Merge branch 'master' of git://git.kernel.org/pub/scm/fs/xfs/xfs
[linux-2.6] / 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, 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         flush_work(&unit->scsi_work);
101
102         down(&zfcp_data.config_sema);
103         zfcp_unit_put(unit);
104 out_unit:
105         zfcp_port_put(port);
106 out_port:
107         zfcp_adapter_put(adapter);
108 out_adapter:
109         up(&zfcp_data.config_sema);
110         return;
111 }
112
113 static struct kmem_cache *zfcp_cache_create(int size, char *name)
114 {
115         int align = 1;
116         while ((size - align) > 0)
117                 align <<= 1;
118         return kmem_cache_create(name , size, align, 0, NULL);
119 }
120
121 static void __init zfcp_init_device_setup(char *devstr)
122 {
123         char *token;
124         char *str;
125         char busid[ZFCP_BUS_ID_SIZE];
126         u64 wwpn, lun;
127
128         /* duplicate devstr and keep the original for sysfs presentation*/
129         str = kmalloc(strlen(devstr) + 1, GFP_KERNEL);
130         if (!str)
131                 return;
132
133         strcpy(str, devstr);
134
135         token = strsep(&str, ",");
136         if (!token || strlen(token) >= ZFCP_BUS_ID_SIZE)
137                 goto err_out;
138         strncpy(busid, token, ZFCP_BUS_ID_SIZE);
139
140         token = strsep(&str, ",");
141         if (!token || strict_strtoull(token, 0, (unsigned long long *) &wwpn))
142                 goto err_out;
143
144         token = strsep(&str, ",");
145         if (!token || strict_strtoull(token, 0, (unsigned long long *) &lun))
146                 goto err_out;
147
148         kfree(str);
149         zfcp_init_device_configure(busid, wwpn, lun);
150         return;
151
152  err_out:
153         kfree(str);
154         pr_err("%s is not a valid SCSI device\n", devstr);
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         sema_init(&zfcp_data.config_sema, 1);
179         rwlock_init(&zfcp_data.config_lock);
180
181         zfcp_data.scsi_transport_template =
182                 fc_attach_transport(&zfcp_transport_functions);
183         if (!zfcp_data.scsi_transport_template)
184                 goto out_transport;
185
186         retval = misc_register(&zfcp_cfdc_misc);
187         if (retval) {
188                 pr_err("Registering the misc device zfcp_cfdc failed\n");
189                 goto out_misc;
190         }
191
192         retval = zfcp_ccw_register();
193         if (retval) {
194                 pr_err("The zfcp device driver could not register with "
195                        "the common I/O layer\n");
196                 goto out_ccw_register;
197         }
198
199         if (init_device)
200                 zfcp_init_device_setup(init_device);
201         return 0;
202
203 out_ccw_register:
204         misc_deregister(&zfcp_cfdc_misc);
205 out_misc:
206         fc_release_transport(zfcp_data.scsi_transport_template);
207 out_transport:
208         kmem_cache_destroy(zfcp_data.gid_pn_cache);
209 out_gid_cache:
210         kmem_cache_destroy(zfcp_data.sr_buffer_cache);
211 out_sr_cache:
212         kmem_cache_destroy(zfcp_data.fsf_req_qtcb_cache);
213 out:
214         return retval;
215 }
216
217 module_init(zfcp_module_init);
218
219 /**
220  * zfcp_get_unit_by_lun - find unit in unit list of port by FCP LUN
221  * @port: pointer to port to search for unit
222  * @fcp_lun: FCP LUN to search for
223  *
224  * Returns: pointer to zfcp_unit or NULL
225  */
226 struct zfcp_unit *zfcp_get_unit_by_lun(struct zfcp_port *port, u64 fcp_lun)
227 {
228         struct zfcp_unit *unit;
229
230         list_for_each_entry(unit, &port->unit_list_head, list)
231                 if ((unit->fcp_lun == fcp_lun) &&
232                     !(atomic_read(&unit->status) & ZFCP_STATUS_COMMON_REMOVE))
233                     return unit;
234         return NULL;
235 }
236
237 /**
238  * zfcp_get_port_by_wwpn - find port in port list of adapter by wwpn
239  * @adapter: pointer to adapter to search for port
240  * @wwpn: wwpn to search for
241  *
242  * Returns: pointer to zfcp_port or NULL
243  */
244 struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *adapter,
245                                         u64 wwpn)
246 {
247         struct zfcp_port *port;
248
249         list_for_each_entry(port, &adapter->port_list_head, list)
250                 if ((port->wwpn == wwpn) &&
251                     !(atomic_read(&port->status) & ZFCP_STATUS_COMMON_REMOVE))
252                         return port;
253         return NULL;
254 }
255
256 static void zfcp_sysfs_unit_release(struct device *dev)
257 {
258         kfree(container_of(dev, struct zfcp_unit, sysfs_device));
259 }
260
261 /**
262  * zfcp_unit_enqueue - enqueue unit to unit list of a port.
263  * @port: pointer to port where unit is added
264  * @fcp_lun: FCP LUN of unit to be enqueued
265  * Returns: pointer to enqueued unit on success, ERR_PTR on error
266  * Locks: config_sema must be held to serialize changes to the unit list
267  *
268  * Sets up some unit internal structures and creates sysfs entry.
269  */
270 struct zfcp_unit *zfcp_unit_enqueue(struct zfcp_port *port, u64 fcp_lun)
271 {
272         struct zfcp_unit *unit;
273
274         unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
275         if (!unit)
276                 return ERR_PTR(-ENOMEM);
277
278         atomic_set(&unit->refcount, 0);
279         init_waitqueue_head(&unit->remove_wq);
280         INIT_WORK(&unit->scsi_work, zfcp_scsi_scan);
281
282         unit->port = port;
283         unit->fcp_lun = fcp_lun;
284
285         dev_set_name(&unit->sysfs_device, "0x%016llx",
286                      (unsigned long long) fcp_lun);
287         unit->sysfs_device.parent = &port->sysfs_device;
288         unit->sysfs_device.release = zfcp_sysfs_unit_release;
289         dev_set_drvdata(&unit->sysfs_device, unit);
290
291         /* mark unit unusable as long as sysfs registration is not complete */
292         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
293
294         spin_lock_init(&unit->latencies.lock);
295         unit->latencies.write.channel.min = 0xFFFFFFFF;
296         unit->latencies.write.fabric.min = 0xFFFFFFFF;
297         unit->latencies.read.channel.min = 0xFFFFFFFF;
298         unit->latencies.read.fabric.min = 0xFFFFFFFF;
299         unit->latencies.cmd.channel.min = 0xFFFFFFFF;
300         unit->latencies.cmd.fabric.min = 0xFFFFFFFF;
301
302         read_lock_irq(&zfcp_data.config_lock);
303         if (zfcp_get_unit_by_lun(port, fcp_lun)) {
304                 read_unlock_irq(&zfcp_data.config_lock);
305                 goto err_out_free;
306         }
307         read_unlock_irq(&zfcp_data.config_lock);
308
309         if (device_register(&unit->sysfs_device))
310                 goto err_out_free;
311
312         if (sysfs_create_group(&unit->sysfs_device.kobj,
313                                &zfcp_sysfs_unit_attrs)) {
314                 device_unregister(&unit->sysfs_device);
315                 return ERR_PTR(-EIO);
316         }
317
318         zfcp_unit_get(unit);
319
320         write_lock_irq(&zfcp_data.config_lock);
321         list_add_tail(&unit->list, &port->unit_list_head);
322         atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
323         atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &unit->status);
324
325         write_unlock_irq(&zfcp_data.config_lock);
326
327         zfcp_port_get(port);
328
329         return unit;
330
331 err_out_free:
332         kfree(unit);
333         return ERR_PTR(-EINVAL);
334 }
335
336 /**
337  * zfcp_unit_dequeue - dequeue unit
338  * @unit: pointer to zfcp_unit
339  *
340  * waits until all work is done on unit and removes it then from the unit->list
341  * of the associated port.
342  */
343 void zfcp_unit_dequeue(struct zfcp_unit *unit)
344 {
345         wait_event(unit->remove_wq, atomic_read(&unit->refcount) == 0);
346         write_lock_irq(&zfcp_data.config_lock);
347         list_del(&unit->list);
348         write_unlock_irq(&zfcp_data.config_lock);
349         zfcp_port_put(unit->port);
350         sysfs_remove_group(&unit->sysfs_device.kobj, &zfcp_sysfs_unit_attrs);
351         device_unregister(&unit->sysfs_device);
352 }
353
354 static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
355 {
356         /* must only be called with zfcp_data.config_sema taken */
357         adapter->pool.fsf_req_erp =
358                 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
359         if (!adapter->pool.fsf_req_erp)
360                 return -ENOMEM;
361
362         adapter->pool.fsf_req_scsi =
363                 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
364         if (!adapter->pool.fsf_req_scsi)
365                 return -ENOMEM;
366
367         adapter->pool.fsf_req_abort =
368                 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
369         if (!adapter->pool.fsf_req_abort)
370                 return -ENOMEM;
371
372         adapter->pool.fsf_req_status_read =
373                 mempool_create_kmalloc_pool(FSF_STATUS_READS_RECOM,
374                                             sizeof(struct zfcp_fsf_req));
375         if (!adapter->pool.fsf_req_status_read)
376                 return -ENOMEM;
377
378         adapter->pool.data_status_read =
379                 mempool_create_slab_pool(FSF_STATUS_READS_RECOM,
380                                          zfcp_data.sr_buffer_cache);
381         if (!adapter->pool.data_status_read)
382                 return -ENOMEM;
383
384         adapter->pool.data_gid_pn =
385                 mempool_create_slab_pool(1, zfcp_data.gid_pn_cache);
386         if (!adapter->pool.data_gid_pn)
387                 return -ENOMEM;
388
389         return 0;
390 }
391
392 static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
393 {
394         /* zfcp_data.config_sema must be held */
395         if (adapter->pool.fsf_req_erp)
396                 mempool_destroy(adapter->pool.fsf_req_erp);
397         if (adapter->pool.fsf_req_scsi)
398                 mempool_destroy(adapter->pool.fsf_req_scsi);
399         if (adapter->pool.fsf_req_abort)
400                 mempool_destroy(adapter->pool.fsf_req_abort);
401         if (adapter->pool.fsf_req_status_read)
402                 mempool_destroy(adapter->pool.fsf_req_status_read);
403         if (adapter->pool.data_status_read)
404                 mempool_destroy(adapter->pool.data_status_read);
405         if (adapter->pool.data_gid_pn)
406                 mempool_destroy(adapter->pool.data_gid_pn);
407 }
408
409 /**
410  * zfcp_status_read_refill - refill the long running status_read_requests
411  * @adapter: ptr to struct zfcp_adapter for which the buffers should be refilled
412  *
413  * Returns: 0 on success, 1 otherwise
414  *
415  * if there are 16 or more status_read requests missing an adapter_reopen
416  * is triggered
417  */
418 int zfcp_status_read_refill(struct zfcp_adapter *adapter)
419 {
420         while (atomic_read(&adapter->stat_miss) > 0)
421                 if (zfcp_fsf_status_read(adapter)) {
422                         if (atomic_read(&adapter->stat_miss) >= 16) {
423                                 zfcp_erp_adapter_reopen(adapter, 0, "axsref1",
424                                                         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 static void zfcp_print_sl(struct seq_file *m, struct service_level *sl)
440 {
441         struct zfcp_adapter *adapter =
442                 container_of(sl, struct zfcp_adapter, service_level);
443
444         seq_printf(m, "zfcp: %s microcode level %x\n",
445                    dev_name(&adapter->ccw_device->dev),
446                    adapter->fsf_lic_version);
447 }
448
449 /**
450  * zfcp_adapter_enqueue - enqueue a new adapter to the list
451  * @ccw_device: pointer to the struct cc_device
452  *
453  * Returns:     0             if a new adapter was successfully enqueued
454  *              -ENOMEM       if alloc failed
455  * Enqueues an adapter at the end of the adapter list in the driver data.
456  * All adapter internal structures are set up.
457  * Proc-fs entries are also created.
458  * locks:       config_sema must be held to serialise changes to the adapter list
459  */
460 int zfcp_adapter_enqueue(struct ccw_device *ccw_device)
461 {
462         struct zfcp_adapter *adapter;
463
464         /*
465          * Note: It is safe to release the list_lock, as any list changes
466          * are protected by the config_sema, which must be held to get here
467          */
468
469         adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
470         if (!adapter)
471                 return -ENOMEM;
472
473         ccw_device->handler = NULL;
474         adapter->ccw_device = ccw_device;
475         atomic_set(&adapter->refcount, 0);
476
477         if (zfcp_qdio_allocate(adapter))
478                 goto qdio_allocate_failed;
479
480         if (zfcp_allocate_low_mem_buffers(adapter))
481                 goto failed_low_mem_buffers;
482
483         if (zfcp_reqlist_alloc(adapter))
484                 goto failed_low_mem_buffers;
485
486         if (zfcp_adapter_debug_register(adapter))
487                 goto debug_register_failed;
488
489         init_waitqueue_head(&adapter->remove_wq);
490         init_waitqueue_head(&adapter->erp_thread_wqh);
491         init_waitqueue_head(&adapter->erp_done_wqh);
492
493         INIT_LIST_HEAD(&adapter->port_list_head);
494         INIT_LIST_HEAD(&adapter->erp_ready_head);
495         INIT_LIST_HEAD(&adapter->erp_running_head);
496
497         spin_lock_init(&adapter->req_list_lock);
498
499         spin_lock_init(&adapter->hba_dbf_lock);
500         spin_lock_init(&adapter->san_dbf_lock);
501         spin_lock_init(&adapter->scsi_dbf_lock);
502         spin_lock_init(&adapter->rec_dbf_lock);
503         spin_lock_init(&adapter->req_q_lock);
504         spin_lock_init(&adapter->qdio_stat_lock);
505
506         rwlock_init(&adapter->erp_lock);
507         rwlock_init(&adapter->abort_lock);
508
509         sema_init(&adapter->erp_ready_sem, 0);
510
511         INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
512         INIT_WORK(&adapter->scan_work, _zfcp_scan_ports_later);
513
514         adapter->service_level.seq_print = zfcp_print_sl;
515
516         /* mark adapter unusable as long as sysfs registration is not complete */
517         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
518
519         dev_set_drvdata(&ccw_device->dev, adapter);
520
521         if (sysfs_create_group(&ccw_device->dev.kobj,
522                                &zfcp_sysfs_adapter_attrs))
523                 goto sysfs_failed;
524
525         atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
526
527         zfcp_fc_nameserver_init(adapter);
528
529         if (!zfcp_adapter_scsi_register(adapter))
530                 return 0;
531
532 sysfs_failed:
533         zfcp_adapter_debug_unregister(adapter);
534 debug_register_failed:
535         dev_set_drvdata(&ccw_device->dev, NULL);
536         kfree(adapter->req_list);
537 failed_low_mem_buffers:
538         zfcp_free_low_mem_buffers(adapter);
539 qdio_allocate_failed:
540         zfcp_qdio_free(adapter);
541         kfree(adapter);
542         return -ENOMEM;
543 }
544
545 /**
546  * zfcp_adapter_dequeue - remove the adapter from the resource list
547  * @adapter: pointer to struct zfcp_adapter which should be removed
548  * locks:       adapter list write lock is assumed to be held by caller
549  */
550 void zfcp_adapter_dequeue(struct zfcp_adapter *adapter)
551 {
552         int retval = 0;
553         unsigned long flags;
554
555         cancel_work_sync(&adapter->scan_work);
556         cancel_work_sync(&adapter->stat_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                 port->rport->dd_data = NULL;
675         zfcp_adapter_put(port->adapter);
676         sysfs_remove_group(&port->sysfs_device.kobj, &zfcp_sysfs_port_attrs);
677         device_unregister(&port->sysfs_device);
678 }
679
680 /**
681  * zfcp_sg_free_table - free memory used by scatterlists
682  * @sg: pointer to scatterlist
683  * @count: number of scatterlist which are to be free'ed
684  * the scatterlist are expected to reference pages always
685  */
686 void zfcp_sg_free_table(struct scatterlist *sg, int count)
687 {
688         int i;
689
690         for (i = 0; i < count; i++, sg++)
691                 if (sg)
692                         free_page((unsigned long) sg_virt(sg));
693                 else
694                         break;
695 }
696
697 /**
698  * zfcp_sg_setup_table - init scatterlist and allocate, assign buffers
699  * @sg: pointer to struct scatterlist
700  * @count: number of scatterlists which should be assigned with buffers
701  * of size page
702  *
703  * Returns: 0 on success, -ENOMEM otherwise
704  */
705 int zfcp_sg_setup_table(struct scatterlist *sg, int count)
706 {
707         void *addr;
708         int i;
709
710         sg_init_table(sg, count);
711         for (i = 0; i < count; i++, sg++) {
712                 addr = (void *) get_zeroed_page(GFP_KERNEL);
713                 if (!addr) {
714                         zfcp_sg_free_table(sg, i);
715                         return -ENOMEM;
716                 }
717                 sg_set_buf(sg, addr, PAGE_SIZE);
718         }
719         return 0;
720 }