id = d_id;
607         port->wwpn = wwpn;
608
609         /* mark port unusable as long as sysfs registration is not complete */
610         atomic_set_mask(status | ZFCP_STATUS_COMMON_REMOVE, &port->status);
611         atomic_set(&port->refcount, 0);
612
613         dev_set_name(&port->sysfs_device, "0x%016llx", wwpn);
614         port->sysfs_device.parent = &adapter->ccw_device->dev;
615
616         port->sysfs_device.release = zfcp_sysfs_port_release;
617         dev_set_drvdata(&port->sysfs_device, port);
618
619         read_lock_irq(&zfcp_data.config_lock);
620         if (!(status & ZFCP_STATUS_PORT_NO_WWPN))
621                 if (zfcp_get_port_by_wwpn(adapter, wwpn)) {
622                         read_unlock_irq(&zfcp_data.config_lock);
623                         goto err_out_free;
624                 }
625         read_unlock_irq(&zfcp_data.config_lock);
626
627         if (device_register(&port->sysfs_device))
628                 goto err_out_free;
629
630         retval = sysfs_create_group(&port->sysfs_device.kobj,
631                                     &zfcp_sysfs_port_attrs);
632
633         if (retval) {
634                 device_unregister(&port->sysfs_device);
635                 goto err_out;
636         }
637
638         zfcp_port_get(port);
639
640         write_lock_irq(&zfcp_data.config_lock);
641         list_add_tail(&port->list, &adapter->port_list_head);
642         atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &port->status);
643         atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &port->status);
644
645         write_unlock_irq(&zfcp_data.config_lock);
646
647         zfcp_adapter_get(adapter);
648         return port;
649
650 err_out_free:
651         kfree(port);
652 err_out:
653         return ERR_PTR(-EINVAL);
654 }
655
656 /**
657  * zfcp_port_dequeue - dequeues a port from the port list of the adapter
658  * @port: pointer to struct zfcp_port which should be removed
659  */
660 void zfcp_port_dequeue(struct zfcp_port *port)
661 {
662         wait_event(port->remove_wq, atomic_read(&port->refcount) == 0);
663         write_lock_irq(&zfcp_data.config_lock);
664         list_del(&port->list);
665         write_unlock_irq(&zfcp_data.config_lock);
666         if (port->rport)
667                 fc_remote_port_delete(port->rport);
668         port->rport = NULL;
669         zfcp_adapter_put(port->adapter);
670         sysfs_remove_group(&port->sysfs_device.kobj, &zfcp_sysfs_port_attrs);
671         device_unregister(&port->sysfs_device);
672 }
673
674 /**
675  * zfcp_sg_free_table - free memory used by scatterlists
676  * @sg: pointer to scatterlist
677  * @count: number of scatterlist which are to be free'ed
678  * the scatterlist are expected to reference pages always
679  */
680 void zfcp_sg_free_table(struct scatterlist *sg, int count)
681 {
682         int i;
683
684         for (i = 0; i < count; i++, sg++)
685                 if (sg)
686                         free_page((unsigned long) sg_virt(sg));
687                 else
688                         break;
689 }
690
691 /**
692  * zfcp_sg_setup_table - init scatterlist and allocate, assign buffers
693  * @sg: pointer to struct scatterlist
694  * @count: number of scatterlists which should be assigned with buffers
695  * of size page
696  *
697  * Returns: 0 on success, -ENOMEM otherwise
698  */
699 int zfcp_sg_setup_table(struct scatterlist *sg, int count)
700 {
701         void *addr;
702         int i;
703
704         sg_init_table(sg, count);
705         for (i = 0; i < count; i++, sg++) {
706                 addr = (void *) get_zeroed_page(GFP_KERNEL);
707                 if (!addr) {
708                         zfcp_sg_free_table(sg, i);
709                         return -ENOMEM;
710                 }
711                 sg_set_buf(sg, addr, PAGE_SIZE);
712         }
713         return 0;
714 }