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);