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