1 /*******************************************************************************
2  *
3  * This file contains the Linux/SCSI LLD virtual SCSI initiator driver
4  * for emulated SAS initiator ports
5  *
6  * © Copyright 2011 RisingTide Systems LLC.
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_transport.h>
37 #include <target/target_core_fabric_ops.h>
38 #include <target/target_core_fabric_configfs.h>
39 #include <target/target_core_fabric_lib.h>
40 #include <target/target_core_configfs.h>
41 #include <target/target_core_device.h>
42 #include <target/target_core_tpg.h>
43 #include <target/target_core_tmr.h>
44 
45 #include "tcm_loop.h"
46 
47 #define to_tcm_loop_hba(hba)	container_of(hba, struct tcm_loop_hba, dev)
48 
49 /* Local pointer to allocated TCM configfs fabric module */
50 static struct target_fabric_configfs *tcm_loop_fabric_configfs;
51 
52 static struct kmem_cache *tcm_loop_cmd_cache;
53 
54 static int tcm_loop_hba_no_cnt;
55 
56 /*
57  * Allocate a tcm_loop cmd descriptor from target_core_mod code
58  *
59  * Can be called from interrupt context in tcm_loop_queuecommand() below
60  */
61 static struct se_cmd *tcm_loop_allocate_core_cmd(
62 	struct tcm_loop_hba *tl_hba,
63 	struct se_portal_group *se_tpg,
64 	struct scsi_cmnd *sc)
65 {
66 	struct se_cmd *se_cmd;
67 	struct se_session *se_sess;
68 	struct tcm_loop_nexus *tl_nexus = tl_hba->tl_nexus;
69 	struct tcm_loop_cmd *tl_cmd;
70 	int sam_task_attr;
71 
72 	if (!tl_nexus) {
73 		scmd_printk(KERN_ERR, sc, "TCM_Loop I_T Nexus"
74 				" does not exist\n");
75 		set_host_byte(sc, DID_ERROR);
76 		return NULL;
77 	}
78 	se_sess = tl_nexus->se_sess;
79 
80 	tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_ATOMIC);
81 	if (!tl_cmd) {
82 		pr_err("Unable to allocate struct tcm_loop_cmd\n");
83 		set_host_byte(sc, DID_ERROR);
84 		return NULL;
85 	}
86 	se_cmd = &tl_cmd->tl_se_cmd;
87 	/*
88 	 * Save the pointer to struct scsi_cmnd *sc
89 	 */
90 	tl_cmd->sc = sc;
91 	/*
92 	 * Locate the SAM Task Attr from struct scsi_cmnd *
93 	 */
94 	if (sc->device->tagged_supported) {
95 		switch (sc->tag) {
96 		case HEAD_OF_QUEUE_TAG:
97 			sam_task_attr = MSG_HEAD_TAG;
98 			break;
99 		case ORDERED_QUEUE_TAG:
100 			sam_task_attr = MSG_ORDERED_TAG;
101 			break;
102 		default:
103 			sam_task_attr = MSG_SIMPLE_TAG;
104 			break;
105 		}
106 	} else
107 		sam_task_attr = MSG_SIMPLE_TAG;
108 
109 	/*
110 	 * Initialize struct se_cmd descriptor from target_core_mod infrastructure
111 	 */
112 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
113 			scsi_bufflen(sc), sc->sc_data_direction, sam_task_attr,
114 			&tl_cmd->tl_sense_buf[0]);
115 
116 	/*
117 	 * Signal BIDI usage with T_TASK(cmd)->t_tasks_bidi
118 	 */
119 	if (scsi_bidi_cmnd(sc))
120 		se_cmd->t_tasks_bidi = 1;
121 	/*
122 	 * Locate the struct se_lun pointer and attach it to struct se_cmd
123 	 */
124 	if (transport_lookup_cmd_lun(se_cmd, tl_cmd->sc->device->lun) < 0) {
125 		kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
126 		set_host_byte(sc, DID_NO_CONNECT);
127 		return NULL;
128 	}
129 
130 	return se_cmd;
131 }
132 
133 /*
134  * Called by struct target_core_fabric_ops->new_cmd_map()
135  *
136  * Always called in process context.  A non zero return value
137  * here will signal to handle an exception based on the return code.
138  */
139 static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
140 {
141 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
142 				struct tcm_loop_cmd, tl_se_cmd);
143 	struct scsi_cmnd *sc = tl_cmd->sc;
144 	struct scatterlist *sgl_bidi = NULL;
145 	u32 sgl_bidi_count = 0;
146 	int ret;
147 	/*
148 	 * Allocate the necessary tasks to complete the received CDB+data
149 	 */
150 	ret = transport_generic_allocate_tasks(se_cmd, sc->cmnd);
151 	if (ret == -ENOMEM) {
152 		/* Out of Resources */
153 		return PYX_TRANSPORT_LU_COMM_FAILURE;
154 	} else if (ret == -EINVAL) {
155 		/*
156 		 * Handle case for SAM_STAT_RESERVATION_CONFLICT
157 		 */
158 		if (se_cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)
159 			return PYX_TRANSPORT_RESERVATION_CONFLICT;
160 		/*
161 		 * Otherwise, return SAM_STAT_CHECK_CONDITION and return
162 		 * sense data.
163 		 */
164 		return PYX_TRANSPORT_USE_SENSE_REASON;
165 	}
166 
167 	/*
168 	 * For BIDI commands, pass in the extra READ buffer
169 	 * to transport_generic_map_mem_to_cmd() below..
170 	 */
171 	if (se_cmd->t_tasks_bidi) {
172 		struct scsi_data_buffer *sdb = scsi_in(sc);
173 
174 		sgl_bidi = sdb->table.sgl;
175 		sgl_bidi_count = sdb->table.nents;
176 	}
177 
178 	/* Tell the core about our preallocated memory */
179 	ret = transport_generic_map_mem_to_cmd(se_cmd, scsi_sglist(sc),
180 			scsi_sg_count(sc), sgl_bidi, sgl_bidi_count);
181 	if (ret < 0)
182 		return PYX_TRANSPORT_LU_COMM_FAILURE;
183 
184 	return 0;
185 }
186 
187 /*
188  * Called from struct target_core_fabric_ops->check_stop_free()
189  */
190 static void tcm_loop_check_stop_free(struct se_cmd *se_cmd)
191 {
192 	/*
193 	 * Do not release struct se_cmd's containing a valid TMR
194 	 * pointer.  These will be released directly in tcm_loop_device_reset()
195 	 * with transport_generic_free_cmd().
196 	 */
197 	if (se_cmd->se_tmr_req)
198 		return;
199 	/*
200 	 * Release the struct se_cmd, which will make a callback to release
201 	 * struct tcm_loop_cmd * in tcm_loop_deallocate_core_cmd()
202 	 */
203 	transport_generic_free_cmd(se_cmd, 0, 0);
204 }
205 
206 static void tcm_loop_release_cmd(struct se_cmd *se_cmd)
207 {
208 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
209 				struct tcm_loop_cmd, tl_se_cmd);
210 
211 	kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
212 }
213 
214 static int tcm_loop_proc_info(struct Scsi_Host *host, char *buffer,
215 				char **start, off_t offset,
216 				int length, int inout)
217 {
218 	return sprintf(buffer, "tcm_loop_proc_info()\n");
219 }
220 
221 static int tcm_loop_driver_probe(struct device *);
222 static int tcm_loop_driver_remove(struct device *);
223 
224 static int pseudo_lld_bus_match(struct device *dev,
225 				struct device_driver *dev_driver)
226 {
227 	return 1;
228 }
229 
230 static struct bus_type tcm_loop_lld_bus = {
231 	.name			= "tcm_loop_bus",
232 	.match			= pseudo_lld_bus_match,
233 	.probe			= tcm_loop_driver_probe,
234 	.remove			= tcm_loop_driver_remove,
235 };
236 
237 static struct device_driver tcm_loop_driverfs = {
238 	.name			= "tcm_loop",
239 	.bus			= &tcm_loop_lld_bus,
240 };
241 /*
242  * Used with root_device_register() in tcm_loop_alloc_core_bus() below
243  */
244 struct device *tcm_loop_primary;
245 
246 /*
247  * Copied from drivers/scsi/libfc/fc_fcp.c:fc_change_queue_depth() and
248  * drivers/scsi/libiscsi.c:iscsi_change_queue_depth()
249  */
250 static int tcm_loop_change_queue_depth(
251 	struct scsi_device *sdev,
252 	int depth,
253 	int reason)
254 {
255 	switch (reason) {
256 	case SCSI_QDEPTH_DEFAULT:
257 		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
258 		break;
259 	case SCSI_QDEPTH_QFULL:
260 		scsi_track_queue_full(sdev, depth);
261 		break;
262 	case SCSI_QDEPTH_RAMP_UP:
263 		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
264 		break;
265 	default:
266 		return -EOPNOTSUPP;
267 	}
268 	return sdev->queue_depth;
269 }
270 
271 /*
272  * Main entry point from struct scsi_host_template for incoming SCSI CDB+Data
273  * from Linux/SCSI subsystem for SCSI low level device drivers (LLDs)
274  */
275 static int tcm_loop_queuecommand(
276 	struct Scsi_Host *sh,
277 	struct scsi_cmnd *sc)
278 {
279 	struct se_cmd *se_cmd;
280 	struct se_portal_group *se_tpg;
281 	struct tcm_loop_hba *tl_hba;
282 	struct tcm_loop_tpg *tl_tpg;
283 
284 	pr_debug("tcm_loop_queuecommand() %d:%d:%d:%d got CDB: 0x%02x"
285 		" scsi_buf_len: %u\n", sc->device->host->host_no,
286 		sc->device->id, sc->device->channel, sc->device->lun,
287 		sc->cmnd[0], scsi_bufflen(sc));
288 	/*
289 	 * Locate the tcm_loop_hba_t pointer
290 	 */
291 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
292 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
293 	se_tpg = &tl_tpg->tl_se_tpg;
294 	/*
295 	 * Determine the SAM Task Attribute and allocate tl_cmd and
296 	 * tl_cmd->tl_se_cmd from TCM infrastructure
297 	 */
298 	se_cmd = tcm_loop_allocate_core_cmd(tl_hba, se_tpg, sc);
299 	if (!se_cmd) {
300 		sc->scsi_done(sc);
301 		return 0;
302 	}
303 	/*
304 	 * Queue up the newly allocated to be processed in TCM thread context.
305 	*/
306 	transport_generic_handle_cdb_map(se_cmd);
307 	return 0;
308 }
309 
310 /*
311  * Called from SCSI EH process context to issue a LUN_RESET TMR
312  * to struct scsi_device
313  */
314 static int tcm_loop_device_reset(struct scsi_cmnd *sc)
315 {
316 	struct se_cmd *se_cmd = NULL;
317 	struct se_portal_group *se_tpg;
318 	struct se_session *se_sess;
319 	struct tcm_loop_cmd *tl_cmd = NULL;
320 	struct tcm_loop_hba *tl_hba;
321 	struct tcm_loop_nexus *tl_nexus;
322 	struct tcm_loop_tmr *tl_tmr = NULL;
323 	struct tcm_loop_tpg *tl_tpg;
324 	int ret = FAILED;
325 	/*
326 	 * Locate the tcm_loop_hba_t pointer
327 	 */
328 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
329 	/*
330 	 * Locate the tl_nexus and se_sess pointers
331 	 */
332 	tl_nexus = tl_hba->tl_nexus;
333 	if (!tl_nexus) {
334 		pr_err("Unable to perform device reset without"
335 				" active I_T Nexus\n");
336 		return FAILED;
337 	}
338 	se_sess = tl_nexus->se_sess;
339 	/*
340 	 * Locate the tl_tpg and se_tpg pointers from TargetID in sc->device->id
341 	 */
342 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
343 	se_tpg = &tl_tpg->tl_se_tpg;
344 
345 	tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_KERNEL);
346 	if (!tl_cmd) {
347 		pr_err("Unable to allocate memory for tl_cmd\n");
348 		return FAILED;
349 	}
350 
351 	tl_tmr = kzalloc(sizeof(struct tcm_loop_tmr), GFP_KERNEL);
352 	if (!tl_tmr) {
353 		pr_err("Unable to allocate memory for tl_tmr\n");
354 		goto release;
355 	}
356 	init_waitqueue_head(&tl_tmr->tl_tmr_wait);
357 
358 	se_cmd = &tl_cmd->tl_se_cmd;
359 	/*
360 	 * Initialize struct se_cmd descriptor from target_core_mod infrastructure
361 	 */
362 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, 0,
363 				DMA_NONE, MSG_SIMPLE_TAG,
364 				&tl_cmd->tl_sense_buf[0]);
365 	/*
366 	 * Allocate the LUN_RESET TMR
367 	 */
368 	se_cmd->se_tmr_req = core_tmr_alloc_req(se_cmd, tl_tmr,
369 				TMR_LUN_RESET);
370 	if (IS_ERR(se_cmd->se_tmr_req))
371 		goto release;
372 	/*
373 	 * Locate the underlying TCM struct se_lun from sc->device->lun
374 	 */
375 	if (transport_lookup_tmr_lun(se_cmd, sc->device->lun) < 0)
376 		goto release;
377 	/*
378 	 * Queue the TMR to TCM Core and sleep waiting for tcm_loop_queue_tm_rsp()
379 	 * to wake us up.
380 	 */
381 	transport_generic_handle_tmr(se_cmd);
382 	wait_event(tl_tmr->tl_tmr_wait, atomic_read(&tl_tmr->tmr_complete));
383 	/*
384 	 * The TMR LUN_RESET has completed, check the response status and
385 	 * then release allocations.
386 	 */
387 	ret = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
388 		SUCCESS : FAILED;
389 release:
390 	if (se_cmd)
391 		transport_generic_free_cmd(se_cmd, 1, 0);
392 	else
393 		kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
394 	kfree(tl_tmr);
395 	return ret;
396 }
397 
398 static int tcm_loop_slave_alloc(struct scsi_device *sd)
399 {
400 	set_bit(QUEUE_FLAG_BIDI, &sd->request_queue->queue_flags);
401 	return 0;
402 }
403 
404 static int tcm_loop_slave_configure(struct scsi_device *sd)
405 {
406 	return 0;
407 }
408 
409 static struct scsi_host_template tcm_loop_driver_template = {
410 	.proc_info		= tcm_loop_proc_info,
411 	.proc_name		= "tcm_loopback",
412 	.name			= "TCM_Loopback",
413 	.queuecommand		= tcm_loop_queuecommand,
414 	.change_queue_depth	= tcm_loop_change_queue_depth,
415 	.eh_device_reset_handler = tcm_loop_device_reset,
416 	.can_queue		= TL_SCSI_CAN_QUEUE,
417 	.this_id		= -1,
418 	.sg_tablesize		= TL_SCSI_SG_TABLESIZE,
419 	.cmd_per_lun		= TL_SCSI_CMD_PER_LUN,
420 	.max_sectors		= TL_SCSI_MAX_SECTORS,
421 	.use_clustering		= DISABLE_CLUSTERING,
422 	.slave_alloc		= tcm_loop_slave_alloc,
423 	.slave_configure	= tcm_loop_slave_configure,
424 	.module			= THIS_MODULE,
425 };
426 
427 static int tcm_loop_driver_probe(struct device *dev)
428 {
429 	struct tcm_loop_hba *tl_hba;
430 	struct Scsi_Host *sh;
431 	int error;
432 
433 	tl_hba = to_tcm_loop_hba(dev);
434 
435 	sh = scsi_host_alloc(&tcm_loop_driver_template,
436 			sizeof(struct tcm_loop_hba));
437 	if (!sh) {
438 		pr_err("Unable to allocate struct scsi_host\n");
439 		return -ENODEV;
440 	}
441 	tl_hba->sh = sh;
442 
443 	/*
444 	 * Assign the struct tcm_loop_hba pointer to struct Scsi_Host->hostdata
445 	 */
446 	*((struct tcm_loop_hba **)sh->hostdata) = tl_hba;
447 	/*
448 	 * Setup single ID, Channel and LUN for now..
449 	 */
450 	sh->max_id = 2;
451 	sh->max_lun = 0;
452 	sh->max_channel = 0;
453 	sh->max_cmd_len = TL_SCSI_MAX_CMD_LEN;
454 
455 	error = scsi_add_host(sh, &tl_hba->dev);
456 	if (error) {
457 		pr_err("%s: scsi_add_host failed\n", __func__);
458 		scsi_host_put(sh);
459 		return -ENODEV;
460 	}
461 	return 0;
462 }
463 
464 static int tcm_loop_driver_remove(struct device *dev)
465 {
466 	struct tcm_loop_hba *tl_hba;
467 	struct Scsi_Host *sh;
468 
469 	tl_hba = to_tcm_loop_hba(dev);
470 	sh = tl_hba->sh;
471 
472 	scsi_remove_host(sh);
473 	scsi_host_put(sh);
474 	return 0;
475 }
476 
477 static void tcm_loop_release_adapter(struct device *dev)
478 {
479 	struct tcm_loop_hba *tl_hba = to_tcm_loop_hba(dev);
480 
481 	kfree(tl_hba);
482 }
483 
484 /*
485  * Called from tcm_loop_make_scsi_hba() in tcm_loop_configfs.c
486  */
487 static int tcm_loop_setup_hba_bus(struct tcm_loop_hba *tl_hba, int tcm_loop_host_id)
488 {
489 	int ret;
490 
491 	tl_hba->dev.bus = &tcm_loop_lld_bus;
492 	tl_hba->dev.parent = tcm_loop_primary;
493 	tl_hba->dev.release = &tcm_loop_release_adapter;
494 	dev_set_name(&tl_hba->dev, "tcm_loop_adapter_%d", tcm_loop_host_id);
495 
496 	ret = device_register(&tl_hba->dev);
497 	if (ret) {
498 		pr_err("device_register() failed for"
499 				" tl_hba->dev: %d\n", ret);
500 		return -ENODEV;
501 	}
502 
503 	return 0;
504 }
505 
506 /*
507  * Called from tcm_loop_fabric_init() in tcl_loop_fabric.c to load the emulated
508  * tcm_loop SCSI bus.
509  */
510 static int tcm_loop_alloc_core_bus(void)
511 {
512 	int ret;
513 
514 	tcm_loop_primary = root_device_register("tcm_loop_0");
515 	if (IS_ERR(tcm_loop_primary)) {
516 		pr_err("Unable to allocate tcm_loop_primary\n");
517 		return PTR_ERR(tcm_loop_primary);
518 	}
519 
520 	ret = bus_register(&tcm_loop_lld_bus);
521 	if (ret) {
522 		pr_err("bus_register() failed for tcm_loop_lld_bus\n");
523 		goto dev_unreg;
524 	}
525 
526 	ret = driver_register(&tcm_loop_driverfs);
527 	if (ret) {
528 		pr_err("driver_register() failed for"
529 				"tcm_loop_driverfs\n");
530 		goto bus_unreg;
531 	}
532 
533 	pr_debug("Initialized TCM Loop Core Bus\n");
534 	return ret;
535 
536 bus_unreg:
537 	bus_unregister(&tcm_loop_lld_bus);
538 dev_unreg:
539 	root_device_unregister(tcm_loop_primary);
540 	return ret;
541 }
542 
543 static void tcm_loop_release_core_bus(void)
544 {
545 	driver_unregister(&tcm_loop_driverfs);
546 	bus_unregister(&tcm_loop_lld_bus);
547 	root_device_unregister(tcm_loop_primary);
548 
549 	pr_debug("Releasing TCM Loop Core BUS\n");
550 }
551 
552 static char *tcm_loop_get_fabric_name(void)
553 {
554 	return "loopback";
555 }
556 
557 static u8 tcm_loop_get_fabric_proto_ident(struct se_portal_group *se_tpg)
558 {
559 	struct tcm_loop_tpg *tl_tpg =
560 			(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
561 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
562 	/*
563 	 * tl_proto_id is set at tcm_loop_configfs.c:tcm_loop_make_scsi_hba()
564 	 * time based on the protocol dependent prefix of the passed configfs group.
565 	 *
566 	 * Based upon tl_proto_id, TCM_Loop emulates the requested fabric
567 	 * ProtocolID using target_core_fabric_lib.c symbols.
568 	 */
569 	switch (tl_hba->tl_proto_id) {
570 	case SCSI_PROTOCOL_SAS:
571 		return sas_get_fabric_proto_ident(se_tpg);
572 	case SCSI_PROTOCOL_FCP:
573 		return fc_get_fabric_proto_ident(se_tpg);
574 	case SCSI_PROTOCOL_ISCSI:
575 		return iscsi_get_fabric_proto_ident(se_tpg);
576 	default:
577 		pr_err("Unknown tl_proto_id: 0x%02x, using"
578 			" SAS emulation\n", tl_hba->tl_proto_id);
579 		break;
580 	}
581 
582 	return sas_get_fabric_proto_ident(se_tpg);
583 }
584 
585 static char *tcm_loop_get_endpoint_wwn(struct se_portal_group *se_tpg)
586 {
587 	struct tcm_loop_tpg *tl_tpg =
588 		(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
589 	/*
590 	 * Return the passed NAA identifier for the SAS Target Port
591 	 */
592 	return &tl_tpg->tl_hba->tl_wwn_address[0];
593 }
594 
595 static u16 tcm_loop_get_tag(struct se_portal_group *se_tpg)
596 {
597 	struct tcm_loop_tpg *tl_tpg =
598 		(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
599 	/*
600 	 * This Tag is used when forming SCSI Name identifier in EVPD=1 0x83
601 	 * to represent the SCSI Target Port.
602 	 */
603 	return tl_tpg->tl_tpgt;
604 }
605 
606 static u32 tcm_loop_get_default_depth(struct se_portal_group *se_tpg)
607 {
608 	return 1;
609 }
610 
611 static u32 tcm_loop_get_pr_transport_id(
612 	struct se_portal_group *se_tpg,
613 	struct se_node_acl *se_nacl,
614 	struct t10_pr_registration *pr_reg,
615 	int *format_code,
616 	unsigned char *buf)
617 {
618 	struct tcm_loop_tpg *tl_tpg =
619 			(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
620 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
621 
622 	switch (tl_hba->tl_proto_id) {
623 	case SCSI_PROTOCOL_SAS:
624 		return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
625 					format_code, buf);
626 	case SCSI_PROTOCOL_FCP:
627 		return fc_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
628 					format_code, buf);
629 	case SCSI_PROTOCOL_ISCSI:
630 		return iscsi_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
631 					format_code, buf);
632 	default:
633 		pr_err("Unknown tl_proto_id: 0x%02x, using"
634 			" SAS emulation\n", tl_hba->tl_proto_id);
635 		break;
636 	}
637 
638 	return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
639 			format_code, buf);
640 }
641 
642 static u32 tcm_loop_get_pr_transport_id_len(
643 	struct se_portal_group *se_tpg,
644 	struct se_node_acl *se_nacl,
645 	struct t10_pr_registration *pr_reg,
646 	int *format_code)
647 {
648 	struct tcm_loop_tpg *tl_tpg =
649 			(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
650 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
651 
652 	switch (tl_hba->tl_proto_id) {
653 	case SCSI_PROTOCOL_SAS:
654 		return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
655 					format_code);
656 	case SCSI_PROTOCOL_FCP:
657 		return fc_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
658 					format_code);
659 	case SCSI_PROTOCOL_ISCSI:
660 		return iscsi_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
661 					format_code);
662 	default:
663 		pr_err("Unknown tl_proto_id: 0x%02x, using"
664 			" SAS emulation\n", tl_hba->tl_proto_id);
665 		break;
666 	}
667 
668 	return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
669 			format_code);
670 }
671 
672 /*
673  * Used for handling SCSI fabric dependent TransportIDs in SPC-3 and above
674  * Persistent Reservation SPEC_I_PT=1 and PROUT REGISTER_AND_MOVE operations.
675  */
676 static char *tcm_loop_parse_pr_out_transport_id(
677 	struct se_portal_group *se_tpg,
678 	const char *buf,
679 	u32 *out_tid_len,
680 	char **port_nexus_ptr)
681 {
682 	struct tcm_loop_tpg *tl_tpg =
683 			(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
684 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
685 
686 	switch (tl_hba->tl_proto_id) {
687 	case SCSI_PROTOCOL_SAS:
688 		return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
689 					port_nexus_ptr);
690 	case SCSI_PROTOCOL_FCP:
691 		return fc_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
692 					port_nexus_ptr);
693 	case SCSI_PROTOCOL_ISCSI:
694 		return iscsi_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
695 					port_nexus_ptr);
696 	default:
697 		pr_err("Unknown tl_proto_id: 0x%02x, using"
698 			" SAS emulation\n", tl_hba->tl_proto_id);
699 		break;
700 	}
701 
702 	return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
703 			port_nexus_ptr);
704 }
705 
706 /*
707  * Returning (1) here allows for target_core_mod struct se_node_acl to be generated
708  * based upon the incoming fabric dependent SCSI Initiator Port
709  */
710 static int tcm_loop_check_demo_mode(struct se_portal_group *se_tpg)
711 {
712 	return 1;
713 }
714 
715 static int tcm_loop_check_demo_mode_cache(struct se_portal_group *se_tpg)
716 {
717 	return 0;
718 }
719 
720 /*
721  * Allow I_T Nexus full READ-WRITE access without explict Initiator Node ACLs for
722  * local virtual Linux/SCSI LLD passthrough into VM hypervisor guest
723  */
724 static int tcm_loop_check_demo_mode_write_protect(struct se_portal_group *se_tpg)
725 {
726 	return 0;
727 }
728 
729 /*
730  * Because TCM_Loop does not use explict ACLs and MappedLUNs, this will
731  * never be called for TCM_Loop by target_core_fabric_configfs.c code.
732  * It has been added here as a nop for target_fabric_tf_ops_check()
733  */
734 static int tcm_loop_check_prod_mode_write_protect(struct se_portal_group *se_tpg)
735 {
736 	return 0;
737 }
738 
739 static struct se_node_acl *tcm_loop_tpg_alloc_fabric_acl(
740 	struct se_portal_group *se_tpg)
741 {
742 	struct tcm_loop_nacl *tl_nacl;
743 
744 	tl_nacl = kzalloc(sizeof(struct tcm_loop_nacl), GFP_KERNEL);
745 	if (!tl_nacl) {
746 		pr_err("Unable to allocate struct tcm_loop_nacl\n");
747 		return NULL;
748 	}
749 
750 	return &tl_nacl->se_node_acl;
751 }
752 
753 static void tcm_loop_tpg_release_fabric_acl(
754 	struct se_portal_group *se_tpg,
755 	struct se_node_acl *se_nacl)
756 {
757 	struct tcm_loop_nacl *tl_nacl = container_of(se_nacl,
758 				struct tcm_loop_nacl, se_node_acl);
759 
760 	kfree(tl_nacl);
761 }
762 
763 static u32 tcm_loop_get_inst_index(struct se_portal_group *se_tpg)
764 {
765 	return 1;
766 }
767 
768 static int tcm_loop_is_state_remove(struct se_cmd *se_cmd)
769 {
770 	/*
771 	 * Assume struct scsi_cmnd is not in remove state..
772 	 */
773 	return 0;
774 }
775 
776 static int tcm_loop_sess_logged_in(struct se_session *se_sess)
777 {
778 	/*
779 	 * Assume that TL Nexus is always active
780 	 */
781 	return 1;
782 }
783 
784 static u32 tcm_loop_sess_get_index(struct se_session *se_sess)
785 {
786 	return 1;
787 }
788 
789 static void tcm_loop_set_default_node_attributes(struct se_node_acl *se_acl)
790 {
791 	return;
792 }
793 
794 static u32 tcm_loop_get_task_tag(struct se_cmd *se_cmd)
795 {
796 	return 1;
797 }
798 
799 static int tcm_loop_get_cmd_state(struct se_cmd *se_cmd)
800 {
801 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
802 			struct tcm_loop_cmd, tl_se_cmd);
803 
804 	return tl_cmd->sc_cmd_state;
805 }
806 
807 static int tcm_loop_shutdown_session(struct se_session *se_sess)
808 {
809 	return 0;
810 }
811 
812 static void tcm_loop_close_session(struct se_session *se_sess)
813 {
814 	return;
815 };
816 
817 static void tcm_loop_stop_session(
818 	struct se_session *se_sess,
819 	int sess_sleep,
820 	int conn_sleep)
821 {
822 	return;
823 }
824 
825 static void tcm_loop_fall_back_to_erl0(struct se_session *se_sess)
826 {
827 	return;
828 }
829 
830 static int tcm_loop_write_pending(struct se_cmd *se_cmd)
831 {
832 	/*
833 	 * Since Linux/SCSI has already sent down a struct scsi_cmnd
834 	 * sc->sc_data_direction of DMA_TO_DEVICE with struct scatterlist array
835 	 * memory, and memory has already been mapped to struct se_cmd->t_mem_list
836 	 * format with transport_generic_map_mem_to_cmd().
837 	 *
838 	 * We now tell TCM to add this WRITE CDB directly into the TCM storage
839 	 * object execution queue.
840 	 */
841 	transport_generic_process_write(se_cmd);
842 	return 0;
843 }
844 
845 static int tcm_loop_write_pending_status(struct se_cmd *se_cmd)
846 {
847 	return 0;
848 }
849 
850 static int tcm_loop_queue_data_in(struct se_cmd *se_cmd)
851 {
852 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
853 				struct tcm_loop_cmd, tl_se_cmd);
854 	struct scsi_cmnd *sc = tl_cmd->sc;
855 
856 	pr_debug("tcm_loop_queue_data_in() called for scsi_cmnd: %p"
857 		     " cdb: 0x%02x\n", sc, sc->cmnd[0]);
858 
859 	sc->result = SAM_STAT_GOOD;
860 	set_host_byte(sc, DID_OK);
861 	sc->scsi_done(sc);
862 	return 0;
863 }
864 
865 static int tcm_loop_queue_status(struct se_cmd *se_cmd)
866 {
867 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
868 				struct tcm_loop_cmd, tl_se_cmd);
869 	struct scsi_cmnd *sc = tl_cmd->sc;
870 
871 	pr_debug("tcm_loop_queue_status() called for scsi_cmnd: %p"
872 			" cdb: 0x%02x\n", sc, sc->cmnd[0]);
873 
874 	if (se_cmd->sense_buffer &&
875 	   ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
876 	    (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE))) {
877 
878 		memcpy(sc->sense_buffer, se_cmd->sense_buffer,
879 				SCSI_SENSE_BUFFERSIZE);
880 		sc->result = SAM_STAT_CHECK_CONDITION;
881 		set_driver_byte(sc, DRIVER_SENSE);
882 	} else
883 		sc->result = se_cmd->scsi_status;
884 
885 	set_host_byte(sc, DID_OK);
886 	sc->scsi_done(sc);
887 	return 0;
888 }
889 
890 static int tcm_loop_queue_tm_rsp(struct se_cmd *se_cmd)
891 {
892 	struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
893 	struct tcm_loop_tmr *tl_tmr = se_tmr->fabric_tmr_ptr;
894 	/*
895 	 * The SCSI EH thread will be sleeping on se_tmr->tl_tmr_wait, go ahead
896 	 * and wake up the wait_queue_head_t in tcm_loop_device_reset()
897 	 */
898 	atomic_set(&tl_tmr->tmr_complete, 1);
899 	wake_up(&tl_tmr->tl_tmr_wait);
900 	return 0;
901 }
902 
903 static u16 tcm_loop_set_fabric_sense_len(struct se_cmd *se_cmd, u32 sense_length)
904 {
905 	return 0;
906 }
907 
908 static u16 tcm_loop_get_fabric_sense_len(void)
909 {
910 	return 0;
911 }
912 
913 static char *tcm_loop_dump_proto_id(struct tcm_loop_hba *tl_hba)
914 {
915 	switch (tl_hba->tl_proto_id) {
916 	case SCSI_PROTOCOL_SAS:
917 		return "SAS";
918 	case SCSI_PROTOCOL_FCP:
919 		return "FCP";
920 	case SCSI_PROTOCOL_ISCSI:
921 		return "iSCSI";
922 	default:
923 		break;
924 	}
925 
926 	return "Unknown";
927 }
928 
929 /* Start items for tcm_loop_port_cit */
930 
931 static int tcm_loop_port_link(
932 	struct se_portal_group *se_tpg,
933 	struct se_lun *lun)
934 {
935 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
936 				struct tcm_loop_tpg, tl_se_tpg);
937 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
938 
939 	atomic_inc(&tl_tpg->tl_tpg_port_count);
940 	smp_mb__after_atomic_inc();
941 	/*
942 	 * Add Linux/SCSI struct scsi_device by HCTL
943 	 */
944 	scsi_add_device(tl_hba->sh, 0, tl_tpg->tl_tpgt, lun->unpacked_lun);
945 
946 	pr_debug("TCM_Loop_ConfigFS: Port Link Successful\n");
947 	return 0;
948 }
949 
950 static void tcm_loop_port_unlink(
951 	struct se_portal_group *se_tpg,
952 	struct se_lun *se_lun)
953 {
954 	struct scsi_device *sd;
955 	struct tcm_loop_hba *tl_hba;
956 	struct tcm_loop_tpg *tl_tpg;
957 
958 	tl_tpg = container_of(se_tpg, struct tcm_loop_tpg, tl_se_tpg);
959 	tl_hba = tl_tpg->tl_hba;
960 
961 	sd = scsi_device_lookup(tl_hba->sh, 0, tl_tpg->tl_tpgt,
962 				se_lun->unpacked_lun);
963 	if (!sd) {
964 		pr_err("Unable to locate struct scsi_device for %d:%d:"
965 			"%d\n", 0, tl_tpg->tl_tpgt, se_lun->unpacked_lun);
966 		return;
967 	}
968 	/*
969 	 * Remove Linux/SCSI struct scsi_device by HCTL
970 	 */
971 	scsi_remove_device(sd);
972 	scsi_device_put(sd);
973 
974 	atomic_dec(&tl_tpg->tl_tpg_port_count);
975 	smp_mb__after_atomic_dec();
976 
977 	pr_debug("TCM_Loop_ConfigFS: Port Unlink Successful\n");
978 }
979 
980 /* End items for tcm_loop_port_cit */
981 
982 /* Start items for tcm_loop_nexus_cit */
983 
984 static int tcm_loop_make_nexus(
985 	struct tcm_loop_tpg *tl_tpg,
986 	const char *name)
987 {
988 	struct se_portal_group *se_tpg;
989 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
990 	struct tcm_loop_nexus *tl_nexus;
991 	int ret = -ENOMEM;
992 
993 	if (tl_tpg->tl_hba->tl_nexus) {
994 		pr_debug("tl_tpg->tl_hba->tl_nexus already exists\n");
995 		return -EEXIST;
996 	}
997 	se_tpg = &tl_tpg->tl_se_tpg;
998 
999 	tl_nexus = kzalloc(sizeof(struct tcm_loop_nexus), GFP_KERNEL);
1000 	if (!tl_nexus) {
1001 		pr_err("Unable to allocate struct tcm_loop_nexus\n");
1002 		return -ENOMEM;
1003 	}
1004 	/*
1005 	 * Initialize the struct se_session pointer
1006 	 */
1007 	tl_nexus->se_sess = transport_init_session();
1008 	if (IS_ERR(tl_nexus->se_sess)) {
1009 		ret = PTR_ERR(tl_nexus->se_sess);
1010 		goto out;
1011 	}
1012 	/*
1013 	 * Since we are running in 'demo mode' this call with generate a
1014 	 * struct se_node_acl for the tcm_loop struct se_portal_group with the SCSI
1015 	 * Initiator port name of the passed configfs group 'name'.
1016 	 */
1017 	tl_nexus->se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1018 				se_tpg, (unsigned char *)name);
1019 	if (!tl_nexus->se_sess->se_node_acl) {
1020 		transport_free_session(tl_nexus->se_sess);
1021 		goto out;
1022 	}
1023 	/*
1024 	 * Now, register the SAS I_T Nexus as active with the call to
1025 	 * transport_register_session()
1026 	 */
1027 	__transport_register_session(se_tpg, tl_nexus->se_sess->se_node_acl,
1028 			tl_nexus->se_sess, tl_nexus);
1029 	tl_tpg->tl_hba->tl_nexus = tl_nexus;
1030 	pr_debug("TCM_Loop_ConfigFS: Established I_T Nexus to emulated"
1031 		" %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
1032 		name);
1033 	return 0;
1034 
1035 out:
1036 	kfree(tl_nexus);
1037 	return ret;
1038 }
1039 
1040 static int tcm_loop_drop_nexus(
1041 	struct tcm_loop_tpg *tpg)
1042 {
1043 	struct se_session *se_sess;
1044 	struct tcm_loop_nexus *tl_nexus;
1045 	struct tcm_loop_hba *tl_hba = tpg->tl_hba;
1046 
1047 	tl_nexus = tpg->tl_hba->tl_nexus;
1048 	if (!tl_nexus)
1049 		return -ENODEV;
1050 
1051 	se_sess = tl_nexus->se_sess;
1052 	if (!se_sess)
1053 		return -ENODEV;
1054 
1055 	if (atomic_read(&tpg->tl_tpg_port_count)) {
1056 		pr_err("Unable to remove TCM_Loop I_T Nexus with"
1057 			" active TPG port count: %d\n",
1058 			atomic_read(&tpg->tl_tpg_port_count));
1059 		return -EPERM;
1060 	}
1061 
1062 	pr_debug("TCM_Loop_ConfigFS: Removing I_T Nexus to emulated"
1063 		" %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
1064 		tl_nexus->se_sess->se_node_acl->initiatorname);
1065 	/*
1066 	 * Release the SCSI I_T Nexus to the emulated SAS Target Port
1067 	 */
1068 	transport_deregister_session(tl_nexus->se_sess);
1069 	tpg->tl_hba->tl_nexus = NULL;
1070 	kfree(tl_nexus);
1071 	return 0;
1072 }
1073 
1074 /* End items for tcm_loop_nexus_cit */
1075 
1076 static ssize_t tcm_loop_tpg_show_nexus(
1077 	struct se_portal_group *se_tpg,
1078 	char *page)
1079 {
1080 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1081 			struct tcm_loop_tpg, tl_se_tpg);
1082 	struct tcm_loop_nexus *tl_nexus;
1083 	ssize_t ret;
1084 
1085 	tl_nexus = tl_tpg->tl_hba->tl_nexus;
1086 	if (!tl_nexus)
1087 		return -ENODEV;
1088 
1089 	ret = snprintf(page, PAGE_SIZE, "%s\n",
1090 		tl_nexus->se_sess->se_node_acl->initiatorname);
1091 
1092 	return ret;
1093 }
1094 
1095 static ssize_t tcm_loop_tpg_store_nexus(
1096 	struct se_portal_group *se_tpg,
1097 	const char *page,
1098 	size_t count)
1099 {
1100 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1101 			struct tcm_loop_tpg, tl_se_tpg);
1102 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
1103 	unsigned char i_port[TL_WWN_ADDR_LEN], *ptr, *port_ptr;
1104 	int ret;
1105 	/*
1106 	 * Shutdown the active I_T nexus if 'NULL' is passed..
1107 	 */
1108 	if (!strncmp(page, "NULL", 4)) {
1109 		ret = tcm_loop_drop_nexus(tl_tpg);
1110 		return (!ret) ? count : ret;
1111 	}
1112 	/*
1113 	 * Otherwise make sure the passed virtual Initiator port WWN matches
1114 	 * the fabric protocol_id set in tcm_loop_make_scsi_hba(), and call
1115 	 * tcm_loop_make_nexus()
1116 	 */
1117 	if (strlen(page) >= TL_WWN_ADDR_LEN) {
1118 		pr_err("Emulated NAA Sas Address: %s, exceeds"
1119 				" max: %d\n", page, TL_WWN_ADDR_LEN);
1120 		return -EINVAL;
1121 	}
1122 	snprintf(&i_port[0], TL_WWN_ADDR_LEN, "%s", page);
1123 
1124 	ptr = strstr(i_port, "naa.");
1125 	if (ptr) {
1126 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_SAS) {
1127 			pr_err("Passed SAS Initiator Port %s does not"
1128 				" match target port protoid: %s\n", i_port,
1129 				tcm_loop_dump_proto_id(tl_hba));
1130 			return -EINVAL;
1131 		}
1132 		port_ptr = &i_port[0];
1133 		goto check_newline;
1134 	}
1135 	ptr = strstr(i_port, "fc.");
1136 	if (ptr) {
1137 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_FCP) {
1138 			pr_err("Passed FCP Initiator Port %s does not"
1139 				" match target port protoid: %s\n", i_port,
1140 				tcm_loop_dump_proto_id(tl_hba));
1141 			return -EINVAL;
1142 		}
1143 		port_ptr = &i_port[3]; /* Skip over "fc." */
1144 		goto check_newline;
1145 	}
1146 	ptr = strstr(i_port, "iqn.");
1147 	if (ptr) {
1148 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_ISCSI) {
1149 			pr_err("Passed iSCSI Initiator Port %s does not"
1150 				" match target port protoid: %s\n", i_port,
1151 				tcm_loop_dump_proto_id(tl_hba));
1152 			return -EINVAL;
1153 		}
1154 		port_ptr = &i_port[0];
1155 		goto check_newline;
1156 	}
1157 	pr_err("Unable to locate prefix for emulated Initiator Port:"
1158 			" %s\n", i_port);
1159 	return -EINVAL;
1160 	/*
1161 	 * Clear any trailing newline for the NAA WWN
1162 	 */
1163 check_newline:
1164 	if (i_port[strlen(i_port)-1] == '\n')
1165 		i_port[strlen(i_port)-1] = '\0';
1166 
1167 	ret = tcm_loop_make_nexus(tl_tpg, port_ptr);
1168 	if (ret < 0)
1169 		return ret;
1170 
1171 	return count;
1172 }
1173 
1174 TF_TPG_BASE_ATTR(tcm_loop, nexus, S_IRUGO | S_IWUSR);
1175 
1176 static struct configfs_attribute *tcm_loop_tpg_attrs[] = {
1177 	&tcm_loop_tpg_nexus.attr,
1178 	NULL,
1179 };
1180 
1181 /* Start items for tcm_loop_naa_cit */
1182 
1183 struct se_portal_group *tcm_loop_make_naa_tpg(
1184 	struct se_wwn *wwn,
1185 	struct config_group *group,
1186 	const char *name)
1187 {
1188 	struct tcm_loop_hba *tl_hba = container_of(wwn,
1189 			struct tcm_loop_hba, tl_hba_wwn);
1190 	struct tcm_loop_tpg *tl_tpg;
1191 	char *tpgt_str, *end_ptr;
1192 	int ret;
1193 	unsigned short int tpgt;
1194 
1195 	tpgt_str = strstr(name, "tpgt_");
1196 	if (!tpgt_str) {
1197 		pr_err("Unable to locate \"tpgt_#\" directory"
1198 				" group\n");
1199 		return ERR_PTR(-EINVAL);
1200 	}
1201 	tpgt_str += 5; /* Skip ahead of "tpgt_" */
1202 	tpgt = (unsigned short int) simple_strtoul(tpgt_str, &end_ptr, 0);
1203 
1204 	if (tpgt >= TL_TPGS_PER_HBA) {
1205 		pr_err("Passed tpgt: %hu exceeds TL_TPGS_PER_HBA:"
1206 				" %u\n", tpgt, TL_TPGS_PER_HBA);
1207 		return ERR_PTR(-EINVAL);
1208 	}
1209 	tl_tpg = &tl_hba->tl_hba_tpgs[tpgt];
1210 	tl_tpg->tl_hba = tl_hba;
1211 	tl_tpg->tl_tpgt = tpgt;
1212 	/*
1213 	 * Register the tl_tpg as a emulated SAS TCM Target Endpoint
1214 	 */
1215 	ret = core_tpg_register(&tcm_loop_fabric_configfs->tf_ops,
1216 			wwn, &tl_tpg->tl_se_tpg, tl_tpg,
1217 			TRANSPORT_TPG_TYPE_NORMAL);
1218 	if (ret < 0)
1219 		return ERR_PTR(-ENOMEM);
1220 
1221 	pr_debug("TCM_Loop_ConfigFS: Allocated Emulated %s"
1222 		" Target Port %s,t,0x%04x\n", tcm_loop_dump_proto_id(tl_hba),
1223 		config_item_name(&wwn->wwn_group.cg_item), tpgt);
1224 
1225 	return &tl_tpg->tl_se_tpg;
1226 }
1227 
1228 void tcm_loop_drop_naa_tpg(
1229 	struct se_portal_group *se_tpg)
1230 {
1231 	struct se_wwn *wwn = se_tpg->se_tpg_wwn;
1232 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1233 				struct tcm_loop_tpg, tl_se_tpg);
1234 	struct tcm_loop_hba *tl_hba;
1235 	unsigned short tpgt;
1236 
1237 	tl_hba = tl_tpg->tl_hba;
1238 	tpgt = tl_tpg->tl_tpgt;
1239 	/*
1240 	 * Release the I_T Nexus for the Virtual SAS link if present
1241 	 */
1242 	tcm_loop_drop_nexus(tl_tpg);
1243 	/*
1244 	 * Deregister the tl_tpg as a emulated SAS TCM Target Endpoint
1245 	 */
1246 	core_tpg_deregister(se_tpg);
1247 
1248 	pr_debug("TCM_Loop_ConfigFS: Deallocated Emulated %s"
1249 		" Target Port %s,t,0x%04x\n", tcm_loop_dump_proto_id(tl_hba),
1250 		config_item_name(&wwn->wwn_group.cg_item), tpgt);
1251 }
1252 
1253 /* End items for tcm_loop_naa_cit */
1254 
1255 /* Start items for tcm_loop_cit */
1256 
1257 struct se_wwn *tcm_loop_make_scsi_hba(
1258 	struct target_fabric_configfs *tf,
1259 	struct config_group *group,
1260 	const char *name)
1261 {
1262 	struct tcm_loop_hba *tl_hba;
1263 	struct Scsi_Host *sh;
1264 	char *ptr;
1265 	int ret, off = 0;
1266 
1267 	tl_hba = kzalloc(sizeof(struct tcm_loop_hba), GFP_KERNEL);
1268 	if (!tl_hba) {
1269 		pr_err("Unable to allocate struct tcm_loop_hba\n");
1270 		return ERR_PTR(-ENOMEM);
1271 	}
1272 	/*
1273 	 * Determine the emulated Protocol Identifier and Target Port Name
1274 	 * based on the incoming configfs directory name.
1275 	 */
1276 	ptr = strstr(name, "naa.");
1277 	if (ptr) {
1278 		tl_hba->tl_proto_id = SCSI_PROTOCOL_SAS;
1279 		goto check_len;
1280 	}
1281 	ptr = strstr(name, "fc.");
1282 	if (ptr) {
1283 		tl_hba->tl_proto_id = SCSI_PROTOCOL_FCP;
1284 		off = 3; /* Skip over "fc." */
1285 		goto check_len;
1286 	}
1287 	ptr = strstr(name, "iqn.");
1288 	if (!ptr) {
1289 		pr_err("Unable to locate prefix for emulated Target "
1290 				"Port: %s\n", name);
1291 		ret = -EINVAL;
1292 		goto out;
1293 	}
1294 	tl_hba->tl_proto_id = SCSI_PROTOCOL_ISCSI;
1295 
1296 check_len:
1297 	if (strlen(name) >= TL_WWN_ADDR_LEN) {
1298 		pr_err("Emulated NAA %s Address: %s, exceeds"
1299 			" max: %d\n", name, tcm_loop_dump_proto_id(tl_hba),
1300 			TL_WWN_ADDR_LEN);
1301 		ret = -EINVAL;
1302 		goto out;
1303 	}
1304 	snprintf(&tl_hba->tl_wwn_address[0], TL_WWN_ADDR_LEN, "%s", &name[off]);
1305 
1306 	/*
1307 	 * Call device_register(tl_hba->dev) to register the emulated
1308 	 * Linux/SCSI LLD of type struct Scsi_Host at tl_hba->sh after
1309 	 * device_register() callbacks in tcm_loop_driver_probe()
1310 	 */
1311 	ret = tcm_loop_setup_hba_bus(tl_hba, tcm_loop_hba_no_cnt);
1312 	if (ret)
1313 		goto out;
1314 
1315 	sh = tl_hba->sh;
1316 	tcm_loop_hba_no_cnt++;
1317 	pr_debug("TCM_Loop_ConfigFS: Allocated emulated Target"
1318 		" %s Address: %s at Linux/SCSI Host ID: %d\n",
1319 		tcm_loop_dump_proto_id(tl_hba), name, sh->host_no);
1320 
1321 	return &tl_hba->tl_hba_wwn;
1322 out:
1323 	kfree(tl_hba);
1324 	return ERR_PTR(ret);
1325 }
1326 
1327 void tcm_loop_drop_scsi_hba(
1328 	struct se_wwn *wwn)
1329 {
1330 	struct tcm_loop_hba *tl_hba = container_of(wwn,
1331 				struct tcm_loop_hba, tl_hba_wwn);
1332 	int host_no = tl_hba->sh->host_no;
1333 	/*
1334 	 * Call device_unregister() on the original tl_hba->dev.
1335 	 * tcm_loop_fabric_scsi.c:tcm_loop_release_adapter() will
1336 	 * release *tl_hba;
1337 	 */
1338 	device_unregister(&tl_hba->dev);
1339 
1340 	pr_debug("TCM_Loop_ConfigFS: Deallocated emulated Target"
1341 		" SAS Address: %s at Linux/SCSI Host ID: %d\n",
1342 		config_item_name(&wwn->wwn_group.cg_item), host_no);
1343 }
1344 
1345 /* Start items for tcm_loop_cit */
1346 static ssize_t tcm_loop_wwn_show_attr_version(
1347 	struct target_fabric_configfs *tf,
1348 	char *page)
1349 {
1350 	return sprintf(page, "TCM Loopback Fabric module %s\n", TCM_LOOP_VERSION);
1351 }
1352 
1353 TF_WWN_ATTR_RO(tcm_loop, version);
1354 
1355 static struct configfs_attribute *tcm_loop_wwn_attrs[] = {
1356 	&tcm_loop_wwn_version.attr,
1357 	NULL,
1358 };
1359 
1360 /* End items for tcm_loop_cit */
1361 
1362 static int tcm_loop_register_configfs(void)
1363 {
1364 	struct target_fabric_configfs *fabric;
1365 	struct config_group *tf_cg;
1366 	int ret;
1367 	/*
1368 	 * Set the TCM Loop HBA counter to zero
1369 	 */
1370 	tcm_loop_hba_no_cnt = 0;
1371 	/*
1372 	 * Register the top level struct config_item_type with TCM core
1373 	 */
1374 	fabric = target_fabric_configfs_init(THIS_MODULE, "loopback");
1375 	if (IS_ERR(fabric)) {
1376 		pr_err("tcm_loop_register_configfs() failed!\n");
1377 		return PTR_ERR(fabric);
1378 	}
1379 	/*
1380 	 * Setup the fabric API of function pointers used by target_core_mod
1381 	 */
1382 	fabric->tf_ops.get_fabric_name = &tcm_loop_get_fabric_name;
1383 	fabric->tf_ops.get_fabric_proto_ident = &tcm_loop_get_fabric_proto_ident;
1384 	fabric->tf_ops.tpg_get_wwn = &tcm_loop_get_endpoint_wwn;
1385 	fabric->tf_ops.tpg_get_tag = &tcm_loop_get_tag;
1386 	fabric->tf_ops.tpg_get_default_depth = &tcm_loop_get_default_depth;
1387 	fabric->tf_ops.tpg_get_pr_transport_id = &tcm_loop_get_pr_transport_id;
1388 	fabric->tf_ops.tpg_get_pr_transport_id_len =
1389 					&tcm_loop_get_pr_transport_id_len;
1390 	fabric->tf_ops.tpg_parse_pr_out_transport_id =
1391 					&tcm_loop_parse_pr_out_transport_id;
1392 	fabric->tf_ops.tpg_check_demo_mode = &tcm_loop_check_demo_mode;
1393 	fabric->tf_ops.tpg_check_demo_mode_cache =
1394 					&tcm_loop_check_demo_mode_cache;
1395 	fabric->tf_ops.tpg_check_demo_mode_write_protect =
1396 					&tcm_loop_check_demo_mode_write_protect;
1397 	fabric->tf_ops.tpg_check_prod_mode_write_protect =
1398 					&tcm_loop_check_prod_mode_write_protect;
1399 	/*
1400 	 * The TCM loopback fabric module runs in demo-mode to a local
1401 	 * virtual SCSI device, so fabric dependent initator ACLs are
1402 	 * not required.
1403 	 */
1404 	fabric->tf_ops.tpg_alloc_fabric_acl = &tcm_loop_tpg_alloc_fabric_acl;
1405 	fabric->tf_ops.tpg_release_fabric_acl =
1406 					&tcm_loop_tpg_release_fabric_acl;
1407 	fabric->tf_ops.tpg_get_inst_index = &tcm_loop_get_inst_index;
1408 	/*
1409 	 * Used for setting up remaining TCM resources in process context
1410 	 */
1411 	fabric->tf_ops.new_cmd_map = &tcm_loop_new_cmd_map;
1412 	fabric->tf_ops.check_stop_free = &tcm_loop_check_stop_free;
1413 	fabric->tf_ops.release_cmd = &tcm_loop_release_cmd;
1414 	fabric->tf_ops.shutdown_session = &tcm_loop_shutdown_session;
1415 	fabric->tf_ops.close_session = &tcm_loop_close_session;
1416 	fabric->tf_ops.stop_session = &tcm_loop_stop_session;
1417 	fabric->tf_ops.fall_back_to_erl0 = &tcm_loop_fall_back_to_erl0;
1418 	fabric->tf_ops.sess_logged_in = &tcm_loop_sess_logged_in;
1419 	fabric->tf_ops.sess_get_index = &tcm_loop_sess_get_index;
1420 	fabric->tf_ops.sess_get_initiator_sid = NULL;
1421 	fabric->tf_ops.write_pending = &tcm_loop_write_pending;
1422 	fabric->tf_ops.write_pending_status = &tcm_loop_write_pending_status;
1423 	/*
1424 	 * Not used for TCM loopback
1425 	 */
1426 	fabric->tf_ops.set_default_node_attributes =
1427 					&tcm_loop_set_default_node_attributes;
1428 	fabric->tf_ops.get_task_tag = &tcm_loop_get_task_tag;
1429 	fabric->tf_ops.get_cmd_state = &tcm_loop_get_cmd_state;
1430 	fabric->tf_ops.queue_data_in = &tcm_loop_queue_data_in;
1431 	fabric->tf_ops.queue_status = &tcm_loop_queue_status;
1432 	fabric->tf_ops.queue_tm_rsp = &tcm_loop_queue_tm_rsp;
1433 	fabric->tf_ops.set_fabric_sense_len = &tcm_loop_set_fabric_sense_len;
1434 	fabric->tf_ops.get_fabric_sense_len = &tcm_loop_get_fabric_sense_len;
1435 	fabric->tf_ops.is_state_remove = &tcm_loop_is_state_remove;
1436 
1437 	tf_cg = &fabric->tf_group;
1438 	/*
1439 	 * Setup function pointers for generic logic in target_core_fabric_configfs.c
1440 	 */
1441 	fabric->tf_ops.fabric_make_wwn = &tcm_loop_make_scsi_hba;
1442 	fabric->tf_ops.fabric_drop_wwn = &tcm_loop_drop_scsi_hba;
1443 	fabric->tf_ops.fabric_make_tpg = &tcm_loop_make_naa_tpg;
1444 	fabric->tf_ops.fabric_drop_tpg = &tcm_loop_drop_naa_tpg;
1445 	/*
1446 	 * fabric_post_link() and fabric_pre_unlink() are used for
1447 	 * registration and release of TCM Loop Virtual SCSI LUNs.
1448 	 */
1449 	fabric->tf_ops.fabric_post_link = &tcm_loop_port_link;
1450 	fabric->tf_ops.fabric_pre_unlink = &tcm_loop_port_unlink;
1451 	fabric->tf_ops.fabric_make_np = NULL;
1452 	fabric->tf_ops.fabric_drop_np = NULL;
1453 	/*
1454 	 * Setup default attribute lists for various fabric->tf_cit_tmpl
1455 	 */
1456 	TF_CIT_TMPL(fabric)->tfc_wwn_cit.ct_attrs = tcm_loop_wwn_attrs;
1457 	TF_CIT_TMPL(fabric)->tfc_tpg_base_cit.ct_attrs = tcm_loop_tpg_attrs;
1458 	TF_CIT_TMPL(fabric)->tfc_tpg_attrib_cit.ct_attrs = NULL;
1459 	TF_CIT_TMPL(fabric)->tfc_tpg_param_cit.ct_attrs = NULL;
1460 	TF_CIT_TMPL(fabric)->tfc_tpg_np_base_cit.ct_attrs = NULL;
1461 	/*
1462 	 * Once fabric->tf_ops has been setup, now register the fabric for
1463 	 * use within TCM
1464 	 */
1465 	ret = target_fabric_configfs_register(fabric);
1466 	if (ret < 0) {
1467 		pr_err("target_fabric_configfs_register() for"
1468 				" TCM_Loop failed!\n");
1469 		target_fabric_configfs_free(fabric);
1470 		return -1;
1471 	}
1472 	/*
1473 	 * Setup our local pointer to *fabric.
1474 	 */
1475 	tcm_loop_fabric_configfs = fabric;
1476 	pr_debug("TCM_LOOP[0] - Set fabric ->"
1477 			" tcm_loop_fabric_configfs\n");
1478 	return 0;
1479 }
1480 
1481 static void tcm_loop_deregister_configfs(void)
1482 {
1483 	if (!tcm_loop_fabric_configfs)
1484 		return;
1485 
1486 	target_fabric_configfs_deregister(tcm_loop_fabric_configfs);
1487 	tcm_loop_fabric_configfs = NULL;
1488 	pr_debug("TCM_LOOP[0] - Cleared"
1489 				" tcm_loop_fabric_configfs\n");
1490 }
1491 
1492 static int __init tcm_loop_fabric_init(void)
1493 {
1494 	int ret;
1495 
1496 	tcm_loop_cmd_cache = kmem_cache_create("tcm_loop_cmd_cache",
1497 				sizeof(struct tcm_loop_cmd),
1498 				__alignof__(struct tcm_loop_cmd),
1499 				0, NULL);
1500 	if (!tcm_loop_cmd_cache) {
1501 		pr_debug("kmem_cache_create() for"
1502 			" tcm_loop_cmd_cache failed\n");
1503 		return -ENOMEM;
1504 	}
1505 
1506 	ret = tcm_loop_alloc_core_bus();
1507 	if (ret)
1508 		return ret;
1509 
1510 	ret = tcm_loop_register_configfs();
1511 	if (ret) {
1512 		tcm_loop_release_core_bus();
1513 		return ret;
1514 	}
1515 
1516 	return 0;
1517 }
1518 
1519 static void __exit tcm_loop_fabric_exit(void)
1520 {
1521 	tcm_loop_deregister_configfs();
1522 	tcm_loop_release_core_bus();
1523 	kmem_cache_destroy(tcm_loop_cmd_cache);
1524 }
1525 
1526 MODULE_DESCRIPTION("TCM loopback virtual Linux/SCSI fabric module");
1527 MODULE_AUTHOR("Nicholas A. Bellinger <nab@risingtidesystems.com>");
1528 MODULE_LICENSE("GPL");
1529 module_init(tcm_loop_fabric_init);
1530 module_exit(tcm_loop_fabric_exit);
1531