GNU Linux-libre 5.10.219-gnu1
[releases.git] / drivers / scsi / scsi_transport_srp.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * SCSI RDMA (SRP) transport class
4  *
5  * Copyright (C) 2007 FUJITA Tomonori <tomof@acm.org>
6  */
7 #include <linux/init.h>
8 #include <linux/module.h>
9 #include <linux/jiffies.h>
10 #include <linux/err.h>
11 #include <linux/slab.h>
12 #include <linux/string.h>
13
14 #include <scsi/scsi.h>
15 #include <scsi/scsi_cmnd.h>
16 #include <scsi/scsi_device.h>
17 #include <scsi/scsi_host.h>
18 #include <scsi/scsi_transport.h>
19 #include <scsi/scsi_transport_srp.h>
20 #include "scsi_priv.h"
21
22 struct srp_host_attrs {
23         atomic_t next_port_id;
24 };
25 #define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
26
27 #define SRP_HOST_ATTRS 0
28 #define SRP_RPORT_ATTRS 8
29
30 struct srp_internal {
31         struct scsi_transport_template t;
32         struct srp_function_template *f;
33
34         struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
35
36         struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
37         struct transport_container rport_attr_cont;
38 };
39
40 static int scsi_is_srp_rport(const struct device *dev);
41
42 #define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
43
44 #define dev_to_rport(d) container_of(d, struct srp_rport, dev)
45 #define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
46 static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
47 {
48         return dev_to_shost(r->dev.parent);
49 }
50
51 static int find_child_rport(struct device *dev, void *data)
52 {
53         struct device **child = data;
54
55         if (scsi_is_srp_rport(dev)) {
56                 WARN_ON_ONCE(*child);
57                 *child = dev;
58         }
59         return 0;
60 }
61
62 static inline struct srp_rport *shost_to_rport(struct Scsi_Host *shost)
63 {
64         struct device *child = NULL;
65
66         WARN_ON_ONCE(device_for_each_child(&shost->shost_gendev, &child,
67                                            find_child_rport) < 0);
68         return child ? dev_to_rport(child) : NULL;
69 }
70
71 /**
72  * srp_tmo_valid() - check timeout combination validity
73  * @reconnect_delay: Reconnect delay in seconds.
74  * @fast_io_fail_tmo: Fast I/O fail timeout in seconds.
75  * @dev_loss_tmo: Device loss timeout in seconds.
76  *
77  * The combination of the timeout parameters must be such that SCSI commands
78  * are finished in a reasonable time. Hence do not allow the fast I/O fail
79  * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT nor allow dev_loss_tmo to
80  * exceed that limit if failing I/O fast has been disabled. Furthermore, these
81  * parameters must be such that multipath can detect failed paths timely.
82  * Hence do not allow all three parameters to be disabled simultaneously.
83  */
84 int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, long dev_loss_tmo)
85 {
86         if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
87                 return -EINVAL;
88         if (reconnect_delay == 0)
89                 return -EINVAL;
90         if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
91                 return -EINVAL;
92         if (fast_io_fail_tmo < 0 &&
93             dev_loss_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
94                 return -EINVAL;
95         if (dev_loss_tmo >= LONG_MAX / HZ)
96                 return -EINVAL;
97         if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
98             fast_io_fail_tmo >= dev_loss_tmo)
99                 return -EINVAL;
100         return 0;
101 }
102 EXPORT_SYMBOL_GPL(srp_tmo_valid);
103
104 static int srp_host_setup(struct transport_container *tc, struct device *dev,
105                           struct device *cdev)
106 {
107         struct Scsi_Host *shost = dev_to_shost(dev);
108         struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
109
110         atomic_set(&srp_host->next_port_id, 0);
111         return 0;
112 }
113
114 static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
115                                NULL, NULL);
116
117 static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
118                                NULL, NULL, NULL);
119
120 static ssize_t
121 show_srp_rport_id(struct device *dev, struct device_attribute *attr,
122                   char *buf)
123 {
124         struct srp_rport *rport = transport_class_to_srp_rport(dev);
125         return sprintf(buf, "%16phC\n", rport->port_id);
126 }
127
128 static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
129
130 static const struct {
131         u32 value;
132         char *name;
133 } srp_rport_role_names[] = {
134         {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
135         {SRP_RPORT_ROLE_TARGET, "SRP Target"},
136 };
137
138 static ssize_t
139 show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
140                      char *buf)
141 {
142         struct srp_rport *rport = transport_class_to_srp_rport(dev);
143         int i;
144         char *name = NULL;
145
146         for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
147                 if (srp_rport_role_names[i].value == rport->roles) {
148                         name = srp_rport_role_names[i].name;
149                         break;
150                 }
151         return sprintf(buf, "%s\n", name ? : "unknown");
152 }
153
154 static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
155
156 static ssize_t store_srp_rport_delete(struct device *dev,
157                                       struct device_attribute *attr,
158                                       const char *buf, size_t count)
159 {
160         struct srp_rport *rport = transport_class_to_srp_rport(dev);
161         struct Scsi_Host *shost = dev_to_shost(dev);
162         struct srp_internal *i = to_srp_internal(shost->transportt);
163
164         if (i->f->rport_delete) {
165                 i->f->rport_delete(rport);
166                 return count;
167         } else {
168                 return -ENOSYS;
169         }
170 }
171
172 static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
173
174 static ssize_t show_srp_rport_state(struct device *dev,
175                                     struct device_attribute *attr,
176                                     char *buf)
177 {
178         static const char *const state_name[] = {
179                 [SRP_RPORT_RUNNING]     = "running",
180                 [SRP_RPORT_BLOCKED]     = "blocked",
181                 [SRP_RPORT_FAIL_FAST]   = "fail-fast",
182                 [SRP_RPORT_LOST]        = "lost",
183         };
184         struct srp_rport *rport = transport_class_to_srp_rport(dev);
185         enum srp_rport_state state = rport->state;
186
187         return sprintf(buf, "%s\n",
188                        (unsigned)state < ARRAY_SIZE(state_name) ?
189                        state_name[state] : "???");
190 }
191
192 static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
193
194 static ssize_t srp_show_tmo(char *buf, int tmo)
195 {
196         return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
197 }
198
199 int srp_parse_tmo(int *tmo, const char *buf)
200 {
201         int res = 0;
202
203         if (strncmp(buf, "off", 3) != 0)
204                 res = kstrtoint(buf, 0, tmo);
205         else
206                 *tmo = -1;
207
208         return res;
209 }
210 EXPORT_SYMBOL(srp_parse_tmo);
211
212 static ssize_t show_reconnect_delay(struct device *dev,
213                                     struct device_attribute *attr, char *buf)
214 {
215         struct srp_rport *rport = transport_class_to_srp_rport(dev);
216
217         return srp_show_tmo(buf, rport->reconnect_delay);
218 }
219
220 static ssize_t store_reconnect_delay(struct device *dev,
221                                      struct device_attribute *attr,
222                                      const char *buf, const size_t count)
223 {
224         struct srp_rport *rport = transport_class_to_srp_rport(dev);
225         int res, delay;
226
227         res = srp_parse_tmo(&delay, buf);
228         if (res)
229                 goto out;
230         res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
231                             rport->dev_loss_tmo);
232         if (res)
233                 goto out;
234
235         if (rport->reconnect_delay <= 0 && delay > 0 &&
236             rport->state != SRP_RPORT_RUNNING) {
237                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
238                                    delay * HZ);
239         } else if (delay <= 0) {
240                 cancel_delayed_work(&rport->reconnect_work);
241         }
242         rport->reconnect_delay = delay;
243         res = count;
244
245 out:
246         return res;
247 }
248
249 static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
250                    store_reconnect_delay);
251
252 static ssize_t show_failed_reconnects(struct device *dev,
253                                       struct device_attribute *attr, char *buf)
254 {
255         struct srp_rport *rport = transport_class_to_srp_rport(dev);
256
257         return sprintf(buf, "%d\n", rport->failed_reconnects);
258 }
259
260 static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
261
262 static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
263                                                struct device_attribute *attr,
264                                                char *buf)
265 {
266         struct srp_rport *rport = transport_class_to_srp_rport(dev);
267
268         return srp_show_tmo(buf, rport->fast_io_fail_tmo);
269 }
270
271 static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
272                                                 struct device_attribute *attr,
273                                                 const char *buf, size_t count)
274 {
275         struct srp_rport *rport = transport_class_to_srp_rport(dev);
276         int res;
277         int fast_io_fail_tmo;
278
279         res = srp_parse_tmo(&fast_io_fail_tmo, buf);
280         if (res)
281                 goto out;
282         res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
283                             rport->dev_loss_tmo);
284         if (res)
285                 goto out;
286         rport->fast_io_fail_tmo = fast_io_fail_tmo;
287         res = count;
288
289 out:
290         return res;
291 }
292
293 static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
294                    show_srp_rport_fast_io_fail_tmo,
295                    store_srp_rport_fast_io_fail_tmo);
296
297 static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
298                                            struct device_attribute *attr,
299                                            char *buf)
300 {
301         struct srp_rport *rport = transport_class_to_srp_rport(dev);
302
303         return srp_show_tmo(buf, rport->dev_loss_tmo);
304 }
305
306 static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
307                                             struct device_attribute *attr,
308                                             const char *buf, size_t count)
309 {
310         struct srp_rport *rport = transport_class_to_srp_rport(dev);
311         int res;
312         int dev_loss_tmo;
313
314         res = srp_parse_tmo(&dev_loss_tmo, buf);
315         if (res)
316                 goto out;
317         res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
318                             dev_loss_tmo);
319         if (res)
320                 goto out;
321         rport->dev_loss_tmo = dev_loss_tmo;
322         res = count;
323
324 out:
325         return res;
326 }
327
328 static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
329                    show_srp_rport_dev_loss_tmo,
330                    store_srp_rport_dev_loss_tmo);
331
332 static int srp_rport_set_state(struct srp_rport *rport,
333                                enum srp_rport_state new_state)
334 {
335         enum srp_rport_state old_state = rport->state;
336
337         lockdep_assert_held(&rport->mutex);
338
339         switch (new_state) {
340         case SRP_RPORT_RUNNING:
341                 switch (old_state) {
342                 case SRP_RPORT_LOST:
343                         goto invalid;
344                 default:
345                         break;
346                 }
347                 break;
348         case SRP_RPORT_BLOCKED:
349                 switch (old_state) {
350                 case SRP_RPORT_RUNNING:
351                         break;
352                 default:
353                         goto invalid;
354                 }
355                 break;
356         case SRP_RPORT_FAIL_FAST:
357                 switch (old_state) {
358                 case SRP_RPORT_LOST:
359                         goto invalid;
360                 default:
361                         break;
362                 }
363                 break;
364         case SRP_RPORT_LOST:
365                 break;
366         }
367         rport->state = new_state;
368         return 0;
369
370 invalid:
371         return -EINVAL;
372 }
373
374 /**
375  * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
376  * @work: Work structure used for scheduling this operation.
377  */
378 static void srp_reconnect_work(struct work_struct *work)
379 {
380         struct srp_rport *rport = container_of(to_delayed_work(work),
381                                         struct srp_rport, reconnect_work);
382         struct Scsi_Host *shost = rport_to_shost(rport);
383         int delay, res;
384
385         res = srp_reconnect_rport(rport);
386         if (res != 0) {
387                 shost_printk(KERN_ERR, shost,
388                              "reconnect attempt %d failed (%d)\n",
389                              ++rport->failed_reconnects, res);
390                 delay = rport->reconnect_delay *
391                         min(100, max(1, rport->failed_reconnects - 10));
392                 if (delay > 0)
393                         queue_delayed_work(system_long_wq,
394                                            &rport->reconnect_work, delay * HZ);
395         }
396 }
397
398 /*
399  * scsi_target_block() must have been called before this function is
400  * called to guarantee that no .queuecommand() calls are in progress.
401  */
402 static void __rport_fail_io_fast(struct srp_rport *rport)
403 {
404         struct Scsi_Host *shost = rport_to_shost(rport);
405         struct srp_internal *i;
406
407         lockdep_assert_held(&rport->mutex);
408
409         if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
410                 return;
411
412         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
413
414         /* Involve the LLD if possible to terminate all I/O on the rport. */
415         i = to_srp_internal(shost->transportt);
416         if (i->f->terminate_rport_io)
417                 i->f->terminate_rport_io(rport);
418 }
419
420 /**
421  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
422  * @work: Work structure used for scheduling this operation.
423  */
424 static void rport_fast_io_fail_timedout(struct work_struct *work)
425 {
426         struct srp_rport *rport = container_of(to_delayed_work(work),
427                                         struct srp_rport, fast_io_fail_work);
428         struct Scsi_Host *shost = rport_to_shost(rport);
429
430         pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
431                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
432
433         mutex_lock(&rport->mutex);
434         if (rport->state == SRP_RPORT_BLOCKED)
435                 __rport_fail_io_fast(rport);
436         mutex_unlock(&rport->mutex);
437 }
438
439 /**
440  * rport_dev_loss_timedout() - device loss timeout handler
441  * @work: Work structure used for scheduling this operation.
442  */
443 static void rport_dev_loss_timedout(struct work_struct *work)
444 {
445         struct srp_rport *rport = container_of(to_delayed_work(work),
446                                         struct srp_rport, dev_loss_work);
447         struct Scsi_Host *shost = rport_to_shost(rport);
448         struct srp_internal *i = to_srp_internal(shost->transportt);
449
450         pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
451                 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
452
453         mutex_lock(&rport->mutex);
454         WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
455         scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
456         mutex_unlock(&rport->mutex);
457
458         i->f->rport_delete(rport);
459 }
460
461 static void __srp_start_tl_fail_timers(struct srp_rport *rport)
462 {
463         struct Scsi_Host *shost = rport_to_shost(rport);
464         int delay, fast_io_fail_tmo, dev_loss_tmo;
465
466         lockdep_assert_held(&rport->mutex);
467
468         delay = rport->reconnect_delay;
469         fast_io_fail_tmo = rport->fast_io_fail_tmo;
470         dev_loss_tmo = rport->dev_loss_tmo;
471         pr_debug("%s current state: %d\n", dev_name(&shost->shost_gendev),
472                  rport->state);
473
474         if (rport->state == SRP_RPORT_LOST)
475                 return;
476         if (delay > 0)
477                 queue_delayed_work(system_long_wq, &rport->reconnect_work,
478                                    1UL * delay * HZ);
479         if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
480             srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
481                 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
482                          rport->state);
483                 scsi_target_block(&shost->shost_gendev);
484                 if (fast_io_fail_tmo >= 0)
485                         queue_delayed_work(system_long_wq,
486                                            &rport->fast_io_fail_work,
487                                            1UL * fast_io_fail_tmo * HZ);
488                 if (dev_loss_tmo >= 0)
489                         queue_delayed_work(system_long_wq,
490                                            &rport->dev_loss_work,
491                                            1UL * dev_loss_tmo * HZ);
492         }
493 }
494
495 /**
496  * srp_start_tl_fail_timers() - start the transport layer failure timers
497  * @rport: SRP target port.
498  *
499  * Start the transport layer fast I/O failure and device loss timers. Do not
500  * modify a timer that was already started.
501  */
502 void srp_start_tl_fail_timers(struct srp_rport *rport)
503 {
504         mutex_lock(&rport->mutex);
505         __srp_start_tl_fail_timers(rport);
506         mutex_unlock(&rport->mutex);
507 }
508 EXPORT_SYMBOL(srp_start_tl_fail_timers);
509
510 /**
511  * srp_reconnect_rport() - reconnect to an SRP target port
512  * @rport: SRP target port.
513  *
514  * Blocks SCSI command queueing before invoking reconnect() such that
515  * queuecommand() won't be invoked concurrently with reconnect() from outside
516  * the SCSI EH. This is important since a reconnect() implementation may
517  * reallocate resources needed by queuecommand().
518  *
519  * Notes:
520  * - This function neither waits until outstanding requests have finished nor
521  *   tries to abort these. It is the responsibility of the reconnect()
522  *   function to finish outstanding commands before reconnecting to the target
523  *   port.
524  * - It is the responsibility of the caller to ensure that the resources
525  *   reallocated by the reconnect() function won't be used while this function
526  *   is in progress. One possible strategy is to invoke this function from
527  *   the context of the SCSI EH thread only. Another possible strategy is to
528  *   lock the rport mutex inside each SCSI LLD callback that can be invoked by
529  *   the SCSI EH (the scsi_host_template.eh_*() functions and also the
530  *   scsi_host_template.queuecommand() function).
531  */
532 int srp_reconnect_rport(struct srp_rport *rport)
533 {
534         struct Scsi_Host *shost = rport_to_shost(rport);
535         struct srp_internal *i = to_srp_internal(shost->transportt);
536         struct scsi_device *sdev;
537         int res;
538
539         pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
540
541         res = mutex_lock_interruptible(&rport->mutex);
542         if (res)
543                 goto out;
544         if (rport->state != SRP_RPORT_FAIL_FAST && rport->state != SRP_RPORT_LOST)
545                 /*
546                  * sdev state must be SDEV_TRANSPORT_OFFLINE, transition
547                  * to SDEV_BLOCK is illegal. Calling scsi_target_unblock()
548                  * later is ok though, scsi_internal_device_unblock_nowait()
549                  * treats SDEV_TRANSPORT_OFFLINE like SDEV_BLOCK.
550                  */
551                 scsi_target_block(&shost->shost_gendev);
552         res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
553         pr_debug("%s (state %d): transport.reconnect() returned %d\n",
554                  dev_name(&shost->shost_gendev), rport->state, res);
555         if (res == 0) {
556                 cancel_delayed_work(&rport->fast_io_fail_work);
557                 cancel_delayed_work(&rport->dev_loss_work);
558
559                 rport->failed_reconnects = 0;
560                 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
561                 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
562                 /*
563                  * If the SCSI error handler has offlined one or more devices,
564                  * invoking scsi_target_unblock() won't change the state of
565                  * these devices into running so do that explicitly.
566                  */
567                 shost_for_each_device(sdev, shost) {
568                         mutex_lock(&sdev->state_mutex);
569                         if (sdev->sdev_state == SDEV_OFFLINE)
570                                 sdev->sdev_state = SDEV_RUNNING;
571                         mutex_unlock(&sdev->state_mutex);
572                 }
573         } else if (rport->state == SRP_RPORT_RUNNING) {
574                 /*
575                  * srp_reconnect_rport() has been invoked with fast_io_fail
576                  * and dev_loss off. Mark the port as failed and start the TL
577                  * failure timers if these had not yet been started.
578                  */
579                 __rport_fail_io_fast(rport);
580                 __srp_start_tl_fail_timers(rport);
581         } else if (rport->state != SRP_RPORT_BLOCKED) {
582                 scsi_target_unblock(&shost->shost_gendev,
583                                     SDEV_TRANSPORT_OFFLINE);
584         }
585         mutex_unlock(&rport->mutex);
586
587 out:
588         return res;
589 }
590 EXPORT_SYMBOL(srp_reconnect_rport);
591
592 /**
593  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
594  * @scmd: SCSI command.
595  *
596  * If a timeout occurs while an rport is in the blocked state, ask the SCSI
597  * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
598  * handle the timeout (BLK_EH_DONE).
599  *
600  * Note: This function is called from soft-IRQ context and with the request
601  * queue lock held.
602  */
603 enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
604 {
605         struct scsi_device *sdev = scmd->device;
606         struct Scsi_Host *shost = sdev->host;
607         struct srp_internal *i = to_srp_internal(shost->transportt);
608         struct srp_rport *rport = shost_to_rport(shost);
609
610         pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
611         return rport && rport->fast_io_fail_tmo < 0 &&
612                 rport->dev_loss_tmo < 0 &&
613                 i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
614                 BLK_EH_RESET_TIMER : BLK_EH_DONE;
615 }
616 EXPORT_SYMBOL(srp_timed_out);
617
618 static void srp_rport_release(struct device *dev)
619 {
620         struct srp_rport *rport = dev_to_rport(dev);
621
622         put_device(dev->parent);
623         kfree(rport);
624 }
625
626 static int scsi_is_srp_rport(const struct device *dev)
627 {
628         return dev->release == srp_rport_release;
629 }
630
631 static int srp_rport_match(struct attribute_container *cont,
632                            struct device *dev)
633 {
634         struct Scsi_Host *shost;
635         struct srp_internal *i;
636
637         if (!scsi_is_srp_rport(dev))
638                 return 0;
639
640         shost = dev_to_shost(dev->parent);
641         if (!shost->transportt)
642                 return 0;
643         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
644                 return 0;
645
646         i = to_srp_internal(shost->transportt);
647         return &i->rport_attr_cont.ac == cont;
648 }
649
650 static int srp_host_match(struct attribute_container *cont, struct device *dev)
651 {
652         struct Scsi_Host *shost;
653         struct srp_internal *i;
654
655         if (!scsi_is_host_device(dev))
656                 return 0;
657
658         shost = dev_to_shost(dev);
659         if (!shost->transportt)
660                 return 0;
661         if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
662                 return 0;
663
664         i = to_srp_internal(shost->transportt);
665         return &i->t.host_attrs.ac == cont;
666 }
667
668 /**
669  * srp_rport_get() - increment rport reference count
670  * @rport: SRP target port.
671  */
672 void srp_rport_get(struct srp_rport *rport)
673 {
674         get_device(&rport->dev);
675 }
676 EXPORT_SYMBOL(srp_rport_get);
677
678 /**
679  * srp_rport_put() - decrement rport reference count
680  * @rport: SRP target port.
681  */
682 void srp_rport_put(struct srp_rport *rport)
683 {
684         put_device(&rport->dev);
685 }
686 EXPORT_SYMBOL(srp_rport_put);
687
688 /**
689  * srp_rport_add - add a SRP remote port to the device hierarchy
690  * @shost:      scsi host the remote port is connected to.
691  * @ids:        The port id for the remote port.
692  *
693  * Publishes a port to the rest of the system.
694  */
695 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
696                                 struct srp_rport_identifiers *ids)
697 {
698         struct srp_rport *rport;
699         struct device *parent = &shost->shost_gendev;
700         struct srp_internal *i = to_srp_internal(shost->transportt);
701         int id, ret;
702
703         rport = kzalloc(sizeof(*rport), GFP_KERNEL);
704         if (!rport)
705                 return ERR_PTR(-ENOMEM);
706
707         mutex_init(&rport->mutex);
708
709         device_initialize(&rport->dev);
710
711         rport->dev.parent = get_device(parent);
712         rport->dev.release = srp_rport_release;
713
714         memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
715         rport->roles = ids->roles;
716
717         if (i->f->reconnect)
718                 rport->reconnect_delay = i->f->reconnect_delay ?
719                         *i->f->reconnect_delay : 10;
720         INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
721         rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
722                 *i->f->fast_io_fail_tmo : 15;
723         rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
724         INIT_DELAYED_WORK(&rport->fast_io_fail_work,
725                           rport_fast_io_fail_timedout);
726         INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
727
728         id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
729         dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
730
731         transport_setup_device(&rport->dev);
732
733         ret = device_add(&rport->dev);
734         if (ret) {
735                 transport_destroy_device(&rport->dev);
736                 put_device(&rport->dev);
737                 return ERR_PTR(ret);
738         }
739
740         transport_add_device(&rport->dev);
741         transport_configure_device(&rport->dev);
742
743         return rport;
744 }
745 EXPORT_SYMBOL_GPL(srp_rport_add);
746
747 /**
748  * srp_rport_del  -  remove a SRP remote port
749  * @rport:      SRP remote port to remove
750  *
751  * Removes the specified SRP remote port.
752  */
753 void srp_rport_del(struct srp_rport *rport)
754 {
755         struct device *dev = &rport->dev;
756
757         transport_remove_device(dev);
758         device_del(dev);
759         transport_destroy_device(dev);
760
761         put_device(dev);
762 }
763 EXPORT_SYMBOL_GPL(srp_rport_del);
764
765 static int do_srp_rport_del(struct device *dev, void *data)
766 {
767         if (scsi_is_srp_rport(dev))
768                 srp_rport_del(dev_to_rport(dev));
769         return 0;
770 }
771
772 /**
773  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
774  * @shost:      Scsi Host that is torn down
775  *
776  * Removes all SRP remote ports for a given Scsi_Host.
777  * Must be called just before scsi_remove_host for SRP HBAs.
778  */
779 void srp_remove_host(struct Scsi_Host *shost)
780 {
781         device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
782 }
783 EXPORT_SYMBOL_GPL(srp_remove_host);
784
785 /**
786  * srp_stop_rport_timers - stop the transport layer recovery timers
787  * @rport: SRP remote port for which to stop the timers.
788  *
789  * Must be called after srp_remove_host() and scsi_remove_host(). The caller
790  * must hold a reference on the rport (rport->dev) and on the SCSI host
791  * (rport->dev.parent).
792  */
793 void srp_stop_rport_timers(struct srp_rport *rport)
794 {
795         mutex_lock(&rport->mutex);
796         if (rport->state == SRP_RPORT_BLOCKED)
797                 __rport_fail_io_fast(rport);
798         srp_rport_set_state(rport, SRP_RPORT_LOST);
799         mutex_unlock(&rport->mutex);
800
801         cancel_delayed_work_sync(&rport->reconnect_work);
802         cancel_delayed_work_sync(&rport->fast_io_fail_work);
803         cancel_delayed_work_sync(&rport->dev_loss_work);
804 }
805 EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
806
807 /**
808  * srp_attach_transport  -  instantiate SRP transport template
809  * @ft:         SRP transport class function template
810  */
811 struct scsi_transport_template *
812 srp_attach_transport(struct srp_function_template *ft)
813 {
814         int count;
815         struct srp_internal *i;
816
817         i = kzalloc(sizeof(*i), GFP_KERNEL);
818         if (!i)
819                 return NULL;
820
821         i->t.host_size = sizeof(struct srp_host_attrs);
822         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
823         i->t.host_attrs.ac.class = &srp_host_class.class;
824         i->t.host_attrs.ac.match = srp_host_match;
825         i->host_attrs[0] = NULL;
826         transport_container_register(&i->t.host_attrs);
827
828         i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
829         i->rport_attr_cont.ac.class = &srp_rport_class.class;
830         i->rport_attr_cont.ac.match = srp_rport_match;
831
832         count = 0;
833         i->rport_attrs[count++] = &dev_attr_port_id;
834         i->rport_attrs[count++] = &dev_attr_roles;
835         if (ft->has_rport_state) {
836                 i->rport_attrs[count++] = &dev_attr_state;
837                 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
838                 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
839         }
840         if (ft->reconnect) {
841                 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
842                 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
843         }
844         if (ft->rport_delete)
845                 i->rport_attrs[count++] = &dev_attr_delete;
846         i->rport_attrs[count++] = NULL;
847         BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
848
849         transport_container_register(&i->rport_attr_cont);
850
851         i->f = ft;
852
853         return &i->t;
854 }
855 EXPORT_SYMBOL_GPL(srp_attach_transport);
856
857 /**
858  * srp_release_transport  -  release SRP transport template instance
859  * @t:          transport template instance
860  */
861 void srp_release_transport(struct scsi_transport_template *t)
862 {
863         struct srp_internal *i = to_srp_internal(t);
864
865         transport_container_unregister(&i->t.host_attrs);
866         transport_container_unregister(&i->rport_attr_cont);
867
868         kfree(i);
869 }
870 EXPORT_SYMBOL_GPL(srp_release_transport);
871
872 static __init int srp_transport_init(void)
873 {
874         int ret;
875
876         ret = transport_class_register(&srp_host_class);
877         if (ret)
878                 return ret;
879         ret = transport_class_register(&srp_rport_class);
880         if (ret)
881                 goto unregister_host_class;
882
883         return 0;
884 unregister_host_class:
885         transport_class_unregister(&srp_host_class);
886         return ret;
887 }
888
889 static void __exit srp_transport_exit(void)
890 {
891         transport_class_unregister(&srp_host_class);
892         transport_class_unregister(&srp_rport_class);
893 }
894
895 MODULE_AUTHOR("FUJITA Tomonori");
896 MODULE_DESCRIPTION("SRP Transport Attributes");
897 MODULE_LICENSE("GPL");
898
899 module_init(srp_transport_init);
900 module_exit(srp_transport_exit);