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1/*
2 * SCSI RDMA (SRP) transport class
3 *
4 * Copyright (C) 2007 FUJITA Tomonori <tomof@acm.org>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation, version 2 of the
9 * License.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19 * 02110-1301 USA
20 */
21#include <linux/init.h>
22#include <linux/module.h>
23#include <linux/jiffies.h>
24#include <linux/err.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27
28#include <scsi/scsi.h>
29#include <scsi/scsi_cmnd.h>
30#include <scsi/scsi_device.h>
31#include <scsi/scsi_host.h>
32#include <scsi/scsi_transport.h>
33#include <scsi/scsi_transport_srp.h>
34#include "scsi_priv.h"
35
36struct srp_host_attrs {
37 atomic_t next_port_id;
38};
39#define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
40
41#define SRP_HOST_ATTRS 0
42#define SRP_RPORT_ATTRS 8
43
44struct srp_internal {
45 struct scsi_transport_template t;
46 struct srp_function_template *f;
47
48 struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
49
50 struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
51 struct transport_container rport_attr_cont;
52};
53
54#define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
55
56#define dev_to_rport(d) container_of(d, struct srp_rport, dev)
57#define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
58static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
59{
60 return dev_to_shost(r->dev.parent);
61}
62
63static inline struct srp_rport *shost_to_rport(struct Scsi_Host *shost)
64{
65 return transport_class_to_srp_rport(&shost->shost_gendev);
66}
67
68/**
69 * srp_tmo_valid() - check timeout combination validity
70 * @reconnect_delay: Reconnect delay in seconds.
71 * @fast_io_fail_tmo: Fast I/O fail timeout in seconds.
72 * @dev_loss_tmo: Device loss timeout in seconds.
73 *
74 * The combination of the timeout parameters must be such that SCSI commands
75 * are finished in a reasonable time. Hence do not allow the fast I/O fail
76 * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT nor allow dev_loss_tmo to
77 * exceed that limit if failing I/O fast has been disabled. Furthermore, these
78 * parameters must be such that multipath can detect failed paths timely.
79 * Hence do not allow all three parameters to be disabled simultaneously.
80 */
81int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
82{
83 if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
84 return -EINVAL;
85 if (reconnect_delay == 0)
86 return -EINVAL;
87 if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
88 return -EINVAL;
89 if (fast_io_fail_tmo < 0 &&
90 dev_loss_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
91 return -EINVAL;
92 if (dev_loss_tmo >= LONG_MAX / HZ)
93 return -EINVAL;
94 if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
95 fast_io_fail_tmo >= dev_loss_tmo)
96 return -EINVAL;
97 return 0;
98}
99EXPORT_SYMBOL_GPL(srp_tmo_valid);
100
101static int srp_host_setup(struct transport_container *tc, struct device *dev,
102 struct device *cdev)
103{
104 struct Scsi_Host *shost = dev_to_shost(dev);
105 struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
106
107 atomic_set(&srp_host->next_port_id, 0);
108 return 0;
109}
110
111static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
112 NULL, NULL);
113
114static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
115 NULL, NULL, NULL);
116
117static ssize_t
118show_srp_rport_id(struct device *dev, struct device_attribute *attr,
119 char *buf)
120{
121 struct srp_rport *rport = transport_class_to_srp_rport(dev);
122 return sprintf(buf, "%16phC\n", rport->port_id);
123}
124
125static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
126
127static const struct {
128 u32 value;
129 char *name;
130} srp_rport_role_names[] = {
131 {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
132 {SRP_RPORT_ROLE_TARGET, "SRP Target"},
133};
134
135static ssize_t
136show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
137 char *buf)
138{
139 struct srp_rport *rport = transport_class_to_srp_rport(dev);
140 int i;
141 char *name = NULL;
142
143 for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
144 if (srp_rport_role_names[i].value == rport->roles) {
145 name = srp_rport_role_names[i].name;
146 break;
147 }
148 return sprintf(buf, "%s\n", name ? : "unknown");
149}
150
151static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
152
153static ssize_t store_srp_rport_delete(struct device *dev,
154 struct device_attribute *attr,
155 const char *buf, size_t count)
156{
157 struct srp_rport *rport = transport_class_to_srp_rport(dev);
158 struct Scsi_Host *shost = dev_to_shost(dev);
159 struct srp_internal *i = to_srp_internal(shost->transportt);
160
161 if (i->f->rport_delete) {
162 i->f->rport_delete(rport);
163 return count;
164 } else {
165 return -ENOSYS;
166 }
167}
168
169static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
170
171static ssize_t show_srp_rport_state(struct device *dev,
172 struct device_attribute *attr,
173 char *buf)
174{
175 static const char *const state_name[] = {
176 [SRP_RPORT_RUNNING] = "running",
177 [SRP_RPORT_BLOCKED] = "blocked",
178 [SRP_RPORT_FAIL_FAST] = "fail-fast",
179 [SRP_RPORT_LOST] = "lost",
180 };
181 struct srp_rport *rport = transport_class_to_srp_rport(dev);
182 enum srp_rport_state state = rport->state;
183
184 return sprintf(buf, "%s\n",
185 (unsigned)state < ARRAY_SIZE(state_name) ?
186 state_name[state] : "???");
187}
188
189static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
190
191static ssize_t srp_show_tmo(char *buf, int tmo)
192{
193 return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
194}
195
196int srp_parse_tmo(int *tmo, const char *buf)
197{
198 int res = 0;
199
200 if (strncmp(buf, "off", 3) != 0)
201 res = kstrtoint(buf, 0, tmo);
202 else
203 *tmo = -1;
204
205 return res;
206}
207EXPORT_SYMBOL(srp_parse_tmo);
208
209static ssize_t show_reconnect_delay(struct device *dev,
210 struct device_attribute *attr, char *buf)
211{
212 struct srp_rport *rport = transport_class_to_srp_rport(dev);
213
214 return srp_show_tmo(buf, rport->reconnect_delay);
215}
216
217static ssize_t store_reconnect_delay(struct device *dev,
218 struct device_attribute *attr,
219 const char *buf, const size_t count)
220{
221 struct srp_rport *rport = transport_class_to_srp_rport(dev);
222 int res, delay;
223
224 res = srp_parse_tmo(&delay, buf);
225 if (res)
226 goto out;
227 res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
228 rport->dev_loss_tmo);
229 if (res)
230 goto out;
231
232 if (rport->reconnect_delay <= 0 && delay > 0 &&
233 rport->state != SRP_RPORT_RUNNING) {
234 queue_delayed_work(system_long_wq, &rport->reconnect_work,
235 delay * HZ);
236 } else if (delay <= 0) {
237 cancel_delayed_work(&rport->reconnect_work);
238 }
239 rport->reconnect_delay = delay;
240 res = count;
241
242out:
243 return res;
244}
245
246static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
247 store_reconnect_delay);
248
249static ssize_t show_failed_reconnects(struct device *dev,
250 struct device_attribute *attr, char *buf)
251{
252 struct srp_rport *rport = transport_class_to_srp_rport(dev);
253
254 return sprintf(buf, "%d\n", rport->failed_reconnects);
255}
256
257static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
258
259static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
260 struct device_attribute *attr,
261 char *buf)
262{
263 struct srp_rport *rport = transport_class_to_srp_rport(dev);
264
265 return srp_show_tmo(buf, rport->fast_io_fail_tmo);
266}
267
268static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
269 struct device_attribute *attr,
270 const char *buf, size_t count)
271{
272 struct srp_rport *rport = transport_class_to_srp_rport(dev);
273 int res;
274 int fast_io_fail_tmo;
275
276 res = srp_parse_tmo(&fast_io_fail_tmo, buf);
277 if (res)
278 goto out;
279 res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
280 rport->dev_loss_tmo);
281 if (res)
282 goto out;
283 rport->fast_io_fail_tmo = fast_io_fail_tmo;
284 res = count;
285
286out:
287 return res;
288}
289
290static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
291 show_srp_rport_fast_io_fail_tmo,
292 store_srp_rport_fast_io_fail_tmo);
293
294static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
295 struct device_attribute *attr,
296 char *buf)
297{
298 struct srp_rport *rport = transport_class_to_srp_rport(dev);
299
300 return srp_show_tmo(buf, rport->dev_loss_tmo);
301}
302
303static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
304 struct device_attribute *attr,
305 const char *buf, size_t count)
306{
307 struct srp_rport *rport = transport_class_to_srp_rport(dev);
308 int res;
309 int dev_loss_tmo;
310
311 res = srp_parse_tmo(&dev_loss_tmo, buf);
312 if (res)
313 goto out;
314 res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
315 dev_loss_tmo);
316 if (res)
317 goto out;
318 rport->dev_loss_tmo = dev_loss_tmo;
319 res = count;
320
321out:
322 return res;
323}
324
325static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
326 show_srp_rport_dev_loss_tmo,
327 store_srp_rport_dev_loss_tmo);
328
329static int srp_rport_set_state(struct srp_rport *rport,
330 enum srp_rport_state new_state)
331{
332 enum srp_rport_state old_state = rport->state;
333
334 lockdep_assert_held(&rport->mutex);
335
336 switch (new_state) {
337 case SRP_RPORT_RUNNING:
338 switch (old_state) {
339 case SRP_RPORT_LOST:
340 goto invalid;
341 default:
342 break;
343 }
344 break;
345 case SRP_RPORT_BLOCKED:
346 switch (old_state) {
347 case SRP_RPORT_RUNNING:
348 break;
349 default:
350 goto invalid;
351 }
352 break;
353 case SRP_RPORT_FAIL_FAST:
354 switch (old_state) {
355 case SRP_RPORT_LOST:
356 goto invalid;
357 default:
358 break;
359 }
360 break;
361 case SRP_RPORT_LOST:
362 break;
363 }
364 rport->state = new_state;
365 return 0;
366
367invalid:
368 return -EINVAL;
369}
370
371/**
372 * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
373 * @work: Work structure used for scheduling this operation.
374 */
375static void srp_reconnect_work(struct work_struct *work)
376{
377 struct srp_rport *rport = container_of(to_delayed_work(work),
378 struct srp_rport, reconnect_work);
379 struct Scsi_Host *shost = rport_to_shost(rport);
380 int delay, res;
381
382 res = srp_reconnect_rport(rport);
383 if (res != 0) {
384 shost_printk(KERN_ERR, shost,
385 "reconnect attempt %d failed (%d)\n",
386 ++rport->failed_reconnects, res);
387 delay = rport->reconnect_delay *
388 min(100, max(1, rport->failed_reconnects - 10));
389 if (delay > 0)
390 queue_delayed_work(system_long_wq,
391 &rport->reconnect_work, delay * HZ);
392 }
393}
394
395static void __rport_fail_io_fast(struct srp_rport *rport)
396{
397 struct Scsi_Host *shost = rport_to_shost(rport);
398 struct srp_internal *i;
399
400 lockdep_assert_held(&rport->mutex);
401
402 if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
403 return;
404 /*
405 * Call scsi_target_block() to wait for ongoing shost->queuecommand()
406 * calls before invoking i->f->terminate_rport_io().
407 */
408 scsi_target_block(rport->dev.parent);
409 scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
410
411 /* Involve the LLD if possible to terminate all I/O on the rport. */
412 i = to_srp_internal(shost->transportt);
413 if (i->f->terminate_rport_io)
414 i->f->terminate_rport_io(rport);
415}
416
417/**
418 * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
419 * @work: Work structure used for scheduling this operation.
420 */
421static void rport_fast_io_fail_timedout(struct work_struct *work)
422{
423 struct srp_rport *rport = container_of(to_delayed_work(work),
424 struct srp_rport, fast_io_fail_work);
425 struct Scsi_Host *shost = rport_to_shost(rport);
426
427 pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
428 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
429
430 mutex_lock(&rport->mutex);
431 if (rport->state == SRP_RPORT_BLOCKED)
432 __rport_fail_io_fast(rport);
433 mutex_unlock(&rport->mutex);
434}
435
436/**
437 * rport_dev_loss_timedout() - device loss timeout handler
438 * @work: Work structure used for scheduling this operation.
439 */
440static void rport_dev_loss_timedout(struct work_struct *work)
441{
442 struct srp_rport *rport = container_of(to_delayed_work(work),
443 struct srp_rport, dev_loss_work);
444 struct Scsi_Host *shost = rport_to_shost(rport);
445 struct srp_internal *i = to_srp_internal(shost->transportt);
446
447 pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
448 dev_name(&rport->dev), dev_name(&shost->shost_gendev));
449
450 mutex_lock(&rport->mutex);
451 WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
452 scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
453 mutex_unlock(&rport->mutex);
454
455 i->f->rport_delete(rport);
456}
457
458static void __srp_start_tl_fail_timers(struct srp_rport *rport)
459{
460 struct Scsi_Host *shost = rport_to_shost(rport);
461 int delay, fast_io_fail_tmo, dev_loss_tmo;
462
463 lockdep_assert_held(&rport->mutex);
464
465 delay = rport->reconnect_delay;
466 fast_io_fail_tmo = rport->fast_io_fail_tmo;
467 dev_loss_tmo = rport->dev_loss_tmo;
468 pr_debug("%s current state: %d\n", dev_name(&shost->shost_gendev),
469 rport->state);
470
471 if (rport->state == SRP_RPORT_LOST)
472 return;
473 if (delay > 0)
474 queue_delayed_work(system_long_wq, &rport->reconnect_work,
475 1UL * delay * HZ);
476 if ((fast_io_fail_tmo >= 0 || dev_loss_tmo >= 0) &&
477 srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
478 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
479 rport->state);
480 scsi_target_block(&shost->shost_gendev);
481 if (fast_io_fail_tmo >= 0)
482 queue_delayed_work(system_long_wq,
483 &rport->fast_io_fail_work,
484 1UL * fast_io_fail_tmo * HZ);
485 if (dev_loss_tmo >= 0)
486 queue_delayed_work(system_long_wq,
487 &rport->dev_loss_work,
488 1UL * dev_loss_tmo * HZ);
489 }
490}
491
492/**
493 * srp_start_tl_fail_timers() - start the transport layer failure timers
494 * @rport: SRP target port.
495 *
496 * Start the transport layer fast I/O failure and device loss timers. Do not
497 * modify a timer that was already started.
498 */
499void srp_start_tl_fail_timers(struct srp_rport *rport)
500{
501 mutex_lock(&rport->mutex);
502 __srp_start_tl_fail_timers(rport);
503 mutex_unlock(&rport->mutex);
504}
505EXPORT_SYMBOL(srp_start_tl_fail_timers);
506
507/**
508 * srp_reconnect_rport() - reconnect to an SRP target port
509 * @rport: SRP target port.
510 *
511 * Blocks SCSI command queueing before invoking reconnect() such that
512 * queuecommand() won't be invoked concurrently with reconnect() from outside
513 * the SCSI EH. This is important since a reconnect() implementation may
514 * reallocate resources needed by queuecommand().
515 *
516 * Notes:
517 * - This function neither waits until outstanding requests have finished nor
518 * tries to abort these. It is the responsibility of the reconnect()
519 * function to finish outstanding commands before reconnecting to the target
520 * port.
521 * - It is the responsibility of the caller to ensure that the resources
522 * reallocated by the reconnect() function won't be used while this function
523 * is in progress. One possible strategy is to invoke this function from
524 * the context of the SCSI EH thread only. Another possible strategy is to
525 * lock the rport mutex inside each SCSI LLD callback that can be invoked by
526 * the SCSI EH (the scsi_host_template.eh_*() functions and also the
527 * scsi_host_template.queuecommand() function).
528 */
529int srp_reconnect_rport(struct srp_rport *rport)
530{
531 struct Scsi_Host *shost = rport_to_shost(rport);
532 struct srp_internal *i = to_srp_internal(shost->transportt);
533 struct scsi_device *sdev;
534 int res;
535
536 pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
537
538 res = mutex_lock_interruptible(&rport->mutex);
539 if (res)
540 goto out;
541 scsi_target_block(&shost->shost_gendev);
542 res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
543 pr_debug("%s (state %d): transport.reconnect() returned %d\n",
544 dev_name(&shost->shost_gendev), rport->state, res);
545 if (res == 0) {
546 cancel_delayed_work(&rport->fast_io_fail_work);
547 cancel_delayed_work(&rport->dev_loss_work);
548
549 rport->failed_reconnects = 0;
550 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
551 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
552 /*
553 * If the SCSI error handler has offlined one or more devices,
554 * invoking scsi_target_unblock() won't change the state of
555 * these devices into running so do that explicitly.
556 */
557 spin_lock_irq(shost->host_lock);
558 __shost_for_each_device(sdev, shost)
559 if (sdev->sdev_state == SDEV_OFFLINE)
560 sdev->sdev_state = SDEV_RUNNING;
561 spin_unlock_irq(shost->host_lock);
562 } else if (rport->state == SRP_RPORT_RUNNING) {
563 /*
564 * srp_reconnect_rport() has been invoked with fast_io_fail
565 * and dev_loss off. Mark the port as failed and start the TL
566 * failure timers if these had not yet been started.
567 */
568 __rport_fail_io_fast(rport);
569 scsi_target_unblock(&shost->shost_gendev,
570 SDEV_TRANSPORT_OFFLINE);
571 __srp_start_tl_fail_timers(rport);
572 } else if (rport->state != SRP_RPORT_BLOCKED) {
573 scsi_target_unblock(&shost->shost_gendev,
574 SDEV_TRANSPORT_OFFLINE);
575 }
576 mutex_unlock(&rport->mutex);
577
578out:
579 return res;
580}
581EXPORT_SYMBOL(srp_reconnect_rport);
582
583/**
584 * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
585 * @scmd: SCSI command.
586 *
587 * If a timeout occurs while an rport is in the blocked state, ask the SCSI
588 * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
589 * handle the timeout (BLK_EH_NOT_HANDLED).
590 *
591 * Note: This function is called from soft-IRQ context and with the request
592 * queue lock held.
593 */
594static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
595{
596 struct scsi_device *sdev = scmd->device;
597 struct Scsi_Host *shost = sdev->host;
598 struct srp_internal *i = to_srp_internal(shost->transportt);
599 struct srp_rport *rport = shost_to_rport(shost);
600
601 pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
602 return rport->fast_io_fail_tmo < 0 && rport->dev_loss_tmo < 0 &&
603 i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
604 BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
605}
606
607static void srp_rport_release(struct device *dev)
608{
609 struct srp_rport *rport = dev_to_rport(dev);
610
611 put_device(dev->parent);
612 kfree(rport);
613}
614
615static int scsi_is_srp_rport(const struct device *dev)
616{
617 return dev->release == srp_rport_release;
618}
619
620static int srp_rport_match(struct attribute_container *cont,
621 struct device *dev)
622{
623 struct Scsi_Host *shost;
624 struct srp_internal *i;
625
626 if (!scsi_is_srp_rport(dev))
627 return 0;
628
629 shost = dev_to_shost(dev->parent);
630 if (!shost->transportt)
631 return 0;
632 if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
633 return 0;
634
635 i = to_srp_internal(shost->transportt);
636 return &i->rport_attr_cont.ac == cont;
637}
638
639static int srp_host_match(struct attribute_container *cont, struct device *dev)
640{
641 struct Scsi_Host *shost;
642 struct srp_internal *i;
643
644 if (!scsi_is_host_device(dev))
645 return 0;
646
647 shost = dev_to_shost(dev);
648 if (!shost->transportt)
649 return 0;
650 if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
651 return 0;
652
653 i = to_srp_internal(shost->transportt);
654 return &i->t.host_attrs.ac == cont;
655}
656
657/**
658 * srp_rport_get() - increment rport reference count
659 * @rport: SRP target port.
660 */
661void srp_rport_get(struct srp_rport *rport)
662{
663 get_device(&rport->dev);
664}
665EXPORT_SYMBOL(srp_rport_get);
666
667/**
668 * srp_rport_put() - decrement rport reference count
669 * @rport: SRP target port.
670 */
671void srp_rport_put(struct srp_rport *rport)
672{
673 put_device(&rport->dev);
674}
675EXPORT_SYMBOL(srp_rport_put);
676
677/**
678 * srp_rport_add - add a SRP remote port to the device hierarchy
679 * @shost: scsi host the remote port is connected to.
680 * @ids: The port id for the remote port.
681 *
682 * Publishes a port to the rest of the system.
683 */
684struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
685 struct srp_rport_identifiers *ids)
686{
687 struct srp_rport *rport;
688 struct device *parent = &shost->shost_gendev;
689 struct srp_internal *i = to_srp_internal(shost->transportt);
690 int id, ret;
691
692 rport = kzalloc(sizeof(*rport), GFP_KERNEL);
693 if (!rport)
694 return ERR_PTR(-ENOMEM);
695
696 mutex_init(&rport->mutex);
697
698 device_initialize(&rport->dev);
699
700 rport->dev.parent = get_device(parent);
701 rport->dev.release = srp_rport_release;
702
703 memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
704 rport->roles = ids->roles;
705
706 if (i->f->reconnect)
707 rport->reconnect_delay = i->f->reconnect_delay ?
708 *i->f->reconnect_delay : 10;
709 INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
710 rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
711 *i->f->fast_io_fail_tmo : 15;
712 rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
713 INIT_DELAYED_WORK(&rport->fast_io_fail_work,
714 rport_fast_io_fail_timedout);
715 INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
716
717 id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
718 dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
719
720 transport_setup_device(&rport->dev);
721
722 ret = device_add(&rport->dev);
723 if (ret) {
724 transport_destroy_device(&rport->dev);
725 put_device(&rport->dev);
726 return ERR_PTR(ret);
727 }
728
729 transport_add_device(&rport->dev);
730 transport_configure_device(&rport->dev);
731
732 return rport;
733}
734EXPORT_SYMBOL_GPL(srp_rport_add);
735
736/**
737 * srp_rport_del - remove a SRP remote port
738 * @rport: SRP remote port to remove
739 *
740 * Removes the specified SRP remote port.
741 */
742void srp_rport_del(struct srp_rport *rport)
743{
744 struct device *dev = &rport->dev;
745
746 transport_remove_device(dev);
747 device_del(dev);
748 transport_destroy_device(dev);
749
750 put_device(dev);
751}
752EXPORT_SYMBOL_GPL(srp_rport_del);
753
754static int do_srp_rport_del(struct device *dev, void *data)
755{
756 if (scsi_is_srp_rport(dev))
757 srp_rport_del(dev_to_rport(dev));
758 return 0;
759}
760
761/**
762 * srp_remove_host - tear down a Scsi_Host's SRP data structures
763 * @shost: Scsi Host that is torn down
764 *
765 * Removes all SRP remote ports for a given Scsi_Host.
766 * Must be called just before scsi_remove_host for SRP HBAs.
767 */
768void srp_remove_host(struct Scsi_Host *shost)
769{
770 device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
771}
772EXPORT_SYMBOL_GPL(srp_remove_host);
773
774/**
775 * srp_stop_rport_timers - stop the transport layer recovery timers
776 * @rport: SRP remote port for which to stop the timers.
777 *
778 * Must be called after srp_remove_host() and scsi_remove_host(). The caller
779 * must hold a reference on the rport (rport->dev) and on the SCSI host
780 * (rport->dev.parent).
781 */
782void srp_stop_rport_timers(struct srp_rport *rport)
783{
784 mutex_lock(&rport->mutex);
785 if (rport->state == SRP_RPORT_BLOCKED)
786 __rport_fail_io_fast(rport);
787 srp_rport_set_state(rport, SRP_RPORT_LOST);
788 mutex_unlock(&rport->mutex);
789
790 cancel_delayed_work_sync(&rport->reconnect_work);
791 cancel_delayed_work_sync(&rport->fast_io_fail_work);
792 cancel_delayed_work_sync(&rport->dev_loss_work);
793}
794EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
795
796static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
797 int result)
798{
799 struct srp_internal *i = to_srp_internal(shost->transportt);
800 return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
801}
802
803static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
804{
805 struct srp_internal *i = to_srp_internal(shost->transportt);
806 return i->f->it_nexus_response(shost, nexus, result);
807}
808
809/**
810 * srp_attach_transport - instantiate SRP transport template
811 * @ft: SRP transport class function template
812 */
813struct scsi_transport_template *
814srp_attach_transport(struct srp_function_template *ft)
815{
816 int count;
817 struct srp_internal *i;
818
819 i = kzalloc(sizeof(*i), GFP_KERNEL);
820 if (!i)
821 return NULL;
822
823 i->t.eh_timed_out = srp_timed_out;
824
825 i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
826 i->t.it_nexus_response = srp_it_nexus_response;
827
828 i->t.host_size = sizeof(struct srp_host_attrs);
829 i->t.host_attrs.ac.attrs = &i->host_attrs[0];
830 i->t.host_attrs.ac.class = &srp_host_class.class;
831 i->t.host_attrs.ac.match = srp_host_match;
832 i->host_attrs[0] = NULL;
833 transport_container_register(&i->t.host_attrs);
834
835 i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
836 i->rport_attr_cont.ac.class = &srp_rport_class.class;
837 i->rport_attr_cont.ac.match = srp_rport_match;
838
839 count = 0;
840 i->rport_attrs[count++] = &dev_attr_port_id;
841 i->rport_attrs[count++] = &dev_attr_roles;
842 if (ft->has_rport_state) {
843 i->rport_attrs[count++] = &dev_attr_state;
844 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
845 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
846 }
847 if (ft->reconnect) {
848 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
849 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
850 }
851 if (ft->rport_delete)
852 i->rport_attrs[count++] = &dev_attr_delete;
853 i->rport_attrs[count++] = NULL;
854 BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
855
856 transport_container_register(&i->rport_attr_cont);
857
858 i->f = ft;
859
860 return &i->t;
861}
862EXPORT_SYMBOL_GPL(srp_attach_transport);
863
864/**
865 * srp_release_transport - release SRP transport template instance
866 * @t: transport template instance
867 */
868void srp_release_transport(struct scsi_transport_template *t)
869{
870 struct srp_internal *i = to_srp_internal(t);
871
872 transport_container_unregister(&i->t.host_attrs);
873 transport_container_unregister(&i->rport_attr_cont);
874
875 kfree(i);
876}
877EXPORT_SYMBOL_GPL(srp_release_transport);
878
879static __init int srp_transport_init(void)
880{
881 int ret;
882
883 ret = transport_class_register(&srp_host_class);
884 if (ret)
885 return ret;
886 ret = transport_class_register(&srp_rport_class);
887 if (ret)
888 goto unregister_host_class;
889
890 return 0;
891unregister_host_class:
892 transport_class_unregister(&srp_host_class);
893 return ret;
894}
895
896static void __exit srp_transport_exit(void)
897{
898 transport_class_unregister(&srp_host_class);
899 transport_class_unregister(&srp_rport_class);
900}
901
902MODULE_AUTHOR("FUJITA Tomonori");
903MODULE_DESCRIPTION("SRP Transport Attributes");
904MODULE_LICENSE("GPL");
905
906module_init(srp_transport_init);
907module_exit(srp_transport_exit);
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
22struct 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
30struct 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
40static 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)
46static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
47{
48 return dev_to_shost(r->dev.parent);
49}
50
51static 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
62static 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 */
84int 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}
102EXPORT_SYMBOL_GPL(srp_tmo_valid);
103
104static 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
114static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
115 NULL, NULL);
116
117static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
118 NULL, NULL, NULL);
119
120static ssize_t
121show_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
128static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
129
130static 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
138static ssize_t
139show_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
154static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
155
156static 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
172static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
173
174static 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
192static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
193
194static 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
199int 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}
210EXPORT_SYMBOL(srp_parse_tmo);
211
212static 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
220static 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
245out:
246 return res;
247}
248
249static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
250 store_reconnect_delay);
251
252static 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
260static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
261
262static 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
271static 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
289out:
290 return res;
291}
292
293static 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
297static 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
306static 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
324out:
325 return res;
326}
327
328static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
329 show_srp_rport_dev_loss_tmo,
330 store_srp_rport_dev_loss_tmo);
331
332static 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
370invalid:
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 */
378static 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_block_targets() must have been called before this function is
400 * called to guarantee that no .queuecommand() calls are in progress.
401 */
402static 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 */
424static 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 */
443static 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
461static 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_block_targets(shost, &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 */
502void 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}
508EXPORT_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 */
532int 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_block_targets(shost, &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
587out:
588 return res;
589}
590EXPORT_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 (SCSI_EH_RESET_TIMER). Otherwise let the SCSI core
598 * handle the timeout (SCSI_EH_NOT_HANDLED).
599 *
600 * Note: This function is called from soft-IRQ context and with the request
601 * queue lock held.
602 */
603enum scsi_timeout_action 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 SCSI_EH_RESET_TIMER : SCSI_EH_NOT_HANDLED;
615}
616EXPORT_SYMBOL(srp_timed_out);
617
618static 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
626static int scsi_is_srp_rport(const struct device *dev)
627{
628 return dev->release == srp_rport_release;
629}
630
631static 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
650static 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 */
672void srp_rport_get(struct srp_rport *rport)
673{
674 get_device(&rport->dev);
675}
676EXPORT_SYMBOL(srp_rport_get);
677
678/**
679 * srp_rport_put() - decrement rport reference count
680 * @rport: SRP target port.
681 */
682void srp_rport_put(struct srp_rport *rport)
683{
684 put_device(&rport->dev);
685}
686EXPORT_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 */
695struct 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}
745EXPORT_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 */
753void 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}
763EXPORT_SYMBOL_GPL(srp_rport_del);
764
765static 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 */
779void srp_remove_host(struct Scsi_Host *shost)
780{
781 device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
782}
783EXPORT_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 */
793void 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}
805EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
806
807/**
808 * srp_attach_transport - instantiate SRP transport template
809 * @ft: SRP transport class function template
810 */
811struct scsi_transport_template *
812srp_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}
855EXPORT_SYMBOL_GPL(srp_attach_transport);
856
857/**
858 * srp_release_transport - release SRP transport template instance
859 * @t: transport template instance
860 */
861void 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}
870EXPORT_SYMBOL_GPL(srp_release_transport);
871
872static __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;
884unregister_host_class:
885 transport_class_unregister(&srp_host_class);
886 return ret;
887}
888
889static void __exit srp_transport_exit(void)
890{
891 transport_class_unregister(&srp_host_class);
892 transport_class_unregister(&srp_rport_class);
893}
894
895MODULE_AUTHOR("FUJITA Tomonori");
896MODULE_DESCRIPTION("SRP Transport Attributes");
897MODULE_LICENSE("GPL");
898
899module_init(srp_transport_init);
900module_exit(srp_transport_exit);