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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#include <linux/delay.h>
28
29#include <scsi/scsi.h>
30#include <scsi/scsi_cmnd.h>
31#include <scsi/scsi_device.h>
32#include <scsi/scsi_host.h>
33#include <scsi/scsi_transport.h>
34#include <scsi/scsi_transport_srp.h>
35#include "scsi_priv.h"
36#include "scsi_transport_srp_internal.h"
37
38struct srp_host_attrs {
39 atomic_t next_port_id;
40};
41#define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
42
43#define SRP_HOST_ATTRS 0
44#define SRP_RPORT_ATTRS 8
45
46struct srp_internal {
47 struct scsi_transport_template t;
48 struct srp_function_template *f;
49
50 struct device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
51
52 struct device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
53 struct transport_container rport_attr_cont;
54};
55
56#define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
57
58#define dev_to_rport(d) container_of(d, struct srp_rport, dev)
59#define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
60static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
61{
62 return dev_to_shost(r->dev.parent);
63}
64
65/**
66 * srp_tmo_valid() - check timeout combination validity
67 * @reconnect_delay: Reconnect delay in seconds.
68 * @fast_io_fail_tmo: Fast I/O fail timeout in seconds.
69 * @dev_loss_tmo: Device loss timeout in seconds.
70 *
71 * The combination of the timeout parameters must be such that SCSI commands
72 * are finished in a reasonable time. Hence do not allow the fast I/O fail
73 * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT nor allow dev_loss_tmo to
74 * exceed that limit if failing I/O fast has been disabled. Furthermore, these
75 * parameters must be such that multipath can detect failed paths timely.
76 * Hence do not allow all three parameters to be disabled simultaneously.
77 */
78int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
79{
80 if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
81 return -EINVAL;
82 if (reconnect_delay == 0)
83 return -EINVAL;
84 if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
85 return -EINVAL;
86 if (fast_io_fail_tmo < 0 &&
87 dev_loss_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
88 return -EINVAL;
89 if (dev_loss_tmo >= LONG_MAX / HZ)
90 return -EINVAL;
91 if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
92 fast_io_fail_tmo >= dev_loss_tmo)
93 return -EINVAL;
94 return 0;
95}
96EXPORT_SYMBOL_GPL(srp_tmo_valid);
97
98static int srp_host_setup(struct transport_container *tc, struct device *dev,
99 struct device *cdev)
100{
101 struct Scsi_Host *shost = dev_to_shost(dev);
102 struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
103
104 atomic_set(&srp_host->next_port_id, 0);
105 return 0;
106}
107
108static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
109 NULL, NULL);
110
111static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
112 NULL, NULL, NULL);
113
114#define SRP_PID(p) \
115 (p)->port_id[0], (p)->port_id[1], (p)->port_id[2], (p)->port_id[3], \
116 (p)->port_id[4], (p)->port_id[5], (p)->port_id[6], (p)->port_id[7], \
117 (p)->port_id[8], (p)->port_id[9], (p)->port_id[10], (p)->port_id[11], \
118 (p)->port_id[12], (p)->port_id[13], (p)->port_id[14], (p)->port_id[15]
119
120#define SRP_PID_FMT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:" \
121 "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"
122
123static ssize_t
124show_srp_rport_id(struct device *dev, struct device_attribute *attr,
125 char *buf)
126{
127 struct srp_rport *rport = transport_class_to_srp_rport(dev);
128 return sprintf(buf, SRP_PID_FMT "\n", SRP_PID(rport));
129}
130
131static DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
132
133static const struct {
134 u32 value;
135 char *name;
136} srp_rport_role_names[] = {
137 {SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
138 {SRP_RPORT_ROLE_TARGET, "SRP Target"},
139};
140
141static ssize_t
142show_srp_rport_roles(struct device *dev, struct device_attribute *attr,
143 char *buf)
144{
145 struct srp_rport *rport = transport_class_to_srp_rport(dev);
146 int i;
147 char *name = NULL;
148
149 for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
150 if (srp_rport_role_names[i].value == rport->roles) {
151 name = srp_rport_role_names[i].name;
152 break;
153 }
154 return sprintf(buf, "%s\n", name ? : "unknown");
155}
156
157static DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
158
159static ssize_t store_srp_rport_delete(struct device *dev,
160 struct device_attribute *attr,
161 const char *buf, size_t count)
162{
163 struct srp_rport *rport = transport_class_to_srp_rport(dev);
164 struct Scsi_Host *shost = dev_to_shost(dev);
165 struct srp_internal *i = to_srp_internal(shost->transportt);
166
167 if (i->f->rport_delete) {
168 i->f->rport_delete(rport);
169 return count;
170 } else {
171 return -ENOSYS;
172 }
173}
174
175static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
176
177static ssize_t show_srp_rport_state(struct device *dev,
178 struct device_attribute *attr,
179 char *buf)
180{
181 static const char *const state_name[] = {
182 [SRP_RPORT_RUNNING] = "running",
183 [SRP_RPORT_BLOCKED] = "blocked",
184 [SRP_RPORT_FAIL_FAST] = "fail-fast",
185 [SRP_RPORT_LOST] = "lost",
186 };
187 struct srp_rport *rport = transport_class_to_srp_rport(dev);
188 enum srp_rport_state state = rport->state;
189
190 return sprintf(buf, "%s\n",
191 (unsigned)state < ARRAY_SIZE(state_name) ?
192 state_name[state] : "???");
193}
194
195static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
196
197static ssize_t srp_show_tmo(char *buf, int tmo)
198{
199 return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
200}
201
202static int srp_parse_tmo(int *tmo, const char *buf)
203{
204 int res = 0;
205
206 if (strncmp(buf, "off", 3) != 0)
207 res = kstrtoint(buf, 0, tmo);
208 else
209 *tmo = -1;
210
211 return res;
212}
213
214static ssize_t show_reconnect_delay(struct device *dev,
215 struct device_attribute *attr, char *buf)
216{
217 struct srp_rport *rport = transport_class_to_srp_rport(dev);
218
219 return srp_show_tmo(buf, rport->reconnect_delay);
220}
221
222static ssize_t store_reconnect_delay(struct device *dev,
223 struct device_attribute *attr,
224 const char *buf, const size_t count)
225{
226 struct srp_rport *rport = transport_class_to_srp_rport(dev);
227 int res, delay;
228
229 res = srp_parse_tmo(&delay, buf);
230 if (res)
231 goto out;
232 res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
233 rport->dev_loss_tmo);
234 if (res)
235 goto out;
236
237 if (rport->reconnect_delay <= 0 && delay > 0 &&
238 rport->state != SRP_RPORT_RUNNING) {
239 queue_delayed_work(system_long_wq, &rport->reconnect_work,
240 delay * HZ);
241 } else if (delay <= 0) {
242 cancel_delayed_work(&rport->reconnect_work);
243 }
244 rport->reconnect_delay = delay;
245 res = count;
246
247out:
248 return res;
249}
250
251static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
252 store_reconnect_delay);
253
254static ssize_t show_failed_reconnects(struct device *dev,
255 struct device_attribute *attr, char *buf)
256{
257 struct srp_rport *rport = transport_class_to_srp_rport(dev);
258
259 return sprintf(buf, "%d\n", rport->failed_reconnects);
260}
261
262static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
263
264static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
265 struct device_attribute *attr,
266 char *buf)
267{
268 struct srp_rport *rport = transport_class_to_srp_rport(dev);
269
270 return srp_show_tmo(buf, rport->fast_io_fail_tmo);
271}
272
273static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
274 struct device_attribute *attr,
275 const char *buf, size_t count)
276{
277 struct srp_rport *rport = transport_class_to_srp_rport(dev);
278 int res;
279 int fast_io_fail_tmo;
280
281 res = srp_parse_tmo(&fast_io_fail_tmo, buf);
282 if (res)
283 goto out;
284 res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
285 rport->dev_loss_tmo);
286 if (res)
287 goto out;
288 rport->fast_io_fail_tmo = fast_io_fail_tmo;
289 res = count;
290
291out:
292 return res;
293}
294
295static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
296 show_srp_rport_fast_io_fail_tmo,
297 store_srp_rport_fast_io_fail_tmo);
298
299static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev,
300 struct device_attribute *attr,
301 char *buf)
302{
303 struct srp_rport *rport = transport_class_to_srp_rport(dev);
304
305 return srp_show_tmo(buf, rport->dev_loss_tmo);
306}
307
308static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
309 struct device_attribute *attr,
310 const char *buf, size_t count)
311{
312 struct srp_rport *rport = transport_class_to_srp_rport(dev);
313 int res;
314 int dev_loss_tmo;
315
316 res = srp_parse_tmo(&dev_loss_tmo, buf);
317 if (res)
318 goto out;
319 res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
320 dev_loss_tmo);
321 if (res)
322 goto out;
323 rport->dev_loss_tmo = dev_loss_tmo;
324 res = count;
325
326out:
327 return res;
328}
329
330static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
331 show_srp_rport_dev_loss_tmo,
332 store_srp_rport_dev_loss_tmo);
333
334static int srp_rport_set_state(struct srp_rport *rport,
335 enum srp_rport_state new_state)
336{
337 enum srp_rport_state old_state = rport->state;
338
339 lockdep_assert_held(&rport->mutex);
340
341 switch (new_state) {
342 case SRP_RPORT_RUNNING:
343 switch (old_state) {
344 case SRP_RPORT_LOST:
345 goto invalid;
346 default:
347 break;
348 }
349 break;
350 case SRP_RPORT_BLOCKED:
351 switch (old_state) {
352 case SRP_RPORT_RUNNING:
353 break;
354 default:
355 goto invalid;
356 }
357 break;
358 case SRP_RPORT_FAIL_FAST:
359 switch (old_state) {
360 case SRP_RPORT_LOST:
361 goto invalid;
362 default:
363 break;
364 }
365 break;
366 case SRP_RPORT_LOST:
367 break;
368 }
369 rport->state = new_state;
370 return 0;
371
372invalid:
373 return -EINVAL;
374}
375
376/**
377 * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
378 * @work: Work structure used for scheduling this operation.
379 */
380static void srp_reconnect_work(struct work_struct *work)
381{
382 struct srp_rport *rport = container_of(to_delayed_work(work),
383 struct srp_rport, reconnect_work);
384 struct Scsi_Host *shost = rport_to_shost(rport);
385 int delay, res;
386
387 res = srp_reconnect_rport(rport);
388 if (res != 0) {
389 shost_printk(KERN_ERR, shost,
390 "reconnect attempt %d failed (%d)\n",
391 ++rport->failed_reconnects, res);
392 delay = rport->reconnect_delay *
393 min(100, max(1, rport->failed_reconnects - 10));
394 if (delay > 0)
395 queue_delayed_work(system_long_wq,
396 &rport->reconnect_work, delay * HZ);
397 }
398}
399
400static void __rport_fail_io_fast(struct srp_rport *rport)
401{
402 struct Scsi_Host *shost = rport_to_shost(rport);
403 struct srp_internal *i;
404
405 lockdep_assert_held(&rport->mutex);
406
407 if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
408 return;
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 (srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
477 pr_debug("%s new state: %d\n", dev_name(&shost->shost_gendev),
478 rport->state);
479 scsi_target_block(&shost->shost_gendev);
480 if (fast_io_fail_tmo >= 0)
481 queue_delayed_work(system_long_wq,
482 &rport->fast_io_fail_work,
483 1UL * fast_io_fail_tmo * HZ);
484 if (dev_loss_tmo >= 0)
485 queue_delayed_work(system_long_wq,
486 &rport->dev_loss_work,
487 1UL * dev_loss_tmo * HZ);
488 }
489}
490
491/**
492 * srp_start_tl_fail_timers() - start the transport layer failure timers
493 * @rport: SRP target port.
494 *
495 * Start the transport layer fast I/O failure and device loss timers. Do not
496 * modify a timer that was already started.
497 */
498void srp_start_tl_fail_timers(struct srp_rport *rport)
499{
500 mutex_lock(&rport->mutex);
501 __srp_start_tl_fail_timers(rport);
502 mutex_unlock(&rport->mutex);
503}
504EXPORT_SYMBOL(srp_start_tl_fail_timers);
505
506/**
507 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
508 * @shost: SCSI host for which to count the number of scsi_request_fn() callers.
509 */
510static int scsi_request_fn_active(struct Scsi_Host *shost)
511{
512 struct scsi_device *sdev;
513 struct request_queue *q;
514 int request_fn_active = 0;
515
516 shost_for_each_device(sdev, shost) {
517 q = sdev->request_queue;
518
519 spin_lock_irq(q->queue_lock);
520 request_fn_active += q->request_fn_active;
521 spin_unlock_irq(q->queue_lock);
522 }
523
524 return request_fn_active;
525}
526
527/**
528 * srp_reconnect_rport() - reconnect to an SRP target port
529 * @rport: SRP target port.
530 *
531 * Blocks SCSI command queueing before invoking reconnect() such that
532 * queuecommand() won't be invoked concurrently with reconnect() from outside
533 * the SCSI EH. This is important since a reconnect() implementation may
534 * reallocate resources needed by queuecommand().
535 *
536 * Notes:
537 * - This function neither waits until outstanding requests have finished nor
538 * tries to abort these. It is the responsibility of the reconnect()
539 * function to finish outstanding commands before reconnecting to the target
540 * port.
541 * - It is the responsibility of the caller to ensure that the resources
542 * reallocated by the reconnect() function won't be used while this function
543 * is in progress. One possible strategy is to invoke this function from
544 * the context of the SCSI EH thread only. Another possible strategy is to
545 * lock the rport mutex inside each SCSI LLD callback that can be invoked by
546 * the SCSI EH (the scsi_host_template.eh_*() functions and also the
547 * scsi_host_template.queuecommand() function).
548 */
549int srp_reconnect_rport(struct srp_rport *rport)
550{
551 struct Scsi_Host *shost = rport_to_shost(rport);
552 struct srp_internal *i = to_srp_internal(shost->transportt);
553 struct scsi_device *sdev;
554 int res;
555
556 pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
557
558 res = mutex_lock_interruptible(&rport->mutex);
559 if (res)
560 goto out;
561 scsi_target_block(&shost->shost_gendev);
562 while (scsi_request_fn_active(shost))
563 msleep(20);
564 res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
565 pr_debug("%s (state %d): transport.reconnect() returned %d\n",
566 dev_name(&shost->shost_gendev), rport->state, res);
567 if (res == 0) {
568 cancel_delayed_work(&rport->fast_io_fail_work);
569 cancel_delayed_work(&rport->dev_loss_work);
570
571 rport->failed_reconnects = 0;
572 srp_rport_set_state(rport, SRP_RPORT_RUNNING);
573 scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
574 /*
575 * If the SCSI error handler has offlined one or more devices,
576 * invoking scsi_target_unblock() won't change the state of
577 * these devices into running so do that explicitly.
578 */
579 spin_lock_irq(shost->host_lock);
580 __shost_for_each_device(sdev, shost)
581 if (sdev->sdev_state == SDEV_OFFLINE)
582 sdev->sdev_state = SDEV_RUNNING;
583 spin_unlock_irq(shost->host_lock);
584 } else if (rport->state == SRP_RPORT_RUNNING) {
585 /*
586 * srp_reconnect_rport() has been invoked with fast_io_fail
587 * and dev_loss off. Mark the port as failed and start the TL
588 * failure timers if these had not yet been started.
589 */
590 __rport_fail_io_fast(rport);
591 scsi_target_unblock(&shost->shost_gendev,
592 SDEV_TRANSPORT_OFFLINE);
593 __srp_start_tl_fail_timers(rport);
594 } else if (rport->state != SRP_RPORT_BLOCKED) {
595 scsi_target_unblock(&shost->shost_gendev,
596 SDEV_TRANSPORT_OFFLINE);
597 }
598 mutex_unlock(&rport->mutex);
599
600out:
601 return res;
602}
603EXPORT_SYMBOL(srp_reconnect_rport);
604
605/**
606 * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
607 * @scmd: SCSI command.
608 *
609 * If a timeout occurs while an rport is in the blocked state, ask the SCSI
610 * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
611 * handle the timeout (BLK_EH_NOT_HANDLED).
612 *
613 * Note: This function is called from soft-IRQ context and with the request
614 * queue lock held.
615 */
616static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
617{
618 struct scsi_device *sdev = scmd->device;
619 struct Scsi_Host *shost = sdev->host;
620 struct srp_internal *i = to_srp_internal(shost->transportt);
621
622 pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
623 return i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
624 BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
625}
626
627static void srp_rport_release(struct device *dev)
628{
629 struct srp_rport *rport = dev_to_rport(dev);
630
631 put_device(dev->parent);
632 kfree(rport);
633}
634
635static int scsi_is_srp_rport(const struct device *dev)
636{
637 return dev->release == srp_rport_release;
638}
639
640static int srp_rport_match(struct attribute_container *cont,
641 struct device *dev)
642{
643 struct Scsi_Host *shost;
644 struct srp_internal *i;
645
646 if (!scsi_is_srp_rport(dev))
647 return 0;
648
649 shost = dev_to_shost(dev->parent);
650 if (!shost->transportt)
651 return 0;
652 if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
653 return 0;
654
655 i = to_srp_internal(shost->transportt);
656 return &i->rport_attr_cont.ac == cont;
657}
658
659static int srp_host_match(struct attribute_container *cont, struct device *dev)
660{
661 struct Scsi_Host *shost;
662 struct srp_internal *i;
663
664 if (!scsi_is_host_device(dev))
665 return 0;
666
667 shost = dev_to_shost(dev);
668 if (!shost->transportt)
669 return 0;
670 if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
671 return 0;
672
673 i = to_srp_internal(shost->transportt);
674 return &i->t.host_attrs.ac == cont;
675}
676
677/**
678 * srp_rport_get() - increment rport reference count
679 * @rport: SRP target port.
680 */
681void srp_rport_get(struct srp_rport *rport)
682{
683 get_device(&rport->dev);
684}
685EXPORT_SYMBOL(srp_rport_get);
686
687/**
688 * srp_rport_put() - decrement rport reference count
689 * @rport: SRP target port.
690 */
691void srp_rport_put(struct srp_rport *rport)
692{
693 put_device(&rport->dev);
694}
695EXPORT_SYMBOL(srp_rport_put);
696
697/**
698 * srp_rport_add - add a SRP remote port to the device hierarchy
699 * @shost: scsi host the remote port is connected to.
700 * @ids: The port id for the remote port.
701 *
702 * Publishes a port to the rest of the system.
703 */
704struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
705 struct srp_rport_identifiers *ids)
706{
707 struct srp_rport *rport;
708 struct device *parent = &shost->shost_gendev;
709 struct srp_internal *i = to_srp_internal(shost->transportt);
710 int id, ret;
711
712 rport = kzalloc(sizeof(*rport), GFP_KERNEL);
713 if (!rport)
714 return ERR_PTR(-ENOMEM);
715
716 mutex_init(&rport->mutex);
717
718 device_initialize(&rport->dev);
719
720 rport->dev.parent = get_device(parent);
721 rport->dev.release = srp_rport_release;
722
723 memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
724 rport->roles = ids->roles;
725
726 if (i->f->reconnect)
727 rport->reconnect_delay = i->f->reconnect_delay ?
728 *i->f->reconnect_delay : 10;
729 INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
730 rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
731 *i->f->fast_io_fail_tmo : 15;
732 rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
733 INIT_DELAYED_WORK(&rport->fast_io_fail_work,
734 rport_fast_io_fail_timedout);
735 INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
736
737 id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
738 dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
739
740 transport_setup_device(&rport->dev);
741
742 ret = device_add(&rport->dev);
743 if (ret) {
744 transport_destroy_device(&rport->dev);
745 put_device(&rport->dev);
746 return ERR_PTR(ret);
747 }
748
749 if (shost->active_mode & MODE_TARGET &&
750 ids->roles == SRP_RPORT_ROLE_INITIATOR) {
751 ret = srp_tgt_it_nexus_create(shost, (unsigned long)rport,
752 rport->port_id);
753 if (ret) {
754 device_del(&rport->dev);
755 transport_destroy_device(&rport->dev);
756 put_device(&rport->dev);
757 return ERR_PTR(ret);
758 }
759 }
760
761 transport_add_device(&rport->dev);
762 transport_configure_device(&rport->dev);
763
764 return rport;
765}
766EXPORT_SYMBOL_GPL(srp_rport_add);
767
768/**
769 * srp_rport_del - remove a SRP remote port
770 * @rport: SRP remote port to remove
771 *
772 * Removes the specified SRP remote port.
773 */
774void srp_rport_del(struct srp_rport *rport)
775{
776 struct device *dev = &rport->dev;
777 struct Scsi_Host *shost = dev_to_shost(dev->parent);
778
779 if (shost->active_mode & MODE_TARGET &&
780 rport->roles == SRP_RPORT_ROLE_INITIATOR)
781 srp_tgt_it_nexus_destroy(shost, (unsigned long)rport);
782
783 transport_remove_device(dev);
784 device_del(dev);
785 transport_destroy_device(dev);
786
787 put_device(dev);
788}
789EXPORT_SYMBOL_GPL(srp_rport_del);
790
791static int do_srp_rport_del(struct device *dev, void *data)
792{
793 if (scsi_is_srp_rport(dev))
794 srp_rport_del(dev_to_rport(dev));
795 return 0;
796}
797
798/**
799 * srp_remove_host - tear down a Scsi_Host's SRP data structures
800 * @shost: Scsi Host that is torn down
801 *
802 * Removes all SRP remote ports for a given Scsi_Host.
803 * Must be called just before scsi_remove_host for SRP HBAs.
804 */
805void srp_remove_host(struct Scsi_Host *shost)
806{
807 device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
808}
809EXPORT_SYMBOL_GPL(srp_remove_host);
810
811/**
812 * srp_stop_rport_timers - stop the transport layer recovery timers
813 * @rport: SRP remote port for which to stop the timers.
814 *
815 * Must be called after srp_remove_host() and scsi_remove_host(). The caller
816 * must hold a reference on the rport (rport->dev) and on the SCSI host
817 * (rport->dev.parent).
818 */
819void srp_stop_rport_timers(struct srp_rport *rport)
820{
821 mutex_lock(&rport->mutex);
822 if (rport->state == SRP_RPORT_BLOCKED)
823 __rport_fail_io_fast(rport);
824 srp_rport_set_state(rport, SRP_RPORT_LOST);
825 mutex_unlock(&rport->mutex);
826
827 cancel_delayed_work_sync(&rport->reconnect_work);
828 cancel_delayed_work_sync(&rport->fast_io_fail_work);
829 cancel_delayed_work_sync(&rport->dev_loss_work);
830}
831EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
832
833static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
834 int result)
835{
836 struct srp_internal *i = to_srp_internal(shost->transportt);
837 return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
838}
839
840static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
841{
842 struct srp_internal *i = to_srp_internal(shost->transportt);
843 return i->f->it_nexus_response(shost, nexus, result);
844}
845
846/**
847 * srp_attach_transport - instantiate SRP transport template
848 * @ft: SRP transport class function template
849 */
850struct scsi_transport_template *
851srp_attach_transport(struct srp_function_template *ft)
852{
853 int count;
854 struct srp_internal *i;
855
856 i = kzalloc(sizeof(*i), GFP_KERNEL);
857 if (!i)
858 return NULL;
859
860 i->t.eh_timed_out = srp_timed_out;
861
862 i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
863 i->t.it_nexus_response = srp_it_nexus_response;
864
865 i->t.host_size = sizeof(struct srp_host_attrs);
866 i->t.host_attrs.ac.attrs = &i->host_attrs[0];
867 i->t.host_attrs.ac.class = &srp_host_class.class;
868 i->t.host_attrs.ac.match = srp_host_match;
869 i->host_attrs[0] = NULL;
870 transport_container_register(&i->t.host_attrs);
871
872 i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
873 i->rport_attr_cont.ac.class = &srp_rport_class.class;
874 i->rport_attr_cont.ac.match = srp_rport_match;
875
876 count = 0;
877 i->rport_attrs[count++] = &dev_attr_port_id;
878 i->rport_attrs[count++] = &dev_attr_roles;
879 if (ft->has_rport_state) {
880 i->rport_attrs[count++] = &dev_attr_state;
881 i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
882 i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
883 }
884 if (ft->reconnect) {
885 i->rport_attrs[count++] = &dev_attr_reconnect_delay;
886 i->rport_attrs[count++] = &dev_attr_failed_reconnects;
887 }
888 if (ft->rport_delete)
889 i->rport_attrs[count++] = &dev_attr_delete;
890 i->rport_attrs[count++] = NULL;
891 BUG_ON(count > ARRAY_SIZE(i->rport_attrs));
892
893 transport_container_register(&i->rport_attr_cont);
894
895 i->f = ft;
896
897 return &i->t;
898}
899EXPORT_SYMBOL_GPL(srp_attach_transport);
900
901/**
902 * srp_release_transport - release SRP transport template instance
903 * @t: transport template instance
904 */
905void srp_release_transport(struct scsi_transport_template *t)
906{
907 struct srp_internal *i = to_srp_internal(t);
908
909 transport_container_unregister(&i->t.host_attrs);
910 transport_container_unregister(&i->rport_attr_cont);
911
912 kfree(i);
913}
914EXPORT_SYMBOL_GPL(srp_release_transport);
915
916static __init int srp_transport_init(void)
917{
918 int ret;
919
920 ret = transport_class_register(&srp_host_class);
921 if (ret)
922 return ret;
923 ret = transport_class_register(&srp_rport_class);
924 if (ret)
925 goto unregister_host_class;
926
927 return 0;
928unregister_host_class:
929 transport_class_unregister(&srp_host_class);
930 return ret;
931}
932
933static void __exit srp_transport_exit(void)
934{
935 transport_class_unregister(&srp_host_class);
936 transport_class_unregister(&srp_rport_class);
937}
938
939MODULE_AUTHOR("FUJITA Tomonori");
940MODULE_DESCRIPTION("SRP Transport Attributes");
941MODULE_LICENSE("GPL");
942
943module_init(srp_transport_init);
944module_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);