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