xref: /openbmc/linux/drivers/xen/xen-scsiback.c (revision 5c73cc4b6c83e88863a5de869cc5df3b913aef4a)
1 /*
2  * Xen SCSI backend driver
3  *
4  * Copyright (c) 2008, FUJITSU Limited
5  *
6  * Based on the blkback driver code.
7  * Adaption to kernel taget core infrastructure taken from vhost/scsi.c
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License version 2
11  * as published by the Free Software Foundation; or, when distributed
12  * separately from the Linux kernel or incorporated into other
13  * software packages, subject to the following license:
14  *
15  * Permission is hereby granted, free of charge, to any person obtaining a copy
16  * of this source file (the "Software"), to deal in the Software without
17  * restriction, including without limitation the rights to use, copy, modify,
18  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
19  * and to permit persons to whom the Software is furnished to do so, subject to
20  * the following conditions:
21  *
22  * The above copyright notice and this permission notice shall be included in
23  * all copies or substantial portions of the Software.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
28  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
29  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
30  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
31  * IN THE SOFTWARE.
32  */
33 
34 #define pr_fmt(fmt) "xen-pvscsi: " fmt
35 
36 #include <stdarg.h>
37 
38 #include <linux/module.h>
39 #include <linux/utsname.h>
40 #include <linux/interrupt.h>
41 #include <linux/slab.h>
42 #include <linux/wait.h>
43 #include <linux/sched.h>
44 #include <linux/list.h>
45 #include <linux/gfp.h>
46 #include <linux/delay.h>
47 #include <linux/spinlock.h>
48 #include <linux/configfs.h>
49 
50 #include <generated/utsrelease.h>
51 
52 #include <scsi/scsi.h>
53 #include <scsi/scsi_dbg.h>
54 #include <scsi/scsi_eh.h>
55 #include <scsi/scsi_tcq.h>
56 
57 #include <target/target_core_base.h>
58 #include <target/target_core_fabric.h>
59 #include <target/target_core_configfs.h>
60 #include <target/target_core_fabric_configfs.h>
61 
62 #include <asm/hypervisor.h>
63 
64 #include <xen/xen.h>
65 #include <xen/balloon.h>
66 #include <xen/events.h>
67 #include <xen/xenbus.h>
68 #include <xen/grant_table.h>
69 #include <xen/page.h>
70 
71 #include <xen/interface/grant_table.h>
72 #include <xen/interface/io/vscsiif.h>
73 
74 #define VSCSI_VERSION	"v0.1"
75 #define VSCSI_NAMELEN	32
76 
77 struct ids_tuple {
78 	unsigned int hst;		/* host    */
79 	unsigned int chn;		/* channel */
80 	unsigned int tgt;		/* target  */
81 	unsigned int lun;		/* LUN     */
82 };
83 
84 struct v2p_entry {
85 	struct ids_tuple v;		/* translate from */
86 	struct scsiback_tpg *tpg;	/* translate to   */
87 	unsigned int lun;
88 	struct kref kref;
89 	struct list_head l;
90 };
91 
92 struct vscsibk_info {
93 	struct xenbus_device *dev;
94 
95 	domid_t domid;
96 	unsigned int irq;
97 
98 	struct vscsiif_back_ring ring;
99 	int ring_error;
100 
101 	spinlock_t ring_lock;
102 	atomic_t nr_unreplied_reqs;
103 
104 	spinlock_t v2p_lock;
105 	struct list_head v2p_entry_lists;
106 
107 	wait_queue_head_t waiting_to_free;
108 };
109 
110 /* theoretical maximum of grants for one request */
111 #define VSCSI_MAX_GRANTS	(SG_ALL + VSCSIIF_SG_TABLESIZE)
112 
113 /*
114  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
115  * call to map/unmap grants. Don't choose it too large, as there are arrays
116  * with VSCSI_GRANT_BATCH elements allocated on the stack.
117  */
118 #define VSCSI_GRANT_BATCH	16
119 
120 struct vscsibk_pend {
121 	uint16_t rqid;
122 
123 	uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
124 	uint8_t cmd_len;
125 
126 	uint8_t sc_data_direction;
127 	uint16_t n_sg;		/* real length of SG list */
128 	uint16_t n_grants;	/* SG pages and potentially SG list */
129 	uint32_t data_len;
130 	uint32_t result;
131 
132 	struct vscsibk_info *info;
133 	struct v2p_entry *v2p;
134 	struct scatterlist *sgl;
135 
136 	uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
137 
138 	grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
139 	struct page *pages[VSCSI_MAX_GRANTS];
140 
141 	struct se_cmd se_cmd;
142 };
143 
144 struct scsiback_tmr {
145 	atomic_t tmr_complete;
146 	wait_queue_head_t tmr_wait;
147 };
148 
149 struct scsiback_nexus {
150 	/* Pointer to TCM session for I_T Nexus */
151 	struct se_session *tvn_se_sess;
152 };
153 
154 struct scsiback_tport {
155 	/* SCSI protocol the tport is providing */
156 	u8 tport_proto_id;
157 	/* Binary World Wide unique Port Name for pvscsi Target port */
158 	u64 tport_wwpn;
159 	/* ASCII formatted WWPN for pvscsi Target port */
160 	char tport_name[VSCSI_NAMELEN];
161 	/* Returned by scsiback_make_tport() */
162 	struct se_wwn tport_wwn;
163 };
164 
165 struct scsiback_tpg {
166 	/* scsiback port target portal group tag for TCM */
167 	u16 tport_tpgt;
168 	/* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
169 	int tv_tpg_port_count;
170 	/* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
171 	int tv_tpg_fe_count;
172 	/* list for scsiback_list */
173 	struct list_head tv_tpg_list;
174 	/* Used to protect access for tpg_nexus */
175 	struct mutex tv_tpg_mutex;
176 	/* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
177 	struct scsiback_nexus *tpg_nexus;
178 	/* Pointer back to scsiback_tport */
179 	struct scsiback_tport *tport;
180 	/* Returned by scsiback_make_tpg() */
181 	struct se_portal_group se_tpg;
182 	/* alias used in xenstore */
183 	char param_alias[VSCSI_NAMELEN];
184 	/* list of info structures related to this target portal group */
185 	struct list_head info_list;
186 };
187 
188 #define SCSIBACK_INVALID_HANDLE (~0)
189 
190 static bool log_print_stat;
191 module_param(log_print_stat, bool, 0644);
192 
193 static int scsiback_max_buffer_pages = 1024;
194 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
195 MODULE_PARM_DESC(max_buffer_pages,
196 "Maximum number of free pages to keep in backend buffer");
197 
198 static struct kmem_cache *scsiback_cachep;
199 static DEFINE_SPINLOCK(free_pages_lock);
200 static int free_pages_num;
201 static LIST_HEAD(scsiback_free_pages);
202 
203 /* Global spinlock to protect scsiback TPG list */
204 static DEFINE_MUTEX(scsiback_mutex);
205 static LIST_HEAD(scsiback_list);
206 
207 /* Local pointer to allocated TCM configfs fabric module */
208 static struct target_fabric_configfs *scsiback_fabric_configfs;
209 
210 static void scsiback_get(struct vscsibk_info *info)
211 {
212 	atomic_inc(&info->nr_unreplied_reqs);
213 }
214 
215 static void scsiback_put(struct vscsibk_info *info)
216 {
217 	if (atomic_dec_and_test(&info->nr_unreplied_reqs))
218 		wake_up(&info->waiting_to_free);
219 }
220 
221 static void put_free_pages(struct page **page, int num)
222 {
223 	unsigned long flags;
224 	int i = free_pages_num + num, n = num;
225 
226 	if (num == 0)
227 		return;
228 	if (i > scsiback_max_buffer_pages) {
229 		n = min(num, i - scsiback_max_buffer_pages);
230 		gnttab_free_pages(n, page + num - n);
231 		n = num - n;
232 	}
233 	spin_lock_irqsave(&free_pages_lock, flags);
234 	for (i = 0; i < n; i++)
235 		list_add(&page[i]->lru, &scsiback_free_pages);
236 	free_pages_num += n;
237 	spin_unlock_irqrestore(&free_pages_lock, flags);
238 }
239 
240 static int get_free_page(struct page **page)
241 {
242 	unsigned long flags;
243 
244 	spin_lock_irqsave(&free_pages_lock, flags);
245 	if (list_empty(&scsiback_free_pages)) {
246 		spin_unlock_irqrestore(&free_pages_lock, flags);
247 		return gnttab_alloc_pages(1, page);
248 	}
249 	page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
250 	list_del(&page[0]->lru);
251 	free_pages_num--;
252 	spin_unlock_irqrestore(&free_pages_lock, flags);
253 	return 0;
254 }
255 
256 static unsigned long vaddr_page(struct page *page)
257 {
258 	unsigned long pfn = page_to_pfn(page);
259 
260 	return (unsigned long)pfn_to_kaddr(pfn);
261 }
262 
263 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
264 {
265 	return vaddr_page(req->pages[seg]);
266 }
267 
268 static void scsiback_print_status(char *sense_buffer, int errors,
269 					struct vscsibk_pend *pending_req)
270 {
271 	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
272 
273 	pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
274 	       tpg->tport->tport_name, pending_req->v2p->lun,
275 	       pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
276 	       host_byte(errors), driver_byte(errors));
277 }
278 
279 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
280 {
281 	struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
282 	struct page *pages[VSCSI_GRANT_BATCH];
283 	unsigned int i, invcount = 0;
284 	grant_handle_t handle;
285 	int err;
286 
287 	kfree(req->sgl);
288 	req->sgl = NULL;
289 	req->n_sg = 0;
290 
291 	if (!req->n_grants)
292 		return;
293 
294 	for (i = 0; i < req->n_grants; i++) {
295 		handle = req->grant_handles[i];
296 		if (handle == SCSIBACK_INVALID_HANDLE)
297 			continue;
298 		gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
299 				    GNTMAP_host_map, handle);
300 		req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
301 		pages[invcount] = req->pages[i];
302 		put_page(pages[invcount]);
303 		invcount++;
304 		if (invcount < VSCSI_GRANT_BATCH)
305 			continue;
306 		err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
307 		BUG_ON(err);
308 		invcount = 0;
309 	}
310 
311 	if (invcount) {
312 		err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
313 		BUG_ON(err);
314 	}
315 
316 	put_free_pages(req->pages, req->n_grants);
317 	req->n_grants = 0;
318 }
319 
320 static void scsiback_free_translation_entry(struct kref *kref)
321 {
322 	struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
323 	struct scsiback_tpg *tpg = entry->tpg;
324 
325 	mutex_lock(&tpg->tv_tpg_mutex);
326 	tpg->tv_tpg_fe_count--;
327 	mutex_unlock(&tpg->tv_tpg_mutex);
328 
329 	kfree(entry);
330 }
331 
332 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
333 			uint32_t resid, struct vscsibk_pend *pending_req)
334 {
335 	struct vscsiif_response *ring_res;
336 	struct vscsibk_info *info = pending_req->info;
337 	int notify;
338 	struct scsi_sense_hdr sshdr;
339 	unsigned long flags;
340 	unsigned len;
341 
342 	spin_lock_irqsave(&info->ring_lock, flags);
343 
344 	ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
345 	info->ring.rsp_prod_pvt++;
346 
347 	ring_res->rslt   = result;
348 	ring_res->rqid   = pending_req->rqid;
349 
350 	if (sense_buffer != NULL &&
351 	    scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
352 				 &sshdr)) {
353 		len = min_t(unsigned, 8 + sense_buffer[7],
354 			    VSCSIIF_SENSE_BUFFERSIZE);
355 		memcpy(ring_res->sense_buffer, sense_buffer, len);
356 		ring_res->sense_len = len;
357 	} else {
358 		ring_res->sense_len = 0;
359 	}
360 
361 	ring_res->residual_len = resid;
362 
363 	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
364 	spin_unlock_irqrestore(&info->ring_lock, flags);
365 
366 	if (notify)
367 		notify_remote_via_irq(info->irq);
368 
369 	if (pending_req->v2p)
370 		kref_put(&pending_req->v2p->kref,
371 			 scsiback_free_translation_entry);
372 }
373 
374 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
375 {
376 	struct vscsibk_info *info = pending_req->info;
377 	unsigned char *sense_buffer;
378 	unsigned int resid;
379 	int errors;
380 
381 	sense_buffer = pending_req->sense_buffer;
382 	resid        = pending_req->se_cmd.residual_count;
383 	errors       = pending_req->result;
384 
385 	if (errors && log_print_stat)
386 		scsiback_print_status(sense_buffer, errors, pending_req);
387 
388 	scsiback_fast_flush_area(pending_req);
389 	scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
390 	scsiback_put(info);
391 }
392 
393 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
394 {
395 	struct se_cmd *se_cmd = &pending_req->se_cmd;
396 	struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
397 	int rc;
398 
399 	memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
400 
401 	memset(se_cmd, 0, sizeof(*se_cmd));
402 
403 	scsiback_get(pending_req->info);
404 	rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
405 			pending_req->sense_buffer, pending_req->v2p->lun,
406 			pending_req->data_len, 0,
407 			pending_req->sc_data_direction, 0,
408 			pending_req->sgl, pending_req->n_sg,
409 			NULL, 0, NULL, 0);
410 	if (rc < 0) {
411 		transport_send_check_condition_and_sense(se_cmd,
412 				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
413 		transport_generic_free_cmd(se_cmd, 0);
414 	}
415 }
416 
417 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
418 	struct page **pg, grant_handle_t *grant, int cnt)
419 {
420 	int err, i;
421 
422 	if (!cnt)
423 		return 0;
424 
425 	err = gnttab_map_refs(map, NULL, pg, cnt);
426 	BUG_ON(err);
427 	for (i = 0; i < cnt; i++) {
428 		if (unlikely(map[i].status != GNTST_okay)) {
429 			pr_err("invalid buffer -- could not remap it\n");
430 			map[i].handle = SCSIBACK_INVALID_HANDLE;
431 			err = -ENOMEM;
432 		} else {
433 			get_page(pg[i]);
434 		}
435 		grant[i] = map[i].handle;
436 	}
437 	return err;
438 }
439 
440 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
441 			struct scsiif_request_segment *seg, struct page **pg,
442 			grant_handle_t *grant, int cnt, u32 flags)
443 {
444 	int mapcount = 0, i, err = 0;
445 	struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
446 	struct vscsibk_info *info = pending_req->info;
447 
448 	for (i = 0; i < cnt; i++) {
449 		if (get_free_page(pg + mapcount)) {
450 			put_free_pages(pg, mapcount);
451 			pr_err("no grant page\n");
452 			return -ENOMEM;
453 		}
454 		gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
455 				  flags, seg[i].gref, info->domid);
456 		mapcount++;
457 		if (mapcount < VSCSI_GRANT_BATCH)
458 			continue;
459 		err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
460 		pg += mapcount;
461 		grant += mapcount;
462 		pending_req->n_grants += mapcount;
463 		if (err)
464 			return err;
465 		mapcount = 0;
466 	}
467 	err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
468 	pending_req->n_grants += mapcount;
469 	return err;
470 }
471 
472 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
473 					struct vscsibk_pend *pending_req)
474 {
475 	u32 flags;
476 	int i, err, n_segs, i_seg = 0;
477 	struct page **pg;
478 	struct scsiif_request_segment *seg;
479 	unsigned long end_seg = 0;
480 	unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
481 	unsigned int nr_sgl = 0;
482 	struct scatterlist *sg;
483 	grant_handle_t *grant;
484 
485 	pending_req->n_sg = 0;
486 	pending_req->n_grants = 0;
487 	pending_req->data_len = 0;
488 
489 	nr_segments &= ~VSCSIIF_SG_GRANT;
490 	if (!nr_segments)
491 		return 0;
492 
493 	if (nr_segments > VSCSIIF_SG_TABLESIZE) {
494 		pr_debug("invalid parameter nr_seg = %d\n",
495 			ring_req->nr_segments);
496 		return -EINVAL;
497 	}
498 
499 	if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
500 		err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
501 			pending_req->pages, pending_req->grant_handles,
502 			nr_segments, GNTMAP_host_map | GNTMAP_readonly);
503 		if (err)
504 			return err;
505 		nr_sgl = nr_segments;
506 		nr_segments = 0;
507 		for (i = 0; i < nr_sgl; i++) {
508 			n_segs = ring_req->seg[i].length /
509 				 sizeof(struct scsiif_request_segment);
510 			if ((unsigned)ring_req->seg[i].offset +
511 			    (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
512 			    n_segs * sizeof(struct scsiif_request_segment) !=
513 			    ring_req->seg[i].length)
514 				return -EINVAL;
515 			nr_segments += n_segs;
516 		}
517 		if (nr_segments > SG_ALL) {
518 			pr_debug("invalid nr_seg = %d\n", nr_segments);
519 			return -EINVAL;
520 		}
521 	}
522 
523 	/* free of (sgl) in fast_flush_area() */
524 	pending_req->sgl = kmalloc_array(nr_segments,
525 					sizeof(struct scatterlist), GFP_KERNEL);
526 	if (!pending_req->sgl)
527 		return -ENOMEM;
528 
529 	sg_init_table(pending_req->sgl, nr_segments);
530 	pending_req->n_sg = nr_segments;
531 
532 	flags = GNTMAP_host_map;
533 	if (pending_req->sc_data_direction == DMA_TO_DEVICE)
534 		flags |= GNTMAP_readonly;
535 
536 	pg = pending_req->pages + nr_sgl;
537 	grant = pending_req->grant_handles + nr_sgl;
538 	if (!nr_sgl) {
539 		seg = ring_req->seg;
540 		err = scsiback_gnttab_data_map_list(pending_req, seg,
541 			pg, grant, nr_segments, flags);
542 		if (err)
543 			return err;
544 	} else {
545 		for (i = 0; i < nr_sgl; i++) {
546 			seg = (struct scsiif_request_segment *)(
547 			      vaddr(pending_req, i) + ring_req->seg[i].offset);
548 			n_segs = ring_req->seg[i].length /
549 				 sizeof(struct scsiif_request_segment);
550 			err = scsiback_gnttab_data_map_list(pending_req, seg,
551 				pg, grant, n_segs, flags);
552 			if (err)
553 				return err;
554 			pg += n_segs;
555 			grant += n_segs;
556 		}
557 		end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
558 		seg = (struct scsiif_request_segment *)end_seg;
559 		end_seg += ring_req->seg[0].length;
560 		pg = pending_req->pages + nr_sgl;
561 	}
562 
563 	for_each_sg(pending_req->sgl, sg, nr_segments, i) {
564 		sg_set_page(sg, pg[i], seg->length, seg->offset);
565 		pending_req->data_len += seg->length;
566 		seg++;
567 		if (nr_sgl && (unsigned long)seg >= end_seg) {
568 			i_seg++;
569 			end_seg = vaddr(pending_req, i_seg) +
570 				  ring_req->seg[i_seg].offset;
571 			seg = (struct scsiif_request_segment *)end_seg;
572 			end_seg += ring_req->seg[i_seg].length;
573 		}
574 		if (sg->offset >= PAGE_SIZE ||
575 		    sg->length > PAGE_SIZE ||
576 		    sg->offset + sg->length > PAGE_SIZE)
577 			return -EINVAL;
578 	}
579 
580 	return 0;
581 }
582 
583 static void scsiback_disconnect(struct vscsibk_info *info)
584 {
585 	wait_event(info->waiting_to_free,
586 		atomic_read(&info->nr_unreplied_reqs) == 0);
587 
588 	unbind_from_irqhandler(info->irq, info);
589 	info->irq = 0;
590 	xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
591 }
592 
593 static void scsiback_device_action(struct vscsibk_pend *pending_req,
594 	enum tcm_tmreq_table act, int tag)
595 {
596 	int rc, err = FAILED;
597 	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
598 	struct se_cmd *se_cmd = &pending_req->se_cmd;
599 	struct scsiback_tmr *tmr;
600 
601 	tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
602 	if (!tmr)
603 		goto out;
604 
605 	init_waitqueue_head(&tmr->tmr_wait);
606 
607 	transport_init_se_cmd(se_cmd, tpg->se_tpg.se_tpg_tfo,
608 		tpg->tpg_nexus->tvn_se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG,
609 		&pending_req->sense_buffer[0]);
610 
611 	rc = core_tmr_alloc_req(se_cmd, tmr, act, GFP_KERNEL);
612 	if (rc < 0)
613 		goto out;
614 
615 	se_cmd->se_tmr_req->ref_task_tag = tag;
616 
617 	if (transport_lookup_tmr_lun(se_cmd, pending_req->v2p->lun) < 0)
618 		goto out;
619 
620 	transport_generic_handle_tmr(se_cmd);
621 	wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));
622 
623 	err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
624 		SUCCESS : FAILED;
625 
626 out:
627 	if (tmr) {
628 		transport_generic_free_cmd(&pending_req->se_cmd, 1);
629 		kfree(tmr);
630 	}
631 
632 	scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
633 
634 	kmem_cache_free(scsiback_cachep, pending_req);
635 }
636 
637 /*
638   Perform virtual to physical translation
639 */
640 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
641 			struct ids_tuple *v)
642 {
643 	struct v2p_entry *entry;
644 	struct list_head *head = &(info->v2p_entry_lists);
645 	unsigned long flags;
646 
647 	spin_lock_irqsave(&info->v2p_lock, flags);
648 	list_for_each_entry(entry, head, l) {
649 		if ((entry->v.chn == v->chn) &&
650 		    (entry->v.tgt == v->tgt) &&
651 		    (entry->v.lun == v->lun)) {
652 			kref_get(&entry->kref);
653 			goto out;
654 		}
655 	}
656 	entry = NULL;
657 
658 out:
659 	spin_unlock_irqrestore(&info->v2p_lock, flags);
660 	return entry;
661 }
662 
663 static int prepare_pending_reqs(struct vscsibk_info *info,
664 				struct vscsiif_request *ring_req,
665 				struct vscsibk_pend *pending_req)
666 {
667 	struct v2p_entry *v2p;
668 	struct ids_tuple vir;
669 
670 	pending_req->rqid       = ring_req->rqid;
671 	pending_req->info       = info;
672 
673 	vir.chn = ring_req->channel;
674 	vir.tgt = ring_req->id;
675 	vir.lun = ring_req->lun;
676 
677 	v2p = scsiback_do_translation(info, &vir);
678 	if (!v2p) {
679 		pending_req->v2p = NULL;
680 		pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
681 			vir.chn, vir.tgt, vir.lun);
682 		return -ENODEV;
683 	}
684 	pending_req->v2p = v2p;
685 
686 	/* request range check from frontend */
687 	pending_req->sc_data_direction = ring_req->sc_data_direction;
688 	if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
689 		(pending_req->sc_data_direction != DMA_TO_DEVICE) &&
690 		(pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
691 		(pending_req->sc_data_direction != DMA_NONE)) {
692 		pr_debug("invalid parameter data_dir = %d\n",
693 			pending_req->sc_data_direction);
694 		return -EINVAL;
695 	}
696 
697 	pending_req->cmd_len = ring_req->cmd_len;
698 	if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
699 		pr_debug("invalid parameter cmd_len = %d\n",
700 			pending_req->cmd_len);
701 		return -EINVAL;
702 	}
703 	memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
704 
705 	return 0;
706 }
707 
708 static int scsiback_do_cmd_fn(struct vscsibk_info *info)
709 {
710 	struct vscsiif_back_ring *ring = &info->ring;
711 	struct vscsiif_request ring_req;
712 	struct vscsibk_pend *pending_req;
713 	RING_IDX rc, rp;
714 	int err, more_to_do;
715 	uint32_t result;
716 
717 	rc = ring->req_cons;
718 	rp = ring->sring->req_prod;
719 	rmb();	/* guest system is accessing ring, too */
720 
721 	if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
722 		rc = ring->rsp_prod_pvt;
723 		pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
724 			   info->domid, rp, rc, rp - rc);
725 		info->ring_error = 1;
726 		return 0;
727 	}
728 
729 	while ((rc != rp)) {
730 		if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
731 			break;
732 		pending_req = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
733 		if (!pending_req)
734 			return 1;
735 
736 		ring_req = *RING_GET_REQUEST(ring, rc);
737 		ring->req_cons = ++rc;
738 
739 		err = prepare_pending_reqs(info, &ring_req, pending_req);
740 		if (err) {
741 			switch (err) {
742 			case -ENODEV:
743 				result = DID_NO_CONNECT;
744 				break;
745 			default:
746 				result = DRIVER_ERROR;
747 				break;
748 			}
749 			scsiback_do_resp_with_sense(NULL, result << 24, 0,
750 						    pending_req);
751 			kmem_cache_free(scsiback_cachep, pending_req);
752 			return 1;
753 		}
754 
755 		switch (ring_req.act) {
756 		case VSCSIIF_ACT_SCSI_CDB:
757 			if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
758 				scsiback_fast_flush_area(pending_req);
759 				scsiback_do_resp_with_sense(NULL,
760 					DRIVER_ERROR << 24, 0, pending_req);
761 				kmem_cache_free(scsiback_cachep, pending_req);
762 			} else {
763 				scsiback_cmd_exec(pending_req);
764 			}
765 			break;
766 		case VSCSIIF_ACT_SCSI_ABORT:
767 			scsiback_device_action(pending_req, TMR_ABORT_TASK,
768 				ring_req.ref_rqid);
769 			break;
770 		case VSCSIIF_ACT_SCSI_RESET:
771 			scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
772 			break;
773 		default:
774 			pr_err_ratelimited("invalid request\n");
775 			scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
776 						    0, pending_req);
777 			kmem_cache_free(scsiback_cachep, pending_req);
778 			break;
779 		}
780 
781 		/* Yield point for this unbounded loop. */
782 		cond_resched();
783 	}
784 
785 	RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
786 	return more_to_do;
787 }
788 
789 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
790 {
791 	struct vscsibk_info *info = dev_id;
792 
793 	if (info->ring_error)
794 		return IRQ_HANDLED;
795 
796 	while (scsiback_do_cmd_fn(info))
797 		cond_resched();
798 
799 	return IRQ_HANDLED;
800 }
801 
802 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
803 			evtchn_port_t evtchn)
804 {
805 	void *area;
806 	struct vscsiif_sring *sring;
807 	int err;
808 
809 	if (info->irq)
810 		return -1;
811 
812 	err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
813 	if (err)
814 		return err;
815 
816 	sring = (struct vscsiif_sring *)area;
817 	BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
818 
819 	err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
820 	if (err < 0)
821 		goto unmap_page;
822 
823 	info->irq = err;
824 
825 	err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
826 				   IRQF_ONESHOT, "vscsiif-backend", info);
827 	if (err)
828 		goto free_irq;
829 
830 	return 0;
831 
832 free_irq:
833 	unbind_from_irqhandler(info->irq, info);
834 	info->irq = 0;
835 unmap_page:
836 	xenbus_unmap_ring_vfree(info->dev, area);
837 
838 	return err;
839 }
840 
841 static int scsiback_map(struct vscsibk_info *info)
842 {
843 	struct xenbus_device *dev = info->dev;
844 	unsigned int ring_ref, evtchn;
845 	int err;
846 
847 	err = xenbus_gather(XBT_NIL, dev->otherend,
848 			"ring-ref", "%u", &ring_ref,
849 			"event-channel", "%u", &evtchn, NULL);
850 	if (err) {
851 		xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
852 		return err;
853 	}
854 
855 	return scsiback_init_sring(info, ring_ref, evtchn);
856 }
857 
858 /*
859   Add a new translation entry
860 */
861 static int scsiback_add_translation_entry(struct vscsibk_info *info,
862 					  char *phy, struct ids_tuple *v)
863 {
864 	int err = 0;
865 	struct v2p_entry *entry;
866 	struct v2p_entry *new;
867 	struct list_head *head = &(info->v2p_entry_lists);
868 	unsigned long flags;
869 	char *lunp;
870 	unsigned int lun;
871 	struct scsiback_tpg *tpg_entry, *tpg = NULL;
872 	char *error = "doesn't exist";
873 
874 	lunp = strrchr(phy, ':');
875 	if (!lunp) {
876 		pr_err("illegal format of physical device %s\n", phy);
877 		return -EINVAL;
878 	}
879 	*lunp = 0;
880 	lunp++;
881 	if (kstrtouint(lunp, 10, &lun) || lun >= TRANSPORT_MAX_LUNS_PER_TPG) {
882 		pr_err("lun number not valid: %s\n", lunp);
883 		return -EINVAL;
884 	}
885 
886 	mutex_lock(&scsiback_mutex);
887 	list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
888 		if (!strcmp(phy, tpg_entry->tport->tport_name) ||
889 		    !strcmp(phy, tpg_entry->param_alias)) {
890 			spin_lock(&tpg_entry->se_tpg.tpg_lun_lock);
891 			if (tpg_entry->se_tpg.tpg_lun_list[lun]->lun_status ==
892 			    TRANSPORT_LUN_STATUS_ACTIVE) {
893 				if (!tpg_entry->tpg_nexus)
894 					error = "nexus undefined";
895 				else
896 					tpg = tpg_entry;
897 			}
898 			spin_unlock(&tpg_entry->se_tpg.tpg_lun_lock);
899 			break;
900 		}
901 	}
902 	if (tpg) {
903 		mutex_lock(&tpg->tv_tpg_mutex);
904 		tpg->tv_tpg_fe_count++;
905 		mutex_unlock(&tpg->tv_tpg_mutex);
906 	}
907 	mutex_unlock(&scsiback_mutex);
908 
909 	if (!tpg) {
910 		pr_err("%s:%d %s\n", phy, lun, error);
911 		return -ENODEV;
912 	}
913 
914 	new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
915 	if (new == NULL) {
916 		err = -ENOMEM;
917 		goto out_free;
918 	}
919 
920 	spin_lock_irqsave(&info->v2p_lock, flags);
921 
922 	/* Check double assignment to identical virtual ID */
923 	list_for_each_entry(entry, head, l) {
924 		if ((entry->v.chn == v->chn) &&
925 		    (entry->v.tgt == v->tgt) &&
926 		    (entry->v.lun == v->lun)) {
927 			pr_warn("Virtual ID is already used. Assignment was not performed.\n");
928 			err = -EEXIST;
929 			goto out;
930 		}
931 
932 	}
933 
934 	/* Create a new translation entry and add to the list */
935 	kref_init(&new->kref);
936 	new->v = *v;
937 	new->tpg = tpg;
938 	new->lun = lun;
939 	list_add_tail(&new->l, head);
940 
941 out:
942 	spin_unlock_irqrestore(&info->v2p_lock, flags);
943 
944 out_free:
945 	mutex_lock(&tpg->tv_tpg_mutex);
946 	tpg->tv_tpg_fe_count--;
947 	mutex_unlock(&tpg->tv_tpg_mutex);
948 
949 	if (err)
950 		kfree(new);
951 
952 	return err;
953 }
954 
955 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
956 {
957 	list_del(&entry->l);
958 	kref_put(&entry->kref, scsiback_free_translation_entry);
959 }
960 
961 /*
962   Delete the translation entry specfied
963 */
964 static int scsiback_del_translation_entry(struct vscsibk_info *info,
965 					  struct ids_tuple *v)
966 {
967 	struct v2p_entry *entry;
968 	struct list_head *head = &(info->v2p_entry_lists);
969 	unsigned long flags;
970 
971 	spin_lock_irqsave(&info->v2p_lock, flags);
972 	/* Find out the translation entry specified */
973 	list_for_each_entry(entry, head, l) {
974 		if ((entry->v.chn == v->chn) &&
975 		    (entry->v.tgt == v->tgt) &&
976 		    (entry->v.lun == v->lun)) {
977 			goto found;
978 		}
979 	}
980 
981 	spin_unlock_irqrestore(&info->v2p_lock, flags);
982 	return 1;
983 
984 found:
985 	/* Delete the translation entry specfied */
986 	__scsiback_del_translation_entry(entry);
987 
988 	spin_unlock_irqrestore(&info->v2p_lock, flags);
989 	return 0;
990 }
991 
992 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
993 				char *phy, struct ids_tuple *vir, int try)
994 {
995 	if (!scsiback_add_translation_entry(info, phy, vir)) {
996 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
997 				  "%d", XenbusStateInitialised)) {
998 			pr_err("xenbus_printf error %s\n", state);
999 			scsiback_del_translation_entry(info, vir);
1000 		}
1001 	} else if (!try) {
1002 		xenbus_printf(XBT_NIL, info->dev->nodename, state,
1003 			      "%d", XenbusStateClosed);
1004 	}
1005 }
1006 
1007 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1008 				struct ids_tuple *vir)
1009 {
1010 	if (!scsiback_del_translation_entry(info, vir)) {
1011 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1012 				  "%d", XenbusStateClosed))
1013 			pr_err("xenbus_printf error %s\n", state);
1014 	}
1015 }
1016 
1017 #define VSCSIBACK_OP_ADD_OR_DEL_LUN	1
1018 #define VSCSIBACK_OP_UPDATEDEV_STATE	2
1019 
1020 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1021 				     char *ent)
1022 {
1023 	int err;
1024 	struct ids_tuple vir;
1025 	char *val;
1026 	int device_state;
1027 	char phy[VSCSI_NAMELEN];
1028 	char str[64];
1029 	char state[64];
1030 	struct xenbus_device *dev = info->dev;
1031 
1032 	/* read status */
1033 	snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1034 	err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1035 	if (XENBUS_EXIST_ERR(err))
1036 		return;
1037 
1038 	/* physical SCSI device */
1039 	snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1040 	val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1041 	if (IS_ERR(val)) {
1042 		xenbus_printf(XBT_NIL, dev->nodename, state,
1043 			      "%d", XenbusStateClosed);
1044 		return;
1045 	}
1046 	strlcpy(phy, val, VSCSI_NAMELEN);
1047 	kfree(val);
1048 
1049 	/* virtual SCSI device */
1050 	snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1051 	err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1052 			   &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1053 	if (XENBUS_EXIST_ERR(err)) {
1054 		xenbus_printf(XBT_NIL, dev->nodename, state,
1055 			      "%d", XenbusStateClosed);
1056 		return;
1057 	}
1058 
1059 	switch (op) {
1060 	case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1061 		switch (device_state) {
1062 		case XenbusStateInitialising:
1063 			scsiback_do_add_lun(info, state, phy, &vir, 0);
1064 			break;
1065 		case XenbusStateConnected:
1066 			scsiback_do_add_lun(info, state, phy, &vir, 1);
1067 			break;
1068 		case XenbusStateClosing:
1069 			scsiback_do_del_lun(info, state, &vir);
1070 			break;
1071 		default:
1072 			break;
1073 		}
1074 		break;
1075 
1076 	case VSCSIBACK_OP_UPDATEDEV_STATE:
1077 		if (device_state == XenbusStateInitialised) {
1078 			/* modify vscsi-devs/dev-x/state */
1079 			if (xenbus_printf(XBT_NIL, dev->nodename, state,
1080 					  "%d", XenbusStateConnected)) {
1081 				pr_err("xenbus_printf error %s\n", str);
1082 				scsiback_del_translation_entry(info, &vir);
1083 				xenbus_printf(XBT_NIL, dev->nodename, state,
1084 					      "%d", XenbusStateClosed);
1085 			}
1086 		}
1087 		break;
1088 	/* When it is necessary, processing is added here. */
1089 	default:
1090 		break;
1091 	}
1092 }
1093 
1094 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1095 {
1096 	int i;
1097 	char **dir;
1098 	unsigned int ndir = 0;
1099 
1100 	dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1101 			       &ndir);
1102 	if (IS_ERR(dir))
1103 		return;
1104 
1105 	for (i = 0; i < ndir; i++)
1106 		scsiback_do_1lun_hotplug(info, op, dir[i]);
1107 
1108 	kfree(dir);
1109 }
1110 
1111 static void scsiback_frontend_changed(struct xenbus_device *dev,
1112 					enum xenbus_state frontend_state)
1113 {
1114 	struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1115 
1116 	switch (frontend_state) {
1117 	case XenbusStateInitialising:
1118 		break;
1119 
1120 	case XenbusStateInitialised:
1121 		if (scsiback_map(info))
1122 			break;
1123 
1124 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1125 		xenbus_switch_state(dev, XenbusStateConnected);
1126 		break;
1127 
1128 	case XenbusStateConnected:
1129 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1130 
1131 		if (dev->state == XenbusStateConnected)
1132 			break;
1133 
1134 		xenbus_switch_state(dev, XenbusStateConnected);
1135 		break;
1136 
1137 	case XenbusStateClosing:
1138 		if (info->irq)
1139 			scsiback_disconnect(info);
1140 
1141 		xenbus_switch_state(dev, XenbusStateClosing);
1142 		break;
1143 
1144 	case XenbusStateClosed:
1145 		xenbus_switch_state(dev, XenbusStateClosed);
1146 		if (xenbus_dev_is_online(dev))
1147 			break;
1148 		/* fall through if not online */
1149 	case XenbusStateUnknown:
1150 		device_unregister(&dev->dev);
1151 		break;
1152 
1153 	case XenbusStateReconfiguring:
1154 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1155 		xenbus_switch_state(dev, XenbusStateReconfigured);
1156 
1157 		break;
1158 
1159 	default:
1160 		xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1161 					frontend_state);
1162 		break;
1163 	}
1164 }
1165 
1166 /*
1167   Release the translation entry specfied
1168 */
1169 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1170 {
1171 	struct v2p_entry *entry, *tmp;
1172 	struct list_head *head = &(info->v2p_entry_lists);
1173 	unsigned long flags;
1174 
1175 	spin_lock_irqsave(&info->v2p_lock, flags);
1176 
1177 	list_for_each_entry_safe(entry, tmp, head, l)
1178 		__scsiback_del_translation_entry(entry);
1179 
1180 	spin_unlock_irqrestore(&info->v2p_lock, flags);
1181 }
1182 
1183 static int scsiback_remove(struct xenbus_device *dev)
1184 {
1185 	struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1186 
1187 	if (info->irq)
1188 		scsiback_disconnect(info);
1189 
1190 	scsiback_release_translation_entry(info);
1191 
1192 	dev_set_drvdata(&dev->dev, NULL);
1193 
1194 	return 0;
1195 }
1196 
1197 static int scsiback_probe(struct xenbus_device *dev,
1198 			   const struct xenbus_device_id *id)
1199 {
1200 	int err;
1201 
1202 	struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1203 					    GFP_KERNEL);
1204 
1205 	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1206 
1207 	if (!info) {
1208 		xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1209 		return -ENOMEM;
1210 	}
1211 	info->dev = dev;
1212 	dev_set_drvdata(&dev->dev, info);
1213 
1214 	info->domid = dev->otherend_id;
1215 	spin_lock_init(&info->ring_lock);
1216 	info->ring_error = 0;
1217 	atomic_set(&info->nr_unreplied_reqs, 0);
1218 	init_waitqueue_head(&info->waiting_to_free);
1219 	info->dev = dev;
1220 	info->irq = 0;
1221 	INIT_LIST_HEAD(&info->v2p_entry_lists);
1222 	spin_lock_init(&info->v2p_lock);
1223 
1224 	err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1225 			    SG_ALL);
1226 	if (err)
1227 		xenbus_dev_error(dev, err, "writing feature-sg-grant");
1228 
1229 	err = xenbus_switch_state(dev, XenbusStateInitWait);
1230 	if (err)
1231 		goto fail;
1232 
1233 	return 0;
1234 
1235 fail:
1236 	pr_warn("%s failed\n", __func__);
1237 	scsiback_remove(dev);
1238 
1239 	return err;
1240 }
1241 
1242 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1243 {
1244 	switch (tport->tport_proto_id) {
1245 	case SCSI_PROTOCOL_SAS:
1246 		return "SAS";
1247 	case SCSI_PROTOCOL_FCP:
1248 		return "FCP";
1249 	case SCSI_PROTOCOL_ISCSI:
1250 		return "iSCSI";
1251 	default:
1252 		break;
1253 	}
1254 
1255 	return "Unknown";
1256 }
1257 
1258 static u8 scsiback_get_fabric_proto_ident(struct se_portal_group *se_tpg)
1259 {
1260 	struct scsiback_tpg *tpg = container_of(se_tpg,
1261 				struct scsiback_tpg, se_tpg);
1262 	struct scsiback_tport *tport = tpg->tport;
1263 
1264 	switch (tport->tport_proto_id) {
1265 	case SCSI_PROTOCOL_SAS:
1266 		return sas_get_fabric_proto_ident(se_tpg);
1267 	case SCSI_PROTOCOL_FCP:
1268 		return fc_get_fabric_proto_ident(se_tpg);
1269 	case SCSI_PROTOCOL_ISCSI:
1270 		return iscsi_get_fabric_proto_ident(se_tpg);
1271 	default:
1272 		pr_err("Unknown tport_proto_id: 0x%02x, using SAS emulation\n",
1273 			tport->tport_proto_id);
1274 		break;
1275 	}
1276 
1277 	return sas_get_fabric_proto_ident(se_tpg);
1278 }
1279 
1280 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1281 {
1282 	struct scsiback_tpg *tpg = container_of(se_tpg,
1283 				struct scsiback_tpg, se_tpg);
1284 	struct scsiback_tport *tport = tpg->tport;
1285 
1286 	return &tport->tport_name[0];
1287 }
1288 
1289 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1290 {
1291 	struct scsiback_tpg *tpg = container_of(se_tpg,
1292 				struct scsiback_tpg, se_tpg);
1293 	return tpg->tport_tpgt;
1294 }
1295 
1296 static u32 scsiback_get_default_depth(struct se_portal_group *se_tpg)
1297 {
1298 	return 1;
1299 }
1300 
1301 static u32
1302 scsiback_get_pr_transport_id(struct se_portal_group *se_tpg,
1303 			      struct se_node_acl *se_nacl,
1304 			      struct t10_pr_registration *pr_reg,
1305 			      int *format_code,
1306 			      unsigned char *buf)
1307 {
1308 	struct scsiback_tpg *tpg = container_of(se_tpg,
1309 				struct scsiback_tpg, se_tpg);
1310 	struct scsiback_tport *tport = tpg->tport;
1311 
1312 	switch (tport->tport_proto_id) {
1313 	case SCSI_PROTOCOL_SAS:
1314 		return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
1315 					format_code, buf);
1316 	case SCSI_PROTOCOL_FCP:
1317 		return fc_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
1318 					format_code, buf);
1319 	case SCSI_PROTOCOL_ISCSI:
1320 		return iscsi_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
1321 					format_code, buf);
1322 	default:
1323 		pr_err("Unknown tport_proto_id: 0x%02x, using SAS emulation\n",
1324 			tport->tport_proto_id);
1325 		break;
1326 	}
1327 
1328 	return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
1329 			format_code, buf);
1330 }
1331 
1332 static u32
1333 scsiback_get_pr_transport_id_len(struct se_portal_group *se_tpg,
1334 				  struct se_node_acl *se_nacl,
1335 				  struct t10_pr_registration *pr_reg,
1336 				  int *format_code)
1337 {
1338 	struct scsiback_tpg *tpg = container_of(se_tpg,
1339 				struct scsiback_tpg, se_tpg);
1340 	struct scsiback_tport *tport = tpg->tport;
1341 
1342 	switch (tport->tport_proto_id) {
1343 	case SCSI_PROTOCOL_SAS:
1344 		return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
1345 					format_code);
1346 	case SCSI_PROTOCOL_FCP:
1347 		return fc_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
1348 					format_code);
1349 	case SCSI_PROTOCOL_ISCSI:
1350 		return iscsi_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
1351 					format_code);
1352 	default:
1353 		pr_err("Unknown tport_proto_id: 0x%02x, using SAS emulation\n",
1354 			tport->tport_proto_id);
1355 		break;
1356 	}
1357 
1358 	return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
1359 			format_code);
1360 }
1361 
1362 static char *
1363 scsiback_parse_pr_out_transport_id(struct se_portal_group *se_tpg,
1364 				    const char *buf,
1365 				    u32 *out_tid_len,
1366 				    char **port_nexus_ptr)
1367 {
1368 	struct scsiback_tpg *tpg = container_of(se_tpg,
1369 				struct scsiback_tpg, se_tpg);
1370 	struct scsiback_tport *tport = tpg->tport;
1371 
1372 	switch (tport->tport_proto_id) {
1373 	case SCSI_PROTOCOL_SAS:
1374 		return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
1375 					port_nexus_ptr);
1376 	case SCSI_PROTOCOL_FCP:
1377 		return fc_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
1378 					port_nexus_ptr);
1379 	case SCSI_PROTOCOL_ISCSI:
1380 		return iscsi_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
1381 					port_nexus_ptr);
1382 	default:
1383 		pr_err("Unknown tport_proto_id: 0x%02x, using SAS emulation\n",
1384 			tport->tport_proto_id);
1385 		break;
1386 	}
1387 
1388 	return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
1389 			port_nexus_ptr);
1390 }
1391 
1392 static struct se_wwn *
1393 scsiback_make_tport(struct target_fabric_configfs *tf,
1394 		     struct config_group *group,
1395 		     const char *name)
1396 {
1397 	struct scsiback_tport *tport;
1398 	char *ptr;
1399 	u64 wwpn = 0;
1400 	int off = 0;
1401 
1402 	tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1403 	if (!tport)
1404 		return ERR_PTR(-ENOMEM);
1405 
1406 	tport->tport_wwpn = wwpn;
1407 	/*
1408 	 * Determine the emulated Protocol Identifier and Target Port Name
1409 	 * based on the incoming configfs directory name.
1410 	 */
1411 	ptr = strstr(name, "naa.");
1412 	if (ptr) {
1413 		tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1414 		goto check_len;
1415 	}
1416 	ptr = strstr(name, "fc.");
1417 	if (ptr) {
1418 		tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1419 		off = 3; /* Skip over "fc." */
1420 		goto check_len;
1421 	}
1422 	ptr = strstr(name, "iqn.");
1423 	if (ptr) {
1424 		tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1425 		goto check_len;
1426 	}
1427 
1428 	pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1429 	kfree(tport);
1430 	return ERR_PTR(-EINVAL);
1431 
1432 check_len:
1433 	if (strlen(name) >= VSCSI_NAMELEN) {
1434 		pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1435 			scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1436 		kfree(tport);
1437 		return ERR_PTR(-EINVAL);
1438 	}
1439 	snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1440 
1441 	pr_debug("Allocated emulated Target %s Address: %s\n",
1442 		 scsiback_dump_proto_id(tport), name);
1443 
1444 	return &tport->tport_wwn;
1445 }
1446 
1447 static void scsiback_drop_tport(struct se_wwn *wwn)
1448 {
1449 	struct scsiback_tport *tport = container_of(wwn,
1450 				struct scsiback_tport, tport_wwn);
1451 
1452 	pr_debug("Deallocating emulated Target %s Address: %s\n",
1453 		 scsiback_dump_proto_id(tport), tport->tport_name);
1454 
1455 	kfree(tport);
1456 }
1457 
1458 static struct se_node_acl *
1459 scsiback_alloc_fabric_acl(struct se_portal_group *se_tpg)
1460 {
1461 	return kzalloc(sizeof(struct se_node_acl), GFP_KERNEL);
1462 }
1463 
1464 static void
1465 scsiback_release_fabric_acl(struct se_portal_group *se_tpg,
1466 			     struct se_node_acl *se_nacl)
1467 {
1468 	kfree(se_nacl);
1469 }
1470 
1471 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1472 {
1473 	return 1;
1474 }
1475 
1476 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1477 {
1478 	/*
1479 	 * Do not release struct se_cmd's containing a valid TMR pointer.
1480 	 * These will be released directly in scsiback_device_action()
1481 	 * with transport_generic_free_cmd().
1482 	 */
1483 	if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1484 		return 0;
1485 
1486 	transport_generic_free_cmd(se_cmd, 0);
1487 	return 1;
1488 }
1489 
1490 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1491 {
1492 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1493 				struct vscsibk_pend, se_cmd);
1494 
1495 	kmem_cache_free(scsiback_cachep, pending_req);
1496 }
1497 
1498 static int scsiback_shutdown_session(struct se_session *se_sess)
1499 {
1500 	return 0;
1501 }
1502 
1503 static void scsiback_close_session(struct se_session *se_sess)
1504 {
1505 }
1506 
1507 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1508 {
1509 	return 0;
1510 }
1511 
1512 static int scsiback_write_pending(struct se_cmd *se_cmd)
1513 {
1514 	/* Go ahead and process the write immediately */
1515 	target_execute_cmd(se_cmd);
1516 
1517 	return 0;
1518 }
1519 
1520 static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1521 {
1522 	return 0;
1523 }
1524 
1525 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1526 {
1527 }
1528 
1529 static u32 scsiback_get_task_tag(struct se_cmd *se_cmd)
1530 {
1531 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1532 				struct vscsibk_pend, se_cmd);
1533 
1534 	return pending_req->rqid;
1535 }
1536 
1537 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1538 {
1539 	return 0;
1540 }
1541 
1542 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1543 {
1544 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1545 				struct vscsibk_pend, se_cmd);
1546 
1547 	pending_req->result = SAM_STAT_GOOD;
1548 	scsiback_cmd_done(pending_req);
1549 	return 0;
1550 }
1551 
1552 static int scsiback_queue_status(struct se_cmd *se_cmd)
1553 {
1554 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1555 				struct vscsibk_pend, se_cmd);
1556 
1557 	if (se_cmd->sense_buffer &&
1558 	    ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1559 	     (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1560 		pending_req->result = (DRIVER_SENSE << 24) |
1561 				      SAM_STAT_CHECK_CONDITION;
1562 	else
1563 		pending_req->result = se_cmd->scsi_status;
1564 
1565 	scsiback_cmd_done(pending_req);
1566 	return 0;
1567 }
1568 
1569 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1570 {
1571 	struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1572 	struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1573 
1574 	atomic_set(&tmr->tmr_complete, 1);
1575 	wake_up(&tmr->tmr_wait);
1576 }
1577 
1578 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1579 {
1580 }
1581 
1582 static ssize_t scsiback_tpg_param_show_alias(struct se_portal_group *se_tpg,
1583 					     char *page)
1584 {
1585 	struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1586 						se_tpg);
1587 	ssize_t rb;
1588 
1589 	mutex_lock(&tpg->tv_tpg_mutex);
1590 	rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1591 	mutex_unlock(&tpg->tv_tpg_mutex);
1592 
1593 	return rb;
1594 }
1595 
1596 static ssize_t scsiback_tpg_param_store_alias(struct se_portal_group *se_tpg,
1597 					      const char *page, size_t count)
1598 {
1599 	struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1600 						se_tpg);
1601 	int len;
1602 
1603 	if (strlen(page) >= VSCSI_NAMELEN) {
1604 		pr_err("param alias: %s, exceeds max: %d\n", page,
1605 			VSCSI_NAMELEN);
1606 		return -EINVAL;
1607 	}
1608 
1609 	mutex_lock(&tpg->tv_tpg_mutex);
1610 	len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1611 	if (tpg->param_alias[len - 1] == '\n')
1612 		tpg->param_alias[len - 1] = '\0';
1613 	mutex_unlock(&tpg->tv_tpg_mutex);
1614 
1615 	return count;
1616 }
1617 
1618 TF_TPG_PARAM_ATTR(scsiback, alias, S_IRUGO | S_IWUSR);
1619 
1620 static struct configfs_attribute *scsiback_param_attrs[] = {
1621 	&scsiback_tpg_param_alias.attr,
1622 	NULL,
1623 };
1624 
1625 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1626 				const char *name)
1627 {
1628 	struct se_portal_group *se_tpg;
1629 	struct se_session *se_sess;
1630 	struct scsiback_nexus *tv_nexus;
1631 
1632 	mutex_lock(&tpg->tv_tpg_mutex);
1633 	if (tpg->tpg_nexus) {
1634 		mutex_unlock(&tpg->tv_tpg_mutex);
1635 		pr_debug("tpg->tpg_nexus already exists\n");
1636 		return -EEXIST;
1637 	}
1638 	se_tpg = &tpg->se_tpg;
1639 
1640 	tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1641 	if (!tv_nexus) {
1642 		mutex_unlock(&tpg->tv_tpg_mutex);
1643 		return -ENOMEM;
1644 	}
1645 	/*
1646 	 * Initialize the struct se_session pointer
1647 	 */
1648 	tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
1649 	if (IS_ERR(tv_nexus->tvn_se_sess)) {
1650 		mutex_unlock(&tpg->tv_tpg_mutex);
1651 		kfree(tv_nexus);
1652 		return -ENOMEM;
1653 	}
1654 	se_sess = tv_nexus->tvn_se_sess;
1655 	/*
1656 	 * Since we are running in 'demo mode' this call with generate a
1657 	 * struct se_node_acl for the scsiback struct se_portal_group with
1658 	 * the SCSI Initiator port name of the passed configfs group 'name'.
1659 	 */
1660 	tv_nexus->tvn_se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1661 				se_tpg, (unsigned char *)name);
1662 	if (!tv_nexus->tvn_se_sess->se_node_acl) {
1663 		mutex_unlock(&tpg->tv_tpg_mutex);
1664 		pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
1665 			 name);
1666 		goto out;
1667 	}
1668 	/* Now register the TCM pvscsi virtual I_T Nexus as active. */
1669 	transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
1670 			tv_nexus->tvn_se_sess, tv_nexus);
1671 	tpg->tpg_nexus = tv_nexus;
1672 
1673 	mutex_unlock(&tpg->tv_tpg_mutex);
1674 	return 0;
1675 
1676 out:
1677 	transport_free_session(se_sess);
1678 	kfree(tv_nexus);
1679 	return -ENOMEM;
1680 }
1681 
1682 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1683 {
1684 	struct se_session *se_sess;
1685 	struct scsiback_nexus *tv_nexus;
1686 
1687 	mutex_lock(&tpg->tv_tpg_mutex);
1688 	tv_nexus = tpg->tpg_nexus;
1689 	if (!tv_nexus) {
1690 		mutex_unlock(&tpg->tv_tpg_mutex);
1691 		return -ENODEV;
1692 	}
1693 
1694 	se_sess = tv_nexus->tvn_se_sess;
1695 	if (!se_sess) {
1696 		mutex_unlock(&tpg->tv_tpg_mutex);
1697 		return -ENODEV;
1698 	}
1699 
1700 	if (tpg->tv_tpg_port_count != 0) {
1701 		mutex_unlock(&tpg->tv_tpg_mutex);
1702 		pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1703 			tpg->tv_tpg_port_count);
1704 		return -EBUSY;
1705 	}
1706 
1707 	if (tpg->tv_tpg_fe_count != 0) {
1708 		mutex_unlock(&tpg->tv_tpg_mutex);
1709 		pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1710 			tpg->tv_tpg_fe_count);
1711 		return -EBUSY;
1712 	}
1713 
1714 	pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1715 		scsiback_dump_proto_id(tpg->tport),
1716 		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1717 
1718 	/*
1719 	 * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1720 	 */
1721 	transport_deregister_session(tv_nexus->tvn_se_sess);
1722 	tpg->tpg_nexus = NULL;
1723 	mutex_unlock(&tpg->tv_tpg_mutex);
1724 
1725 	kfree(tv_nexus);
1726 	return 0;
1727 }
1728 
1729 static ssize_t scsiback_tpg_show_nexus(struct se_portal_group *se_tpg,
1730 					char *page)
1731 {
1732 	struct scsiback_tpg *tpg = container_of(se_tpg,
1733 				struct scsiback_tpg, se_tpg);
1734 	struct scsiback_nexus *tv_nexus;
1735 	ssize_t ret;
1736 
1737 	mutex_lock(&tpg->tv_tpg_mutex);
1738 	tv_nexus = tpg->tpg_nexus;
1739 	if (!tv_nexus) {
1740 		mutex_unlock(&tpg->tv_tpg_mutex);
1741 		return -ENODEV;
1742 	}
1743 	ret = snprintf(page, PAGE_SIZE, "%s\n",
1744 			tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1745 	mutex_unlock(&tpg->tv_tpg_mutex);
1746 
1747 	return ret;
1748 }
1749 
1750 static ssize_t scsiback_tpg_store_nexus(struct se_portal_group *se_tpg,
1751 					 const char *page,
1752 					 size_t count)
1753 {
1754 	struct scsiback_tpg *tpg = container_of(se_tpg,
1755 				struct scsiback_tpg, se_tpg);
1756 	struct scsiback_tport *tport_wwn = tpg->tport;
1757 	unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1758 	int ret;
1759 	/*
1760 	 * Shutdown the active I_T nexus if 'NULL' is passed.
1761 	 */
1762 	if (!strncmp(page, "NULL", 4)) {
1763 		ret = scsiback_drop_nexus(tpg);
1764 		return (!ret) ? count : ret;
1765 	}
1766 	/*
1767 	 * Otherwise make sure the passed virtual Initiator port WWN matches
1768 	 * the fabric protocol_id set in scsiback_make_tport(), and call
1769 	 * scsiback_make_nexus().
1770 	 */
1771 	if (strlen(page) >= VSCSI_NAMELEN) {
1772 		pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1773 			page, VSCSI_NAMELEN);
1774 		return -EINVAL;
1775 	}
1776 	snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1777 
1778 	ptr = strstr(i_port, "naa.");
1779 	if (ptr) {
1780 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1781 			pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1782 				i_port, scsiback_dump_proto_id(tport_wwn));
1783 			return -EINVAL;
1784 		}
1785 		port_ptr = &i_port[0];
1786 		goto check_newline;
1787 	}
1788 	ptr = strstr(i_port, "fc.");
1789 	if (ptr) {
1790 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1791 			pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1792 				i_port, scsiback_dump_proto_id(tport_wwn));
1793 			return -EINVAL;
1794 		}
1795 		port_ptr = &i_port[3]; /* Skip over "fc." */
1796 		goto check_newline;
1797 	}
1798 	ptr = strstr(i_port, "iqn.");
1799 	if (ptr) {
1800 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1801 			pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1802 				i_port, scsiback_dump_proto_id(tport_wwn));
1803 			return -EINVAL;
1804 		}
1805 		port_ptr = &i_port[0];
1806 		goto check_newline;
1807 	}
1808 	pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1809 		i_port);
1810 	return -EINVAL;
1811 	/*
1812 	 * Clear any trailing newline for the NAA WWN
1813 	 */
1814 check_newline:
1815 	if (i_port[strlen(i_port) - 1] == '\n')
1816 		i_port[strlen(i_port) - 1] = '\0';
1817 
1818 	ret = scsiback_make_nexus(tpg, port_ptr);
1819 	if (ret < 0)
1820 		return ret;
1821 
1822 	return count;
1823 }
1824 
1825 TF_TPG_BASE_ATTR(scsiback, nexus, S_IRUGO | S_IWUSR);
1826 
1827 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1828 	&scsiback_tpg_nexus.attr,
1829 	NULL,
1830 };
1831 
1832 static ssize_t
1833 scsiback_wwn_show_attr_version(struct target_fabric_configfs *tf,
1834 				char *page)
1835 {
1836 	return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1837 		UTS_RELEASE"\n",
1838 		VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1839 }
1840 
1841 TF_WWN_ATTR_RO(scsiback, version);
1842 
1843 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1844 	&scsiback_wwn_version.attr,
1845 	NULL,
1846 };
1847 
1848 static char *scsiback_get_fabric_name(void)
1849 {
1850 	return "xen-pvscsi";
1851 }
1852 
1853 static int scsiback_port_link(struct se_portal_group *se_tpg,
1854 			       struct se_lun *lun)
1855 {
1856 	struct scsiback_tpg *tpg = container_of(se_tpg,
1857 				struct scsiback_tpg, se_tpg);
1858 
1859 	mutex_lock(&tpg->tv_tpg_mutex);
1860 	tpg->tv_tpg_port_count++;
1861 	mutex_unlock(&tpg->tv_tpg_mutex);
1862 
1863 	return 0;
1864 }
1865 
1866 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1867 				  struct se_lun *lun)
1868 {
1869 	struct scsiback_tpg *tpg = container_of(se_tpg,
1870 				struct scsiback_tpg, se_tpg);
1871 
1872 	mutex_lock(&tpg->tv_tpg_mutex);
1873 	tpg->tv_tpg_port_count--;
1874 	mutex_unlock(&tpg->tv_tpg_mutex);
1875 }
1876 
1877 static struct se_portal_group *
1878 scsiback_make_tpg(struct se_wwn *wwn,
1879 		   struct config_group *group,
1880 		   const char *name)
1881 {
1882 	struct scsiback_tport *tport = container_of(wwn,
1883 			struct scsiback_tport, tport_wwn);
1884 
1885 	struct scsiback_tpg *tpg;
1886 	u16 tpgt;
1887 	int ret;
1888 
1889 	if (strstr(name, "tpgt_") != name)
1890 		return ERR_PTR(-EINVAL);
1891 	ret = kstrtou16(name + 5, 10, &tpgt);
1892 	if (ret)
1893 		return ERR_PTR(ret);
1894 
1895 	tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1896 	if (!tpg)
1897 		return ERR_PTR(-ENOMEM);
1898 
1899 	mutex_init(&tpg->tv_tpg_mutex);
1900 	INIT_LIST_HEAD(&tpg->tv_tpg_list);
1901 	INIT_LIST_HEAD(&tpg->info_list);
1902 	tpg->tport = tport;
1903 	tpg->tport_tpgt = tpgt;
1904 
1905 	ret = core_tpg_register(&scsiback_fabric_configfs->tf_ops, wwn,
1906 				&tpg->se_tpg, tpg, TRANSPORT_TPG_TYPE_NORMAL);
1907 	if (ret < 0) {
1908 		kfree(tpg);
1909 		return NULL;
1910 	}
1911 	mutex_lock(&scsiback_mutex);
1912 	list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1913 	mutex_unlock(&scsiback_mutex);
1914 
1915 	return &tpg->se_tpg;
1916 }
1917 
1918 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1919 {
1920 	struct scsiback_tpg *tpg = container_of(se_tpg,
1921 				struct scsiback_tpg, se_tpg);
1922 
1923 	mutex_lock(&scsiback_mutex);
1924 	list_del(&tpg->tv_tpg_list);
1925 	mutex_unlock(&scsiback_mutex);
1926 	/*
1927 	 * Release the virtual I_T Nexus for this xen-pvscsi TPG
1928 	 */
1929 	scsiback_drop_nexus(tpg);
1930 	/*
1931 	 * Deregister the se_tpg from TCM.
1932 	 */
1933 	core_tpg_deregister(se_tpg);
1934 	kfree(tpg);
1935 }
1936 
1937 static int scsiback_check_true(struct se_portal_group *se_tpg)
1938 {
1939 	return 1;
1940 }
1941 
1942 static int scsiback_check_false(struct se_portal_group *se_tpg)
1943 {
1944 	return 0;
1945 }
1946 
1947 static struct target_core_fabric_ops scsiback_ops = {
1948 	.get_fabric_name		= scsiback_get_fabric_name,
1949 	.get_fabric_proto_ident		= scsiback_get_fabric_proto_ident,
1950 	.tpg_get_wwn			= scsiback_get_fabric_wwn,
1951 	.tpg_get_tag			= scsiback_get_tag,
1952 	.tpg_get_default_depth		= scsiback_get_default_depth,
1953 	.tpg_get_pr_transport_id	= scsiback_get_pr_transport_id,
1954 	.tpg_get_pr_transport_id_len	= scsiback_get_pr_transport_id_len,
1955 	.tpg_parse_pr_out_transport_id	= scsiback_parse_pr_out_transport_id,
1956 	.tpg_check_demo_mode		= scsiback_check_true,
1957 	.tpg_check_demo_mode_cache	= scsiback_check_true,
1958 	.tpg_check_demo_mode_write_protect = scsiback_check_false,
1959 	.tpg_check_prod_mode_write_protect = scsiback_check_false,
1960 	.tpg_alloc_fabric_acl		= scsiback_alloc_fabric_acl,
1961 	.tpg_release_fabric_acl		= scsiback_release_fabric_acl,
1962 	.tpg_get_inst_index		= scsiback_tpg_get_inst_index,
1963 	.check_stop_free		= scsiback_check_stop_free,
1964 	.release_cmd			= scsiback_release_cmd,
1965 	.put_session			= NULL,
1966 	.shutdown_session		= scsiback_shutdown_session,
1967 	.close_session			= scsiback_close_session,
1968 	.sess_get_index			= scsiback_sess_get_index,
1969 	.sess_get_initiator_sid		= NULL,
1970 	.write_pending			= scsiback_write_pending,
1971 	.write_pending_status		= scsiback_write_pending_status,
1972 	.set_default_node_attributes	= scsiback_set_default_node_attrs,
1973 	.get_task_tag			= scsiback_get_task_tag,
1974 	.get_cmd_state			= scsiback_get_cmd_state,
1975 	.queue_data_in			= scsiback_queue_data_in,
1976 	.queue_status			= scsiback_queue_status,
1977 	.queue_tm_rsp			= scsiback_queue_tm_rsp,
1978 	.aborted_task			= scsiback_aborted_task,
1979 	/*
1980 	 * Setup callers for generic logic in target_core_fabric_configfs.c
1981 	 */
1982 	.fabric_make_wwn		= scsiback_make_tport,
1983 	.fabric_drop_wwn		= scsiback_drop_tport,
1984 	.fabric_make_tpg		= scsiback_make_tpg,
1985 	.fabric_drop_tpg		= scsiback_drop_tpg,
1986 	.fabric_post_link		= scsiback_port_link,
1987 	.fabric_pre_unlink		= scsiback_port_unlink,
1988 	.fabric_make_np			= NULL,
1989 	.fabric_drop_np			= NULL,
1990 #if 0
1991 	.fabric_make_nodeacl		= scsiback_make_nodeacl,
1992 	.fabric_drop_nodeacl		= scsiback_drop_nodeacl,
1993 #endif
1994 };
1995 
1996 static int scsiback_register_configfs(void)
1997 {
1998 	struct target_fabric_configfs *fabric;
1999 	int ret;
2000 
2001 	pr_debug("fabric module %s on %s/%s on "UTS_RELEASE"\n",
2002 		 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
2003 	/*
2004 	 * Register the top level struct config_item_type with TCM core
2005 	 */
2006 	fabric = target_fabric_configfs_init(THIS_MODULE, "xen-pvscsi");
2007 	if (IS_ERR(fabric))
2008 		return PTR_ERR(fabric);
2009 
2010 	/*
2011 	 * Setup fabric->tf_ops from our local scsiback_ops
2012 	 */
2013 	fabric->tf_ops = scsiback_ops;
2014 	/*
2015 	 * Setup default attribute lists for various fabric->tf_cit_tmpl
2016 	 */
2017 	fabric->tf_cit_tmpl.tfc_wwn_cit.ct_attrs = scsiback_wwn_attrs;
2018 	fabric->tf_cit_tmpl.tfc_tpg_base_cit.ct_attrs = scsiback_tpg_attrs;
2019 	fabric->tf_cit_tmpl.tfc_tpg_attrib_cit.ct_attrs = NULL;
2020 	fabric->tf_cit_tmpl.tfc_tpg_param_cit.ct_attrs = scsiback_param_attrs;
2021 	fabric->tf_cit_tmpl.tfc_tpg_np_base_cit.ct_attrs = NULL;
2022 	fabric->tf_cit_tmpl.tfc_tpg_nacl_base_cit.ct_attrs = NULL;
2023 	fabric->tf_cit_tmpl.tfc_tpg_nacl_attrib_cit.ct_attrs = NULL;
2024 	fabric->tf_cit_tmpl.tfc_tpg_nacl_auth_cit.ct_attrs = NULL;
2025 	fabric->tf_cit_tmpl.tfc_tpg_nacl_param_cit.ct_attrs = NULL;
2026 	/*
2027 	 * Register the fabric for use within TCM
2028 	 */
2029 	ret = target_fabric_configfs_register(fabric);
2030 	if (ret < 0) {
2031 		target_fabric_configfs_free(fabric);
2032 		return ret;
2033 	}
2034 	/*
2035 	 * Setup our local pointer to *fabric
2036 	 */
2037 	scsiback_fabric_configfs = fabric;
2038 	pr_debug("Set fabric -> scsiback_fabric_configfs\n");
2039 	return 0;
2040 };
2041 
2042 static void scsiback_deregister_configfs(void)
2043 {
2044 	if (!scsiback_fabric_configfs)
2045 		return;
2046 
2047 	target_fabric_configfs_deregister(scsiback_fabric_configfs);
2048 	scsiback_fabric_configfs = NULL;
2049 	pr_debug("Cleared scsiback_fabric_configfs\n");
2050 };
2051 
2052 static const struct xenbus_device_id scsiback_ids[] = {
2053 	{ "vscsi" },
2054 	{ "" }
2055 };
2056 
2057 static struct xenbus_driver scsiback_driver = {
2058 	.ids			= scsiback_ids,
2059 	.probe			= scsiback_probe,
2060 	.remove			= scsiback_remove,
2061 	.otherend_changed	= scsiback_frontend_changed
2062 };
2063 
2064 static void scsiback_init_pend(void *p)
2065 {
2066 	struct vscsibk_pend *pend = p;
2067 	int i;
2068 
2069 	memset(pend, 0, sizeof(*pend));
2070 	for (i = 0; i < VSCSI_MAX_GRANTS; i++)
2071 		pend->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
2072 }
2073 
2074 static int __init scsiback_init(void)
2075 {
2076 	int ret;
2077 
2078 	if (!xen_domain())
2079 		return -ENODEV;
2080 
2081 	scsiback_cachep = kmem_cache_create("vscsiif_cache",
2082 		sizeof(struct vscsibk_pend), 0, 0, scsiback_init_pend);
2083 	if (!scsiback_cachep)
2084 		return -ENOMEM;
2085 
2086 	ret = xenbus_register_backend(&scsiback_driver);
2087 	if (ret)
2088 		goto out_cache_destroy;
2089 
2090 	ret = scsiback_register_configfs();
2091 	if (ret)
2092 		goto out_unregister_xenbus;
2093 
2094 	return 0;
2095 
2096 out_unregister_xenbus:
2097 	xenbus_unregister_driver(&scsiback_driver);
2098 out_cache_destroy:
2099 	kmem_cache_destroy(scsiback_cachep);
2100 	pr_err("%s: error %d\n", __func__, ret);
2101 	return ret;
2102 }
2103 
2104 static void __exit scsiback_exit(void)
2105 {
2106 	struct page *page;
2107 
2108 	while (free_pages_num) {
2109 		if (get_free_page(&page))
2110 			BUG();
2111 		gnttab_free_pages(1, &page);
2112 	}
2113 	scsiback_deregister_configfs();
2114 	xenbus_unregister_driver(&scsiback_driver);
2115 	kmem_cache_destroy(scsiback_cachep);
2116 }
2117 
2118 module_init(scsiback_init);
2119 module_exit(scsiback_exit);
2120 
2121 MODULE_DESCRIPTION("Xen SCSI backend driver");
2122 MODULE_LICENSE("Dual BSD/GPL");
2123 MODULE_ALIAS("xen-backend:vscsi");
2124 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
2125