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, transfer_length;
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 
216 	transfer_length = scsi_transfer_length(sc);
217 	if (!scsi_prot_sg_count(sc) &&
218 	    scsi_get_prot_op(sc) != SCSI_PROT_NORMAL) {
219 		se_cmd->prot_pto = true;
220 		/*
221 		 * loopback transport doesn't support
222 		 * WRITE_GENERATE, READ_STRIP protection
223 		 * information operations, go ahead unprotected.
224 		 */
225 		transfer_length = scsi_bufflen(sc);
226 	}
227 
228 	rc = target_submit_cmd_map_sgls(se_cmd, tl_nexus->se_sess, sc->cmnd,
229 			&tl_cmd->tl_sense_buf[0], tl_cmd->sc->device->lun,
230 			transfer_length, tcm_loop_sam_attr(sc),
231 			sc->sc_data_direction, 0,
232 			scsi_sglist(sc), scsi_sg_count(sc),
233 			sgl_bidi, sgl_bidi_count,
234 			scsi_prot_sglist(sc), scsi_prot_sg_count(sc));
235 	if (rc < 0) {
236 		set_host_byte(sc, DID_NO_CONNECT);
237 		goto out_done;
238 	}
239 	return;
240 
241 out_done:
242 	kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
243 	sc->scsi_done(sc);
244 	return;
245 }
246 
247 /*
248  * ->queuecommand can be and usually is called from interrupt context, so
249  * defer the actual submission to a workqueue.
250  */
251 static int tcm_loop_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
252 {
253 	struct tcm_loop_cmd *tl_cmd;
254 
255 	pr_debug("tcm_loop_queuecommand() %d:%d:%d:%d got CDB: 0x%02x"
256 		" scsi_buf_len: %u\n", sc->device->host->host_no,
257 		sc->device->id, sc->device->channel, sc->device->lun,
258 		sc->cmnd[0], scsi_bufflen(sc));
259 
260 	tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_ATOMIC);
261 	if (!tl_cmd) {
262 		pr_err("Unable to allocate struct tcm_loop_cmd\n");
263 		set_host_byte(sc, DID_ERROR);
264 		sc->scsi_done(sc);
265 		return 0;
266 	}
267 
268 	tl_cmd->sc = sc;
269 	tl_cmd->sc_cmd_tag = sc->tag;
270 	INIT_WORK(&tl_cmd->work, tcm_loop_submission_work);
271 	queue_work(tcm_loop_workqueue, &tl_cmd->work);
272 	return 0;
273 }
274 
275 /*
276  * Called from SCSI EH process context to issue a LUN_RESET TMR
277  * to struct scsi_device
278  */
279 static int tcm_loop_issue_tmr(struct tcm_loop_tpg *tl_tpg,
280 			      struct tcm_loop_nexus *tl_nexus,
281 			      int lun, int task, enum tcm_tmreq_table tmr)
282 {
283 	struct se_cmd *se_cmd = NULL;
284 	struct se_session *se_sess;
285 	struct se_portal_group *se_tpg;
286 	struct tcm_loop_cmd *tl_cmd = NULL;
287 	struct tcm_loop_tmr *tl_tmr = NULL;
288 	int ret = TMR_FUNCTION_FAILED, rc;
289 
290 	tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_KERNEL);
291 	if (!tl_cmd) {
292 		pr_err("Unable to allocate memory for tl_cmd\n");
293 		return ret;
294 	}
295 
296 	tl_tmr = kzalloc(sizeof(struct tcm_loop_tmr), GFP_KERNEL);
297 	if (!tl_tmr) {
298 		pr_err("Unable to allocate memory for tl_tmr\n");
299 		goto release;
300 	}
301 	init_waitqueue_head(&tl_tmr->tl_tmr_wait);
302 
303 	se_cmd = &tl_cmd->tl_se_cmd;
304 	se_tpg = &tl_tpg->tl_se_tpg;
305 	se_sess = tl_nexus->se_sess;
306 	/*
307 	 * Initialize struct se_cmd descriptor from target_core_mod infrastructure
308 	 */
309 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, 0,
310 				DMA_NONE, MSG_SIMPLE_TAG,
311 				&tl_cmd->tl_sense_buf[0]);
312 
313 	rc = core_tmr_alloc_req(se_cmd, tl_tmr, tmr, GFP_KERNEL);
314 	if (rc < 0)
315 		goto release;
316 
317 	if (tmr == TMR_ABORT_TASK)
318 		se_cmd->se_tmr_req->ref_task_tag = task;
319 
320 	/*
321 	 * Locate the underlying TCM struct se_lun
322 	 */
323 	if (transport_lookup_tmr_lun(se_cmd, lun) < 0) {
324 		ret = TMR_LUN_DOES_NOT_EXIST;
325 		goto release;
326 	}
327 	/*
328 	 * Queue the TMR to TCM Core and sleep waiting for
329 	 * tcm_loop_queue_tm_rsp() to wake us up.
330 	 */
331 	transport_generic_handle_tmr(se_cmd);
332 	wait_event(tl_tmr->tl_tmr_wait, atomic_read(&tl_tmr->tmr_complete));
333 	/*
334 	 * The TMR LUN_RESET has completed, check the response status and
335 	 * then release allocations.
336 	 */
337 	ret = se_cmd->se_tmr_req->response;
338 release:
339 	if (se_cmd)
340 		transport_generic_free_cmd(se_cmd, 1);
341 	else
342 		kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
343 	kfree(tl_tmr);
344 	return ret;
345 }
346 
347 static int tcm_loop_abort_task(struct scsi_cmnd *sc)
348 {
349 	struct tcm_loop_hba *tl_hba;
350 	struct tcm_loop_nexus *tl_nexus;
351 	struct tcm_loop_tpg *tl_tpg;
352 	int ret = FAILED;
353 
354 	/*
355 	 * Locate the tcm_loop_hba_t pointer
356 	 */
357 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
358 	/*
359 	 * Locate the tl_nexus and se_sess pointers
360 	 */
361 	tl_nexus = tl_hba->tl_nexus;
362 	if (!tl_nexus) {
363 		pr_err("Unable to perform device reset without"
364 				" active I_T Nexus\n");
365 		return FAILED;
366 	}
367 
368 	/*
369 	 * Locate the tl_tpg pointer from TargetID in sc->device->id
370 	 */
371 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
372 	ret = tcm_loop_issue_tmr(tl_tpg, tl_nexus, sc->device->lun,
373 				 sc->tag, TMR_ABORT_TASK);
374 	return (ret == TMR_FUNCTION_COMPLETE) ? SUCCESS : FAILED;
375 }
376 
377 /*
378  * Called from SCSI EH process context to issue a LUN_RESET TMR
379  * to struct scsi_device
380  */
381 static int tcm_loop_device_reset(struct scsi_cmnd *sc)
382 {
383 	struct tcm_loop_hba *tl_hba;
384 	struct tcm_loop_nexus *tl_nexus;
385 	struct tcm_loop_tpg *tl_tpg;
386 	int ret = FAILED;
387 
388 	/*
389 	 * Locate the tcm_loop_hba_t pointer
390 	 */
391 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
392 	/*
393 	 * Locate the tl_nexus and se_sess pointers
394 	 */
395 	tl_nexus = tl_hba->tl_nexus;
396 	if (!tl_nexus) {
397 		pr_err("Unable to perform device reset without"
398 				" active I_T Nexus\n");
399 		return FAILED;
400 	}
401 	/*
402 	 * Locate the tl_tpg pointer from TargetID in sc->device->id
403 	 */
404 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
405 	ret = tcm_loop_issue_tmr(tl_tpg, tl_nexus, sc->device->lun,
406 				 0, TMR_LUN_RESET);
407 	return (ret == TMR_FUNCTION_COMPLETE) ? SUCCESS : FAILED;
408 }
409 
410 static int tcm_loop_target_reset(struct scsi_cmnd *sc)
411 {
412 	struct tcm_loop_hba *tl_hba;
413 	struct tcm_loop_tpg *tl_tpg;
414 
415 	/*
416 	 * Locate the tcm_loop_hba_t pointer
417 	 */
418 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
419 	if (!tl_hba) {
420 		pr_err("Unable to perform device reset without"
421 				" active I_T Nexus\n");
422 		return FAILED;
423 	}
424 	/*
425 	 * Locate the tl_tpg pointer from TargetID in sc->device->id
426 	 */
427 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
428 	if (tl_tpg) {
429 		tl_tpg->tl_transport_status = TCM_TRANSPORT_ONLINE;
430 		return SUCCESS;
431 	}
432 	return FAILED;
433 }
434 
435 static int tcm_loop_slave_alloc(struct scsi_device *sd)
436 {
437 	set_bit(QUEUE_FLAG_BIDI, &sd->request_queue->queue_flags);
438 	return 0;
439 }
440 
441 static int tcm_loop_slave_configure(struct scsi_device *sd)
442 {
443 	if (sd->tagged_supported) {
444 		scsi_activate_tcq(sd, sd->queue_depth);
445 		scsi_adjust_queue_depth(sd, MSG_SIMPLE_TAG,
446 					sd->host->cmd_per_lun);
447 	} else {
448 		scsi_adjust_queue_depth(sd, 0,
449 					sd->host->cmd_per_lun);
450 	}
451 
452 	return 0;
453 }
454 
455 static struct scsi_host_template tcm_loop_driver_template = {
456 	.show_info		= tcm_loop_show_info,
457 	.proc_name		= "tcm_loopback",
458 	.name			= "TCM_Loopback",
459 	.queuecommand		= tcm_loop_queuecommand,
460 	.change_queue_depth	= tcm_loop_change_queue_depth,
461 	.change_queue_type	= tcm_loop_change_queue_type,
462 	.eh_abort_handler = tcm_loop_abort_task,
463 	.eh_device_reset_handler = tcm_loop_device_reset,
464 	.eh_target_reset_handler = tcm_loop_target_reset,
465 	.can_queue		= 1024,
466 	.this_id		= -1,
467 	.sg_tablesize		= 256,
468 	.cmd_per_lun		= 1024,
469 	.max_sectors		= 0xFFFF,
470 	.use_clustering		= DISABLE_CLUSTERING,
471 	.slave_alloc		= tcm_loop_slave_alloc,
472 	.slave_configure	= tcm_loop_slave_configure,
473 	.module			= THIS_MODULE,
474 };
475 
476 static int tcm_loop_driver_probe(struct device *dev)
477 {
478 	struct tcm_loop_hba *tl_hba;
479 	struct Scsi_Host *sh;
480 	int error, host_prot;
481 
482 	tl_hba = to_tcm_loop_hba(dev);
483 
484 	sh = scsi_host_alloc(&tcm_loop_driver_template,
485 			sizeof(struct tcm_loop_hba));
486 	if (!sh) {
487 		pr_err("Unable to allocate struct scsi_host\n");
488 		return -ENODEV;
489 	}
490 	tl_hba->sh = sh;
491 
492 	/*
493 	 * Assign the struct tcm_loop_hba pointer to struct Scsi_Host->hostdata
494 	 */
495 	*((struct tcm_loop_hba **)sh->hostdata) = tl_hba;
496 	/*
497 	 * Setup single ID, Channel and LUN for now..
498 	 */
499 	sh->max_id = 2;
500 	sh->max_lun = 0;
501 	sh->max_channel = 0;
502 	sh->max_cmd_len = TL_SCSI_MAX_CMD_LEN;
503 
504 	host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
505 		    SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
506 		    SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
507 
508 	scsi_host_set_prot(sh, host_prot);
509 	scsi_host_set_guard(sh, SHOST_DIX_GUARD_CRC);
510 
511 	error = scsi_add_host(sh, &tl_hba->dev);
512 	if (error) {
513 		pr_err("%s: scsi_add_host failed\n", __func__);
514 		scsi_host_put(sh);
515 		return -ENODEV;
516 	}
517 	return 0;
518 }
519 
520 static int tcm_loop_driver_remove(struct device *dev)
521 {
522 	struct tcm_loop_hba *tl_hba;
523 	struct Scsi_Host *sh;
524 
525 	tl_hba = to_tcm_loop_hba(dev);
526 	sh = tl_hba->sh;
527 
528 	scsi_remove_host(sh);
529 	scsi_host_put(sh);
530 	return 0;
531 }
532 
533 static void tcm_loop_release_adapter(struct device *dev)
534 {
535 	struct tcm_loop_hba *tl_hba = to_tcm_loop_hba(dev);
536 
537 	kfree(tl_hba);
538 }
539 
540 /*
541  * Called from tcm_loop_make_scsi_hba() in tcm_loop_configfs.c
542  */
543 static int tcm_loop_setup_hba_bus(struct tcm_loop_hba *tl_hba, int tcm_loop_host_id)
544 {
545 	int ret;
546 
547 	tl_hba->dev.bus = &tcm_loop_lld_bus;
548 	tl_hba->dev.parent = tcm_loop_primary;
549 	tl_hba->dev.release = &tcm_loop_release_adapter;
550 	dev_set_name(&tl_hba->dev, "tcm_loop_adapter_%d", tcm_loop_host_id);
551 
552 	ret = device_register(&tl_hba->dev);
553 	if (ret) {
554 		pr_err("device_register() failed for"
555 				" tl_hba->dev: %d\n", ret);
556 		return -ENODEV;
557 	}
558 
559 	return 0;
560 }
561 
562 /*
563  * Called from tcm_loop_fabric_init() in tcl_loop_fabric.c to load the emulated
564  * tcm_loop SCSI bus.
565  */
566 static int tcm_loop_alloc_core_bus(void)
567 {
568 	int ret;
569 
570 	tcm_loop_primary = root_device_register("tcm_loop_0");
571 	if (IS_ERR(tcm_loop_primary)) {
572 		pr_err("Unable to allocate tcm_loop_primary\n");
573 		return PTR_ERR(tcm_loop_primary);
574 	}
575 
576 	ret = bus_register(&tcm_loop_lld_bus);
577 	if (ret) {
578 		pr_err("bus_register() failed for tcm_loop_lld_bus\n");
579 		goto dev_unreg;
580 	}
581 
582 	ret = driver_register(&tcm_loop_driverfs);
583 	if (ret) {
584 		pr_err("driver_register() failed for"
585 				"tcm_loop_driverfs\n");
586 		goto bus_unreg;
587 	}
588 
589 	pr_debug("Initialized TCM Loop Core Bus\n");
590 	return ret;
591 
592 bus_unreg:
593 	bus_unregister(&tcm_loop_lld_bus);
594 dev_unreg:
595 	root_device_unregister(tcm_loop_primary);
596 	return ret;
597 }
598 
599 static void tcm_loop_release_core_bus(void)
600 {
601 	driver_unregister(&tcm_loop_driverfs);
602 	bus_unregister(&tcm_loop_lld_bus);
603 	root_device_unregister(tcm_loop_primary);
604 
605 	pr_debug("Releasing TCM Loop Core BUS\n");
606 }
607 
608 static char *tcm_loop_get_fabric_name(void)
609 {
610 	return "loopback";
611 }
612 
613 static u8 tcm_loop_get_fabric_proto_ident(struct se_portal_group *se_tpg)
614 {
615 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
616 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
617 	/*
618 	 * tl_proto_id is set at tcm_loop_configfs.c:tcm_loop_make_scsi_hba()
619 	 * time based on the protocol dependent prefix of the passed configfs group.
620 	 *
621 	 * Based upon tl_proto_id, TCM_Loop emulates the requested fabric
622 	 * ProtocolID using target_core_fabric_lib.c symbols.
623 	 */
624 	switch (tl_hba->tl_proto_id) {
625 	case SCSI_PROTOCOL_SAS:
626 		return sas_get_fabric_proto_ident(se_tpg);
627 	case SCSI_PROTOCOL_FCP:
628 		return fc_get_fabric_proto_ident(se_tpg);
629 	case SCSI_PROTOCOL_ISCSI:
630 		return iscsi_get_fabric_proto_ident(se_tpg);
631 	default:
632 		pr_err("Unknown tl_proto_id: 0x%02x, using"
633 			" SAS emulation\n", tl_hba->tl_proto_id);
634 		break;
635 	}
636 
637 	return sas_get_fabric_proto_ident(se_tpg);
638 }
639 
640 static char *tcm_loop_get_endpoint_wwn(struct se_portal_group *se_tpg)
641 {
642 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
643 	/*
644 	 * Return the passed NAA identifier for the SAS Target Port
645 	 */
646 	return &tl_tpg->tl_hba->tl_wwn_address[0];
647 }
648 
649 static u16 tcm_loop_get_tag(struct se_portal_group *se_tpg)
650 {
651 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
652 	/*
653 	 * This Tag is used when forming SCSI Name identifier in EVPD=1 0x83
654 	 * to represent the SCSI Target Port.
655 	 */
656 	return tl_tpg->tl_tpgt;
657 }
658 
659 static u32 tcm_loop_get_default_depth(struct se_portal_group *se_tpg)
660 {
661 	return 1;
662 }
663 
664 static u32 tcm_loop_get_pr_transport_id(
665 	struct se_portal_group *se_tpg,
666 	struct se_node_acl *se_nacl,
667 	struct t10_pr_registration *pr_reg,
668 	int *format_code,
669 	unsigned char *buf)
670 {
671 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
672 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
673 
674 	switch (tl_hba->tl_proto_id) {
675 	case SCSI_PROTOCOL_SAS:
676 		return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
677 					format_code, buf);
678 	case SCSI_PROTOCOL_FCP:
679 		return fc_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
680 					format_code, buf);
681 	case SCSI_PROTOCOL_ISCSI:
682 		return iscsi_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
683 					format_code, buf);
684 	default:
685 		pr_err("Unknown tl_proto_id: 0x%02x, using"
686 			" SAS emulation\n", tl_hba->tl_proto_id);
687 		break;
688 	}
689 
690 	return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
691 			format_code, buf);
692 }
693 
694 static u32 tcm_loop_get_pr_transport_id_len(
695 	struct se_portal_group *se_tpg,
696 	struct se_node_acl *se_nacl,
697 	struct t10_pr_registration *pr_reg,
698 	int *format_code)
699 {
700 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
701 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
702 
703 	switch (tl_hba->tl_proto_id) {
704 	case SCSI_PROTOCOL_SAS:
705 		return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
706 					format_code);
707 	case SCSI_PROTOCOL_FCP:
708 		return fc_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
709 					format_code);
710 	case SCSI_PROTOCOL_ISCSI:
711 		return iscsi_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
712 					format_code);
713 	default:
714 		pr_err("Unknown tl_proto_id: 0x%02x, using"
715 			" SAS emulation\n", tl_hba->tl_proto_id);
716 		break;
717 	}
718 
719 	return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
720 			format_code);
721 }
722 
723 /*
724  * Used for handling SCSI fabric dependent TransportIDs in SPC-3 and above
725  * Persistent Reservation SPEC_I_PT=1 and PROUT REGISTER_AND_MOVE operations.
726  */
727 static char *tcm_loop_parse_pr_out_transport_id(
728 	struct se_portal_group *se_tpg,
729 	const char *buf,
730 	u32 *out_tid_len,
731 	char **port_nexus_ptr)
732 {
733 	struct tcm_loop_tpg *tl_tpg = se_tpg->se_tpg_fabric_ptr;
734 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
735 
736 	switch (tl_hba->tl_proto_id) {
737 	case SCSI_PROTOCOL_SAS:
738 		return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
739 					port_nexus_ptr);
740 	case SCSI_PROTOCOL_FCP:
741 		return fc_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
742 					port_nexus_ptr);
743 	case SCSI_PROTOCOL_ISCSI:
744 		return iscsi_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
745 					port_nexus_ptr);
746 	default:
747 		pr_err("Unknown tl_proto_id: 0x%02x, using"
748 			" SAS emulation\n", tl_hba->tl_proto_id);
749 		break;
750 	}
751 
752 	return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
753 			port_nexus_ptr);
754 }
755 
756 /*
757  * Returning (1) here allows for target_core_mod struct se_node_acl to be generated
758  * based upon the incoming fabric dependent SCSI Initiator Port
759  */
760 static int tcm_loop_check_demo_mode(struct se_portal_group *se_tpg)
761 {
762 	return 1;
763 }
764 
765 static int tcm_loop_check_demo_mode_cache(struct se_portal_group *se_tpg)
766 {
767 	return 0;
768 }
769 
770 /*
771  * Allow I_T Nexus full READ-WRITE access without explict Initiator Node ACLs for
772  * local virtual Linux/SCSI LLD passthrough into VM hypervisor guest
773  */
774 static int tcm_loop_check_demo_mode_write_protect(struct se_portal_group *se_tpg)
775 {
776 	return 0;
777 }
778 
779 /*
780  * Because TCM_Loop does not use explict ACLs and MappedLUNs, this will
781  * never be called for TCM_Loop by target_core_fabric_configfs.c code.
782  * It has been added here as a nop for target_fabric_tf_ops_check()
783  */
784 static int tcm_loop_check_prod_mode_write_protect(struct se_portal_group *se_tpg)
785 {
786 	return 0;
787 }
788 
789 static struct se_node_acl *tcm_loop_tpg_alloc_fabric_acl(
790 	struct se_portal_group *se_tpg)
791 {
792 	struct tcm_loop_nacl *tl_nacl;
793 
794 	tl_nacl = kzalloc(sizeof(struct tcm_loop_nacl), GFP_KERNEL);
795 	if (!tl_nacl) {
796 		pr_err("Unable to allocate struct tcm_loop_nacl\n");
797 		return NULL;
798 	}
799 
800 	return &tl_nacl->se_node_acl;
801 }
802 
803 static void tcm_loop_tpg_release_fabric_acl(
804 	struct se_portal_group *se_tpg,
805 	struct se_node_acl *se_nacl)
806 {
807 	struct tcm_loop_nacl *tl_nacl = container_of(se_nacl,
808 				struct tcm_loop_nacl, se_node_acl);
809 
810 	kfree(tl_nacl);
811 }
812 
813 static u32 tcm_loop_get_inst_index(struct se_portal_group *se_tpg)
814 {
815 	return 1;
816 }
817 
818 static u32 tcm_loop_sess_get_index(struct se_session *se_sess)
819 {
820 	return 1;
821 }
822 
823 static void tcm_loop_set_default_node_attributes(struct se_node_acl *se_acl)
824 {
825 	return;
826 }
827 
828 static u32 tcm_loop_get_task_tag(struct se_cmd *se_cmd)
829 {
830 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
831 			struct tcm_loop_cmd, tl_se_cmd);
832 
833 	return tl_cmd->sc_cmd_tag;
834 }
835 
836 static int tcm_loop_get_cmd_state(struct se_cmd *se_cmd)
837 {
838 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
839 			struct tcm_loop_cmd, tl_se_cmd);
840 
841 	return tl_cmd->sc_cmd_state;
842 }
843 
844 static int tcm_loop_shutdown_session(struct se_session *se_sess)
845 {
846 	return 0;
847 }
848 
849 static void tcm_loop_close_session(struct se_session *se_sess)
850 {
851 	return;
852 };
853 
854 static int tcm_loop_write_pending(struct se_cmd *se_cmd)
855 {
856 	/*
857 	 * Since Linux/SCSI has already sent down a struct scsi_cmnd
858 	 * sc->sc_data_direction of DMA_TO_DEVICE with struct scatterlist array
859 	 * memory, and memory has already been mapped to struct se_cmd->t_mem_list
860 	 * format with transport_generic_map_mem_to_cmd().
861 	 *
862 	 * We now tell TCM to add this WRITE CDB directly into the TCM storage
863 	 * object execution queue.
864 	 */
865 	target_execute_cmd(se_cmd);
866 	return 0;
867 }
868 
869 static int tcm_loop_write_pending_status(struct se_cmd *se_cmd)
870 {
871 	return 0;
872 }
873 
874 static int tcm_loop_queue_data_in(struct se_cmd *se_cmd)
875 {
876 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
877 				struct tcm_loop_cmd, tl_se_cmd);
878 	struct scsi_cmnd *sc = tl_cmd->sc;
879 
880 	pr_debug("tcm_loop_queue_data_in() called for scsi_cmnd: %p"
881 		     " cdb: 0x%02x\n", sc, sc->cmnd[0]);
882 
883 	sc->result = SAM_STAT_GOOD;
884 	set_host_byte(sc, DID_OK);
885 	if ((se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) ||
886 	    (se_cmd->se_cmd_flags & SCF_UNDERFLOW_BIT))
887 		scsi_set_resid(sc, se_cmd->residual_count);
888 	sc->scsi_done(sc);
889 	return 0;
890 }
891 
892 static int tcm_loop_queue_status(struct se_cmd *se_cmd)
893 {
894 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
895 				struct tcm_loop_cmd, tl_se_cmd);
896 	struct scsi_cmnd *sc = tl_cmd->sc;
897 
898 	pr_debug("tcm_loop_queue_status() called for scsi_cmnd: %p"
899 			" cdb: 0x%02x\n", sc, sc->cmnd[0]);
900 
901 	if (se_cmd->sense_buffer &&
902 	   ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
903 	    (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE))) {
904 
905 		memcpy(sc->sense_buffer, se_cmd->sense_buffer,
906 				SCSI_SENSE_BUFFERSIZE);
907 		sc->result = SAM_STAT_CHECK_CONDITION;
908 		set_driver_byte(sc, DRIVER_SENSE);
909 	} else
910 		sc->result = se_cmd->scsi_status;
911 
912 	set_host_byte(sc, DID_OK);
913 	if ((se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) ||
914 	    (se_cmd->se_cmd_flags & SCF_UNDERFLOW_BIT))
915 		scsi_set_resid(sc, se_cmd->residual_count);
916 	sc->scsi_done(sc);
917 	return 0;
918 }
919 
920 static void tcm_loop_queue_tm_rsp(struct se_cmd *se_cmd)
921 {
922 	struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
923 	struct tcm_loop_tmr *tl_tmr = se_tmr->fabric_tmr_ptr;
924 	/*
925 	 * The SCSI EH thread will be sleeping on se_tmr->tl_tmr_wait, go ahead
926 	 * and wake up the wait_queue_head_t in tcm_loop_device_reset()
927 	 */
928 	atomic_set(&tl_tmr->tmr_complete, 1);
929 	wake_up(&tl_tmr->tl_tmr_wait);
930 }
931 
932 static void tcm_loop_aborted_task(struct se_cmd *se_cmd)
933 {
934 	return;
935 }
936 
937 static char *tcm_loop_dump_proto_id(struct tcm_loop_hba *tl_hba)
938 {
939 	switch (tl_hba->tl_proto_id) {
940 	case SCSI_PROTOCOL_SAS:
941 		return "SAS";
942 	case SCSI_PROTOCOL_FCP:
943 		return "FCP";
944 	case SCSI_PROTOCOL_ISCSI:
945 		return "iSCSI";
946 	default:
947 		break;
948 	}
949 
950 	return "Unknown";
951 }
952 
953 /* Start items for tcm_loop_port_cit */
954 
955 static int tcm_loop_port_link(
956 	struct se_portal_group *se_tpg,
957 	struct se_lun *lun)
958 {
959 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
960 				struct tcm_loop_tpg, tl_se_tpg);
961 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
962 
963 	atomic_inc(&tl_tpg->tl_tpg_port_count);
964 	smp_mb__after_atomic();
965 	/*
966 	 * Add Linux/SCSI struct scsi_device by HCTL
967 	 */
968 	scsi_add_device(tl_hba->sh, 0, tl_tpg->tl_tpgt, lun->unpacked_lun);
969 
970 	pr_debug("TCM_Loop_ConfigFS: Port Link Successful\n");
971 	return 0;
972 }
973 
974 static void tcm_loop_port_unlink(
975 	struct se_portal_group *se_tpg,
976 	struct se_lun *se_lun)
977 {
978 	struct scsi_device *sd;
979 	struct tcm_loop_hba *tl_hba;
980 	struct tcm_loop_tpg *tl_tpg;
981 
982 	tl_tpg = container_of(se_tpg, struct tcm_loop_tpg, tl_se_tpg);
983 	tl_hba = tl_tpg->tl_hba;
984 
985 	sd = scsi_device_lookup(tl_hba->sh, 0, tl_tpg->tl_tpgt,
986 				se_lun->unpacked_lun);
987 	if (!sd) {
988 		pr_err("Unable to locate struct scsi_device for %d:%d:"
989 			"%d\n", 0, tl_tpg->tl_tpgt, se_lun->unpacked_lun);
990 		return;
991 	}
992 	/*
993 	 * Remove Linux/SCSI struct scsi_device by HCTL
994 	 */
995 	scsi_remove_device(sd);
996 	scsi_device_put(sd);
997 
998 	atomic_dec(&tl_tpg->tl_tpg_port_count);
999 	smp_mb__after_atomic();
1000 
1001 	pr_debug("TCM_Loop_ConfigFS: Port Unlink Successful\n");
1002 }
1003 
1004 /* End items for tcm_loop_port_cit */
1005 
1006 /* Start items for tcm_loop_nexus_cit */
1007 
1008 static int tcm_loop_make_nexus(
1009 	struct tcm_loop_tpg *tl_tpg,
1010 	const char *name)
1011 {
1012 	struct se_portal_group *se_tpg;
1013 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
1014 	struct tcm_loop_nexus *tl_nexus;
1015 	int ret = -ENOMEM;
1016 
1017 	if (tl_tpg->tl_hba->tl_nexus) {
1018 		pr_debug("tl_tpg->tl_hba->tl_nexus already exists\n");
1019 		return -EEXIST;
1020 	}
1021 	se_tpg = &tl_tpg->tl_se_tpg;
1022 
1023 	tl_nexus = kzalloc(sizeof(struct tcm_loop_nexus), GFP_KERNEL);
1024 	if (!tl_nexus) {
1025 		pr_err("Unable to allocate struct tcm_loop_nexus\n");
1026 		return -ENOMEM;
1027 	}
1028 	/*
1029 	 * Initialize the struct se_session pointer
1030 	 */
1031 	tl_nexus->se_sess = transport_init_session(TARGET_PROT_ALL);
1032 	if (IS_ERR(tl_nexus->se_sess)) {
1033 		ret = PTR_ERR(tl_nexus->se_sess);
1034 		goto out;
1035 	}
1036 	/*
1037 	 * Since we are running in 'demo mode' this call with generate a
1038 	 * struct se_node_acl for the tcm_loop struct se_portal_group with the SCSI
1039 	 * Initiator port name of the passed configfs group 'name'.
1040 	 */
1041 	tl_nexus->se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1042 				se_tpg, (unsigned char *)name);
1043 	if (!tl_nexus->se_sess->se_node_acl) {
1044 		transport_free_session(tl_nexus->se_sess);
1045 		goto out;
1046 	}
1047 	/*
1048 	 * Now, register the SAS I_T Nexus as active with the call to
1049 	 * transport_register_session()
1050 	 */
1051 	__transport_register_session(se_tpg, tl_nexus->se_sess->se_node_acl,
1052 			tl_nexus->se_sess, tl_nexus);
1053 	tl_tpg->tl_hba->tl_nexus = tl_nexus;
1054 	pr_debug("TCM_Loop_ConfigFS: Established I_T Nexus to emulated"
1055 		" %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
1056 		name);
1057 	return 0;
1058 
1059 out:
1060 	kfree(tl_nexus);
1061 	return ret;
1062 }
1063 
1064 static int tcm_loop_drop_nexus(
1065 	struct tcm_loop_tpg *tpg)
1066 {
1067 	struct se_session *se_sess;
1068 	struct tcm_loop_nexus *tl_nexus;
1069 	struct tcm_loop_hba *tl_hba = tpg->tl_hba;
1070 
1071 	if (!tl_hba)
1072 		return -ENODEV;
1073 
1074 	tl_nexus = tl_hba->tl_nexus;
1075 	if (!tl_nexus)
1076 		return -ENODEV;
1077 
1078 	se_sess = tl_nexus->se_sess;
1079 	if (!se_sess)
1080 		return -ENODEV;
1081 
1082 	if (atomic_read(&tpg->tl_tpg_port_count)) {
1083 		pr_err("Unable to remove TCM_Loop I_T Nexus with"
1084 			" active TPG port count: %d\n",
1085 			atomic_read(&tpg->tl_tpg_port_count));
1086 		return -EPERM;
1087 	}
1088 
1089 	pr_debug("TCM_Loop_ConfigFS: Removing I_T Nexus to emulated"
1090 		" %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
1091 		tl_nexus->se_sess->se_node_acl->initiatorname);
1092 	/*
1093 	 * Release the SCSI I_T Nexus to the emulated SAS Target Port
1094 	 */
1095 	transport_deregister_session(tl_nexus->se_sess);
1096 	tpg->tl_hba->tl_nexus = NULL;
1097 	kfree(tl_nexus);
1098 	return 0;
1099 }
1100 
1101 /* End items for tcm_loop_nexus_cit */
1102 
1103 static ssize_t tcm_loop_tpg_show_nexus(
1104 	struct se_portal_group *se_tpg,
1105 	char *page)
1106 {
1107 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1108 			struct tcm_loop_tpg, tl_se_tpg);
1109 	struct tcm_loop_nexus *tl_nexus;
1110 	ssize_t ret;
1111 
1112 	tl_nexus = tl_tpg->tl_hba->tl_nexus;
1113 	if (!tl_nexus)
1114 		return -ENODEV;
1115 
1116 	ret = snprintf(page, PAGE_SIZE, "%s\n",
1117 		tl_nexus->se_sess->se_node_acl->initiatorname);
1118 
1119 	return ret;
1120 }
1121 
1122 static ssize_t tcm_loop_tpg_store_nexus(
1123 	struct se_portal_group *se_tpg,
1124 	const char *page,
1125 	size_t count)
1126 {
1127 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1128 			struct tcm_loop_tpg, tl_se_tpg);
1129 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
1130 	unsigned char i_port[TL_WWN_ADDR_LEN], *ptr, *port_ptr;
1131 	int ret;
1132 	/*
1133 	 * Shutdown the active I_T nexus if 'NULL' is passed..
1134 	 */
1135 	if (!strncmp(page, "NULL", 4)) {
1136 		ret = tcm_loop_drop_nexus(tl_tpg);
1137 		return (!ret) ? count : ret;
1138 	}
1139 	/*
1140 	 * Otherwise make sure the passed virtual Initiator port WWN matches
1141 	 * the fabric protocol_id set in tcm_loop_make_scsi_hba(), and call
1142 	 * tcm_loop_make_nexus()
1143 	 */
1144 	if (strlen(page) >= TL_WWN_ADDR_LEN) {
1145 		pr_err("Emulated NAA Sas Address: %s, exceeds"
1146 				" max: %d\n", page, TL_WWN_ADDR_LEN);
1147 		return -EINVAL;
1148 	}
1149 	snprintf(&i_port[0], TL_WWN_ADDR_LEN, "%s", page);
1150 
1151 	ptr = strstr(i_port, "naa.");
1152 	if (ptr) {
1153 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_SAS) {
1154 			pr_err("Passed SAS Initiator Port %s does not"
1155 				" match target port protoid: %s\n", i_port,
1156 				tcm_loop_dump_proto_id(tl_hba));
1157 			return -EINVAL;
1158 		}
1159 		port_ptr = &i_port[0];
1160 		goto check_newline;
1161 	}
1162 	ptr = strstr(i_port, "fc.");
1163 	if (ptr) {
1164 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_FCP) {
1165 			pr_err("Passed FCP Initiator Port %s does not"
1166 				" match target port protoid: %s\n", i_port,
1167 				tcm_loop_dump_proto_id(tl_hba));
1168 			return -EINVAL;
1169 		}
1170 		port_ptr = &i_port[3]; /* Skip over "fc." */
1171 		goto check_newline;
1172 	}
1173 	ptr = strstr(i_port, "iqn.");
1174 	if (ptr) {
1175 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_ISCSI) {
1176 			pr_err("Passed iSCSI Initiator Port %s does not"
1177 				" match target port protoid: %s\n", i_port,
1178 				tcm_loop_dump_proto_id(tl_hba));
1179 			return -EINVAL;
1180 		}
1181 		port_ptr = &i_port[0];
1182 		goto check_newline;
1183 	}
1184 	pr_err("Unable to locate prefix for emulated Initiator Port:"
1185 			" %s\n", i_port);
1186 	return -EINVAL;
1187 	/*
1188 	 * Clear any trailing newline for the NAA WWN
1189 	 */
1190 check_newline:
1191 	if (i_port[strlen(i_port)-1] == '\n')
1192 		i_port[strlen(i_port)-1] = '\0';
1193 
1194 	ret = tcm_loop_make_nexus(tl_tpg, port_ptr);
1195 	if (ret < 0)
1196 		return ret;
1197 
1198 	return count;
1199 }
1200 
1201 TF_TPG_BASE_ATTR(tcm_loop, nexus, S_IRUGO | S_IWUSR);
1202 
1203 static ssize_t tcm_loop_tpg_show_transport_status(
1204 	struct se_portal_group *se_tpg,
1205 	char *page)
1206 {
1207 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1208 			struct tcm_loop_tpg, tl_se_tpg);
1209 	const char *status = NULL;
1210 	ssize_t ret = -EINVAL;
1211 
1212 	switch (tl_tpg->tl_transport_status) {
1213 	case TCM_TRANSPORT_ONLINE:
1214 		status = "online";
1215 		break;
1216 	case TCM_TRANSPORT_OFFLINE:
1217 		status = "offline";
1218 		break;
1219 	default:
1220 		break;
1221 	}
1222 
1223 	if (status)
1224 		ret = snprintf(page, PAGE_SIZE, "%s\n", status);
1225 
1226 	return ret;
1227 }
1228 
1229 static ssize_t tcm_loop_tpg_store_transport_status(
1230 	struct se_portal_group *se_tpg,
1231 	const char *page,
1232 	size_t count)
1233 {
1234 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1235 			struct tcm_loop_tpg, tl_se_tpg);
1236 
1237 	if (!strncmp(page, "online", 6)) {
1238 		tl_tpg->tl_transport_status = TCM_TRANSPORT_ONLINE;
1239 		return count;
1240 	}
1241 	if (!strncmp(page, "offline", 7)) {
1242 		tl_tpg->tl_transport_status = TCM_TRANSPORT_OFFLINE;
1243 		return count;
1244 	}
1245 	return -EINVAL;
1246 }
1247 
1248 TF_TPG_BASE_ATTR(tcm_loop, transport_status, S_IRUGO | S_IWUSR);
1249 
1250 static struct configfs_attribute *tcm_loop_tpg_attrs[] = {
1251 	&tcm_loop_tpg_nexus.attr,
1252 	&tcm_loop_tpg_transport_status.attr,
1253 	NULL,
1254 };
1255 
1256 /* Start items for tcm_loop_naa_cit */
1257 
1258 static struct se_portal_group *tcm_loop_make_naa_tpg(
1259 	struct se_wwn *wwn,
1260 	struct config_group *group,
1261 	const char *name)
1262 {
1263 	struct tcm_loop_hba *tl_hba = container_of(wwn,
1264 			struct tcm_loop_hba, tl_hba_wwn);
1265 	struct tcm_loop_tpg *tl_tpg;
1266 	char *tpgt_str, *end_ptr;
1267 	int ret;
1268 	unsigned short int tpgt;
1269 
1270 	tpgt_str = strstr(name, "tpgt_");
1271 	if (!tpgt_str) {
1272 		pr_err("Unable to locate \"tpgt_#\" directory"
1273 				" group\n");
1274 		return ERR_PTR(-EINVAL);
1275 	}
1276 	tpgt_str += 5; /* Skip ahead of "tpgt_" */
1277 	tpgt = (unsigned short int) simple_strtoul(tpgt_str, &end_ptr, 0);
1278 
1279 	if (tpgt >= TL_TPGS_PER_HBA) {
1280 		pr_err("Passed tpgt: %hu exceeds TL_TPGS_PER_HBA:"
1281 				" %u\n", tpgt, TL_TPGS_PER_HBA);
1282 		return ERR_PTR(-EINVAL);
1283 	}
1284 	tl_tpg = &tl_hba->tl_hba_tpgs[tpgt];
1285 	tl_tpg->tl_hba = tl_hba;
1286 	tl_tpg->tl_tpgt = tpgt;
1287 	/*
1288 	 * Register the tl_tpg as a emulated SAS TCM Target Endpoint
1289 	 */
1290 	ret = core_tpg_register(&tcm_loop_fabric_configfs->tf_ops,
1291 			wwn, &tl_tpg->tl_se_tpg, tl_tpg,
1292 			TRANSPORT_TPG_TYPE_NORMAL);
1293 	if (ret < 0)
1294 		return ERR_PTR(-ENOMEM);
1295 
1296 	pr_debug("TCM_Loop_ConfigFS: Allocated Emulated %s"
1297 		" Target Port %s,t,0x%04x\n", tcm_loop_dump_proto_id(tl_hba),
1298 		config_item_name(&wwn->wwn_group.cg_item), tpgt);
1299 
1300 	return &tl_tpg->tl_se_tpg;
1301 }
1302 
1303 static void tcm_loop_drop_naa_tpg(
1304 	struct se_portal_group *se_tpg)
1305 {
1306 	struct se_wwn *wwn = se_tpg->se_tpg_wwn;
1307 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1308 				struct tcm_loop_tpg, tl_se_tpg);
1309 	struct tcm_loop_hba *tl_hba;
1310 	unsigned short tpgt;
1311 
1312 	tl_hba = tl_tpg->tl_hba;
1313 	tpgt = tl_tpg->tl_tpgt;
1314 	/*
1315 	 * Release the I_T Nexus for the Virtual SAS link if present
1316 	 */
1317 	tcm_loop_drop_nexus(tl_tpg);
1318 	/*
1319 	 * Deregister the tl_tpg as a emulated SAS TCM Target Endpoint
1320 	 */
1321 	core_tpg_deregister(se_tpg);
1322 
1323 	tl_tpg->tl_hba = NULL;
1324 	tl_tpg->tl_tpgt = 0;
1325 
1326 	pr_debug("TCM_Loop_ConfigFS: Deallocated Emulated %s"
1327 		" Target Port %s,t,0x%04x\n", tcm_loop_dump_proto_id(tl_hba),
1328 		config_item_name(&wwn->wwn_group.cg_item), tpgt);
1329 }
1330 
1331 /* End items for tcm_loop_naa_cit */
1332 
1333 /* Start items for tcm_loop_cit */
1334 
1335 static struct se_wwn *tcm_loop_make_scsi_hba(
1336 	struct target_fabric_configfs *tf,
1337 	struct config_group *group,
1338 	const char *name)
1339 {
1340 	struct tcm_loop_hba *tl_hba;
1341 	struct Scsi_Host *sh;
1342 	char *ptr;
1343 	int ret, off = 0;
1344 
1345 	tl_hba = kzalloc(sizeof(struct tcm_loop_hba), GFP_KERNEL);
1346 	if (!tl_hba) {
1347 		pr_err("Unable to allocate struct tcm_loop_hba\n");
1348 		return ERR_PTR(-ENOMEM);
1349 	}
1350 	/*
1351 	 * Determine the emulated Protocol Identifier and Target Port Name
1352 	 * based on the incoming configfs directory name.
1353 	 */
1354 	ptr = strstr(name, "naa.");
1355 	if (ptr) {
1356 		tl_hba->tl_proto_id = SCSI_PROTOCOL_SAS;
1357 		goto check_len;
1358 	}
1359 	ptr = strstr(name, "fc.");
1360 	if (ptr) {
1361 		tl_hba->tl_proto_id = SCSI_PROTOCOL_FCP;
1362 		off = 3; /* Skip over "fc." */
1363 		goto check_len;
1364 	}
1365 	ptr = strstr(name, "iqn.");
1366 	if (!ptr) {
1367 		pr_err("Unable to locate prefix for emulated Target "
1368 				"Port: %s\n", name);
1369 		ret = -EINVAL;
1370 		goto out;
1371 	}
1372 	tl_hba->tl_proto_id = SCSI_PROTOCOL_ISCSI;
1373 
1374 check_len:
1375 	if (strlen(name) >= TL_WWN_ADDR_LEN) {
1376 		pr_err("Emulated NAA %s Address: %s, exceeds"
1377 			" max: %d\n", name, tcm_loop_dump_proto_id(tl_hba),
1378 			TL_WWN_ADDR_LEN);
1379 		ret = -EINVAL;
1380 		goto out;
1381 	}
1382 	snprintf(&tl_hba->tl_wwn_address[0], TL_WWN_ADDR_LEN, "%s", &name[off]);
1383 
1384 	/*
1385 	 * Call device_register(tl_hba->dev) to register the emulated
1386 	 * Linux/SCSI LLD of type struct Scsi_Host at tl_hba->sh after
1387 	 * device_register() callbacks in tcm_loop_driver_probe()
1388 	 */
1389 	ret = tcm_loop_setup_hba_bus(tl_hba, tcm_loop_hba_no_cnt);
1390 	if (ret)
1391 		goto out;
1392 
1393 	sh = tl_hba->sh;
1394 	tcm_loop_hba_no_cnt++;
1395 	pr_debug("TCM_Loop_ConfigFS: Allocated emulated Target"
1396 		" %s Address: %s at Linux/SCSI Host ID: %d\n",
1397 		tcm_loop_dump_proto_id(tl_hba), name, sh->host_no);
1398 
1399 	return &tl_hba->tl_hba_wwn;
1400 out:
1401 	kfree(tl_hba);
1402 	return ERR_PTR(ret);
1403 }
1404 
1405 static void tcm_loop_drop_scsi_hba(
1406 	struct se_wwn *wwn)
1407 {
1408 	struct tcm_loop_hba *tl_hba = container_of(wwn,
1409 				struct tcm_loop_hba, tl_hba_wwn);
1410 
1411 	pr_debug("TCM_Loop_ConfigFS: Deallocating emulated Target"
1412 		" SAS Address: %s at Linux/SCSI Host ID: %d\n",
1413 		tl_hba->tl_wwn_address, tl_hba->sh->host_no);
1414 	/*
1415 	 * Call device_unregister() on the original tl_hba->dev.
1416 	 * tcm_loop_fabric_scsi.c:tcm_loop_release_adapter() will
1417 	 * release *tl_hba;
1418 	 */
1419 	device_unregister(&tl_hba->dev);
1420 }
1421 
1422 /* Start items for tcm_loop_cit */
1423 static ssize_t tcm_loop_wwn_show_attr_version(
1424 	struct target_fabric_configfs *tf,
1425 	char *page)
1426 {
1427 	return sprintf(page, "TCM Loopback Fabric module %s\n", TCM_LOOP_VERSION);
1428 }
1429 
1430 TF_WWN_ATTR_RO(tcm_loop, version);
1431 
1432 static struct configfs_attribute *tcm_loop_wwn_attrs[] = {
1433 	&tcm_loop_wwn_version.attr,
1434 	NULL,
1435 };
1436 
1437 /* End items for tcm_loop_cit */
1438 
1439 static int tcm_loop_register_configfs(void)
1440 {
1441 	struct target_fabric_configfs *fabric;
1442 	int ret;
1443 	/*
1444 	 * Set the TCM Loop HBA counter to zero
1445 	 */
1446 	tcm_loop_hba_no_cnt = 0;
1447 	/*
1448 	 * Register the top level struct config_item_type with TCM core
1449 	 */
1450 	fabric = target_fabric_configfs_init(THIS_MODULE, "loopback");
1451 	if (IS_ERR(fabric)) {
1452 		pr_err("tcm_loop_register_configfs() failed!\n");
1453 		return PTR_ERR(fabric);
1454 	}
1455 	/*
1456 	 * Setup the fabric API of function pointers used by target_core_mod
1457 	 */
1458 	fabric->tf_ops.get_fabric_name = &tcm_loop_get_fabric_name;
1459 	fabric->tf_ops.get_fabric_proto_ident = &tcm_loop_get_fabric_proto_ident;
1460 	fabric->tf_ops.tpg_get_wwn = &tcm_loop_get_endpoint_wwn;
1461 	fabric->tf_ops.tpg_get_tag = &tcm_loop_get_tag;
1462 	fabric->tf_ops.tpg_get_default_depth = &tcm_loop_get_default_depth;
1463 	fabric->tf_ops.tpg_get_pr_transport_id = &tcm_loop_get_pr_transport_id;
1464 	fabric->tf_ops.tpg_get_pr_transport_id_len =
1465 					&tcm_loop_get_pr_transport_id_len;
1466 	fabric->tf_ops.tpg_parse_pr_out_transport_id =
1467 					&tcm_loop_parse_pr_out_transport_id;
1468 	fabric->tf_ops.tpg_check_demo_mode = &tcm_loop_check_demo_mode;
1469 	fabric->tf_ops.tpg_check_demo_mode_cache =
1470 					&tcm_loop_check_demo_mode_cache;
1471 	fabric->tf_ops.tpg_check_demo_mode_write_protect =
1472 					&tcm_loop_check_demo_mode_write_protect;
1473 	fabric->tf_ops.tpg_check_prod_mode_write_protect =
1474 					&tcm_loop_check_prod_mode_write_protect;
1475 	/*
1476 	 * The TCM loopback fabric module runs in demo-mode to a local
1477 	 * virtual SCSI device, so fabric dependent initator ACLs are
1478 	 * not required.
1479 	 */
1480 	fabric->tf_ops.tpg_alloc_fabric_acl = &tcm_loop_tpg_alloc_fabric_acl;
1481 	fabric->tf_ops.tpg_release_fabric_acl =
1482 					&tcm_loop_tpg_release_fabric_acl;
1483 	fabric->tf_ops.tpg_get_inst_index = &tcm_loop_get_inst_index;
1484 	/*
1485 	 * Used for setting up remaining TCM resources in process context
1486 	 */
1487 	fabric->tf_ops.check_stop_free = &tcm_loop_check_stop_free;
1488 	fabric->tf_ops.release_cmd = &tcm_loop_release_cmd;
1489 	fabric->tf_ops.shutdown_session = &tcm_loop_shutdown_session;
1490 	fabric->tf_ops.close_session = &tcm_loop_close_session;
1491 	fabric->tf_ops.sess_get_index = &tcm_loop_sess_get_index;
1492 	fabric->tf_ops.sess_get_initiator_sid = NULL;
1493 	fabric->tf_ops.write_pending = &tcm_loop_write_pending;
1494 	fabric->tf_ops.write_pending_status = &tcm_loop_write_pending_status;
1495 	/*
1496 	 * Not used for TCM loopback
1497 	 */
1498 	fabric->tf_ops.set_default_node_attributes =
1499 					&tcm_loop_set_default_node_attributes;
1500 	fabric->tf_ops.get_task_tag = &tcm_loop_get_task_tag;
1501 	fabric->tf_ops.get_cmd_state = &tcm_loop_get_cmd_state;
1502 	fabric->tf_ops.queue_data_in = &tcm_loop_queue_data_in;
1503 	fabric->tf_ops.queue_status = &tcm_loop_queue_status;
1504 	fabric->tf_ops.queue_tm_rsp = &tcm_loop_queue_tm_rsp;
1505 	fabric->tf_ops.aborted_task = &tcm_loop_aborted_task;
1506 
1507 	/*
1508 	 * Setup function pointers for generic logic in target_core_fabric_configfs.c
1509 	 */
1510 	fabric->tf_ops.fabric_make_wwn = &tcm_loop_make_scsi_hba;
1511 	fabric->tf_ops.fabric_drop_wwn = &tcm_loop_drop_scsi_hba;
1512 	fabric->tf_ops.fabric_make_tpg = &tcm_loop_make_naa_tpg;
1513 	fabric->tf_ops.fabric_drop_tpg = &tcm_loop_drop_naa_tpg;
1514 	/*
1515 	 * fabric_post_link() and fabric_pre_unlink() are used for
1516 	 * registration and release of TCM Loop Virtual SCSI LUNs.
1517 	 */
1518 	fabric->tf_ops.fabric_post_link = &tcm_loop_port_link;
1519 	fabric->tf_ops.fabric_pre_unlink = &tcm_loop_port_unlink;
1520 	fabric->tf_ops.fabric_make_np = NULL;
1521 	fabric->tf_ops.fabric_drop_np = NULL;
1522 	/*
1523 	 * Setup default attribute lists for various fabric->tf_cit_tmpl
1524 	 */
1525 	fabric->tf_cit_tmpl.tfc_wwn_cit.ct_attrs = tcm_loop_wwn_attrs;
1526 	fabric->tf_cit_tmpl.tfc_tpg_base_cit.ct_attrs = tcm_loop_tpg_attrs;
1527 	fabric->tf_cit_tmpl.tfc_tpg_attrib_cit.ct_attrs = NULL;
1528 	fabric->tf_cit_tmpl.tfc_tpg_param_cit.ct_attrs = NULL;
1529 	fabric->tf_cit_tmpl.tfc_tpg_np_base_cit.ct_attrs = NULL;
1530 	/*
1531 	 * Once fabric->tf_ops has been setup, now register the fabric for
1532 	 * use within TCM
1533 	 */
1534 	ret = target_fabric_configfs_register(fabric);
1535 	if (ret < 0) {
1536 		pr_err("target_fabric_configfs_register() for"
1537 				" TCM_Loop failed!\n");
1538 		target_fabric_configfs_free(fabric);
1539 		return -1;
1540 	}
1541 	/*
1542 	 * Setup our local pointer to *fabric.
1543 	 */
1544 	tcm_loop_fabric_configfs = fabric;
1545 	pr_debug("TCM_LOOP[0] - Set fabric ->"
1546 			" tcm_loop_fabric_configfs\n");
1547 	return 0;
1548 }
1549 
1550 static void tcm_loop_deregister_configfs(void)
1551 {
1552 	if (!tcm_loop_fabric_configfs)
1553 		return;
1554 
1555 	target_fabric_configfs_deregister(tcm_loop_fabric_configfs);
1556 	tcm_loop_fabric_configfs = NULL;
1557 	pr_debug("TCM_LOOP[0] - Cleared"
1558 				" tcm_loop_fabric_configfs\n");
1559 }
1560 
1561 static int __init tcm_loop_fabric_init(void)
1562 {
1563 	int ret = -ENOMEM;
1564 
1565 	tcm_loop_workqueue = alloc_workqueue("tcm_loop", 0, 0);
1566 	if (!tcm_loop_workqueue)
1567 		goto out;
1568 
1569 	tcm_loop_cmd_cache = kmem_cache_create("tcm_loop_cmd_cache",
1570 				sizeof(struct tcm_loop_cmd),
1571 				__alignof__(struct tcm_loop_cmd),
1572 				0, NULL);
1573 	if (!tcm_loop_cmd_cache) {
1574 		pr_debug("kmem_cache_create() for"
1575 			" tcm_loop_cmd_cache failed\n");
1576 		goto out_destroy_workqueue;
1577 	}
1578 
1579 	ret = tcm_loop_alloc_core_bus();
1580 	if (ret)
1581 		goto out_destroy_cache;
1582 
1583 	ret = tcm_loop_register_configfs();
1584 	if (ret)
1585 		goto out_release_core_bus;
1586 
1587 	return 0;
1588 
1589 out_release_core_bus:
1590 	tcm_loop_release_core_bus();
1591 out_destroy_cache:
1592 	kmem_cache_destroy(tcm_loop_cmd_cache);
1593 out_destroy_workqueue:
1594 	destroy_workqueue(tcm_loop_workqueue);
1595 out:
1596 	return ret;
1597 }
1598 
1599 static void __exit tcm_loop_fabric_exit(void)
1600 {
1601 	tcm_loop_deregister_configfs();
1602 	tcm_loop_release_core_bus();
1603 	kmem_cache_destroy(tcm_loop_cmd_cache);
1604 	destroy_workqueue(tcm_loop_workqueue);
1605 }
1606 
1607 MODULE_DESCRIPTION("TCM loopback virtual Linux/SCSI fabric module");
1608 MODULE_AUTHOR("Nicholas A. Bellinger <nab@risingtidesystems.com>");
1609 MODULE_LICENSE("GPL");
1610 module_init(tcm_loop_fabric_init);
1611 module_exit(tcm_loop_fabric_exit);
1612