xref: /linux/drivers/target/loopback/tcm_loop.c (revision db4e83957f961f9053282409c5062c6baef857a4)
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);
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 	/*
294 	 * Ensure that this tl_tpg reference from the incoming sc->device->id
295 	 * has already been configured via tcm_loop_make_naa_tpg().
296 	 */
297 	if (!tl_tpg->tl_hba) {
298 		set_host_byte(sc, DID_NO_CONNECT);
299 		sc->scsi_done(sc);
300 		return 0;
301 	}
302 	se_tpg = &tl_tpg->tl_se_tpg;
303 	/*
304 	 * Determine the SAM Task Attribute and allocate tl_cmd and
305 	 * tl_cmd->tl_se_cmd from TCM infrastructure
306 	 */
307 	se_cmd = tcm_loop_allocate_core_cmd(tl_hba, se_tpg, sc);
308 	if (!se_cmd) {
309 		sc->scsi_done(sc);
310 		return 0;
311 	}
312 	/*
313 	 * Queue up the newly allocated to be processed in TCM thread context.
314 	*/
315 	transport_generic_handle_cdb_map(se_cmd);
316 	return 0;
317 }
318 
319 /*
320  * Called from SCSI EH process context to issue a LUN_RESET TMR
321  * to struct scsi_device
322  */
323 static int tcm_loop_device_reset(struct scsi_cmnd *sc)
324 {
325 	struct se_cmd *se_cmd = NULL;
326 	struct se_portal_group *se_tpg;
327 	struct se_session *se_sess;
328 	struct tcm_loop_cmd *tl_cmd = NULL;
329 	struct tcm_loop_hba *tl_hba;
330 	struct tcm_loop_nexus *tl_nexus;
331 	struct tcm_loop_tmr *tl_tmr = NULL;
332 	struct tcm_loop_tpg *tl_tpg;
333 	int ret = FAILED;
334 	/*
335 	 * Locate the tcm_loop_hba_t pointer
336 	 */
337 	tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
338 	/*
339 	 * Locate the tl_nexus and se_sess pointers
340 	 */
341 	tl_nexus = tl_hba->tl_nexus;
342 	if (!tl_nexus) {
343 		pr_err("Unable to perform device reset without"
344 				" active I_T Nexus\n");
345 		return FAILED;
346 	}
347 	se_sess = tl_nexus->se_sess;
348 	/*
349 	 * Locate the tl_tpg and se_tpg pointers from TargetID in sc->device->id
350 	 */
351 	tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
352 	se_tpg = &tl_tpg->tl_se_tpg;
353 
354 	tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_KERNEL);
355 	if (!tl_cmd) {
356 		pr_err("Unable to allocate memory for tl_cmd\n");
357 		return FAILED;
358 	}
359 
360 	tl_tmr = kzalloc(sizeof(struct tcm_loop_tmr), GFP_KERNEL);
361 	if (!tl_tmr) {
362 		pr_err("Unable to allocate memory for tl_tmr\n");
363 		goto release;
364 	}
365 	init_waitqueue_head(&tl_tmr->tl_tmr_wait);
366 
367 	se_cmd = &tl_cmd->tl_se_cmd;
368 	/*
369 	 * Initialize struct se_cmd descriptor from target_core_mod infrastructure
370 	 */
371 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, 0,
372 				DMA_NONE, MSG_SIMPLE_TAG,
373 				&tl_cmd->tl_sense_buf[0]);
374 	/*
375 	 * Allocate the LUN_RESET TMR
376 	 */
377 	se_cmd->se_tmr_req = core_tmr_alloc_req(se_cmd, tl_tmr,
378 						TMR_LUN_RESET, GFP_KERNEL);
379 	if (IS_ERR(se_cmd->se_tmr_req))
380 		goto release;
381 	/*
382 	 * Locate the underlying TCM struct se_lun from sc->device->lun
383 	 */
384 	if (transport_lookup_tmr_lun(se_cmd, sc->device->lun) < 0)
385 		goto release;
386 	/*
387 	 * Queue the TMR to TCM Core and sleep waiting for tcm_loop_queue_tm_rsp()
388 	 * to wake us up.
389 	 */
390 	transport_generic_handle_tmr(se_cmd);
391 	wait_event(tl_tmr->tl_tmr_wait, atomic_read(&tl_tmr->tmr_complete));
392 	/*
393 	 * The TMR LUN_RESET has completed, check the response status and
394 	 * then release allocations.
395 	 */
396 	ret = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
397 		SUCCESS : FAILED;
398 release:
399 	if (se_cmd)
400 		transport_generic_free_cmd(se_cmd, 1);
401 	else
402 		kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
403 	kfree(tl_tmr);
404 	return ret;
405 }
406 
407 static int tcm_loop_slave_alloc(struct scsi_device *sd)
408 {
409 	set_bit(QUEUE_FLAG_BIDI, &sd->request_queue->queue_flags);
410 	return 0;
411 }
412 
413 static int tcm_loop_slave_configure(struct scsi_device *sd)
414 {
415 	return 0;
416 }
417 
418 static struct scsi_host_template tcm_loop_driver_template = {
419 	.proc_info		= tcm_loop_proc_info,
420 	.proc_name		= "tcm_loopback",
421 	.name			= "TCM_Loopback",
422 	.queuecommand		= tcm_loop_queuecommand,
423 	.change_queue_depth	= tcm_loop_change_queue_depth,
424 	.eh_device_reset_handler = tcm_loop_device_reset,
425 	.can_queue		= TL_SCSI_CAN_QUEUE,
426 	.this_id		= -1,
427 	.sg_tablesize		= TL_SCSI_SG_TABLESIZE,
428 	.cmd_per_lun		= TL_SCSI_CMD_PER_LUN,
429 	.max_sectors		= TL_SCSI_MAX_SECTORS,
430 	.use_clustering		= DISABLE_CLUSTERING,
431 	.slave_alloc		= tcm_loop_slave_alloc,
432 	.slave_configure	= tcm_loop_slave_configure,
433 	.module			= THIS_MODULE,
434 };
435 
436 static int tcm_loop_driver_probe(struct device *dev)
437 {
438 	struct tcm_loop_hba *tl_hba;
439 	struct Scsi_Host *sh;
440 	int error;
441 
442 	tl_hba = to_tcm_loop_hba(dev);
443 
444 	sh = scsi_host_alloc(&tcm_loop_driver_template,
445 			sizeof(struct tcm_loop_hba));
446 	if (!sh) {
447 		pr_err("Unable to allocate struct scsi_host\n");
448 		return -ENODEV;
449 	}
450 	tl_hba->sh = sh;
451 
452 	/*
453 	 * Assign the struct tcm_loop_hba pointer to struct Scsi_Host->hostdata
454 	 */
455 	*((struct tcm_loop_hba **)sh->hostdata) = tl_hba;
456 	/*
457 	 * Setup single ID, Channel and LUN for now..
458 	 */
459 	sh->max_id = 2;
460 	sh->max_lun = 0;
461 	sh->max_channel = 0;
462 	sh->max_cmd_len = TL_SCSI_MAX_CMD_LEN;
463 
464 	error = scsi_add_host(sh, &tl_hba->dev);
465 	if (error) {
466 		pr_err("%s: scsi_add_host failed\n", __func__);
467 		scsi_host_put(sh);
468 		return -ENODEV;
469 	}
470 	return 0;
471 }
472 
473 static int tcm_loop_driver_remove(struct device *dev)
474 {
475 	struct tcm_loop_hba *tl_hba;
476 	struct Scsi_Host *sh;
477 
478 	tl_hba = to_tcm_loop_hba(dev);
479 	sh = tl_hba->sh;
480 
481 	scsi_remove_host(sh);
482 	scsi_host_put(sh);
483 	return 0;
484 }
485 
486 static void tcm_loop_release_adapter(struct device *dev)
487 {
488 	struct tcm_loop_hba *tl_hba = to_tcm_loop_hba(dev);
489 
490 	kfree(tl_hba);
491 }
492 
493 /*
494  * Called from tcm_loop_make_scsi_hba() in tcm_loop_configfs.c
495  */
496 static int tcm_loop_setup_hba_bus(struct tcm_loop_hba *tl_hba, int tcm_loop_host_id)
497 {
498 	int ret;
499 
500 	tl_hba->dev.bus = &tcm_loop_lld_bus;
501 	tl_hba->dev.parent = tcm_loop_primary;
502 	tl_hba->dev.release = &tcm_loop_release_adapter;
503 	dev_set_name(&tl_hba->dev, "tcm_loop_adapter_%d", tcm_loop_host_id);
504 
505 	ret = device_register(&tl_hba->dev);
506 	if (ret) {
507 		pr_err("device_register() failed for"
508 				" tl_hba->dev: %d\n", ret);
509 		return -ENODEV;
510 	}
511 
512 	return 0;
513 }
514 
515 /*
516  * Called from tcm_loop_fabric_init() in tcl_loop_fabric.c to load the emulated
517  * tcm_loop SCSI bus.
518  */
519 static int tcm_loop_alloc_core_bus(void)
520 {
521 	int ret;
522 
523 	tcm_loop_primary = root_device_register("tcm_loop_0");
524 	if (IS_ERR(tcm_loop_primary)) {
525 		pr_err("Unable to allocate tcm_loop_primary\n");
526 		return PTR_ERR(tcm_loop_primary);
527 	}
528 
529 	ret = bus_register(&tcm_loop_lld_bus);
530 	if (ret) {
531 		pr_err("bus_register() failed for tcm_loop_lld_bus\n");
532 		goto dev_unreg;
533 	}
534 
535 	ret = driver_register(&tcm_loop_driverfs);
536 	if (ret) {
537 		pr_err("driver_register() failed for"
538 				"tcm_loop_driverfs\n");
539 		goto bus_unreg;
540 	}
541 
542 	pr_debug("Initialized TCM Loop Core Bus\n");
543 	return ret;
544 
545 bus_unreg:
546 	bus_unregister(&tcm_loop_lld_bus);
547 dev_unreg:
548 	root_device_unregister(tcm_loop_primary);
549 	return ret;
550 }
551 
552 static void tcm_loop_release_core_bus(void)
553 {
554 	driver_unregister(&tcm_loop_driverfs);
555 	bus_unregister(&tcm_loop_lld_bus);
556 	root_device_unregister(tcm_loop_primary);
557 
558 	pr_debug("Releasing TCM Loop Core BUS\n");
559 }
560 
561 static char *tcm_loop_get_fabric_name(void)
562 {
563 	return "loopback";
564 }
565 
566 static u8 tcm_loop_get_fabric_proto_ident(struct se_portal_group *se_tpg)
567 {
568 	struct tcm_loop_tpg *tl_tpg =
569 			(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
570 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
571 	/*
572 	 * tl_proto_id is set at tcm_loop_configfs.c:tcm_loop_make_scsi_hba()
573 	 * time based on the protocol dependent prefix of the passed configfs group.
574 	 *
575 	 * Based upon tl_proto_id, TCM_Loop emulates the requested fabric
576 	 * ProtocolID using target_core_fabric_lib.c symbols.
577 	 */
578 	switch (tl_hba->tl_proto_id) {
579 	case SCSI_PROTOCOL_SAS:
580 		return sas_get_fabric_proto_ident(se_tpg);
581 	case SCSI_PROTOCOL_FCP:
582 		return fc_get_fabric_proto_ident(se_tpg);
583 	case SCSI_PROTOCOL_ISCSI:
584 		return iscsi_get_fabric_proto_ident(se_tpg);
585 	default:
586 		pr_err("Unknown tl_proto_id: 0x%02x, using"
587 			" SAS emulation\n", tl_hba->tl_proto_id);
588 		break;
589 	}
590 
591 	return sas_get_fabric_proto_ident(se_tpg);
592 }
593 
594 static char *tcm_loop_get_endpoint_wwn(struct se_portal_group *se_tpg)
595 {
596 	struct tcm_loop_tpg *tl_tpg =
597 		(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
598 	/*
599 	 * Return the passed NAA identifier for the SAS Target Port
600 	 */
601 	return &tl_tpg->tl_hba->tl_wwn_address[0];
602 }
603 
604 static u16 tcm_loop_get_tag(struct se_portal_group *se_tpg)
605 {
606 	struct tcm_loop_tpg *tl_tpg =
607 		(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
608 	/*
609 	 * This Tag is used when forming SCSI Name identifier in EVPD=1 0x83
610 	 * to represent the SCSI Target Port.
611 	 */
612 	return tl_tpg->tl_tpgt;
613 }
614 
615 static u32 tcm_loop_get_default_depth(struct se_portal_group *se_tpg)
616 {
617 	return 1;
618 }
619 
620 static u32 tcm_loop_get_pr_transport_id(
621 	struct se_portal_group *se_tpg,
622 	struct se_node_acl *se_nacl,
623 	struct t10_pr_registration *pr_reg,
624 	int *format_code,
625 	unsigned char *buf)
626 {
627 	struct tcm_loop_tpg *tl_tpg =
628 			(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
629 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
630 
631 	switch (tl_hba->tl_proto_id) {
632 	case SCSI_PROTOCOL_SAS:
633 		return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
634 					format_code, buf);
635 	case SCSI_PROTOCOL_FCP:
636 		return fc_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
637 					format_code, buf);
638 	case SCSI_PROTOCOL_ISCSI:
639 		return iscsi_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
640 					format_code, buf);
641 	default:
642 		pr_err("Unknown tl_proto_id: 0x%02x, using"
643 			" SAS emulation\n", tl_hba->tl_proto_id);
644 		break;
645 	}
646 
647 	return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
648 			format_code, buf);
649 }
650 
651 static u32 tcm_loop_get_pr_transport_id_len(
652 	struct se_portal_group *se_tpg,
653 	struct se_node_acl *se_nacl,
654 	struct t10_pr_registration *pr_reg,
655 	int *format_code)
656 {
657 	struct tcm_loop_tpg *tl_tpg =
658 			(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
659 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
660 
661 	switch (tl_hba->tl_proto_id) {
662 	case SCSI_PROTOCOL_SAS:
663 		return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
664 					format_code);
665 	case SCSI_PROTOCOL_FCP:
666 		return fc_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
667 					format_code);
668 	case SCSI_PROTOCOL_ISCSI:
669 		return iscsi_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
670 					format_code);
671 	default:
672 		pr_err("Unknown tl_proto_id: 0x%02x, using"
673 			" SAS emulation\n", tl_hba->tl_proto_id);
674 		break;
675 	}
676 
677 	return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
678 			format_code);
679 }
680 
681 /*
682  * Used for handling SCSI fabric dependent TransportIDs in SPC-3 and above
683  * Persistent Reservation SPEC_I_PT=1 and PROUT REGISTER_AND_MOVE operations.
684  */
685 static char *tcm_loop_parse_pr_out_transport_id(
686 	struct se_portal_group *se_tpg,
687 	const char *buf,
688 	u32 *out_tid_len,
689 	char **port_nexus_ptr)
690 {
691 	struct tcm_loop_tpg *tl_tpg =
692 			(struct tcm_loop_tpg *)se_tpg->se_tpg_fabric_ptr;
693 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
694 
695 	switch (tl_hba->tl_proto_id) {
696 	case SCSI_PROTOCOL_SAS:
697 		return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
698 					port_nexus_ptr);
699 	case SCSI_PROTOCOL_FCP:
700 		return fc_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
701 					port_nexus_ptr);
702 	case SCSI_PROTOCOL_ISCSI:
703 		return iscsi_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
704 					port_nexus_ptr);
705 	default:
706 		pr_err("Unknown tl_proto_id: 0x%02x, using"
707 			" SAS emulation\n", tl_hba->tl_proto_id);
708 		break;
709 	}
710 
711 	return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
712 			port_nexus_ptr);
713 }
714 
715 /*
716  * Returning (1) here allows for target_core_mod struct se_node_acl to be generated
717  * based upon the incoming fabric dependent SCSI Initiator Port
718  */
719 static int tcm_loop_check_demo_mode(struct se_portal_group *se_tpg)
720 {
721 	return 1;
722 }
723 
724 static int tcm_loop_check_demo_mode_cache(struct se_portal_group *se_tpg)
725 {
726 	return 0;
727 }
728 
729 /*
730  * Allow I_T Nexus full READ-WRITE access without explict Initiator Node ACLs for
731  * local virtual Linux/SCSI LLD passthrough into VM hypervisor guest
732  */
733 static int tcm_loop_check_demo_mode_write_protect(struct se_portal_group *se_tpg)
734 {
735 	return 0;
736 }
737 
738 /*
739  * Because TCM_Loop does not use explict ACLs and MappedLUNs, this will
740  * never be called for TCM_Loop by target_core_fabric_configfs.c code.
741  * It has been added here as a nop for target_fabric_tf_ops_check()
742  */
743 static int tcm_loop_check_prod_mode_write_protect(struct se_portal_group *se_tpg)
744 {
745 	return 0;
746 }
747 
748 static struct se_node_acl *tcm_loop_tpg_alloc_fabric_acl(
749 	struct se_portal_group *se_tpg)
750 {
751 	struct tcm_loop_nacl *tl_nacl;
752 
753 	tl_nacl = kzalloc(sizeof(struct tcm_loop_nacl), GFP_KERNEL);
754 	if (!tl_nacl) {
755 		pr_err("Unable to allocate struct tcm_loop_nacl\n");
756 		return NULL;
757 	}
758 
759 	return &tl_nacl->se_node_acl;
760 }
761 
762 static void tcm_loop_tpg_release_fabric_acl(
763 	struct se_portal_group *se_tpg,
764 	struct se_node_acl *se_nacl)
765 {
766 	struct tcm_loop_nacl *tl_nacl = container_of(se_nacl,
767 				struct tcm_loop_nacl, se_node_acl);
768 
769 	kfree(tl_nacl);
770 }
771 
772 static u32 tcm_loop_get_inst_index(struct se_portal_group *se_tpg)
773 {
774 	return 1;
775 }
776 
777 static int tcm_loop_is_state_remove(struct se_cmd *se_cmd)
778 {
779 	/*
780 	 * Assume struct scsi_cmnd is not in remove state..
781 	 */
782 	return 0;
783 }
784 
785 static int tcm_loop_sess_logged_in(struct se_session *se_sess)
786 {
787 	/*
788 	 * Assume that TL Nexus is always active
789 	 */
790 	return 1;
791 }
792 
793 static u32 tcm_loop_sess_get_index(struct se_session *se_sess)
794 {
795 	return 1;
796 }
797 
798 static void tcm_loop_set_default_node_attributes(struct se_node_acl *se_acl)
799 {
800 	return;
801 }
802 
803 static u32 tcm_loop_get_task_tag(struct se_cmd *se_cmd)
804 {
805 	return 1;
806 }
807 
808 static int tcm_loop_get_cmd_state(struct se_cmd *se_cmd)
809 {
810 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
811 			struct tcm_loop_cmd, tl_se_cmd);
812 
813 	return tl_cmd->sc_cmd_state;
814 }
815 
816 static int tcm_loop_shutdown_session(struct se_session *se_sess)
817 {
818 	return 0;
819 }
820 
821 static void tcm_loop_close_session(struct se_session *se_sess)
822 {
823 	return;
824 };
825 
826 static void tcm_loop_stop_session(
827 	struct se_session *se_sess,
828 	int sess_sleep,
829 	int conn_sleep)
830 {
831 	return;
832 }
833 
834 static void tcm_loop_fall_back_to_erl0(struct se_session *se_sess)
835 {
836 	return;
837 }
838 
839 static int tcm_loop_write_pending(struct se_cmd *se_cmd)
840 {
841 	/*
842 	 * Since Linux/SCSI has already sent down a struct scsi_cmnd
843 	 * sc->sc_data_direction of DMA_TO_DEVICE with struct scatterlist array
844 	 * memory, and memory has already been mapped to struct se_cmd->t_mem_list
845 	 * format with transport_generic_map_mem_to_cmd().
846 	 *
847 	 * We now tell TCM to add this WRITE CDB directly into the TCM storage
848 	 * object execution queue.
849 	 */
850 	transport_generic_process_write(se_cmd);
851 	return 0;
852 }
853 
854 static int tcm_loop_write_pending_status(struct se_cmd *se_cmd)
855 {
856 	return 0;
857 }
858 
859 static int tcm_loop_queue_data_in(struct se_cmd *se_cmd)
860 {
861 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
862 				struct tcm_loop_cmd, tl_se_cmd);
863 	struct scsi_cmnd *sc = tl_cmd->sc;
864 
865 	pr_debug("tcm_loop_queue_data_in() called for scsi_cmnd: %p"
866 		     " cdb: 0x%02x\n", sc, sc->cmnd[0]);
867 
868 	sc->result = SAM_STAT_GOOD;
869 	set_host_byte(sc, DID_OK);
870 	sc->scsi_done(sc);
871 	return 0;
872 }
873 
874 static int tcm_loop_queue_status(struct se_cmd *se_cmd)
875 {
876 	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
877 				struct tcm_loop_cmd, tl_se_cmd);
878 	struct scsi_cmnd *sc = tl_cmd->sc;
879 
880 	pr_debug("tcm_loop_queue_status() called for scsi_cmnd: %p"
881 			" cdb: 0x%02x\n", sc, sc->cmnd[0]);
882 
883 	if (se_cmd->sense_buffer &&
884 	   ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
885 	    (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE))) {
886 
887 		memcpy(sc->sense_buffer, se_cmd->sense_buffer,
888 				SCSI_SENSE_BUFFERSIZE);
889 		sc->result = SAM_STAT_CHECK_CONDITION;
890 		set_driver_byte(sc, DRIVER_SENSE);
891 	} else
892 		sc->result = se_cmd->scsi_status;
893 
894 	set_host_byte(sc, DID_OK);
895 	sc->scsi_done(sc);
896 	return 0;
897 }
898 
899 static int tcm_loop_queue_tm_rsp(struct se_cmd *se_cmd)
900 {
901 	struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
902 	struct tcm_loop_tmr *tl_tmr = se_tmr->fabric_tmr_ptr;
903 	/*
904 	 * The SCSI EH thread will be sleeping on se_tmr->tl_tmr_wait, go ahead
905 	 * and wake up the wait_queue_head_t in tcm_loop_device_reset()
906 	 */
907 	atomic_set(&tl_tmr->tmr_complete, 1);
908 	wake_up(&tl_tmr->tl_tmr_wait);
909 	return 0;
910 }
911 
912 static u16 tcm_loop_set_fabric_sense_len(struct se_cmd *se_cmd, u32 sense_length)
913 {
914 	return 0;
915 }
916 
917 static u16 tcm_loop_get_fabric_sense_len(void)
918 {
919 	return 0;
920 }
921 
922 static char *tcm_loop_dump_proto_id(struct tcm_loop_hba *tl_hba)
923 {
924 	switch (tl_hba->tl_proto_id) {
925 	case SCSI_PROTOCOL_SAS:
926 		return "SAS";
927 	case SCSI_PROTOCOL_FCP:
928 		return "FCP";
929 	case SCSI_PROTOCOL_ISCSI:
930 		return "iSCSI";
931 	default:
932 		break;
933 	}
934 
935 	return "Unknown";
936 }
937 
938 /* Start items for tcm_loop_port_cit */
939 
940 static int tcm_loop_port_link(
941 	struct se_portal_group *se_tpg,
942 	struct se_lun *lun)
943 {
944 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
945 				struct tcm_loop_tpg, tl_se_tpg);
946 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
947 
948 	atomic_inc(&tl_tpg->tl_tpg_port_count);
949 	smp_mb__after_atomic_inc();
950 	/*
951 	 * Add Linux/SCSI struct scsi_device by HCTL
952 	 */
953 	scsi_add_device(tl_hba->sh, 0, tl_tpg->tl_tpgt, lun->unpacked_lun);
954 
955 	pr_debug("TCM_Loop_ConfigFS: Port Link Successful\n");
956 	return 0;
957 }
958 
959 static void tcm_loop_port_unlink(
960 	struct se_portal_group *se_tpg,
961 	struct se_lun *se_lun)
962 {
963 	struct scsi_device *sd;
964 	struct tcm_loop_hba *tl_hba;
965 	struct tcm_loop_tpg *tl_tpg;
966 
967 	tl_tpg = container_of(se_tpg, struct tcm_loop_tpg, tl_se_tpg);
968 	tl_hba = tl_tpg->tl_hba;
969 
970 	sd = scsi_device_lookup(tl_hba->sh, 0, tl_tpg->tl_tpgt,
971 				se_lun->unpacked_lun);
972 	if (!sd) {
973 		pr_err("Unable to locate struct scsi_device for %d:%d:"
974 			"%d\n", 0, tl_tpg->tl_tpgt, se_lun->unpacked_lun);
975 		return;
976 	}
977 	/*
978 	 * Remove Linux/SCSI struct scsi_device by HCTL
979 	 */
980 	scsi_remove_device(sd);
981 	scsi_device_put(sd);
982 
983 	atomic_dec(&tl_tpg->tl_tpg_port_count);
984 	smp_mb__after_atomic_dec();
985 
986 	pr_debug("TCM_Loop_ConfigFS: Port Unlink Successful\n");
987 }
988 
989 /* End items for tcm_loop_port_cit */
990 
991 /* Start items for tcm_loop_nexus_cit */
992 
993 static int tcm_loop_make_nexus(
994 	struct tcm_loop_tpg *tl_tpg,
995 	const char *name)
996 {
997 	struct se_portal_group *se_tpg;
998 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
999 	struct tcm_loop_nexus *tl_nexus;
1000 	int ret = -ENOMEM;
1001 
1002 	if (tl_tpg->tl_hba->tl_nexus) {
1003 		pr_debug("tl_tpg->tl_hba->tl_nexus already exists\n");
1004 		return -EEXIST;
1005 	}
1006 	se_tpg = &tl_tpg->tl_se_tpg;
1007 
1008 	tl_nexus = kzalloc(sizeof(struct tcm_loop_nexus), GFP_KERNEL);
1009 	if (!tl_nexus) {
1010 		pr_err("Unable to allocate struct tcm_loop_nexus\n");
1011 		return -ENOMEM;
1012 	}
1013 	/*
1014 	 * Initialize the struct se_session pointer
1015 	 */
1016 	tl_nexus->se_sess = transport_init_session();
1017 	if (IS_ERR(tl_nexus->se_sess)) {
1018 		ret = PTR_ERR(tl_nexus->se_sess);
1019 		goto out;
1020 	}
1021 	/*
1022 	 * Since we are running in 'demo mode' this call with generate a
1023 	 * struct se_node_acl for the tcm_loop struct se_portal_group with the SCSI
1024 	 * Initiator port name of the passed configfs group 'name'.
1025 	 */
1026 	tl_nexus->se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1027 				se_tpg, (unsigned char *)name);
1028 	if (!tl_nexus->se_sess->se_node_acl) {
1029 		transport_free_session(tl_nexus->se_sess);
1030 		goto out;
1031 	}
1032 	/*
1033 	 * Now, register the SAS I_T Nexus as active with the call to
1034 	 * transport_register_session()
1035 	 */
1036 	__transport_register_session(se_tpg, tl_nexus->se_sess->se_node_acl,
1037 			tl_nexus->se_sess, tl_nexus);
1038 	tl_tpg->tl_hba->tl_nexus = tl_nexus;
1039 	pr_debug("TCM_Loop_ConfigFS: Established I_T Nexus to emulated"
1040 		" %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
1041 		name);
1042 	return 0;
1043 
1044 out:
1045 	kfree(tl_nexus);
1046 	return ret;
1047 }
1048 
1049 static int tcm_loop_drop_nexus(
1050 	struct tcm_loop_tpg *tpg)
1051 {
1052 	struct se_session *se_sess;
1053 	struct tcm_loop_nexus *tl_nexus;
1054 	struct tcm_loop_hba *tl_hba = tpg->tl_hba;
1055 
1056 	tl_nexus = tpg->tl_hba->tl_nexus;
1057 	if (!tl_nexus)
1058 		return -ENODEV;
1059 
1060 	se_sess = tl_nexus->se_sess;
1061 	if (!se_sess)
1062 		return -ENODEV;
1063 
1064 	if (atomic_read(&tpg->tl_tpg_port_count)) {
1065 		pr_err("Unable to remove TCM_Loop I_T Nexus with"
1066 			" active TPG port count: %d\n",
1067 			atomic_read(&tpg->tl_tpg_port_count));
1068 		return -EPERM;
1069 	}
1070 
1071 	pr_debug("TCM_Loop_ConfigFS: Removing I_T Nexus to emulated"
1072 		" %s Initiator Port: %s\n", tcm_loop_dump_proto_id(tl_hba),
1073 		tl_nexus->se_sess->se_node_acl->initiatorname);
1074 	/*
1075 	 * Release the SCSI I_T Nexus to the emulated SAS Target Port
1076 	 */
1077 	transport_deregister_session(tl_nexus->se_sess);
1078 	tpg->tl_hba->tl_nexus = NULL;
1079 	kfree(tl_nexus);
1080 	return 0;
1081 }
1082 
1083 /* End items for tcm_loop_nexus_cit */
1084 
1085 static ssize_t tcm_loop_tpg_show_nexus(
1086 	struct se_portal_group *se_tpg,
1087 	char *page)
1088 {
1089 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1090 			struct tcm_loop_tpg, tl_se_tpg);
1091 	struct tcm_loop_nexus *tl_nexus;
1092 	ssize_t ret;
1093 
1094 	tl_nexus = tl_tpg->tl_hba->tl_nexus;
1095 	if (!tl_nexus)
1096 		return -ENODEV;
1097 
1098 	ret = snprintf(page, PAGE_SIZE, "%s\n",
1099 		tl_nexus->se_sess->se_node_acl->initiatorname);
1100 
1101 	return ret;
1102 }
1103 
1104 static ssize_t tcm_loop_tpg_store_nexus(
1105 	struct se_portal_group *se_tpg,
1106 	const char *page,
1107 	size_t count)
1108 {
1109 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1110 			struct tcm_loop_tpg, tl_se_tpg);
1111 	struct tcm_loop_hba *tl_hba = tl_tpg->tl_hba;
1112 	unsigned char i_port[TL_WWN_ADDR_LEN], *ptr, *port_ptr;
1113 	int ret;
1114 	/*
1115 	 * Shutdown the active I_T nexus if 'NULL' is passed..
1116 	 */
1117 	if (!strncmp(page, "NULL", 4)) {
1118 		ret = tcm_loop_drop_nexus(tl_tpg);
1119 		return (!ret) ? count : ret;
1120 	}
1121 	/*
1122 	 * Otherwise make sure the passed virtual Initiator port WWN matches
1123 	 * the fabric protocol_id set in tcm_loop_make_scsi_hba(), and call
1124 	 * tcm_loop_make_nexus()
1125 	 */
1126 	if (strlen(page) >= TL_WWN_ADDR_LEN) {
1127 		pr_err("Emulated NAA Sas Address: %s, exceeds"
1128 				" max: %d\n", page, TL_WWN_ADDR_LEN);
1129 		return -EINVAL;
1130 	}
1131 	snprintf(&i_port[0], TL_WWN_ADDR_LEN, "%s", page);
1132 
1133 	ptr = strstr(i_port, "naa.");
1134 	if (ptr) {
1135 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_SAS) {
1136 			pr_err("Passed SAS Initiator Port %s does not"
1137 				" match target port protoid: %s\n", i_port,
1138 				tcm_loop_dump_proto_id(tl_hba));
1139 			return -EINVAL;
1140 		}
1141 		port_ptr = &i_port[0];
1142 		goto check_newline;
1143 	}
1144 	ptr = strstr(i_port, "fc.");
1145 	if (ptr) {
1146 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_FCP) {
1147 			pr_err("Passed FCP Initiator Port %s does not"
1148 				" match target port protoid: %s\n", i_port,
1149 				tcm_loop_dump_proto_id(tl_hba));
1150 			return -EINVAL;
1151 		}
1152 		port_ptr = &i_port[3]; /* Skip over "fc." */
1153 		goto check_newline;
1154 	}
1155 	ptr = strstr(i_port, "iqn.");
1156 	if (ptr) {
1157 		if (tl_hba->tl_proto_id != SCSI_PROTOCOL_ISCSI) {
1158 			pr_err("Passed iSCSI Initiator Port %s does not"
1159 				" match target port protoid: %s\n", i_port,
1160 				tcm_loop_dump_proto_id(tl_hba));
1161 			return -EINVAL;
1162 		}
1163 		port_ptr = &i_port[0];
1164 		goto check_newline;
1165 	}
1166 	pr_err("Unable to locate prefix for emulated Initiator Port:"
1167 			" %s\n", i_port);
1168 	return -EINVAL;
1169 	/*
1170 	 * Clear any trailing newline for the NAA WWN
1171 	 */
1172 check_newline:
1173 	if (i_port[strlen(i_port)-1] == '\n')
1174 		i_port[strlen(i_port)-1] = '\0';
1175 
1176 	ret = tcm_loop_make_nexus(tl_tpg, port_ptr);
1177 	if (ret < 0)
1178 		return ret;
1179 
1180 	return count;
1181 }
1182 
1183 TF_TPG_BASE_ATTR(tcm_loop, nexus, S_IRUGO | S_IWUSR);
1184 
1185 static struct configfs_attribute *tcm_loop_tpg_attrs[] = {
1186 	&tcm_loop_tpg_nexus.attr,
1187 	NULL,
1188 };
1189 
1190 /* Start items for tcm_loop_naa_cit */
1191 
1192 struct se_portal_group *tcm_loop_make_naa_tpg(
1193 	struct se_wwn *wwn,
1194 	struct config_group *group,
1195 	const char *name)
1196 {
1197 	struct tcm_loop_hba *tl_hba = container_of(wwn,
1198 			struct tcm_loop_hba, tl_hba_wwn);
1199 	struct tcm_loop_tpg *tl_tpg;
1200 	char *tpgt_str, *end_ptr;
1201 	int ret;
1202 	unsigned short int tpgt;
1203 
1204 	tpgt_str = strstr(name, "tpgt_");
1205 	if (!tpgt_str) {
1206 		pr_err("Unable to locate \"tpgt_#\" directory"
1207 				" group\n");
1208 		return ERR_PTR(-EINVAL);
1209 	}
1210 	tpgt_str += 5; /* Skip ahead of "tpgt_" */
1211 	tpgt = (unsigned short int) simple_strtoul(tpgt_str, &end_ptr, 0);
1212 
1213 	if (tpgt >= TL_TPGS_PER_HBA) {
1214 		pr_err("Passed tpgt: %hu exceeds TL_TPGS_PER_HBA:"
1215 				" %u\n", tpgt, TL_TPGS_PER_HBA);
1216 		return ERR_PTR(-EINVAL);
1217 	}
1218 	tl_tpg = &tl_hba->tl_hba_tpgs[tpgt];
1219 	tl_tpg->tl_hba = tl_hba;
1220 	tl_tpg->tl_tpgt = tpgt;
1221 	/*
1222 	 * Register the tl_tpg as a emulated SAS TCM Target Endpoint
1223 	 */
1224 	ret = core_tpg_register(&tcm_loop_fabric_configfs->tf_ops,
1225 			wwn, &tl_tpg->tl_se_tpg, tl_tpg,
1226 			TRANSPORT_TPG_TYPE_NORMAL);
1227 	if (ret < 0)
1228 		return ERR_PTR(-ENOMEM);
1229 
1230 	pr_debug("TCM_Loop_ConfigFS: Allocated Emulated %s"
1231 		" Target Port %s,t,0x%04x\n", tcm_loop_dump_proto_id(tl_hba),
1232 		config_item_name(&wwn->wwn_group.cg_item), tpgt);
1233 
1234 	return &tl_tpg->tl_se_tpg;
1235 }
1236 
1237 void tcm_loop_drop_naa_tpg(
1238 	struct se_portal_group *se_tpg)
1239 {
1240 	struct se_wwn *wwn = se_tpg->se_tpg_wwn;
1241 	struct tcm_loop_tpg *tl_tpg = container_of(se_tpg,
1242 				struct tcm_loop_tpg, tl_se_tpg);
1243 	struct tcm_loop_hba *tl_hba;
1244 	unsigned short tpgt;
1245 
1246 	tl_hba = tl_tpg->tl_hba;
1247 	tpgt = tl_tpg->tl_tpgt;
1248 	/*
1249 	 * Release the I_T Nexus for the Virtual SAS link if present
1250 	 */
1251 	tcm_loop_drop_nexus(tl_tpg);
1252 	/*
1253 	 * Deregister the tl_tpg as a emulated SAS TCM Target Endpoint
1254 	 */
1255 	core_tpg_deregister(se_tpg);
1256 
1257 	tl_tpg->tl_hba = NULL;
1258 	tl_tpg->tl_tpgt = 0;
1259 
1260 	pr_debug("TCM_Loop_ConfigFS: Deallocated Emulated %s"
1261 		" Target Port %s,t,0x%04x\n", tcm_loop_dump_proto_id(tl_hba),
1262 		config_item_name(&wwn->wwn_group.cg_item), tpgt);
1263 }
1264 
1265 /* End items for tcm_loop_naa_cit */
1266 
1267 /* Start items for tcm_loop_cit */
1268 
1269 struct se_wwn *tcm_loop_make_scsi_hba(
1270 	struct target_fabric_configfs *tf,
1271 	struct config_group *group,
1272 	const char *name)
1273 {
1274 	struct tcm_loop_hba *tl_hba;
1275 	struct Scsi_Host *sh;
1276 	char *ptr;
1277 	int ret, off = 0;
1278 
1279 	tl_hba = kzalloc(sizeof(struct tcm_loop_hba), GFP_KERNEL);
1280 	if (!tl_hba) {
1281 		pr_err("Unable to allocate struct tcm_loop_hba\n");
1282 		return ERR_PTR(-ENOMEM);
1283 	}
1284 	/*
1285 	 * Determine the emulated Protocol Identifier and Target Port Name
1286 	 * based on the incoming configfs directory name.
1287 	 */
1288 	ptr = strstr(name, "naa.");
1289 	if (ptr) {
1290 		tl_hba->tl_proto_id = SCSI_PROTOCOL_SAS;
1291 		goto check_len;
1292 	}
1293 	ptr = strstr(name, "fc.");
1294 	if (ptr) {
1295 		tl_hba->tl_proto_id = SCSI_PROTOCOL_FCP;
1296 		off = 3; /* Skip over "fc." */
1297 		goto check_len;
1298 	}
1299 	ptr = strstr(name, "iqn.");
1300 	if (!ptr) {
1301 		pr_err("Unable to locate prefix for emulated Target "
1302 				"Port: %s\n", name);
1303 		ret = -EINVAL;
1304 		goto out;
1305 	}
1306 	tl_hba->tl_proto_id = SCSI_PROTOCOL_ISCSI;
1307 
1308 check_len:
1309 	if (strlen(name) >= TL_WWN_ADDR_LEN) {
1310 		pr_err("Emulated NAA %s Address: %s, exceeds"
1311 			" max: %d\n", name, tcm_loop_dump_proto_id(tl_hba),
1312 			TL_WWN_ADDR_LEN);
1313 		ret = -EINVAL;
1314 		goto out;
1315 	}
1316 	snprintf(&tl_hba->tl_wwn_address[0], TL_WWN_ADDR_LEN, "%s", &name[off]);
1317 
1318 	/*
1319 	 * Call device_register(tl_hba->dev) to register the emulated
1320 	 * Linux/SCSI LLD of type struct Scsi_Host at tl_hba->sh after
1321 	 * device_register() callbacks in tcm_loop_driver_probe()
1322 	 */
1323 	ret = tcm_loop_setup_hba_bus(tl_hba, tcm_loop_hba_no_cnt);
1324 	if (ret)
1325 		goto out;
1326 
1327 	sh = tl_hba->sh;
1328 	tcm_loop_hba_no_cnt++;
1329 	pr_debug("TCM_Loop_ConfigFS: Allocated emulated Target"
1330 		" %s Address: %s at Linux/SCSI Host ID: %d\n",
1331 		tcm_loop_dump_proto_id(tl_hba), name, sh->host_no);
1332 
1333 	return &tl_hba->tl_hba_wwn;
1334 out:
1335 	kfree(tl_hba);
1336 	return ERR_PTR(ret);
1337 }
1338 
1339 void tcm_loop_drop_scsi_hba(
1340 	struct se_wwn *wwn)
1341 {
1342 	struct tcm_loop_hba *tl_hba = container_of(wwn,
1343 				struct tcm_loop_hba, tl_hba_wwn);
1344 	int host_no = tl_hba->sh->host_no;
1345 	/*
1346 	 * Call device_unregister() on the original tl_hba->dev.
1347 	 * tcm_loop_fabric_scsi.c:tcm_loop_release_adapter() will
1348 	 * release *tl_hba;
1349 	 */
1350 	device_unregister(&tl_hba->dev);
1351 
1352 	pr_debug("TCM_Loop_ConfigFS: Deallocated emulated Target"
1353 		" SAS Address: %s at Linux/SCSI Host ID: %d\n",
1354 		config_item_name(&wwn->wwn_group.cg_item), host_no);
1355 }
1356 
1357 /* Start items for tcm_loop_cit */
1358 static ssize_t tcm_loop_wwn_show_attr_version(
1359 	struct target_fabric_configfs *tf,
1360 	char *page)
1361 {
1362 	return sprintf(page, "TCM Loopback Fabric module %s\n", TCM_LOOP_VERSION);
1363 }
1364 
1365 TF_WWN_ATTR_RO(tcm_loop, version);
1366 
1367 static struct configfs_attribute *tcm_loop_wwn_attrs[] = {
1368 	&tcm_loop_wwn_version.attr,
1369 	NULL,
1370 };
1371 
1372 /* End items for tcm_loop_cit */
1373 
1374 static int tcm_loop_register_configfs(void)
1375 {
1376 	struct target_fabric_configfs *fabric;
1377 	struct config_group *tf_cg;
1378 	int ret;
1379 	/*
1380 	 * Set the TCM Loop HBA counter to zero
1381 	 */
1382 	tcm_loop_hba_no_cnt = 0;
1383 	/*
1384 	 * Register the top level struct config_item_type with TCM core
1385 	 */
1386 	fabric = target_fabric_configfs_init(THIS_MODULE, "loopback");
1387 	if (IS_ERR(fabric)) {
1388 		pr_err("tcm_loop_register_configfs() failed!\n");
1389 		return PTR_ERR(fabric);
1390 	}
1391 	/*
1392 	 * Setup the fabric API of function pointers used by target_core_mod
1393 	 */
1394 	fabric->tf_ops.get_fabric_name = &tcm_loop_get_fabric_name;
1395 	fabric->tf_ops.get_fabric_proto_ident = &tcm_loop_get_fabric_proto_ident;
1396 	fabric->tf_ops.tpg_get_wwn = &tcm_loop_get_endpoint_wwn;
1397 	fabric->tf_ops.tpg_get_tag = &tcm_loop_get_tag;
1398 	fabric->tf_ops.tpg_get_default_depth = &tcm_loop_get_default_depth;
1399 	fabric->tf_ops.tpg_get_pr_transport_id = &tcm_loop_get_pr_transport_id;
1400 	fabric->tf_ops.tpg_get_pr_transport_id_len =
1401 					&tcm_loop_get_pr_transport_id_len;
1402 	fabric->tf_ops.tpg_parse_pr_out_transport_id =
1403 					&tcm_loop_parse_pr_out_transport_id;
1404 	fabric->tf_ops.tpg_check_demo_mode = &tcm_loop_check_demo_mode;
1405 	fabric->tf_ops.tpg_check_demo_mode_cache =
1406 					&tcm_loop_check_demo_mode_cache;
1407 	fabric->tf_ops.tpg_check_demo_mode_write_protect =
1408 					&tcm_loop_check_demo_mode_write_protect;
1409 	fabric->tf_ops.tpg_check_prod_mode_write_protect =
1410 					&tcm_loop_check_prod_mode_write_protect;
1411 	/*
1412 	 * The TCM loopback fabric module runs in demo-mode to a local
1413 	 * virtual SCSI device, so fabric dependent initator ACLs are
1414 	 * not required.
1415 	 */
1416 	fabric->tf_ops.tpg_alloc_fabric_acl = &tcm_loop_tpg_alloc_fabric_acl;
1417 	fabric->tf_ops.tpg_release_fabric_acl =
1418 					&tcm_loop_tpg_release_fabric_acl;
1419 	fabric->tf_ops.tpg_get_inst_index = &tcm_loop_get_inst_index;
1420 	/*
1421 	 * Used for setting up remaining TCM resources in process context
1422 	 */
1423 	fabric->tf_ops.new_cmd_map = &tcm_loop_new_cmd_map;
1424 	fabric->tf_ops.check_stop_free = &tcm_loop_check_stop_free;
1425 	fabric->tf_ops.release_cmd = &tcm_loop_release_cmd;
1426 	fabric->tf_ops.shutdown_session = &tcm_loop_shutdown_session;
1427 	fabric->tf_ops.close_session = &tcm_loop_close_session;
1428 	fabric->tf_ops.stop_session = &tcm_loop_stop_session;
1429 	fabric->tf_ops.fall_back_to_erl0 = &tcm_loop_fall_back_to_erl0;
1430 	fabric->tf_ops.sess_logged_in = &tcm_loop_sess_logged_in;
1431 	fabric->tf_ops.sess_get_index = &tcm_loop_sess_get_index;
1432 	fabric->tf_ops.sess_get_initiator_sid = NULL;
1433 	fabric->tf_ops.write_pending = &tcm_loop_write_pending;
1434 	fabric->tf_ops.write_pending_status = &tcm_loop_write_pending_status;
1435 	/*
1436 	 * Not used for TCM loopback
1437 	 */
1438 	fabric->tf_ops.set_default_node_attributes =
1439 					&tcm_loop_set_default_node_attributes;
1440 	fabric->tf_ops.get_task_tag = &tcm_loop_get_task_tag;
1441 	fabric->tf_ops.get_cmd_state = &tcm_loop_get_cmd_state;
1442 	fabric->tf_ops.queue_data_in = &tcm_loop_queue_data_in;
1443 	fabric->tf_ops.queue_status = &tcm_loop_queue_status;
1444 	fabric->tf_ops.queue_tm_rsp = &tcm_loop_queue_tm_rsp;
1445 	fabric->tf_ops.set_fabric_sense_len = &tcm_loop_set_fabric_sense_len;
1446 	fabric->tf_ops.get_fabric_sense_len = &tcm_loop_get_fabric_sense_len;
1447 	fabric->tf_ops.is_state_remove = &tcm_loop_is_state_remove;
1448 
1449 	tf_cg = &fabric->tf_group;
1450 	/*
1451 	 * Setup function pointers for generic logic in target_core_fabric_configfs.c
1452 	 */
1453 	fabric->tf_ops.fabric_make_wwn = &tcm_loop_make_scsi_hba;
1454 	fabric->tf_ops.fabric_drop_wwn = &tcm_loop_drop_scsi_hba;
1455 	fabric->tf_ops.fabric_make_tpg = &tcm_loop_make_naa_tpg;
1456 	fabric->tf_ops.fabric_drop_tpg = &tcm_loop_drop_naa_tpg;
1457 	/*
1458 	 * fabric_post_link() and fabric_pre_unlink() are used for
1459 	 * registration and release of TCM Loop Virtual SCSI LUNs.
1460 	 */
1461 	fabric->tf_ops.fabric_post_link = &tcm_loop_port_link;
1462 	fabric->tf_ops.fabric_pre_unlink = &tcm_loop_port_unlink;
1463 	fabric->tf_ops.fabric_make_np = NULL;
1464 	fabric->tf_ops.fabric_drop_np = NULL;
1465 	/*
1466 	 * Setup default attribute lists for various fabric->tf_cit_tmpl
1467 	 */
1468 	TF_CIT_TMPL(fabric)->tfc_wwn_cit.ct_attrs = tcm_loop_wwn_attrs;
1469 	TF_CIT_TMPL(fabric)->tfc_tpg_base_cit.ct_attrs = tcm_loop_tpg_attrs;
1470 	TF_CIT_TMPL(fabric)->tfc_tpg_attrib_cit.ct_attrs = NULL;
1471 	TF_CIT_TMPL(fabric)->tfc_tpg_param_cit.ct_attrs = NULL;
1472 	TF_CIT_TMPL(fabric)->tfc_tpg_np_base_cit.ct_attrs = NULL;
1473 	/*
1474 	 * Once fabric->tf_ops has been setup, now register the fabric for
1475 	 * use within TCM
1476 	 */
1477 	ret = target_fabric_configfs_register(fabric);
1478 	if (ret < 0) {
1479 		pr_err("target_fabric_configfs_register() for"
1480 				" TCM_Loop failed!\n");
1481 		target_fabric_configfs_free(fabric);
1482 		return -1;
1483 	}
1484 	/*
1485 	 * Setup our local pointer to *fabric.
1486 	 */
1487 	tcm_loop_fabric_configfs = fabric;
1488 	pr_debug("TCM_LOOP[0] - Set fabric ->"
1489 			" tcm_loop_fabric_configfs\n");
1490 	return 0;
1491 }
1492 
1493 static void tcm_loop_deregister_configfs(void)
1494 {
1495 	if (!tcm_loop_fabric_configfs)
1496 		return;
1497 
1498 	target_fabric_configfs_deregister(tcm_loop_fabric_configfs);
1499 	tcm_loop_fabric_configfs = NULL;
1500 	pr_debug("TCM_LOOP[0] - Cleared"
1501 				" tcm_loop_fabric_configfs\n");
1502 }
1503 
1504 static int __init tcm_loop_fabric_init(void)
1505 {
1506 	int ret;
1507 
1508 	tcm_loop_cmd_cache = kmem_cache_create("tcm_loop_cmd_cache",
1509 				sizeof(struct tcm_loop_cmd),
1510 				__alignof__(struct tcm_loop_cmd),
1511 				0, NULL);
1512 	if (!tcm_loop_cmd_cache) {
1513 		pr_debug("kmem_cache_create() for"
1514 			" tcm_loop_cmd_cache failed\n");
1515 		return -ENOMEM;
1516 	}
1517 
1518 	ret = tcm_loop_alloc_core_bus();
1519 	if (ret)
1520 		return ret;
1521 
1522 	ret = tcm_loop_register_configfs();
1523 	if (ret) {
1524 		tcm_loop_release_core_bus();
1525 		return ret;
1526 	}
1527 
1528 	return 0;
1529 }
1530 
1531 static void __exit tcm_loop_fabric_exit(void)
1532 {
1533 	tcm_loop_deregister_configfs();
1534 	tcm_loop_release_core_bus();
1535 	kmem_cache_destroy(tcm_loop_cmd_cache);
1536 }
1537 
1538 MODULE_DESCRIPTION("TCM loopback virtual Linux/SCSI fabric module");
1539 MODULE_AUTHOR("Nicholas A. Bellinger <nab@risingtidesystems.com>");
1540 MODULE_LICENSE("GPL");
1541 module_init(tcm_loop_fabric_init);
1542 module_exit(tcm_loop_fabric_exit);
1543