1 /*******************************************************************************
2  *
3  * This file contains the Linux/SCSI LLD virtual SCSI initiator driver
4  * for emulated SAS initiator ports
5  *
6  * © Copyright 2011-2013 Datera, Inc.
7  *
8  * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
9  *
10  * Author: Nicholas A. Bellinger <nab@risingtidesystems.com>
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License as published by
14  * the Free Software Foundation; either version 2 of the License, or
15  * (at your option) any later version.
16  *
17  * This program is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  * GNU General Public License for more details.
21  ****************************************************************************/
22 
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/init.h>
26 #include <linux/slab.h>
27 #include <linux/types.h>
28 #include <linux/configfs.h>
29 #include <scsi/scsi.h>
30 #include <scsi/scsi_tcq.h>
31 #include <scsi/scsi_host.h>
32 #include <scsi/scsi_device.h>
33 #include <scsi/scsi_cmnd.h>
34 
35 #include <target/target_core_base.h>
36 #include <target/target_core_fabric.h>
37 #include <target/target_core_fabric_configfs.h>
38 #include <target/target_core_configfs.h>
39 
40 #include "tcm_loop.h"
41 
42 #define to_tcm_loop_hba(hba)	container_of(hba, struct tcm_loop_hba, dev)
43 
44 /* Local pointer to allocated TCM configfs fabric module */
45 static struct target_fabric_configfs *tcm_loop_fabric_configfs;
46 
47 static struct workqueue_struct *tcm_loop_workqueue;
48 static struct kmem_cache *tcm_loop_cmd_cache;
49 
50 static int tcm_loop_hba_no_cnt;
51 
52 static int tcm_loop_queue_status(struct se_cmd *se_cmd);
53 
54 /*
55  * Called from struct target_core_fabric_ops->check_stop_free()
56  */
57 static int tcm_loop_check_stop_free(struct se_cmd *se_cmd)
58 {
59 	/*
60 	 * Do not release struct se_cmd's containing a valid TMR
61 	 * pointer.  These will be released directly in tcm_loop_device_reset()
62 	 * with transport_generic_free_cmd().
63 	 */
64 	if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
65 		return 0;
66 	/*
67 	 * Release the struct se_cmd, which will make a callback to release
68 	 * struct tcm_loop_cmd * in tcm_loop_deallocate_core_cmd()
69 	 */
70 	transport_generic_free_cmd(se_cmd, 0);
71 	return 1;
72 }
73 
74 static void tcm_loop_release_cmd(struct se_cmd *se_cmd)
75 {
76 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
77 				struct tcm_loop_cmd, tl_se_cmd);
78 
79 	kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
80 }
81 
82 static int tcm_loop_show_info(struct seq_file *m, struct Scsi_Host *host)
83 {
84 	seq_printf(m, "tcm_loop_proc_info()\n");
85 	return 0;
86 }
87 
88 static int tcm_loop_driver_probe(struct device *);
89 static int tcm_loop_driver_remove(struct device *);
90 
91 static int pseudo_lld_bus_match(struct device *dev,
92 				struct device_driver *dev_driver)
93 {
94 	return 1;
95 }
96 
97 static struct bus_type tcm_loop_lld_bus = {
98 	.name			= "tcm_loop_bus",
99 	.match			= pseudo_lld_bus_match,
100 	.probe			= tcm_loop_driver_probe,
101 	.remove			= tcm_loop_driver_remove,
102 };
103 
104 static struct device_driver tcm_loop_driverfs = {
105 	.name			= "tcm_loop",
106 	.bus			= &tcm_loop_lld_bus,
107 };
108 /*
109  * Used with root_device_register() in tcm_loop_alloc_core_bus() below
110  */
111 struct device *tcm_loop_primary;
112 
113 /*
114  * Copied from drivers/scsi/libfc/fc_fcp.c:fc_change_queue_depth() and
115  * drivers/scsi/libiscsi.c:iscsi_change_queue_depth()
116  */
117 static int tcm_loop_change_queue_depth(
118 	struct scsi_device *sdev,
119 	int depth,
120 	int reason)
121 {
122 	switch (reason) {
123 	case SCSI_QDEPTH_DEFAULT:
124 		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
125 		break;
126 	case SCSI_QDEPTH_QFULL:
127 		scsi_track_queue_full(sdev, depth);
128 		break;
129 	case SCSI_QDEPTH_RAMP_UP:
130 		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
131 		break;
132 	default:
133 		return -EOPNOTSUPP;
134 	}
135 	return sdev->queue_depth;
136 }
137 
138 static int tcm_loop_change_queue_type(struct scsi_device *sdev, int tag)
139 {
140 	if (sdev->tagged_supported) {
141 		scsi_set_tag_type(sdev, tag);
142 
143 		if (tag)
144 			scsi_activate_tcq(sdev, sdev->queue_depth);
145 		else
146 			scsi_deactivate_tcq(sdev, sdev->queue_depth);
147 	} else
148 		tag = 0;
149 
150 	return tag;
151 }
152 
153 /*
154  * Locate the SAM Task Attr from struct scsi_cmnd *
155  */
156 static int tcm_loop_sam_attr(struct scsi_cmnd *sc)
157 {
158 	if (sc->device->tagged_supported) {
159 		switch (sc->tag) {
160 		case HEAD_OF_QUEUE_TAG:
161 			return MSG_HEAD_TAG;
162 		case ORDERED_QUEUE_TAG:
163 			return MSG_ORDERED_TAG;
164 		default:
165 			break;
166 		}
167 	}
168 
169 	return MSG_SIMPLE_TAG;
170 }
171 
172 static void tcm_loop_submission_work(struct work_struct *work)
173 {
174 	struct tcm_loop_cmd *tl_cmd =
175 		container_of(work, struct tcm_loop_cmd, work);
176 	struct se_cmd *se_cmd = &tl_cmd->tl_se_cmd;
177 	struct scsi_cmnd *sc = tl_cmd->sc;
178 	struct tcm_loop_nexus *tl_nexus;
179 	struct tcm_loop_hba *tl_hba;
180 	struct tcm_loop_tpg *tl_tpg;
181 	struct scatterlist *sgl_bidi = NULL;
182 	u32 sgl_bidi_count = 0;
183 	int rc;
184 
185 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
186 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
187 
188 	/*
189 	 * Ensure that this tl_tpg reference from the incoming sc->device->id
190 	 * has already been configured via tcm_loop_make_naa_tpg().
191 	 */
192 	if (!tl_tpg->tl_hba) {
193 		set_host_byte(sc, DID_NO_CONNECT);
194 		goto out_done;
195 	}
196 	if (tl_tpg->tl_transport_status == TCM_TRANSPORT_OFFLINE) {
197 		set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
198 		goto out_done;
199 	}
200 	tl_nexus = tl_hba->tl_nexus;
201 	if (!tl_nexus) {
202 		scmd_printk(KERN_ERR, sc, "TCM_Loop I_T Nexus"
203 				" does not exist\n");
204 		set_host_byte(sc, DID_ERROR);
205 		goto out_done;
206 	}
207 	if (scsi_bidi_cmnd(sc)) {
208 		struct scsi_data_buffer *sdb = scsi_in(sc);
209 
210 		sgl_bidi = sdb->table.sgl;
211 		sgl_bidi_count = sdb->table.nents;
212 		se_cmd->se_cmd_flags |= SCF_BIDI;
213 
214 	}
215 	rc = target_submit_cmd_map_sgls(se_cmd, tl_nexus->se_sess, sc->cmnd,
216 			&tl_cmd->tl_sense_buf[0], tl_cmd->sc->device->lun,
217 			scsi_bufflen(sc), tcm_loop_sam_attr(sc),
218 			sc->sc_data_direction, 0,
219 			scsi_sglist(sc), scsi_sg_count(sc),
220 			sgl_bidi, sgl_bidi_count,
221 			scsi_prot_sglist(sc), scsi_prot_sg_count(sc));
222 	if (rc < 0) {
223 		set_host_byte(sc, DID_NO_CONNECT);
224 		goto out_done;
225 	}
226 	return;
227 
228 out_done:
229 	sc->scsi_done(sc);
230 	return;
231 }
232 
233 /*
234  * ->queuecommand can be and usually is called from interrupt context, so
235  * defer the actual submission to a workqueue.
236  */
237 static int tcm_loop_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
238 {
239 	struct tcm_loop_cmd *tl_cmd;
240 
241 	pr_debug("tcm_loop_queuecommand() %d:%d:%d:%d got CDB: 0x%02x"
242 		" scsi_buf_len: %u\n", sc->device->host->host_no,
243 		sc->device->id, sc->device->channel, sc->device->lun,
244 		sc->cmnd[0], scsi_bufflen(sc));
245 
246 	tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_ATOMIC);
247 	if (!tl_cmd) {
248 		pr_err("Unable to allocate struct tcm_loop_cmd\n");
249 		set_host_byte(sc, DID_ERROR);
250 		sc->scsi_done(sc);
251 		return 0;
252 	}
253 
254 	tl_cmd->sc = sc;
255 	tl_cmd->sc_cmd_tag = sc->tag;
256 	INIT_WORK(&tl_cmd->work, tcm_loop_submission_work);
257 	queue_work(tcm_loop_workqueue, &tl_cmd->work);
258 	return 0;
259 }
260 
261 /*
262  * Called from SCSI EH process context to issue a LUN_RESET TMR
263  * to struct scsi_device
264  */
265 static int tcm_loop_issue_tmr(struct tcm_loop_tpg *tl_tpg,
266 			      struct tcm_loop_nexus *tl_nexus,
267 			      int lun, int task, enum tcm_tmreq_table tmr)
268 {
269 	struct se_cmd *se_cmd = NULL;
270 	struct se_session *se_sess;
271 	struct se_portal_group *se_tpg;
272 	struct tcm_loop_cmd *tl_cmd = NULL;
273 	struct tcm_loop_tmr *tl_tmr = NULL;
274 	int ret = TMR_FUNCTION_FAILED, rc;
275 
276 	tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_KERNEL);
277 	if (!tl_cmd) {
278 		pr_err("Unable to allocate memory for tl_cmd\n");
279 		return ret;
280 	}
281 
282 	tl_tmr = kzalloc(sizeof(struct tcm_loop_tmr), GFP_KERNEL);
283 	if (!tl_tmr) {
284 		pr_err("Unable to allocate memory for tl_tmr\n");
285 		goto release;
286 	}
287 	init_waitqueue_head(&tl_tmr->tl_tmr_wait);
288 
289 	se_cmd = &tl_cmd->tl_se_cmd;
290 	se_tpg = &tl_tpg->tl_se_tpg;
291 	se_sess = tl_nexus->se_sess;
292 	/*
293 	 * Initialize struct se_cmd descriptor from target_core_mod infrastructure
294 	 */
295 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, 0,
296 				DMA_NONE, MSG_SIMPLE_TAG,
297 				&tl_cmd->tl_sense_buf[0]);
298 
299 	rc = core_tmr_alloc_req(se_cmd, tl_tmr, tmr, GFP_KERNEL);
300 	if (rc < 0)
301 		goto release;
302 
303 	if (tmr == TMR_ABORT_TASK)
304 		se_cmd->se_tmr_req->ref_task_tag = task;
305 
306 	/*
307 	 * Locate the underlying TCM struct se_lun
308 	 */
309 	if (transport_lookup_tmr_lun(se_cmd, lun) < 0) {
310 		ret = TMR_LUN_DOES_NOT_EXIST;
311 		goto release;
312 	}
313 	/*
314 	 * Queue the TMR to TCM Core and sleep waiting for
315 	 * tcm_loop_queue_tm_rsp() to wake us up.
316 	 */
317 	transport_generic_handle_tmr(se_cmd);
318 	wait_event(tl_tmr->tl_tmr_wait, atomic_read(&tl_tmr->tmr_complete));
319 	/*
320 	 * The TMR LUN_RESET has completed, check the response status and
321 	 * then release allocations.
322 	 */
323 	ret = se_cmd->se_tmr_req->response;
324 release:
325 	if (se_cmd)
326 		transport_generic_free_cmd(se_cmd, 1);
327 	else
328 		kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
329 	kfree(tl_tmr);
330 	return ret;
331 }
332 
333 static int tcm_loop_abort_task(struct scsi_cmnd *sc)
334 {
335 	struct tcm_loop_hba *tl_hba;
336 	struct tcm_loop_nexus *tl_nexus;
337 	struct tcm_loop_tpg *tl_tpg;
338 	int ret = FAILED;
339 
340 	/*
341 	 * Locate the tcm_loop_hba_t pointer
342 	 */
343 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
344 	/*
345 	 * Locate the tl_nexus and se_sess pointers
346 	 */
347 	tl_nexus = tl_hba->tl_nexus;
348 	if (!tl_nexus) {
349 		pr_err("Unable to perform device reset without"
350 				" active I_T Nexus\n");
351 		return FAILED;
352 	}
353 
354 	/*
355 	 * Locate the tl_tpg pointer from TargetID in sc->device->id
356 	 */
357 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
358 	ret = tcm_loop_issue_tmr(tl_tpg, tl_nexus, sc->device->lun,
359 				 sc->tag, TMR_ABORT_TASK);
360 	return (ret == TMR_FUNCTION_COMPLETE) ? SUCCESS : FAILED;
361 }
362 
363 /*
364  * Called from SCSI EH process context to issue a LUN_RESET TMR
365  * to struct scsi_device
366  */
367 static int tcm_loop_device_reset(struct scsi_cmnd *sc)
368 {
369 	struct tcm_loop_hba *tl_hba;
370 	struct tcm_loop_nexus *tl_nexus;
371 	struct tcm_loop_tpg *tl_tpg;
372 	int ret = FAILED;
373 
374 	/*
375 	 * Locate the tcm_loop_hba_t pointer
376 	 */
377 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
378 	/*
379 	 * Locate the tl_nexus and se_sess pointers
380 	 */
381 	tl_nexus = tl_hba->tl_nexus;
382 	if (!tl_nexus) {
383 		pr_err("Unable to perform device reset without"
384 				" active I_T Nexus\n");
385 		return FAILED;
386 	}
387 	/*
388 	 * Locate the tl_tpg pointer from TargetID in sc->device->id
389 	 */
390 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
391 	ret = tcm_loop_issue_tmr(tl_tpg, tl_nexus, sc->device->lun,
392 				 0, TMR_LUN_RESET);
393 	return (ret == TMR_FUNCTION_COMPLETE) ? SUCCESS : FAILED;
394 }
395 
396 static int tcm_loop_target_reset(struct scsi_cmnd *sc)
397 {
398 	struct tcm_loop_hba *tl_hba;
399 	struct tcm_loop_tpg *tl_tpg;
400 
401 	/*
402 	 * Locate the tcm_loop_hba_t pointer
403 	 */
404 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
405 	if (!tl_hba) {
406 		pr_err("Unable to perform device reset without"
407 				" active I_T Nexus\n");
408 		return FAILED;
409 	}
410 	/*
411 	 * Locate the tl_tpg pointer from TargetID in sc->device->id
412 	 */
413 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
414 	if (tl_tpg) {
415 		tl_tpg->tl_transport_status = TCM_TRANSPORT_ONLINE;
416 		return SUCCESS;
417 	}
418 	return FAILED;
419 }
420 
421 static int tcm_loop_slave_alloc(struct scsi_device *sd)
422 {
423 	set_bit(QUEUE_FLAG_BIDI, &sd->request_queue->queue_flags);
424 	return 0;
425 }
426 
427 static int tcm_loop_slave_configure(struct scsi_device *sd)
428 {
429 	if (sd->tagged_supported) {
430 		scsi_activate_tcq(sd, sd->queue_depth);
431 		scsi_adjust_queue_depth(sd, MSG_SIMPLE_TAG,
432 					sd->host->cmd_per_lun);
433 	} else {
434 		scsi_adjust_queue_depth(sd, 0,
435 					sd->host->cmd_per_lun);
436 	}
437 
438 	return 0;
439 }
440 
441 static struct scsi_host_template tcm_loop_driver_template = {
442 	.show_info		= tcm_loop_show_info,
443 	.proc_name		= "tcm_loopback",
444 	.name			= "TCM_Loopback",
445 	.queuecommand		= tcm_loop_queuecommand,
446 	.change_queue_depth	= tcm_loop_change_queue_depth,
447 	.change_queue_type	= tcm_loop_change_queue_type,
448 	.eh_abort_handler = tcm_loop_abort_task,
449 	.eh_device_reset_handler = tcm_loop_device_reset,
450 	.eh_target_reset_handler = tcm_loop_target_reset,
451 	.can_queue		= 1024,
452 	.this_id		= -1,
453 	.sg_tablesize		= 256,
454 	.cmd_per_lun		= 1024,
455 	.max_sectors		= 0xFFFF,
456 	.use_clustering		= DISABLE_CLUSTERING,
457 	.slave_alloc		= tcm_loop_slave_alloc,
458 	.slave_configure	= tcm_loop_slave_configure,
459 	.module			= THIS_MODULE,
460 };
461 
462 static int tcm_loop_driver_probe(struct device *dev)
463 {
464 	struct tcm_loop_hba *tl_hba;
465 	struct Scsi_Host *sh;
466 	int error, host_prot;
467 
468 	tl_hba = to_tcm_loop_hba(dev);
469 
470 	sh = scsi_host_alloc(&tcm_loop_driver_template,
471 			sizeof(struct tcm_loop_hba));
472 	if (!sh) {
473 		pr_err("Unable to allocate struct scsi_host\n");
474 		return -ENODEV;
475 	}
476 	tl_hba->sh = sh;
477 
478 	/*
479 	 * Assign the struct tcm_loop_hba pointer to struct Scsi_Host->hostdata
480 	 */
481 	*((struct tcm_loop_hba **)sh->hostdata) = tl_hba;
482 	/*
483 	 * Setup single ID, Channel and LUN for now..
484 	 */
485 	sh->max_id = 2;
486 	sh->max_lun = 0;
487 	sh->max_channel = 0;
488 	sh->max_cmd_len = TL_SCSI_MAX_CMD_LEN;
489 
490 	host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
491 		    SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
492 		    SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
493 
494 	scsi_host_set_prot(sh, host_prot);
495 	scsi_host_set_guard(sh, SHOST_DIX_GUARD_CRC);
496 
497 	error = scsi_add_host(sh, &tl_hba->dev);
498 	if (error) {
499 		pr_err("%s: scsi_add_host failed\n", __func__);
500 		scsi_host_put(sh);
501 		return -ENODEV;
502 	}
503 	return 0;
504 }
505 
506 static int tcm_loop_driver_remove(struct device *dev)
507 {
508 	struct tcm_loop_hba *tl_hba;
509 	struct Scsi_Host *sh;
510 
511 	tl_hba = to_tcm_loop_hba(dev);
512 	sh = tl_hba->sh;
513 
514 	scsi_remove_host(sh);
515 	scsi_host_put(sh);
516 	return 0;
517 }
518 
519 static void tcm_loop_release_adapter(struct device *dev)
520 {
521 	struct tcm_loop_hba *tl_hba = to_tcm_loop_hba(dev);
522 
523 	kfree(tl_hba);
524 }
525 
526 /*
527  * Called from tcm_loop_make_scsi_hba() in tcm_loop_configfs.c
528  */
529 static int tcm_loop_setup_hba_bus(struct tcm_loop_hba *tl_hba, int tcm_loop_host_id)
530 {
531 	int ret;
532 
533 	tl_hba->dev.bus = &tcm_loop_lld_bus;
534 	tl_hba->dev.parent = tcm_loop_primary;
535 	tl_hba->dev.release = &tcm_loop_release_adapter;
536 	dev_set_name(&tl_hba->dev, "tcm_loop_adapter_%d", tcm_loop_host_id);
537 
538 	ret = device_register(&tl_hba->dev);
539 	if (ret) {
540 		pr_err("device_register() failed for"
541 				" tl_hba->dev: %d\n", ret);
542 		return -ENODEV;
543 	}
544 
545 	return 0;
546 }
547 
548 /*
549  * Called from tcm_loop_fabric_init() in tcl_loop_fabric.c to load the emulated
550  * tcm_loop SCSI bus.
551  */
552 static int tcm_loop_alloc_core_bus(void)
553 {
554 	int ret;
555 
556 	tcm_loop_primary = root_device_register("tcm_loop_0");
557 	if (IS_ERR(tcm_loop_primary)) {
558 		pr_err("Unable to allocate tcm_loop_primary\n");
559 		return PTR_ERR(tcm_loop_primary);
560 	}
561 
562 	ret = bus_register(&tcm_loop_lld_bus);
563 	if (ret) {
564 		pr_err("bus_register() failed for tcm_loop_lld_bus\n");
565 		goto dev_unreg;
566 	}
567 
568 	ret = driver_register(&tcm_loop_driverfs);
569 	if (ret) {
570 		pr_err("driver_register() failed for"
571 				"tcm_loop_driverfs\n");
572 		goto bus_unreg;
573 	}
574 
575 	pr_debug("Initialized TCM Loop Core Bus\n");
576 	return ret;
577 
578 bus_unreg:
579 	bus_unregister(&tcm_loop_lld_bus);
580 dev_unreg:
581 	root_device_unregister(tcm_loop_primary);
582 	return ret;
583 }
584 
585 static void tcm_loop_release_core_bus(void)
586 {
587 	driver_unregister(&tcm_loop_driverfs);
588 	bus_unregister(&tcm_loop_lld_bus);
589 	root_device_unregister(tcm_loop_primary);
590 
591 	pr_debug("Releasing TCM Loop Core BUS\n");
592 }
593 
594 static char *tcm_loop_get_fabric_name(void)
595 {
596 	return "loopback";
597 }
598 
599 static u8 tcm_loop_get_fabric_proto_ident(struct se_portal_group *se_tpg)
600 {
601 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
602 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
603 	/*
604 	 * tl_proto_id is set at tcm_loop_configfs.c:tcm_loop_make_scsi_hba()
605 	 * time based on the protocol dependent prefix of the passed configfs group.
606 	 *
607 	 * Based upon tl_proto_id, TCM_Loop emulates the requested fabric
608 	 * ProtocolID using target_core_fabric_lib.c symbols.
609 	 */
610 	switch (tl_hba->tl_proto_id) {
611 	case SCSI_PROTOCOL_SAS:
612 		return sas_get_fabric_proto_ident(se_tpg);
613 	case SCSI_PROTOCOL_FCP:
614 		return fc_get_fabric_proto_ident(se_tpg);
615 	case SCSI_PROTOCOL_ISCSI:
616 		return iscsi_get_fabric_proto_ident(se_tpg);
617 	default:
618 		pr_err("Unknown tl_proto_id: 0x%02x, using"
619 			" SAS emulation\n", tl_hba->tl_proto_id);
620 		break;
621 	}
622 
623 	return sas_get_fabric_proto_ident(se_tpg);
624 }
625 
626 static char *tcm_loop_get_endpoint_wwn(struct se_portal_group *se_tpg)
627 {
628 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
629 	/*
630 	 * Return the passed NAA identifier for the SAS Target Port
631 	 */
632 	return &tl_tpg->tl_hba->tl_wwn_address[0];
633 }
634 
635 static u16 tcm_loop_get_tag(struct se_portal_group *se_tpg)
636 {
637 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
638 	/*
639 	 * This Tag is used when forming SCSI Name identifier in EVPD=1 0x83
640 	 * to represent the SCSI Target Port.
641 	 */
642 	return tl_tpg->tl_tpgt;
643 }
644 
645 static u32 tcm_loop_get_default_depth(struct se_portal_group *se_tpg)
646 {
647 	return 1;
648 }
649 
650 static u32 tcm_loop_get_pr_transport_id(
651 	struct se_portal_group *se_tpg,
652 	struct se_node_acl *se_nacl,
653 	struct t10_pr_registration *pr_reg,
654 	int *format_code,
655 	unsigned char *buf)
656 {
657 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
658 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
659 
660 	switch (tl_hba->tl_proto_id) {
661 	case SCSI_PROTOCOL_SAS:
662 		return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
663 					format_code, buf);
664 	case SCSI_PROTOCOL_FCP:
665 		return fc_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
666 					format_code, buf);
667 	case SCSI_PROTOCOL_ISCSI:
668 		return iscsi_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
669 					format_code, buf);
670 	default:
671 		pr_err("Unknown tl_proto_id: 0x%02x, using"
672 			" SAS emulation\n", tl_hba->tl_proto_id);
673 		break;
674 	}
675 
676 	return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
677 			format_code, buf);
678 }
679 
680 static u32 tcm_loop_get_pr_transport_id_len(
681 	struct se_portal_group *se_tpg,
682 	struct se_node_acl *se_nacl,
683 	struct t10_pr_registration *pr_reg,
684 	int *format_code)
685 {
686 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
687 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
688 
689 	switch (tl_hba->tl_proto_id) {
690 	case SCSI_PROTOCOL_SAS:
691 		return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
692 					format_code);
693 	case SCSI_PROTOCOL_FCP:
694 		return fc_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
695 					format_code);
696 	case SCSI_PROTOCOL_ISCSI:
697 		return iscsi_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
698 					format_code);
699 	default:
700 		pr_err("Unknown tl_proto_id: 0x%02x, using"
701 			" SAS emulation\n", tl_hba->tl_proto_id);
702 		break;
703 	}
704 
705 	return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
706 			format_code);
707 }
708 
709 /*
710  * Used for handling SCSI fabric dependent TransportIDs in SPC-3 and above
711  * Persistent Reservation SPEC_I_PT=1 and PROUT REGISTER_AND_MOVE operations.
712  */
713 static char *tcm_loop_parse_pr_out_transport_id(
714 	struct se_portal_group *se_tpg,
715 	const char *buf,
716 	u32 *out_tid_len,
717 	char **port_nexus_ptr)
718 {
719 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
720 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
721 
722 	switch (tl_hba->tl_proto_id) {
723 	case SCSI_PROTOCOL_SAS:
724 		return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
725 					port_nexus_ptr);
726 	case SCSI_PROTOCOL_FCP:
727 		return fc_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
728 					port_nexus_ptr);
729 	case SCSI_PROTOCOL_ISCSI:
730 		return iscsi_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
731 					port_nexus_ptr);
732 	default:
733 		pr_err("Unknown tl_proto_id: 0x%02x, using"
734 			" SAS emulation\n", tl_hba->tl_proto_id);
735 		break;
736 	}
737 
738 	return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
739 			port_nexus_ptr);
740 }
741 
742 /*
743  * Returning (1) here allows for target_core_mod struct se_node_acl to be generated
744  * based upon the incoming fabric dependent SCSI Initiator Port
745  */
746 static int tcm_loop_check_demo_mode(struct se_portal_group *se_tpg)
747 {
748 	return 1;
749 }
750 
751 static int tcm_loop_check_demo_mode_cache(struct se_portal_group *se_tpg)
752 {
753 	return 0;
754 }
755 
756 /*
757  * Allow I_T Nexus full READ-WRITE access without explict Initiator Node ACLs for
758  * local virtual Linux/SCSI LLD passthrough into VM hypervisor guest
759  */
760 static int tcm_loop_check_demo_mode_write_protect(struct se_portal_group *se_tpg)
761 {
762 	return 0;
763 }
764 
765 /*
766  * Because TCM_Loop does not use explict ACLs and MappedLUNs, this will
767  * never be called for TCM_Loop by target_core_fabric_configfs.c code.
768  * It has been added here as a nop for target_fabric_tf_ops_check()
769  */
770 static int tcm_loop_check_prod_mode_write_protect(struct se_portal_group *se_tpg)
771 {
772 	return 0;
773 }
774 
775 static struct se_node_acl *tcm_loop_tpg_alloc_fabric_acl(
776 	struct se_portal_group *se_tpg)
777 {
778 	struct tcm_loop_nacl *tl_nacl;
779 
780 	tl_nacl = kzalloc(sizeof(struct tcm_loop_nacl), GFP_KERNEL);
781 	if (!tl_nacl) {
782 		pr_err("Unable to allocate struct tcm_loop_nacl\n");
783 		return NULL;
784 	}
785 
786 	return &tl_nacl->se_node_acl;
787 }
788 
789 static void tcm_loop_tpg_release_fabric_acl(
790 	struct se_portal_group *se_tpg,
791 	struct se_node_acl *se_nacl)
792 {
793 	struct tcm_loop_nacl *tl_nacl = container_of(se_nacl,
794 				struct tcm_loop_nacl, se_node_acl);
795 
796 	kfree(tl_nacl);
797 }
798 
799 static u32 tcm_loop_get_inst_index(struct se_portal_group *se_tpg)
800 {
801 	return 1;
802 }
803 
804 static u32 tcm_loop_sess_get_index(struct se_session *se_sess)
805 {
806 	return 1;
807 }
808 
809 static void tcm_loop_set_default_node_attributes(struct se_node_acl *se_acl)
810 {
811 	return;
812 }
813 
814 static u32 tcm_loop_get_task_tag(struct se_cmd *se_cmd)
815 {
816 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
817 			struct tcm_loop_cmd, tl_se_cmd);
818 
819 	return tl_cmd->sc_cmd_tag;
820 }
821 
822 static int tcm_loop_get_cmd_state(struct se_cmd *se_cmd)
823 {
824 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
825 			struct tcm_loop_cmd, tl_se_cmd);
826 
827 	return tl_cmd->sc_cmd_state;
828 }
829 
830 static int tcm_loop_shutdown_session(struct se_session *se_sess)
831 {
832 	return 0;
833 }
834 
835 static void tcm_loop_close_session(struct se_session *se_sess)
836 {
837 	return;
838 };
839 
840 static int tcm_loop_write_pending(struct se_cmd *se_cmd)
841 {
842 	/*
843 	 * Since Linux/SCSI has already sent down a struct scsi_cmnd
844 	 * sc->sc_data_direction of DMA_TO_DEVICE with struct scatterlist array
845 	 * memory, and memory has already been mapped to struct se_cmd->t_mem_list
846 	 * format with transport_generic_map_mem_to_cmd().
847 	 *
848 	 * We now tell TCM to add this WRITE CDB directly into the TCM storage
849 	 * object execution queue.
850 	 */
851 	target_execute_cmd(se_cmd);
852 	return 0;
853 }
854 
855 static int tcm_loop_write_pending_status(struct se_cmd *se_cmd)
856 {
857 	return 0;
858 }
859 
860 static int tcm_loop_queue_data_in(struct se_cmd *se_cmd)
861 {
862 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
863 				struct tcm_loop_cmd, tl_se_cmd);
864 	struct scsi_cmnd *sc = tl_cmd->sc;
865 
866 	pr_debug("tcm_loop_queue_data_in() called for scsi_cmnd: %p"
867 		     " cdb: 0x%02x\n", sc, sc->cmnd[0]);
868 
869 	sc->result = SAM_STAT_GOOD;
870 	set_host_byte(sc, DID_OK);
871 	if ((se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) ||
872 	    (se_cmd->se_cmd_flags & SCF_UNDERFLOW_BIT))
873 		scsi_set_resid(sc, se_cmd->residual_count);
874 	sc->scsi_done(sc);
875 	return 0;
876 }
877 
878 static int tcm_loop_queue_status(struct se_cmd *se_cmd)
879 {
880 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
881 				struct tcm_loop_cmd, tl_se_cmd);
882 	struct scsi_cmnd *sc = tl_cmd->sc;
883 
884 	pr_debug("tcm_loop_queue_status() called for scsi_cmnd: %p"
885 			" cdb: 0x%02x\n", sc, sc->cmnd[0]);
886 
887 	if (se_cmd->sense_buffer &&
888 	   ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
889 	    (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE))) {
890 
891 		memcpy(sc->sense_buffer, se_cmd->sense_buffer,
892 				SCSI_SENSE_BUFFERSIZE);
893 		sc->result = SAM_STAT_CHECK_CONDITION;
894 		set_driver_byte(sc, DRIVER_SENSE);
895 	} else
896 		sc->result = se_cmd->scsi_status;
897 
898 	set_host_byte(sc, DID_OK);
899 	if ((se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) ||
900 	    (se_cmd->se_cmd_flags & SCF_UNDERFLOW_BIT))
901 		scsi_set_resid(sc, se_cmd->residual_count);
902 	sc->scsi_done(sc);
903 	return 0;
904 }
905 
906 static void tcm_loop_queue_tm_rsp(struct se_cmd *se_cmd)
907 {
908 	struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
909 	struct tcm_loop_tmr *tl_tmr = se_tmr->fabric_tmr_ptr;
910 	/*
911 	 * The SCSI EH thread will be sleeping on se_tmr->tl_tmr_wait, go ahead
912 	 * and wake up the wait_queue_head_t in tcm_loop_device_reset()
913 	 */
914 	atomic_set(&tl_tmr->tmr_complete, 1);
915 	wake_up(&tl_tmr->tl_tmr_wait);
916 }
917 
918 static char *tcm_loop_dump_proto_id(struct tcm_loop_hba *tl_hba)
919 {
920 	switch (tl_hba->tl_proto_id) {
921 	case SCSI_PROTOCOL_SAS:
922 		return "SAS";
923 	case SCSI_PROTOCOL_FCP:
924 		return "FCP";
925 	case SCSI_PROTOCOL_ISCSI:
926 		return "iSCSI";
927 	default:
928 		break;
929 	}
930 
931 	return "Unknown";
932 }
933 
934 /* Start items for tcm_loop_port_cit */
935 
936 static int tcm_loop_port_link(
937 	struct se_portal_group *se_tpg,
938 	struct se_lun *lun)
939 {
940 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
941 				struct tcm_loop_tpg, tl_se_tpg);
942 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
943 
944 	atomic_inc(&tl_tpg->tl_tpg_port_count);
945 	smp_mb__after_atomic_inc();
946 	/*
947 	 * Add Linux/SCSI struct scsi_device by HCTL
948 	 */
949 	scsi_add_device(tl_hba->sh, 0, tl_tpg->tl_tpgt, lun->unpacked_lun);
950 
951 	pr_debug("TCM_Loop_ConfigFS: Port Link Successful\n");
952 	return 0;
953 }
954 
955 static void tcm_loop_port_unlink(
956 	struct se_portal_group *se_tpg,
957 	struct se_lun *se_lun)
958 {
959 	struct scsi_device *sd;
960 	struct tcm_loop_hba *tl_hba;
961 	struct tcm_loop_tpg *tl_tpg;
962 
963 	tl_tpg = container_of(se_tpg, struct tcm_loop_tpg, tl_se_tpg);
964 	tl_hba = tl_tpg->tl_hba;
965 
966 	sd = scsi_device_lookup(tl_hba->sh, 0, tl_tpg->tl_tpgt,
967 				se_lun->unpacked_lun);
968 	if (!sd) {
969 		pr_err("Unable to locate struct scsi_device for %d:%d:"
970 			"%d\n", 0, tl_tpg->tl_tpgt, se_lun->unpacked_lun);
971 		return;
972 	}
973 	/*
974 	 * Remove Linux/SCSI struct scsi_device by HCTL
975 	 */
976 	scsi_remove_device(sd);
977 	scsi_device_put(sd);
978 
979 	atomic_dec(&tl_tpg->tl_tpg_port_count);
980 	smp_mb__after_atomic_dec();
981 
982 	pr_debug("TCM_Loop_ConfigFS: Port Unlink Successful\n");
983 }
984 
985 /* End items for tcm_loop_port_cit */
986 
987 /* Start items for tcm_loop_nexus_cit */
988 
989 static int tcm_loop_make_nexus(
990 	struct tcm_loop_tpg *tl_tpg,
991 	const char *name)
992 {
993 	struct se_portal_group *se_tpg;
994 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
995 	struct tcm_loop_nexus *tl_nexus;
996 	int ret = -ENOMEM;
997 
998 	if (tl_tpg->tl_hba->tl_nexus) {
999 		pr_debug("tl_tpg->tl_hba->tl_nexus already exists\n");
1000 		return -EEXIST;
1001 	}
1002 	se_tpg = &tl_tpg->tl_se_tpg;
1003 
1004 	tl_nexus = kzalloc(sizeof(struct tcm_loop_nexus), GFP_KERNEL);
1005 	if (!tl_nexus) {
1006 		pr_err("Unable to allocate struct tcm_loop_nexus\n");
1007 		return -ENOMEM;
1008 	}
1009 	/*
1010 	 * Initialize the struct se_session pointer
1011 	 */
1012 	tl_nexus->se_sess = transport_init_session();
1013 	if (IS_ERR(tl_nexus->se_sess)) {
1014 		ret = PTR_ERR(tl_nexus->se_sess);
1015 		goto out;
1016 	}
1017 	/*
1018 	 * Since we are running in 'demo mode' this call with generate a
1019 	 * struct se_node_acl for the tcm_loop struct se_portal_group with the SCSI
1020 	 * Initiator port name of the passed configfs group 'name'.
1021 	 */
1022 	tl_nexus->se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1023 				se_tpg, (unsigned char *)name);
1024 	if (!tl_nexus->se_sess->se_node_acl) {
1025 		transport_free_session(tl_nexus->se_sess);
1026 		goto out;
1027 	}
1028 	/*
1029 	 * Now, register the SAS I_T Nexus as active with the call to
1030 	 * transport_register_session()
1031 	 */
1032 	__transport_register_session(se_tpg, tl_nexus->se_sess->se_node_acl,
1033 			tl_nexus->se_sess, tl_nexus);
1034 	tl_tpg->tl_hba->tl_nexus = tl_nexus;
1035 	pr_debug("TCM_Loop_ConfigFS: Established I_T Nexus to emulated"
1036 		" %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
1037 		name);
1038 	return 0;
1039 
1040 out:
1041 	kfree(tl_nexus);
1042 	return ret;
1043 }
1044 
1045 static int tcm_loop_drop_nexus(
1046 	struct tcm_loop_tpg *tpg)
1047 {
1048 	struct se_session *se_sess;
1049 	struct tcm_loop_nexus *tl_nexus;
1050 	struct tcm_loop_hba *tl_hba = tpg->tl_hba;
1051 
1052 	if (!tl_hba)
1053 		return -ENODEV;
1054 
1055 	tl_nexus = tl_hba->tl_nexus;
1056 	if (!tl_nexus)
1057 		return -ENODEV;
1058 
1059 	se_sess = tl_nexus->se_sess;
1060 	if (!se_sess)
1061 		return -ENODEV;
1062 
1063 	if (atomic_read(&tpg->tl_tpg_port_count)) {
1064 		pr_err("Unable to remove TCM_Loop I_T Nexus with"
1065 			" active TPG port count: %d\n",
1066 			atomic_read(&tpg->tl_tpg_port_count));
1067 		return -EPERM;
1068 	}
1069 
1070 	pr_debug("TCM_Loop_ConfigFS: Removing I_T Nexus to emulated"
1071 		" %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
1072 		tl_nexus->se_sess->se_node_acl->initiatorname);
1073 	/*
1074 	 * Release the SCSI I_T Nexus to the emulated SAS Target Port
1075 	 */
1076 	transport_deregister_session(tl_nexus->se_sess);
1077 	tpg->tl_hba->tl_nexus = NULL;
1078 	kfree(tl_nexus);
1079 	return 0;
1080 }
1081 
1082 /* End items for tcm_loop_nexus_cit */
1083 
1084 static ssize_t tcm_loop_tpg_show_nexus(
1085 	struct se_portal_group *se_tpg,
1086 	char *page)
1087 {
1088 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1089 			struct tcm_loop_tpg, tl_se_tpg);
1090 	struct tcm_loop_nexus *tl_nexus;
1091 	ssize_t ret;
1092 
1093 	tl_nexus = tl_tpg->tl_hba->tl_nexus;
1094 	if (!tl_nexus)
1095 		return -ENODEV;
1096 
1097 	ret = snprintf(page, PAGE_SIZE, "%s\n",
1098 		tl_nexus->se_sess->se_node_acl->initiatorname);
1099 
1100 	return ret;
1101 }
1102 
1103 static ssize_t tcm_loop_tpg_store_nexus(
1104 	struct se_portal_group *se_tpg,
1105 	const char *page,
1106 	size_t count)
1107 {
1108 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1109 			struct tcm_loop_tpg, tl_se_tpg);
1110 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
1111 	unsigned char i_port[TL_WWN_ADDR_LEN], *ptr, *port_ptr;
1112 	int ret;
1113 	/*
1114 	 * Shutdown the active I_T nexus if 'NULL' is passed..
1115 	 */
1116 	if (!strncmp(page, "NULL", 4)) {
1117 		ret = tcm_loop_drop_nexus(tl_tpg);
1118 		return (!ret) ? count : ret;
1119 	}
1120 	/*
1121 	 * Otherwise make sure the passed virtual Initiator port WWN matches
1122 	 * the fabric protocol_id set in tcm_loop_make_scsi_hba(), and call
1123 	 * tcm_loop_make_nexus()
1124 	 */
1125 	if (strlen(page) >= TL_WWN_ADDR_LEN) {
1126 		pr_err("Emulated NAA Sas Address: %s, exceeds"
1127 				" max: %d\n", page, TL_WWN_ADDR_LEN);
1128 		return -EINVAL;
1129 	}
1130 	snprintf(&i_port[0], TL_WWN_ADDR_LEN, "%s", page);
1131 
1132 	ptr = strstr(i_port, "naa.");
1133 	if (ptr) {
1134 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_SAS) {
1135 			pr_err("Passed SAS Initiator Port %s does not"
1136 				" match target port protoid: %s\n", i_port,
1137 				tcm_loop_dump_proto_id(tl_hba));
1138 			return -EINVAL;
1139 		}
1140 		port_ptr = &i_port[0];
1141 		goto check_newline;
1142 	}
1143 	ptr = strstr(i_port, "fc.");
1144 	if (ptr) {
1145 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_FCP) {
1146 			pr_err("Passed FCP Initiator Port %s does not"
1147 				" match target port protoid: %s\n", i_port,
1148 				tcm_loop_dump_proto_id(tl_hba));
1149 			return -EINVAL;
1150 		}
1151 		port_ptr = &i_port[3]; /* Skip over "fc." */
1152 		goto check_newline;
1153 	}
1154 	ptr = strstr(i_port, "iqn.");
1155 	if (ptr) {
1156 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_ISCSI) {
1157 			pr_err("Passed iSCSI Initiator Port %s does not"
1158 				" match target port protoid: %s\n", i_port,
1159 				tcm_loop_dump_proto_id(tl_hba));
1160 			return -EINVAL;
1161 		}
1162 		port_ptr = &i_port[0];
1163 		goto check_newline;
1164 	}
1165 	pr_err("Unable to locate prefix for emulated Initiator Port:"
1166 			" %s\n", i_port);
1167 	return -EINVAL;
1168 	/*
1169 	 * Clear any trailing newline for the NAA WWN
1170 	 */
1171 check_newline:
1172 	if (i_port[strlen(i_port)-1] == '\n')
1173 		i_port[strlen(i_port)-1] = '\0';
1174 
1175 	ret = tcm_loop_make_nexus(tl_tpg, port_ptr);
1176 	if (ret < 0)
1177 		return ret;
1178 
1179 	return count;
1180 }
1181 
1182 TF_TPG_BASE_ATTR(tcm_loop, nexus, S_IRUGO | S_IWUSR);
1183 
1184 static ssize_t tcm_loop_tpg_show_transport_status(
1185 	struct se_portal_group *se_tpg,
1186 	char *page)
1187 {
1188 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1189 			struct tcm_loop_tpg, tl_se_tpg);
1190 	const char *status = NULL;
1191 	ssize_t ret = -EINVAL;
1192 
1193 	switch (tl_tpg->tl_transport_status) {
1194 	case TCM_TRANSPORT_ONLINE:
1195 		status = "online";
1196 		break;
1197 	case TCM_TRANSPORT_OFFLINE:
1198 		status = "offline";
1199 		break;
1200 	default:
1201 		break;
1202 	}
1203 
1204 	if (status)
1205 		ret = snprintf(page, PAGE_SIZE, "%s\n", status);
1206 
1207 	return ret;
1208 }
1209 
1210 static ssize_t tcm_loop_tpg_store_transport_status(
1211 	struct se_portal_group *se_tpg,
1212 	const char *page,
1213 	size_t count)
1214 {
1215 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1216 			struct tcm_loop_tpg, tl_se_tpg);
1217 
1218 	if (!strncmp(page, "online", 6)) {
1219 		tl_tpg->tl_transport_status = TCM_TRANSPORT_ONLINE;
1220 		return count;
1221 	}
1222 	if (!strncmp(page, "offline", 7)) {
1223 		tl_tpg->tl_transport_status = TCM_TRANSPORT_OFFLINE;
1224 		return count;
1225 	}
1226 	return -EINVAL;
1227 }
1228 
1229 TF_TPG_BASE_ATTR(tcm_loop, transport_status, S_IRUGO | S_IWUSR);
1230 
1231 static struct configfs_attribute *tcm_loop_tpg_attrs[] = {
1232 	&tcm_loop_tpg_nexus.attr,
1233 	&tcm_loop_tpg_transport_status.attr,
1234 	NULL,
1235 };
1236 
1237 /* Start items for tcm_loop_naa_cit */
1238 
1239 static struct se_portal_group *tcm_loop_make_naa_tpg(
1240 	struct se_wwn *wwn,
1241 	struct config_group *group,
1242 	const char *name)
1243 {
1244 	struct tcm_loop_hba *tl_hba = container_of(wwn,
1245 			struct tcm_loop_hba, tl_hba_wwn);
1246 	struct tcm_loop_tpg *tl_tpg;
1247 	char *tpgt_str, *end_ptr;
1248 	int ret;
1249 	unsigned short int tpgt;
1250 
1251 	tpgt_str = strstr(name, "tpgt_");
1252 	if (!tpgt_str) {
1253 		pr_err("Unable to locate \"tpgt_#\" directory"
1254 				" group\n");
1255 		return ERR_PTR(-EINVAL);
1256 	}
1257 	tpgt_str += 5; /* Skip ahead of "tpgt_" */
1258 	tpgt = (unsigned short int) simple_strtoul(tpgt_str, &end_ptr, 0);
1259 
1260 	if (tpgt >= TL_TPGS_PER_HBA) {
1261 		pr_err("Passed tpgt: %hu exceeds TL_TPGS_PER_HBA:"
1262 				" %u\n", tpgt, TL_TPGS_PER_HBA);
1263 		return ERR_PTR(-EINVAL);
1264 	}
1265 	tl_tpg = &tl_hba->tl_hba_tpgs[tpgt];
1266 	tl_tpg->tl_hba = tl_hba;
1267 	tl_tpg->tl_tpgt = tpgt;
1268 	/*
1269 	 * Register the tl_tpg as a emulated SAS TCM Target Endpoint
1270 	 */
1271 	ret = core_tpg_register(&tcm_loop_fabric_configfs->tf_ops,
1272 			wwn, &tl_tpg->tl_se_tpg, tl_tpg,
1273 			TRANSPORT_TPG_TYPE_NORMAL);
1274 	if (ret < 0)
1275 		return ERR_PTR(-ENOMEM);
1276 
1277 	pr_debug("TCM_Loop_ConfigFS: Allocated Emulated %s"
1278 		" Target Port %s,t,0x%04x\n", tcm_loop_dump_proto_id(tl_hba),
1279 		config_item_name(&wwn->wwn_group.cg_item), tpgt);
1280 
1281 	return &tl_tpg->tl_se_tpg;
1282 }
1283 
1284 static void tcm_loop_drop_naa_tpg(
1285 	struct se_portal_group *se_tpg)
1286 {
1287 	struct se_wwn *wwn = se_tpg->se_tpg_wwn;
1288 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1289 				struct tcm_loop_tpg, tl_se_tpg);
1290 	struct tcm_loop_hba *tl_hba;
1291 	unsigned short tpgt;
1292 
1293 	tl_hba = tl_tpg->tl_hba;
1294 	tpgt = tl_tpg->tl_tpgt;
1295 	/*
1296 	 * Release the I_T Nexus for the Virtual SAS link if present
1297 	 */
1298 	tcm_loop_drop_nexus(tl_tpg);
1299 	/*
1300 	 * Deregister the tl_tpg as a emulated SAS TCM Target Endpoint
1301 	 */
1302 	core_tpg_deregister(se_tpg);
1303 
1304 	tl_tpg->tl_hba = NULL;
1305 	tl_tpg->tl_tpgt = 0;
1306 
1307 	pr_debug("TCM_Loop_ConfigFS: Deallocated Emulated %s"
1308 		" Target Port %s,t,0x%04x\n", tcm_loop_dump_proto_id(tl_hba),
1309 		config_item_name(&wwn->wwn_group.cg_item), tpgt);
1310 }
1311 
1312 /* End items for tcm_loop_naa_cit */
1313 
1314 /* Start items for tcm_loop_cit */
1315 
1316 static struct se_wwn *tcm_loop_make_scsi_hba(
1317 	struct target_fabric_configfs *tf,
1318 	struct config_group *group,
1319 	const char *name)
1320 {
1321 	struct tcm_loop_hba *tl_hba;
1322 	struct Scsi_Host *sh;
1323 	char *ptr;
1324 	int ret, off = 0;
1325 
1326 	tl_hba = kzalloc(sizeof(struct tcm_loop_hba), GFP_KERNEL);
1327 	if (!tl_hba) {
1328 		pr_err("Unable to allocate struct tcm_loop_hba\n");
1329 		return ERR_PTR(-ENOMEM);
1330 	}
1331 	/*
1332 	 * Determine the emulated Protocol Identifier and Target Port Name
1333 	 * based on the incoming configfs directory name.
1334 	 */
1335 	ptr = strstr(name, "naa.");
1336 	if (ptr) {
1337 		tl_hba->tl_proto_id = SCSI_PROTOCOL_SAS;
1338 		goto check_len;
1339 	}
1340 	ptr = strstr(name, "fc.");
1341 	if (ptr) {
1342 		tl_hba->tl_proto_id = SCSI_PROTOCOL_FCP;
1343 		off = 3; /* Skip over "fc." */
1344 		goto check_len;
1345 	}
1346 	ptr = strstr(name, "iqn.");
1347 	if (!ptr) {
1348 		pr_err("Unable to locate prefix for emulated Target "
1349 				"Port: %s\n", name);
1350 		ret = -EINVAL;
1351 		goto out;
1352 	}
1353 	tl_hba->tl_proto_id = SCSI_PROTOCOL_ISCSI;
1354 
1355 check_len:
1356 	if (strlen(name) >= TL_WWN_ADDR_LEN) {
1357 		pr_err("Emulated NAA %s Address: %s, exceeds"
1358 			" max: %d\n", name, tcm_loop_dump_proto_id(tl_hba),
1359 			TL_WWN_ADDR_LEN);
1360 		ret = -EINVAL;
1361 		goto out;
1362 	}
1363 	snprintf(&tl_hba->tl_wwn_address[0], TL_WWN_ADDR_LEN, "%s", &name[off]);
1364 
1365 	/*
1366 	 * Call device_register(tl_hba->dev) to register the emulated
1367 	 * Linux/SCSI LLD of type struct Scsi_Host at tl_hba->sh after
1368 	 * device_register() callbacks in tcm_loop_driver_probe()
1369 	 */
1370 	ret = tcm_loop_setup_hba_bus(tl_hba, tcm_loop_hba_no_cnt);
1371 	if (ret)
1372 		goto out;
1373 
1374 	sh = tl_hba->sh;
1375 	tcm_loop_hba_no_cnt++;
1376 	pr_debug("TCM_Loop_ConfigFS: Allocated emulated Target"
1377 		" %s Address: %s at Linux/SCSI Host ID: %d\n",
1378 		tcm_loop_dump_proto_id(tl_hba), name, sh->host_no);
1379 
1380 	return &tl_hba->tl_hba_wwn;
1381 out:
1382 	kfree(tl_hba);
1383 	return ERR_PTR(ret);
1384 }
1385 
1386 static void tcm_loop_drop_scsi_hba(
1387 	struct se_wwn *wwn)
1388 {
1389 	struct tcm_loop_hba *tl_hba = container_of(wwn,
1390 				struct tcm_loop_hba, tl_hba_wwn);
1391 
1392 	pr_debug("TCM_Loop_ConfigFS: Deallocating emulated Target"
1393 		" SAS Address: %s at Linux/SCSI Host ID: %d\n",
1394 		tl_hba->tl_wwn_address, tl_hba->sh->host_no);
1395 	/*
1396 	 * Call device_unregister() on the original tl_hba->dev.
1397 	 * tcm_loop_fabric_scsi.c:tcm_loop_release_adapter() will
1398 	 * release *tl_hba;
1399 	 */
1400 	device_unregister(&tl_hba->dev);
1401 }
1402 
1403 /* Start items for tcm_loop_cit */
1404 static ssize_t tcm_loop_wwn_show_attr_version(
1405 	struct target_fabric_configfs *tf,
1406 	char *page)
1407 {
1408 	return sprintf(page, "TCM Loopback Fabric module %s\n", TCM_LOOP_VERSION);
1409 }
1410 
1411 TF_WWN_ATTR_RO(tcm_loop, version);
1412 
1413 static struct configfs_attribute *tcm_loop_wwn_attrs[] = {
1414 	&tcm_loop_wwn_version.attr,
1415 	NULL,
1416 };
1417 
1418 /* End items for tcm_loop_cit */
1419 
1420 static int tcm_loop_register_configfs(void)
1421 {
1422 	struct target_fabric_configfs *fabric;
1423 	int ret;
1424 	/*
1425 	 * Set the TCM Loop HBA counter to zero
1426 	 */
1427 	tcm_loop_hba_no_cnt = 0;
1428 	/*
1429 	 * Register the top level struct config_item_type with TCM core
1430 	 */
1431 	fabric = target_fabric_configfs_init(THIS_MODULE, "loopback");
1432 	if (IS_ERR(fabric)) {
1433 		pr_err("tcm_loop_register_configfs() failed!\n");
1434 		return PTR_ERR(fabric);
1435 	}
1436 	/*
1437 	 * Setup the fabric API of function pointers used by target_core_mod
1438 	 */
1439 	fabric->tf_ops.get_fabric_name = &tcm_loop_get_fabric_name;
1440 	fabric->tf_ops.get_fabric_proto_ident = &tcm_loop_get_fabric_proto_ident;
1441 	fabric->tf_ops.tpg_get_wwn = &tcm_loop_get_endpoint_wwn;
1442 	fabric->tf_ops.tpg_get_tag = &tcm_loop_get_tag;
1443 	fabric->tf_ops.tpg_get_default_depth = &tcm_loop_get_default_depth;
1444 	fabric->tf_ops.tpg_get_pr_transport_id = &tcm_loop_get_pr_transport_id;
1445 	fabric->tf_ops.tpg_get_pr_transport_id_len =
1446 					&tcm_loop_get_pr_transport_id_len;
1447 	fabric->tf_ops.tpg_parse_pr_out_transport_id =
1448 					&tcm_loop_parse_pr_out_transport_id;
1449 	fabric->tf_ops.tpg_check_demo_mode = &tcm_loop_check_demo_mode;
1450 	fabric->tf_ops.tpg_check_demo_mode_cache =
1451 					&tcm_loop_check_demo_mode_cache;
1452 	fabric->tf_ops.tpg_check_demo_mode_write_protect =
1453 					&tcm_loop_check_demo_mode_write_protect;
1454 	fabric->tf_ops.tpg_check_prod_mode_write_protect =
1455 					&tcm_loop_check_prod_mode_write_protect;
1456 	/*
1457 	 * The TCM loopback fabric module runs in demo-mode to a local
1458 	 * virtual SCSI device, so fabric dependent initator ACLs are
1459 	 * not required.
1460 	 */
1461 	fabric->tf_ops.tpg_alloc_fabric_acl = &tcm_loop_tpg_alloc_fabric_acl;
1462 	fabric->tf_ops.tpg_release_fabric_acl =
1463 					&tcm_loop_tpg_release_fabric_acl;
1464 	fabric->tf_ops.tpg_get_inst_index = &tcm_loop_get_inst_index;
1465 	/*
1466 	 * Used for setting up remaining TCM resources in process context
1467 	 */
1468 	fabric->tf_ops.check_stop_free = &tcm_loop_check_stop_free;
1469 	fabric->tf_ops.release_cmd = &tcm_loop_release_cmd;
1470 	fabric->tf_ops.shutdown_session = &tcm_loop_shutdown_session;
1471 	fabric->tf_ops.close_session = &tcm_loop_close_session;
1472 	fabric->tf_ops.sess_get_index = &tcm_loop_sess_get_index;
1473 	fabric->tf_ops.sess_get_initiator_sid = NULL;
1474 	fabric->tf_ops.write_pending = &tcm_loop_write_pending;
1475 	fabric->tf_ops.write_pending_status = &tcm_loop_write_pending_status;
1476 	/*
1477 	 * Not used for TCM loopback
1478 	 */
1479 	fabric->tf_ops.set_default_node_attributes =
1480 					&tcm_loop_set_default_node_attributes;
1481 	fabric->tf_ops.get_task_tag = &tcm_loop_get_task_tag;
1482 	fabric->tf_ops.get_cmd_state = &tcm_loop_get_cmd_state;
1483 	fabric->tf_ops.queue_data_in = &tcm_loop_queue_data_in;
1484 	fabric->tf_ops.queue_status = &tcm_loop_queue_status;
1485 	fabric->tf_ops.queue_tm_rsp = &tcm_loop_queue_tm_rsp;
1486 
1487 	/*
1488 	 * Setup function pointers for generic logic in target_core_fabric_configfs.c
1489 	 */
1490 	fabric->tf_ops.fabric_make_wwn = &tcm_loop_make_scsi_hba;
1491 	fabric->tf_ops.fabric_drop_wwn = &tcm_loop_drop_scsi_hba;
1492 	fabric->tf_ops.fabric_make_tpg = &tcm_loop_make_naa_tpg;
1493 	fabric->tf_ops.fabric_drop_tpg = &tcm_loop_drop_naa_tpg;
1494 	/*
1495 	 * fabric_post_link() and fabric_pre_unlink() are used for
1496 	 * registration and release of TCM Loop Virtual SCSI LUNs.
1497 	 */
1498 	fabric->tf_ops.fabric_post_link = &tcm_loop_port_link;
1499 	fabric->tf_ops.fabric_pre_unlink = &tcm_loop_port_unlink;
1500 	fabric->tf_ops.fabric_make_np = NULL;
1501 	fabric->tf_ops.fabric_drop_np = NULL;
1502 	/*
1503 	 * Setup default attribute lists for various fabric->tf_cit_tmpl
1504 	 */
1505 	fabric->tf_cit_tmpl.tfc_wwn_cit.ct_attrs = tcm_loop_wwn_attrs;
1506 	fabric->tf_cit_tmpl.tfc_tpg_base_cit.ct_attrs = tcm_loop_tpg_attrs;
1507 	fabric->tf_cit_tmpl.tfc_tpg_attrib_cit.ct_attrs = NULL;
1508 	fabric->tf_cit_tmpl.tfc_tpg_param_cit.ct_attrs = NULL;
1509 	fabric->tf_cit_tmpl.tfc_tpg_np_base_cit.ct_attrs = NULL;
1510 	/*
1511 	 * Once fabric->tf_ops has been setup, now register the fabric for
1512 	 * use within TCM
1513 	 */
1514 	ret = target_fabric_configfs_register(fabric);
1515 	if (ret < 0) {
1516 		pr_err("target_fabric_configfs_register() for"
1517 				" TCM_Loop failed!\n");
1518 		target_fabric_configfs_free(fabric);
1519 		return -1;
1520 	}
1521 	/*
1522 	 * Setup our local pointer to *fabric.
1523 	 */
1524 	tcm_loop_fabric_configfs = fabric;
1525 	pr_debug("TCM_LOOP[0] - Set fabric ->"
1526 			" tcm_loop_fabric_configfs\n");
1527 	return 0;
1528 }
1529 
1530 static void tcm_loop_deregister_configfs(void)
1531 {
1532 	if (!tcm_loop_fabric_configfs)
1533 		return;
1534 
1535 	target_fabric_configfs_deregister(tcm_loop_fabric_configfs);
1536 	tcm_loop_fabric_configfs = NULL;
1537 	pr_debug("TCM_LOOP[0] - Cleared"
1538 				" tcm_loop_fabric_configfs\n");
1539 }
1540 
1541 static int __init tcm_loop_fabric_init(void)
1542 {
1543 	int ret = -ENOMEM;
1544 
1545 	tcm_loop_workqueue = alloc_workqueue("tcm_loop", 0, 0);
1546 	if (!tcm_loop_workqueue)
1547 		goto out;
1548 
1549 	tcm_loop_cmd_cache = kmem_cache_create("tcm_loop_cmd_cache",
1550 				sizeof(struct tcm_loop_cmd),
1551 				__alignof__(struct tcm_loop_cmd),
1552 				0, NULL);
1553 	if (!tcm_loop_cmd_cache) {
1554 		pr_debug("kmem_cache_create() for"
1555 			" tcm_loop_cmd_cache failed\n");
1556 		goto out_destroy_workqueue;
1557 	}
1558 
1559 	ret = tcm_loop_alloc_core_bus();
1560 	if (ret)
1561 		goto out_destroy_cache;
1562 
1563 	ret = tcm_loop_register_configfs();
1564 	if (ret)
1565 		goto out_release_core_bus;
1566 
1567 	return 0;
1568 
1569 out_release_core_bus:
1570 	tcm_loop_release_core_bus();
1571 out_destroy_cache:
1572 	kmem_cache_destroy(tcm_loop_cmd_cache);
1573 out_destroy_workqueue:
1574 	destroy_workqueue(tcm_loop_workqueue);
1575 out:
1576 	return ret;
1577 }
1578 
1579 static void __exit tcm_loop_fabric_exit(void)
1580 {
1581 	tcm_loop_deregister_configfs();
1582 	tcm_loop_release_core_bus();
1583 	kmem_cache_destroy(tcm_loop_cmd_cache);
1584 	destroy_workqueue(tcm_loop_workqueue);
1585 }
1586 
1587 MODULE_DESCRIPTION("TCM loopback virtual Linux/SCSI fabric module");
1588 MODULE_AUTHOR("Nicholas A. Bellinger <nab@risingtidesystems.com>");
1589 MODULE_LICENSE("GPL");
1590 module_init(tcm_loop_fabric_init);
1591 module_exit(tcm_loop_fabric_exit);
1592