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