xref: /openbmc/linux/drivers/xen/xen-scsiback.c (revision 45471cd98decae5fced8b38e46c223f54a924814)
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_host.h> /* SG_ALL */
53 
54 #include <target/target_core_base.h>
55 #include <target/target_core_fabric.h>
56 #include <target/target_core_configfs.h>
57 #include <target/target_core_fabric_configfs.h>
58 
59 #include <asm/hypervisor.h>
60 
61 #include <xen/xen.h>
62 #include <xen/balloon.h>
63 #include <xen/events.h>
64 #include <xen/xenbus.h>
65 #include <xen/grant_table.h>
66 #include <xen/page.h>
67 
68 #include <xen/interface/grant_table.h>
69 #include <xen/interface/io/vscsiif.h>
70 
71 #define VSCSI_VERSION	"v0.1"
72 #define VSCSI_NAMELEN	32
73 
74 struct ids_tuple {
75 	unsigned int hst;		/* host    */
76 	unsigned int chn;		/* channel */
77 	unsigned int tgt;		/* target  */
78 	unsigned int lun;		/* LUN     */
79 };
80 
81 struct v2p_entry {
82 	struct ids_tuple v;		/* translate from */
83 	struct scsiback_tpg *tpg;	/* translate to   */
84 	unsigned int lun;
85 	struct kref kref;
86 	struct list_head l;
87 };
88 
89 struct vscsibk_info {
90 	struct xenbus_device *dev;
91 
92 	domid_t domid;
93 	unsigned int irq;
94 
95 	struct vscsiif_back_ring ring;
96 	int ring_error;
97 
98 	spinlock_t ring_lock;
99 	atomic_t nr_unreplied_reqs;
100 
101 	spinlock_t v2p_lock;
102 	struct list_head v2p_entry_lists;
103 
104 	wait_queue_head_t waiting_to_free;
105 };
106 
107 /* theoretical maximum of grants for one request */
108 #define VSCSI_MAX_GRANTS	(SG_ALL + VSCSIIF_SG_TABLESIZE)
109 
110 /*
111  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
112  * call to map/unmap grants. Don't choose it too large, as there are arrays
113  * with VSCSI_GRANT_BATCH elements allocated on the stack.
114  */
115 #define VSCSI_GRANT_BATCH	16
116 
117 struct vscsibk_pend {
118 	uint16_t rqid;
119 
120 	uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
121 	uint8_t cmd_len;
122 
123 	uint8_t sc_data_direction;
124 	uint16_t n_sg;		/* real length of SG list */
125 	uint16_t n_grants;	/* SG pages and potentially SG list */
126 	uint32_t data_len;
127 	uint32_t result;
128 
129 	struct vscsibk_info *info;
130 	struct v2p_entry *v2p;
131 	struct scatterlist *sgl;
132 
133 	uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
134 
135 	grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
136 	struct page *pages[VSCSI_MAX_GRANTS];
137 
138 	struct se_cmd se_cmd;
139 };
140 
141 struct scsiback_tmr {
142 	atomic_t tmr_complete;
143 	wait_queue_head_t tmr_wait;
144 };
145 
146 struct scsiback_nexus {
147 	/* Pointer to TCM session for I_T Nexus */
148 	struct se_session *tvn_se_sess;
149 };
150 
151 struct scsiback_tport {
152 	/* SCSI protocol the tport is providing */
153 	u8 tport_proto_id;
154 	/* Binary World Wide unique Port Name for pvscsi Target port */
155 	u64 tport_wwpn;
156 	/* ASCII formatted WWPN for pvscsi Target port */
157 	char tport_name[VSCSI_NAMELEN];
158 	/* Returned by scsiback_make_tport() */
159 	struct se_wwn tport_wwn;
160 };
161 
162 struct scsiback_tpg {
163 	/* scsiback port target portal group tag for TCM */
164 	u16 tport_tpgt;
165 	/* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
166 	int tv_tpg_port_count;
167 	/* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
168 	int tv_tpg_fe_count;
169 	/* list for scsiback_list */
170 	struct list_head tv_tpg_list;
171 	/* Used to protect access for tpg_nexus */
172 	struct mutex tv_tpg_mutex;
173 	/* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
174 	struct scsiback_nexus *tpg_nexus;
175 	/* Pointer back to scsiback_tport */
176 	struct scsiback_tport *tport;
177 	/* Returned by scsiback_make_tpg() */
178 	struct se_portal_group se_tpg;
179 	/* alias used in xenstore */
180 	char param_alias[VSCSI_NAMELEN];
181 	/* list of info structures related to this target portal group */
182 	struct list_head info_list;
183 };
184 
185 #define SCSIBACK_INVALID_HANDLE (~0)
186 
187 static bool log_print_stat;
188 module_param(log_print_stat, bool, 0644);
189 
190 static int scsiback_max_buffer_pages = 1024;
191 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
192 MODULE_PARM_DESC(max_buffer_pages,
193 "Maximum number of free pages to keep in backend buffer");
194 
195 static struct kmem_cache *scsiback_cachep;
196 static DEFINE_SPINLOCK(free_pages_lock);
197 static int free_pages_num;
198 static LIST_HEAD(scsiback_free_pages);
199 
200 /* Global spinlock to protect scsiback TPG list */
201 static DEFINE_MUTEX(scsiback_mutex);
202 static LIST_HEAD(scsiback_list);
203 
204 static const struct target_core_fabric_ops scsiback_ops;
205 
206 static void scsiback_get(struct vscsibk_info *info)
207 {
208 	atomic_inc(&info->nr_unreplied_reqs);
209 }
210 
211 static void scsiback_put(struct vscsibk_info *info)
212 {
213 	if (atomic_dec_and_test(&info->nr_unreplied_reqs))
214 		wake_up(&info->waiting_to_free);
215 }
216 
217 static void put_free_pages(struct page **page, int num)
218 {
219 	unsigned long flags;
220 	int i = free_pages_num + num, n = num;
221 
222 	if (num == 0)
223 		return;
224 	if (i > scsiback_max_buffer_pages) {
225 		n = min(num, i - scsiback_max_buffer_pages);
226 		gnttab_free_pages(n, page + num - n);
227 		n = num - n;
228 	}
229 	spin_lock_irqsave(&free_pages_lock, flags);
230 	for (i = 0; i < n; i++)
231 		list_add(&page[i]->lru, &scsiback_free_pages);
232 	free_pages_num += n;
233 	spin_unlock_irqrestore(&free_pages_lock, flags);
234 }
235 
236 static int get_free_page(struct page **page)
237 {
238 	unsigned long flags;
239 
240 	spin_lock_irqsave(&free_pages_lock, flags);
241 	if (list_empty(&scsiback_free_pages)) {
242 		spin_unlock_irqrestore(&free_pages_lock, flags);
243 		return gnttab_alloc_pages(1, page);
244 	}
245 	page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
246 	list_del(&page[0]->lru);
247 	free_pages_num--;
248 	spin_unlock_irqrestore(&free_pages_lock, flags);
249 	return 0;
250 }
251 
252 static unsigned long vaddr_page(struct page *page)
253 {
254 	unsigned long pfn = page_to_pfn(page);
255 
256 	return (unsigned long)pfn_to_kaddr(pfn);
257 }
258 
259 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
260 {
261 	return vaddr_page(req->pages[seg]);
262 }
263 
264 static void scsiback_print_status(char *sense_buffer, int errors,
265 					struct vscsibk_pend *pending_req)
266 {
267 	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
268 
269 	pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
270 	       tpg->tport->tport_name, pending_req->v2p->lun,
271 	       pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
272 	       host_byte(errors), driver_byte(errors));
273 }
274 
275 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
276 {
277 	struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
278 	struct page *pages[VSCSI_GRANT_BATCH];
279 	unsigned int i, invcount = 0;
280 	grant_handle_t handle;
281 	int err;
282 
283 	kfree(req->sgl);
284 	req->sgl = NULL;
285 	req->n_sg = 0;
286 
287 	if (!req->n_grants)
288 		return;
289 
290 	for (i = 0; i < req->n_grants; i++) {
291 		handle = req->grant_handles[i];
292 		if (handle == SCSIBACK_INVALID_HANDLE)
293 			continue;
294 		gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
295 				    GNTMAP_host_map, handle);
296 		req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
297 		pages[invcount] = req->pages[i];
298 		put_page(pages[invcount]);
299 		invcount++;
300 		if (invcount < VSCSI_GRANT_BATCH)
301 			continue;
302 		err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
303 		BUG_ON(err);
304 		invcount = 0;
305 	}
306 
307 	if (invcount) {
308 		err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
309 		BUG_ON(err);
310 	}
311 
312 	put_free_pages(req->pages, req->n_grants);
313 	req->n_grants = 0;
314 }
315 
316 static void scsiback_free_translation_entry(struct kref *kref)
317 {
318 	struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
319 	struct scsiback_tpg *tpg = entry->tpg;
320 
321 	mutex_lock(&tpg->tv_tpg_mutex);
322 	tpg->tv_tpg_fe_count--;
323 	mutex_unlock(&tpg->tv_tpg_mutex);
324 
325 	kfree(entry);
326 }
327 
328 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
329 			uint32_t resid, struct vscsibk_pend *pending_req)
330 {
331 	struct vscsiif_response *ring_res;
332 	struct vscsibk_info *info = pending_req->info;
333 	int notify;
334 	struct scsi_sense_hdr sshdr;
335 	unsigned long flags;
336 	unsigned len;
337 
338 	spin_lock_irqsave(&info->ring_lock, flags);
339 
340 	ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
341 	info->ring.rsp_prod_pvt++;
342 
343 	ring_res->rslt   = result;
344 	ring_res->rqid   = pending_req->rqid;
345 
346 	if (sense_buffer != NULL &&
347 	    scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
348 				 &sshdr)) {
349 		len = min_t(unsigned, 8 + sense_buffer[7],
350 			    VSCSIIF_SENSE_BUFFERSIZE);
351 		memcpy(ring_res->sense_buffer, sense_buffer, len);
352 		ring_res->sense_len = len;
353 	} else {
354 		ring_res->sense_len = 0;
355 	}
356 
357 	ring_res->residual_len = resid;
358 
359 	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
360 	spin_unlock_irqrestore(&info->ring_lock, flags);
361 
362 	if (notify)
363 		notify_remote_via_irq(info->irq);
364 
365 	if (pending_req->v2p)
366 		kref_put(&pending_req->v2p->kref,
367 			 scsiback_free_translation_entry);
368 }
369 
370 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
371 {
372 	struct vscsibk_info *info = pending_req->info;
373 	unsigned char *sense_buffer;
374 	unsigned int resid;
375 	int errors;
376 
377 	sense_buffer = pending_req->sense_buffer;
378 	resid        = pending_req->se_cmd.residual_count;
379 	errors       = pending_req->result;
380 
381 	if (errors && log_print_stat)
382 		scsiback_print_status(sense_buffer, errors, pending_req);
383 
384 	scsiback_fast_flush_area(pending_req);
385 	scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
386 	scsiback_put(info);
387 }
388 
389 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
390 {
391 	struct se_cmd *se_cmd = &pending_req->se_cmd;
392 	struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
393 	int rc;
394 
395 	memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
396 
397 	memset(se_cmd, 0, sizeof(*se_cmd));
398 
399 	scsiback_get(pending_req->info);
400 	rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
401 			pending_req->sense_buffer, pending_req->v2p->lun,
402 			pending_req->data_len, 0,
403 			pending_req->sc_data_direction, 0,
404 			pending_req->sgl, pending_req->n_sg,
405 			NULL, 0, NULL, 0);
406 	if (rc < 0) {
407 		transport_send_check_condition_and_sense(se_cmd,
408 				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
409 		transport_generic_free_cmd(se_cmd, 0);
410 	}
411 }
412 
413 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
414 	struct page **pg, grant_handle_t *grant, int cnt)
415 {
416 	int err, i;
417 
418 	if (!cnt)
419 		return 0;
420 
421 	err = gnttab_map_refs(map, NULL, pg, cnt);
422 	BUG_ON(err);
423 	for (i = 0; i < cnt; i++) {
424 		if (unlikely(map[i].status != GNTST_okay)) {
425 			pr_err("invalid buffer -- could not remap it\n");
426 			map[i].handle = SCSIBACK_INVALID_HANDLE;
427 			err = -ENOMEM;
428 		} else {
429 			get_page(pg[i]);
430 		}
431 		grant[i] = map[i].handle;
432 	}
433 	return err;
434 }
435 
436 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
437 			struct scsiif_request_segment *seg, struct page **pg,
438 			grant_handle_t *grant, int cnt, u32 flags)
439 {
440 	int mapcount = 0, i, err = 0;
441 	struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
442 	struct vscsibk_info *info = pending_req->info;
443 
444 	for (i = 0; i < cnt; i++) {
445 		if (get_free_page(pg + mapcount)) {
446 			put_free_pages(pg, mapcount);
447 			pr_err("no grant page\n");
448 			return -ENOMEM;
449 		}
450 		gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
451 				  flags, seg[i].gref, info->domid);
452 		mapcount++;
453 		if (mapcount < VSCSI_GRANT_BATCH)
454 			continue;
455 		err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
456 		pg += mapcount;
457 		grant += mapcount;
458 		pending_req->n_grants += mapcount;
459 		if (err)
460 			return err;
461 		mapcount = 0;
462 	}
463 	err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
464 	pending_req->n_grants += mapcount;
465 	return err;
466 }
467 
468 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
469 					struct vscsibk_pend *pending_req)
470 {
471 	u32 flags;
472 	int i, err, n_segs, i_seg = 0;
473 	struct page **pg;
474 	struct scsiif_request_segment *seg;
475 	unsigned long end_seg = 0;
476 	unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
477 	unsigned int nr_sgl = 0;
478 	struct scatterlist *sg;
479 	grant_handle_t *grant;
480 
481 	pending_req->n_sg = 0;
482 	pending_req->n_grants = 0;
483 	pending_req->data_len = 0;
484 
485 	nr_segments &= ~VSCSIIF_SG_GRANT;
486 	if (!nr_segments)
487 		return 0;
488 
489 	if (nr_segments > VSCSIIF_SG_TABLESIZE) {
490 		pr_debug("invalid parameter nr_seg = %d\n",
491 			ring_req->nr_segments);
492 		return -EINVAL;
493 	}
494 
495 	if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
496 		err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
497 			pending_req->pages, pending_req->grant_handles,
498 			nr_segments, GNTMAP_host_map | GNTMAP_readonly);
499 		if (err)
500 			return err;
501 		nr_sgl = nr_segments;
502 		nr_segments = 0;
503 		for (i = 0; i < nr_sgl; i++) {
504 			n_segs = ring_req->seg[i].length /
505 				 sizeof(struct scsiif_request_segment);
506 			if ((unsigned)ring_req->seg[i].offset +
507 			    (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
508 			    n_segs * sizeof(struct scsiif_request_segment) !=
509 			    ring_req->seg[i].length)
510 				return -EINVAL;
511 			nr_segments += n_segs;
512 		}
513 		if (nr_segments > SG_ALL) {
514 			pr_debug("invalid nr_seg = %d\n", nr_segments);
515 			return -EINVAL;
516 		}
517 	}
518 
519 	/* free of (sgl) in fast_flush_area() */
520 	pending_req->sgl = kmalloc_array(nr_segments,
521 					sizeof(struct scatterlist), GFP_KERNEL);
522 	if (!pending_req->sgl)
523 		return -ENOMEM;
524 
525 	sg_init_table(pending_req->sgl, nr_segments);
526 	pending_req->n_sg = nr_segments;
527 
528 	flags = GNTMAP_host_map;
529 	if (pending_req->sc_data_direction == DMA_TO_DEVICE)
530 		flags |= GNTMAP_readonly;
531 
532 	pg = pending_req->pages + nr_sgl;
533 	grant = pending_req->grant_handles + nr_sgl;
534 	if (!nr_sgl) {
535 		seg = ring_req->seg;
536 		err = scsiback_gnttab_data_map_list(pending_req, seg,
537 			pg, grant, nr_segments, flags);
538 		if (err)
539 			return err;
540 	} else {
541 		for (i = 0; i < nr_sgl; i++) {
542 			seg = (struct scsiif_request_segment *)(
543 			      vaddr(pending_req, i) + ring_req->seg[i].offset);
544 			n_segs = ring_req->seg[i].length /
545 				 sizeof(struct scsiif_request_segment);
546 			err = scsiback_gnttab_data_map_list(pending_req, seg,
547 				pg, grant, n_segs, flags);
548 			if (err)
549 				return err;
550 			pg += n_segs;
551 			grant += n_segs;
552 		}
553 		end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
554 		seg = (struct scsiif_request_segment *)end_seg;
555 		end_seg += ring_req->seg[0].length;
556 		pg = pending_req->pages + nr_sgl;
557 	}
558 
559 	for_each_sg(pending_req->sgl, sg, nr_segments, i) {
560 		sg_set_page(sg, pg[i], seg->length, seg->offset);
561 		pending_req->data_len += seg->length;
562 		seg++;
563 		if (nr_sgl && (unsigned long)seg >= end_seg) {
564 			i_seg++;
565 			end_seg = vaddr(pending_req, i_seg) +
566 				  ring_req->seg[i_seg].offset;
567 			seg = (struct scsiif_request_segment *)end_seg;
568 			end_seg += ring_req->seg[i_seg].length;
569 		}
570 		if (sg->offset >= PAGE_SIZE ||
571 		    sg->length > PAGE_SIZE ||
572 		    sg->offset + sg->length > PAGE_SIZE)
573 			return -EINVAL;
574 	}
575 
576 	return 0;
577 }
578 
579 static void scsiback_disconnect(struct vscsibk_info *info)
580 {
581 	wait_event(info->waiting_to_free,
582 		atomic_read(&info->nr_unreplied_reqs) == 0);
583 
584 	unbind_from_irqhandler(info->irq, info);
585 	info->irq = 0;
586 	xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
587 }
588 
589 static void scsiback_device_action(struct vscsibk_pend *pending_req,
590 	enum tcm_tmreq_table act, int tag)
591 {
592 	int rc, err = FAILED;
593 	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
594 	struct se_cmd *se_cmd = &pending_req->se_cmd;
595 	struct scsiback_tmr *tmr;
596 
597 	tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
598 	if (!tmr)
599 		goto out;
600 
601 	init_waitqueue_head(&tmr->tmr_wait);
602 
603 	transport_init_se_cmd(se_cmd, tpg->se_tpg.se_tpg_tfo,
604 		tpg->tpg_nexus->tvn_se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG,
605 		&pending_req->sense_buffer[0]);
606 
607 	rc = core_tmr_alloc_req(se_cmd, tmr, act, GFP_KERNEL);
608 	if (rc < 0)
609 		goto out;
610 
611 	se_cmd->se_tmr_req->ref_task_tag = tag;
612 
613 	if (transport_lookup_tmr_lun(se_cmd, pending_req->v2p->lun) < 0)
614 		goto out;
615 
616 	transport_generic_handle_tmr(se_cmd);
617 	wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));
618 
619 	err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
620 		SUCCESS : FAILED;
621 
622 out:
623 	if (tmr) {
624 		transport_generic_free_cmd(&pending_req->se_cmd, 1);
625 		kfree(tmr);
626 	}
627 
628 	scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
629 
630 	kmem_cache_free(scsiback_cachep, pending_req);
631 }
632 
633 /*
634   Perform virtual to physical translation
635 */
636 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
637 			struct ids_tuple *v)
638 {
639 	struct v2p_entry *entry;
640 	struct list_head *head = &(info->v2p_entry_lists);
641 	unsigned long flags;
642 
643 	spin_lock_irqsave(&info->v2p_lock, flags);
644 	list_for_each_entry(entry, head, l) {
645 		if ((entry->v.chn == v->chn) &&
646 		    (entry->v.tgt == v->tgt) &&
647 		    (entry->v.lun == v->lun)) {
648 			kref_get(&entry->kref);
649 			goto out;
650 		}
651 	}
652 	entry = NULL;
653 
654 out:
655 	spin_unlock_irqrestore(&info->v2p_lock, flags);
656 	return entry;
657 }
658 
659 static int prepare_pending_reqs(struct vscsibk_info *info,
660 				struct vscsiif_request *ring_req,
661 				struct vscsibk_pend *pending_req)
662 {
663 	struct v2p_entry *v2p;
664 	struct ids_tuple vir;
665 
666 	pending_req->rqid       = ring_req->rqid;
667 	pending_req->info       = info;
668 
669 	vir.chn = ring_req->channel;
670 	vir.tgt = ring_req->id;
671 	vir.lun = ring_req->lun;
672 
673 	v2p = scsiback_do_translation(info, &vir);
674 	if (!v2p) {
675 		pending_req->v2p = NULL;
676 		pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
677 			vir.chn, vir.tgt, vir.lun);
678 		return -ENODEV;
679 	}
680 	pending_req->v2p = v2p;
681 
682 	/* request range check from frontend */
683 	pending_req->sc_data_direction = ring_req->sc_data_direction;
684 	if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
685 		(pending_req->sc_data_direction != DMA_TO_DEVICE) &&
686 		(pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
687 		(pending_req->sc_data_direction != DMA_NONE)) {
688 		pr_debug("invalid parameter data_dir = %d\n",
689 			pending_req->sc_data_direction);
690 		return -EINVAL;
691 	}
692 
693 	pending_req->cmd_len = ring_req->cmd_len;
694 	if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
695 		pr_debug("invalid parameter cmd_len = %d\n",
696 			pending_req->cmd_len);
697 		return -EINVAL;
698 	}
699 	memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
700 
701 	return 0;
702 }
703 
704 static int scsiback_do_cmd_fn(struct vscsibk_info *info)
705 {
706 	struct vscsiif_back_ring *ring = &info->ring;
707 	struct vscsiif_request ring_req;
708 	struct vscsibk_pend *pending_req;
709 	RING_IDX rc, rp;
710 	int err, more_to_do;
711 	uint32_t result;
712 
713 	rc = ring->req_cons;
714 	rp = ring->sring->req_prod;
715 	rmb();	/* guest system is accessing ring, too */
716 
717 	if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
718 		rc = ring->rsp_prod_pvt;
719 		pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
720 			   info->domid, rp, rc, rp - rc);
721 		info->ring_error = 1;
722 		return 0;
723 	}
724 
725 	while ((rc != rp)) {
726 		if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
727 			break;
728 		pending_req = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
729 		if (!pending_req)
730 			return 1;
731 
732 		ring_req = *RING_GET_REQUEST(ring, rc);
733 		ring->req_cons = ++rc;
734 
735 		err = prepare_pending_reqs(info, &ring_req, pending_req);
736 		if (err) {
737 			switch (err) {
738 			case -ENODEV:
739 				result = DID_NO_CONNECT;
740 				break;
741 			default:
742 				result = DRIVER_ERROR;
743 				break;
744 			}
745 			scsiback_do_resp_with_sense(NULL, result << 24, 0,
746 						    pending_req);
747 			kmem_cache_free(scsiback_cachep, pending_req);
748 			return 1;
749 		}
750 
751 		switch (ring_req.act) {
752 		case VSCSIIF_ACT_SCSI_CDB:
753 			if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
754 				scsiback_fast_flush_area(pending_req);
755 				scsiback_do_resp_with_sense(NULL,
756 					DRIVER_ERROR << 24, 0, pending_req);
757 				kmem_cache_free(scsiback_cachep, pending_req);
758 			} else {
759 				scsiback_cmd_exec(pending_req);
760 			}
761 			break;
762 		case VSCSIIF_ACT_SCSI_ABORT:
763 			scsiback_device_action(pending_req, TMR_ABORT_TASK,
764 				ring_req.ref_rqid);
765 			break;
766 		case VSCSIIF_ACT_SCSI_RESET:
767 			scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
768 			break;
769 		default:
770 			pr_err_ratelimited("invalid request\n");
771 			scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
772 						    0, pending_req);
773 			kmem_cache_free(scsiback_cachep, pending_req);
774 			break;
775 		}
776 
777 		/* Yield point for this unbounded loop. */
778 		cond_resched();
779 	}
780 
781 	RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
782 	return more_to_do;
783 }
784 
785 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
786 {
787 	struct vscsibk_info *info = dev_id;
788 
789 	if (info->ring_error)
790 		return IRQ_HANDLED;
791 
792 	while (scsiback_do_cmd_fn(info))
793 		cond_resched();
794 
795 	return IRQ_HANDLED;
796 }
797 
798 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
799 			evtchn_port_t evtchn)
800 {
801 	void *area;
802 	struct vscsiif_sring *sring;
803 	int err;
804 
805 	if (info->irq)
806 		return -1;
807 
808 	err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
809 	if (err)
810 		return err;
811 
812 	sring = (struct vscsiif_sring *)area;
813 	BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
814 
815 	err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
816 	if (err < 0)
817 		goto unmap_page;
818 
819 	info->irq = err;
820 
821 	err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
822 				   IRQF_ONESHOT, "vscsiif-backend", info);
823 	if (err)
824 		goto free_irq;
825 
826 	return 0;
827 
828 free_irq:
829 	unbind_from_irqhandler(info->irq, info);
830 	info->irq = 0;
831 unmap_page:
832 	xenbus_unmap_ring_vfree(info->dev, area);
833 
834 	return err;
835 }
836 
837 static int scsiback_map(struct vscsibk_info *info)
838 {
839 	struct xenbus_device *dev = info->dev;
840 	unsigned int ring_ref, evtchn;
841 	int err;
842 
843 	err = xenbus_gather(XBT_NIL, dev->otherend,
844 			"ring-ref", "%u", &ring_ref,
845 			"event-channel", "%u", &evtchn, NULL);
846 	if (err) {
847 		xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
848 		return err;
849 	}
850 
851 	return scsiback_init_sring(info, ring_ref, evtchn);
852 }
853 
854 /*
855   Add a new translation entry
856 */
857 static int scsiback_add_translation_entry(struct vscsibk_info *info,
858 					  char *phy, struct ids_tuple *v)
859 {
860 	int err = 0;
861 	struct v2p_entry *entry;
862 	struct v2p_entry *new;
863 	struct list_head *head = &(info->v2p_entry_lists);
864 	unsigned long flags;
865 	char *lunp;
866 	unsigned int lun;
867 	struct scsiback_tpg *tpg_entry, *tpg = NULL;
868 	char *error = "doesn't exist";
869 
870 	lunp = strrchr(phy, ':');
871 	if (!lunp) {
872 		pr_err("illegal format of physical device %s\n", phy);
873 		return -EINVAL;
874 	}
875 	*lunp = 0;
876 	lunp++;
877 	if (kstrtouint(lunp, 10, &lun) || lun >= TRANSPORT_MAX_LUNS_PER_TPG) {
878 		pr_err("lun number not valid: %s\n", lunp);
879 		return -EINVAL;
880 	}
881 
882 	mutex_lock(&scsiback_mutex);
883 	list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
884 		if (!strcmp(phy, tpg_entry->tport->tport_name) ||
885 		    !strcmp(phy, tpg_entry->param_alias)) {
886 			spin_lock(&tpg_entry->se_tpg.tpg_lun_lock);
887 			if (tpg_entry->se_tpg.tpg_lun_list[lun]->lun_status ==
888 			    TRANSPORT_LUN_STATUS_ACTIVE) {
889 				if (!tpg_entry->tpg_nexus)
890 					error = "nexus undefined";
891 				else
892 					tpg = tpg_entry;
893 			}
894 			spin_unlock(&tpg_entry->se_tpg.tpg_lun_lock);
895 			break;
896 		}
897 	}
898 	if (tpg) {
899 		mutex_lock(&tpg->tv_tpg_mutex);
900 		tpg->tv_tpg_fe_count++;
901 		mutex_unlock(&tpg->tv_tpg_mutex);
902 	}
903 	mutex_unlock(&scsiback_mutex);
904 
905 	if (!tpg) {
906 		pr_err("%s:%d %s\n", phy, lun, error);
907 		return -ENODEV;
908 	}
909 
910 	new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
911 	if (new == NULL) {
912 		err = -ENOMEM;
913 		goto out_free;
914 	}
915 
916 	spin_lock_irqsave(&info->v2p_lock, flags);
917 
918 	/* Check double assignment to identical virtual ID */
919 	list_for_each_entry(entry, head, l) {
920 		if ((entry->v.chn == v->chn) &&
921 		    (entry->v.tgt == v->tgt) &&
922 		    (entry->v.lun == v->lun)) {
923 			pr_warn("Virtual ID is already used. Assignment was not performed.\n");
924 			err = -EEXIST;
925 			goto out;
926 		}
927 
928 	}
929 
930 	/* Create a new translation entry and add to the list */
931 	kref_init(&new->kref);
932 	new->v = *v;
933 	new->tpg = tpg;
934 	new->lun = lun;
935 	list_add_tail(&new->l, head);
936 
937 out:
938 	spin_unlock_irqrestore(&info->v2p_lock, flags);
939 
940 out_free:
941 	mutex_lock(&tpg->tv_tpg_mutex);
942 	tpg->tv_tpg_fe_count--;
943 	mutex_unlock(&tpg->tv_tpg_mutex);
944 
945 	if (err)
946 		kfree(new);
947 
948 	return err;
949 }
950 
951 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
952 {
953 	list_del(&entry->l);
954 	kref_put(&entry->kref, scsiback_free_translation_entry);
955 }
956 
957 /*
958   Delete the translation entry specfied
959 */
960 static int scsiback_del_translation_entry(struct vscsibk_info *info,
961 					  struct ids_tuple *v)
962 {
963 	struct v2p_entry *entry;
964 	struct list_head *head = &(info->v2p_entry_lists);
965 	unsigned long flags;
966 
967 	spin_lock_irqsave(&info->v2p_lock, flags);
968 	/* Find out the translation entry specified */
969 	list_for_each_entry(entry, head, l) {
970 		if ((entry->v.chn == v->chn) &&
971 		    (entry->v.tgt == v->tgt) &&
972 		    (entry->v.lun == v->lun)) {
973 			goto found;
974 		}
975 	}
976 
977 	spin_unlock_irqrestore(&info->v2p_lock, flags);
978 	return 1;
979 
980 found:
981 	/* Delete the translation entry specfied */
982 	__scsiback_del_translation_entry(entry);
983 
984 	spin_unlock_irqrestore(&info->v2p_lock, flags);
985 	return 0;
986 }
987 
988 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
989 				char *phy, struct ids_tuple *vir, int try)
990 {
991 	if (!scsiback_add_translation_entry(info, phy, vir)) {
992 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
993 				  "%d", XenbusStateInitialised)) {
994 			pr_err("xenbus_printf error %s\n", state);
995 			scsiback_del_translation_entry(info, vir);
996 		}
997 	} else if (!try) {
998 		xenbus_printf(XBT_NIL, info->dev->nodename, state,
999 			      "%d", XenbusStateClosed);
1000 	}
1001 }
1002 
1003 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1004 				struct ids_tuple *vir)
1005 {
1006 	if (!scsiback_del_translation_entry(info, vir)) {
1007 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1008 				  "%d", XenbusStateClosed))
1009 			pr_err("xenbus_printf error %s\n", state);
1010 	}
1011 }
1012 
1013 #define VSCSIBACK_OP_ADD_OR_DEL_LUN	1
1014 #define VSCSIBACK_OP_UPDATEDEV_STATE	2
1015 
1016 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1017 				     char *ent)
1018 {
1019 	int err;
1020 	struct ids_tuple vir;
1021 	char *val;
1022 	int device_state;
1023 	char phy[VSCSI_NAMELEN];
1024 	char str[64];
1025 	char state[64];
1026 	struct xenbus_device *dev = info->dev;
1027 
1028 	/* read status */
1029 	snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1030 	err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1031 	if (XENBUS_EXIST_ERR(err))
1032 		return;
1033 
1034 	/* physical SCSI device */
1035 	snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1036 	val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1037 	if (IS_ERR(val)) {
1038 		xenbus_printf(XBT_NIL, dev->nodename, state,
1039 			      "%d", XenbusStateClosed);
1040 		return;
1041 	}
1042 	strlcpy(phy, val, VSCSI_NAMELEN);
1043 	kfree(val);
1044 
1045 	/* virtual SCSI device */
1046 	snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1047 	err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1048 			   &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1049 	if (XENBUS_EXIST_ERR(err)) {
1050 		xenbus_printf(XBT_NIL, dev->nodename, state,
1051 			      "%d", XenbusStateClosed);
1052 		return;
1053 	}
1054 
1055 	switch (op) {
1056 	case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1057 		switch (device_state) {
1058 		case XenbusStateInitialising:
1059 			scsiback_do_add_lun(info, state, phy, &vir, 0);
1060 			break;
1061 		case XenbusStateConnected:
1062 			scsiback_do_add_lun(info, state, phy, &vir, 1);
1063 			break;
1064 		case XenbusStateClosing:
1065 			scsiback_do_del_lun(info, state, &vir);
1066 			break;
1067 		default:
1068 			break;
1069 		}
1070 		break;
1071 
1072 	case VSCSIBACK_OP_UPDATEDEV_STATE:
1073 		if (device_state == XenbusStateInitialised) {
1074 			/* modify vscsi-devs/dev-x/state */
1075 			if (xenbus_printf(XBT_NIL, dev->nodename, state,
1076 					  "%d", XenbusStateConnected)) {
1077 				pr_err("xenbus_printf error %s\n", str);
1078 				scsiback_del_translation_entry(info, &vir);
1079 				xenbus_printf(XBT_NIL, dev->nodename, state,
1080 					      "%d", XenbusStateClosed);
1081 			}
1082 		}
1083 		break;
1084 	/* When it is necessary, processing is added here. */
1085 	default:
1086 		break;
1087 	}
1088 }
1089 
1090 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1091 {
1092 	int i;
1093 	char **dir;
1094 	unsigned int ndir = 0;
1095 
1096 	dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1097 			       &ndir);
1098 	if (IS_ERR(dir))
1099 		return;
1100 
1101 	for (i = 0; i < ndir; i++)
1102 		scsiback_do_1lun_hotplug(info, op, dir[i]);
1103 
1104 	kfree(dir);
1105 }
1106 
1107 static void scsiback_frontend_changed(struct xenbus_device *dev,
1108 					enum xenbus_state frontend_state)
1109 {
1110 	struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1111 
1112 	switch (frontend_state) {
1113 	case XenbusStateInitialising:
1114 		break;
1115 
1116 	case XenbusStateInitialised:
1117 		if (scsiback_map(info))
1118 			break;
1119 
1120 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1121 		xenbus_switch_state(dev, XenbusStateConnected);
1122 		break;
1123 
1124 	case XenbusStateConnected:
1125 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1126 
1127 		if (dev->state == XenbusStateConnected)
1128 			break;
1129 
1130 		xenbus_switch_state(dev, XenbusStateConnected);
1131 		break;
1132 
1133 	case XenbusStateClosing:
1134 		if (info->irq)
1135 			scsiback_disconnect(info);
1136 
1137 		xenbus_switch_state(dev, XenbusStateClosing);
1138 		break;
1139 
1140 	case XenbusStateClosed:
1141 		xenbus_switch_state(dev, XenbusStateClosed);
1142 		if (xenbus_dev_is_online(dev))
1143 			break;
1144 		/* fall through if not online */
1145 	case XenbusStateUnknown:
1146 		device_unregister(&dev->dev);
1147 		break;
1148 
1149 	case XenbusStateReconfiguring:
1150 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1151 		xenbus_switch_state(dev, XenbusStateReconfigured);
1152 
1153 		break;
1154 
1155 	default:
1156 		xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1157 					frontend_state);
1158 		break;
1159 	}
1160 }
1161 
1162 /*
1163   Release the translation entry specfied
1164 */
1165 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1166 {
1167 	struct v2p_entry *entry, *tmp;
1168 	struct list_head *head = &(info->v2p_entry_lists);
1169 	unsigned long flags;
1170 
1171 	spin_lock_irqsave(&info->v2p_lock, flags);
1172 
1173 	list_for_each_entry_safe(entry, tmp, head, l)
1174 		__scsiback_del_translation_entry(entry);
1175 
1176 	spin_unlock_irqrestore(&info->v2p_lock, flags);
1177 }
1178 
1179 static int scsiback_remove(struct xenbus_device *dev)
1180 {
1181 	struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1182 
1183 	if (info->irq)
1184 		scsiback_disconnect(info);
1185 
1186 	scsiback_release_translation_entry(info);
1187 
1188 	dev_set_drvdata(&dev->dev, NULL);
1189 
1190 	return 0;
1191 }
1192 
1193 static int scsiback_probe(struct xenbus_device *dev,
1194 			   const struct xenbus_device_id *id)
1195 {
1196 	int err;
1197 
1198 	struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1199 					    GFP_KERNEL);
1200 
1201 	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1202 
1203 	if (!info) {
1204 		xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1205 		return -ENOMEM;
1206 	}
1207 	info->dev = dev;
1208 	dev_set_drvdata(&dev->dev, info);
1209 
1210 	info->domid = dev->otherend_id;
1211 	spin_lock_init(&info->ring_lock);
1212 	info->ring_error = 0;
1213 	atomic_set(&info->nr_unreplied_reqs, 0);
1214 	init_waitqueue_head(&info->waiting_to_free);
1215 	info->dev = dev;
1216 	info->irq = 0;
1217 	INIT_LIST_HEAD(&info->v2p_entry_lists);
1218 	spin_lock_init(&info->v2p_lock);
1219 
1220 	err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1221 			    SG_ALL);
1222 	if (err)
1223 		xenbus_dev_error(dev, err, "writing feature-sg-grant");
1224 
1225 	err = xenbus_switch_state(dev, XenbusStateInitWait);
1226 	if (err)
1227 		goto fail;
1228 
1229 	return 0;
1230 
1231 fail:
1232 	pr_warn("%s failed\n", __func__);
1233 	scsiback_remove(dev);
1234 
1235 	return err;
1236 }
1237 
1238 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1239 {
1240 	switch (tport->tport_proto_id) {
1241 	case SCSI_PROTOCOL_SAS:
1242 		return "SAS";
1243 	case SCSI_PROTOCOL_FCP:
1244 		return "FCP";
1245 	case SCSI_PROTOCOL_ISCSI:
1246 		return "iSCSI";
1247 	default:
1248 		break;
1249 	}
1250 
1251 	return "Unknown";
1252 }
1253 
1254 static u8 scsiback_get_fabric_proto_ident(struct se_portal_group *se_tpg)
1255 {
1256 	struct scsiback_tpg *tpg = container_of(se_tpg,
1257 				struct scsiback_tpg, se_tpg);
1258 	struct scsiback_tport *tport = tpg->tport;
1259 
1260 	switch (tport->tport_proto_id) {
1261 	case SCSI_PROTOCOL_SAS:
1262 		return sas_get_fabric_proto_ident(se_tpg);
1263 	case SCSI_PROTOCOL_FCP:
1264 		return fc_get_fabric_proto_ident(se_tpg);
1265 	case SCSI_PROTOCOL_ISCSI:
1266 		return iscsi_get_fabric_proto_ident(se_tpg);
1267 	default:
1268 		pr_err("Unknown tport_proto_id: 0x%02x, using SAS emulation\n",
1269 			tport->tport_proto_id);
1270 		break;
1271 	}
1272 
1273 	return sas_get_fabric_proto_ident(se_tpg);
1274 }
1275 
1276 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1277 {
1278 	struct scsiback_tpg *tpg = container_of(se_tpg,
1279 				struct scsiback_tpg, se_tpg);
1280 	struct scsiback_tport *tport = tpg->tport;
1281 
1282 	return &tport->tport_name[0];
1283 }
1284 
1285 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1286 {
1287 	struct scsiback_tpg *tpg = container_of(se_tpg,
1288 				struct scsiback_tpg, se_tpg);
1289 	return tpg->tport_tpgt;
1290 }
1291 
1292 static u32 scsiback_get_default_depth(struct se_portal_group *se_tpg)
1293 {
1294 	return 1;
1295 }
1296 
1297 static u32
1298 scsiback_get_pr_transport_id(struct se_portal_group *se_tpg,
1299 			      struct se_node_acl *se_nacl,
1300 			      struct t10_pr_registration *pr_reg,
1301 			      int *format_code,
1302 			      unsigned char *buf)
1303 {
1304 	struct scsiback_tpg *tpg = container_of(se_tpg,
1305 				struct scsiback_tpg, se_tpg);
1306 	struct scsiback_tport *tport = tpg->tport;
1307 
1308 	switch (tport->tport_proto_id) {
1309 	case SCSI_PROTOCOL_SAS:
1310 		return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
1311 					format_code, buf);
1312 	case SCSI_PROTOCOL_FCP:
1313 		return fc_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
1314 					format_code, buf);
1315 	case SCSI_PROTOCOL_ISCSI:
1316 		return iscsi_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
1317 					format_code, buf);
1318 	default:
1319 		pr_err("Unknown tport_proto_id: 0x%02x, using SAS emulation\n",
1320 			tport->tport_proto_id);
1321 		break;
1322 	}
1323 
1324 	return sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
1325 			format_code, buf);
1326 }
1327 
1328 static u32
1329 scsiback_get_pr_transport_id_len(struct se_portal_group *se_tpg,
1330 				  struct se_node_acl *se_nacl,
1331 				  struct t10_pr_registration *pr_reg,
1332 				  int *format_code)
1333 {
1334 	struct scsiback_tpg *tpg = container_of(se_tpg,
1335 				struct scsiback_tpg, se_tpg);
1336 	struct scsiback_tport *tport = tpg->tport;
1337 
1338 	switch (tport->tport_proto_id) {
1339 	case SCSI_PROTOCOL_SAS:
1340 		return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
1341 					format_code);
1342 	case SCSI_PROTOCOL_FCP:
1343 		return fc_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
1344 					format_code);
1345 	case SCSI_PROTOCOL_ISCSI:
1346 		return iscsi_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
1347 					format_code);
1348 	default:
1349 		pr_err("Unknown tport_proto_id: 0x%02x, using SAS emulation\n",
1350 			tport->tport_proto_id);
1351 		break;
1352 	}
1353 
1354 	return sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
1355 			format_code);
1356 }
1357 
1358 static char *
1359 scsiback_parse_pr_out_transport_id(struct se_portal_group *se_tpg,
1360 				    const char *buf,
1361 				    u32 *out_tid_len,
1362 				    char **port_nexus_ptr)
1363 {
1364 	struct scsiback_tpg *tpg = container_of(se_tpg,
1365 				struct scsiback_tpg, se_tpg);
1366 	struct scsiback_tport *tport = tpg->tport;
1367 
1368 	switch (tport->tport_proto_id) {
1369 	case SCSI_PROTOCOL_SAS:
1370 		return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
1371 					port_nexus_ptr);
1372 	case SCSI_PROTOCOL_FCP:
1373 		return fc_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
1374 					port_nexus_ptr);
1375 	case SCSI_PROTOCOL_ISCSI:
1376 		return iscsi_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
1377 					port_nexus_ptr);
1378 	default:
1379 		pr_err("Unknown tport_proto_id: 0x%02x, using SAS emulation\n",
1380 			tport->tport_proto_id);
1381 		break;
1382 	}
1383 
1384 	return sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
1385 			port_nexus_ptr);
1386 }
1387 
1388 static struct se_wwn *
1389 scsiback_make_tport(struct target_fabric_configfs *tf,
1390 		     struct config_group *group,
1391 		     const char *name)
1392 {
1393 	struct scsiback_tport *tport;
1394 	char *ptr;
1395 	u64 wwpn = 0;
1396 	int off = 0;
1397 
1398 	tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1399 	if (!tport)
1400 		return ERR_PTR(-ENOMEM);
1401 
1402 	tport->tport_wwpn = wwpn;
1403 	/*
1404 	 * Determine the emulated Protocol Identifier and Target Port Name
1405 	 * based on the incoming configfs directory name.
1406 	 */
1407 	ptr = strstr(name, "naa.");
1408 	if (ptr) {
1409 		tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1410 		goto check_len;
1411 	}
1412 	ptr = strstr(name, "fc.");
1413 	if (ptr) {
1414 		tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1415 		off = 3; /* Skip over "fc." */
1416 		goto check_len;
1417 	}
1418 	ptr = strstr(name, "iqn.");
1419 	if (ptr) {
1420 		tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1421 		goto check_len;
1422 	}
1423 
1424 	pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1425 	kfree(tport);
1426 	return ERR_PTR(-EINVAL);
1427 
1428 check_len:
1429 	if (strlen(name) >= VSCSI_NAMELEN) {
1430 		pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1431 			scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1432 		kfree(tport);
1433 		return ERR_PTR(-EINVAL);
1434 	}
1435 	snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1436 
1437 	pr_debug("Allocated emulated Target %s Address: %s\n",
1438 		 scsiback_dump_proto_id(tport), name);
1439 
1440 	return &tport->tport_wwn;
1441 }
1442 
1443 static void scsiback_drop_tport(struct se_wwn *wwn)
1444 {
1445 	struct scsiback_tport *tport = container_of(wwn,
1446 				struct scsiback_tport, tport_wwn);
1447 
1448 	pr_debug("Deallocating emulated Target %s Address: %s\n",
1449 		 scsiback_dump_proto_id(tport), tport->tport_name);
1450 
1451 	kfree(tport);
1452 }
1453 
1454 static struct se_node_acl *
1455 scsiback_alloc_fabric_acl(struct se_portal_group *se_tpg)
1456 {
1457 	return kzalloc(sizeof(struct se_node_acl), GFP_KERNEL);
1458 }
1459 
1460 static void
1461 scsiback_release_fabric_acl(struct se_portal_group *se_tpg,
1462 			     struct se_node_acl *se_nacl)
1463 {
1464 	kfree(se_nacl);
1465 }
1466 
1467 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1468 {
1469 	return 1;
1470 }
1471 
1472 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1473 {
1474 	/*
1475 	 * Do not release struct se_cmd's containing a valid TMR pointer.
1476 	 * These will be released directly in scsiback_device_action()
1477 	 * with transport_generic_free_cmd().
1478 	 */
1479 	if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1480 		return 0;
1481 
1482 	transport_generic_free_cmd(se_cmd, 0);
1483 	return 1;
1484 }
1485 
1486 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1487 {
1488 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1489 				struct vscsibk_pend, se_cmd);
1490 
1491 	kmem_cache_free(scsiback_cachep, pending_req);
1492 }
1493 
1494 static int scsiback_shutdown_session(struct se_session *se_sess)
1495 {
1496 	return 0;
1497 }
1498 
1499 static void scsiback_close_session(struct se_session *se_sess)
1500 {
1501 }
1502 
1503 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1504 {
1505 	return 0;
1506 }
1507 
1508 static int scsiback_write_pending(struct se_cmd *se_cmd)
1509 {
1510 	/* Go ahead and process the write immediately */
1511 	target_execute_cmd(se_cmd);
1512 
1513 	return 0;
1514 }
1515 
1516 static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1517 {
1518 	return 0;
1519 }
1520 
1521 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1522 {
1523 }
1524 
1525 static u32 scsiback_get_task_tag(struct se_cmd *se_cmd)
1526 {
1527 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1528 				struct vscsibk_pend, se_cmd);
1529 
1530 	return pending_req->rqid;
1531 }
1532 
1533 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1534 {
1535 	return 0;
1536 }
1537 
1538 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1539 {
1540 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1541 				struct vscsibk_pend, se_cmd);
1542 
1543 	pending_req->result = SAM_STAT_GOOD;
1544 	scsiback_cmd_done(pending_req);
1545 	return 0;
1546 }
1547 
1548 static int scsiback_queue_status(struct se_cmd *se_cmd)
1549 {
1550 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1551 				struct vscsibk_pend, se_cmd);
1552 
1553 	if (se_cmd->sense_buffer &&
1554 	    ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1555 	     (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1556 		pending_req->result = (DRIVER_SENSE << 24) |
1557 				      SAM_STAT_CHECK_CONDITION;
1558 	else
1559 		pending_req->result = se_cmd->scsi_status;
1560 
1561 	scsiback_cmd_done(pending_req);
1562 	return 0;
1563 }
1564 
1565 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1566 {
1567 	struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1568 	struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1569 
1570 	atomic_set(&tmr->tmr_complete, 1);
1571 	wake_up(&tmr->tmr_wait);
1572 }
1573 
1574 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1575 {
1576 }
1577 
1578 static ssize_t scsiback_tpg_param_show_alias(struct se_portal_group *se_tpg,
1579 					     char *page)
1580 {
1581 	struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1582 						se_tpg);
1583 	ssize_t rb;
1584 
1585 	mutex_lock(&tpg->tv_tpg_mutex);
1586 	rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1587 	mutex_unlock(&tpg->tv_tpg_mutex);
1588 
1589 	return rb;
1590 }
1591 
1592 static ssize_t scsiback_tpg_param_store_alias(struct se_portal_group *se_tpg,
1593 					      const char *page, size_t count)
1594 {
1595 	struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1596 						se_tpg);
1597 	int len;
1598 
1599 	if (strlen(page) >= VSCSI_NAMELEN) {
1600 		pr_err("param alias: %s, exceeds max: %d\n", page,
1601 			VSCSI_NAMELEN);
1602 		return -EINVAL;
1603 	}
1604 
1605 	mutex_lock(&tpg->tv_tpg_mutex);
1606 	len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1607 	if (tpg->param_alias[len - 1] == '\n')
1608 		tpg->param_alias[len - 1] = '\0';
1609 	mutex_unlock(&tpg->tv_tpg_mutex);
1610 
1611 	return count;
1612 }
1613 
1614 TF_TPG_PARAM_ATTR(scsiback, alias, S_IRUGO | S_IWUSR);
1615 
1616 static struct configfs_attribute *scsiback_param_attrs[] = {
1617 	&scsiback_tpg_param_alias.attr,
1618 	NULL,
1619 };
1620 
1621 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1622 				const char *name)
1623 {
1624 	struct se_portal_group *se_tpg;
1625 	struct se_session *se_sess;
1626 	struct scsiback_nexus *tv_nexus;
1627 
1628 	mutex_lock(&tpg->tv_tpg_mutex);
1629 	if (tpg->tpg_nexus) {
1630 		mutex_unlock(&tpg->tv_tpg_mutex);
1631 		pr_debug("tpg->tpg_nexus already exists\n");
1632 		return -EEXIST;
1633 	}
1634 	se_tpg = &tpg->se_tpg;
1635 
1636 	tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1637 	if (!tv_nexus) {
1638 		mutex_unlock(&tpg->tv_tpg_mutex);
1639 		return -ENOMEM;
1640 	}
1641 	/*
1642 	 * Initialize the struct se_session pointer
1643 	 */
1644 	tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
1645 	if (IS_ERR(tv_nexus->tvn_se_sess)) {
1646 		mutex_unlock(&tpg->tv_tpg_mutex);
1647 		kfree(tv_nexus);
1648 		return -ENOMEM;
1649 	}
1650 	se_sess = tv_nexus->tvn_se_sess;
1651 	/*
1652 	 * Since we are running in 'demo mode' this call with generate a
1653 	 * struct se_node_acl for the scsiback struct se_portal_group with
1654 	 * the SCSI Initiator port name of the passed configfs group 'name'.
1655 	 */
1656 	tv_nexus->tvn_se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1657 				se_tpg, (unsigned char *)name);
1658 	if (!tv_nexus->tvn_se_sess->se_node_acl) {
1659 		mutex_unlock(&tpg->tv_tpg_mutex);
1660 		pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
1661 			 name);
1662 		goto out;
1663 	}
1664 	/* Now register the TCM pvscsi virtual I_T Nexus as active. */
1665 	transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
1666 			tv_nexus->tvn_se_sess, tv_nexus);
1667 	tpg->tpg_nexus = tv_nexus;
1668 
1669 	mutex_unlock(&tpg->tv_tpg_mutex);
1670 	return 0;
1671 
1672 out:
1673 	transport_free_session(se_sess);
1674 	kfree(tv_nexus);
1675 	return -ENOMEM;
1676 }
1677 
1678 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1679 {
1680 	struct se_session *se_sess;
1681 	struct scsiback_nexus *tv_nexus;
1682 
1683 	mutex_lock(&tpg->tv_tpg_mutex);
1684 	tv_nexus = tpg->tpg_nexus;
1685 	if (!tv_nexus) {
1686 		mutex_unlock(&tpg->tv_tpg_mutex);
1687 		return -ENODEV;
1688 	}
1689 
1690 	se_sess = tv_nexus->tvn_se_sess;
1691 	if (!se_sess) {
1692 		mutex_unlock(&tpg->tv_tpg_mutex);
1693 		return -ENODEV;
1694 	}
1695 
1696 	if (tpg->tv_tpg_port_count != 0) {
1697 		mutex_unlock(&tpg->tv_tpg_mutex);
1698 		pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1699 			tpg->tv_tpg_port_count);
1700 		return -EBUSY;
1701 	}
1702 
1703 	if (tpg->tv_tpg_fe_count != 0) {
1704 		mutex_unlock(&tpg->tv_tpg_mutex);
1705 		pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1706 			tpg->tv_tpg_fe_count);
1707 		return -EBUSY;
1708 	}
1709 
1710 	pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1711 		scsiback_dump_proto_id(tpg->tport),
1712 		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1713 
1714 	/*
1715 	 * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1716 	 */
1717 	transport_deregister_session(tv_nexus->tvn_se_sess);
1718 	tpg->tpg_nexus = NULL;
1719 	mutex_unlock(&tpg->tv_tpg_mutex);
1720 
1721 	kfree(tv_nexus);
1722 	return 0;
1723 }
1724 
1725 static ssize_t scsiback_tpg_show_nexus(struct se_portal_group *se_tpg,
1726 					char *page)
1727 {
1728 	struct scsiback_tpg *tpg = container_of(se_tpg,
1729 				struct scsiback_tpg, se_tpg);
1730 	struct scsiback_nexus *tv_nexus;
1731 	ssize_t ret;
1732 
1733 	mutex_lock(&tpg->tv_tpg_mutex);
1734 	tv_nexus = tpg->tpg_nexus;
1735 	if (!tv_nexus) {
1736 		mutex_unlock(&tpg->tv_tpg_mutex);
1737 		return -ENODEV;
1738 	}
1739 	ret = snprintf(page, PAGE_SIZE, "%s\n",
1740 			tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1741 	mutex_unlock(&tpg->tv_tpg_mutex);
1742 
1743 	return ret;
1744 }
1745 
1746 static ssize_t scsiback_tpg_store_nexus(struct se_portal_group *se_tpg,
1747 					 const char *page,
1748 					 size_t count)
1749 {
1750 	struct scsiback_tpg *tpg = container_of(se_tpg,
1751 				struct scsiback_tpg, se_tpg);
1752 	struct scsiback_tport *tport_wwn = tpg->tport;
1753 	unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1754 	int ret;
1755 	/*
1756 	 * Shutdown the active I_T nexus if 'NULL' is passed.
1757 	 */
1758 	if (!strncmp(page, "NULL", 4)) {
1759 		ret = scsiback_drop_nexus(tpg);
1760 		return (!ret) ? count : ret;
1761 	}
1762 	/*
1763 	 * Otherwise make sure the passed virtual Initiator port WWN matches
1764 	 * the fabric protocol_id set in scsiback_make_tport(), and call
1765 	 * scsiback_make_nexus().
1766 	 */
1767 	if (strlen(page) >= VSCSI_NAMELEN) {
1768 		pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1769 			page, VSCSI_NAMELEN);
1770 		return -EINVAL;
1771 	}
1772 	snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1773 
1774 	ptr = strstr(i_port, "naa.");
1775 	if (ptr) {
1776 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1777 			pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1778 				i_port, scsiback_dump_proto_id(tport_wwn));
1779 			return -EINVAL;
1780 		}
1781 		port_ptr = &i_port[0];
1782 		goto check_newline;
1783 	}
1784 	ptr = strstr(i_port, "fc.");
1785 	if (ptr) {
1786 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1787 			pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1788 				i_port, scsiback_dump_proto_id(tport_wwn));
1789 			return -EINVAL;
1790 		}
1791 		port_ptr = &i_port[3]; /* Skip over "fc." */
1792 		goto check_newline;
1793 	}
1794 	ptr = strstr(i_port, "iqn.");
1795 	if (ptr) {
1796 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1797 			pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1798 				i_port, scsiback_dump_proto_id(tport_wwn));
1799 			return -EINVAL;
1800 		}
1801 		port_ptr = &i_port[0];
1802 		goto check_newline;
1803 	}
1804 	pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1805 		i_port);
1806 	return -EINVAL;
1807 	/*
1808 	 * Clear any trailing newline for the NAA WWN
1809 	 */
1810 check_newline:
1811 	if (i_port[strlen(i_port) - 1] == '\n')
1812 		i_port[strlen(i_port) - 1] = '\0';
1813 
1814 	ret = scsiback_make_nexus(tpg, port_ptr);
1815 	if (ret < 0)
1816 		return ret;
1817 
1818 	return count;
1819 }
1820 
1821 TF_TPG_BASE_ATTR(scsiback, nexus, S_IRUGO | S_IWUSR);
1822 
1823 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1824 	&scsiback_tpg_nexus.attr,
1825 	NULL,
1826 };
1827 
1828 static ssize_t
1829 scsiback_wwn_show_attr_version(struct target_fabric_configfs *tf,
1830 				char *page)
1831 {
1832 	return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1833 		UTS_RELEASE"\n",
1834 		VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1835 }
1836 
1837 TF_WWN_ATTR_RO(scsiback, version);
1838 
1839 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1840 	&scsiback_wwn_version.attr,
1841 	NULL,
1842 };
1843 
1844 static char *scsiback_get_fabric_name(void)
1845 {
1846 	return "xen-pvscsi";
1847 }
1848 
1849 static int scsiback_port_link(struct se_portal_group *se_tpg,
1850 			       struct se_lun *lun)
1851 {
1852 	struct scsiback_tpg *tpg = container_of(se_tpg,
1853 				struct scsiback_tpg, se_tpg);
1854 
1855 	mutex_lock(&tpg->tv_tpg_mutex);
1856 	tpg->tv_tpg_port_count++;
1857 	mutex_unlock(&tpg->tv_tpg_mutex);
1858 
1859 	return 0;
1860 }
1861 
1862 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1863 				  struct se_lun *lun)
1864 {
1865 	struct scsiback_tpg *tpg = container_of(se_tpg,
1866 				struct scsiback_tpg, se_tpg);
1867 
1868 	mutex_lock(&tpg->tv_tpg_mutex);
1869 	tpg->tv_tpg_port_count--;
1870 	mutex_unlock(&tpg->tv_tpg_mutex);
1871 }
1872 
1873 static struct se_portal_group *
1874 scsiback_make_tpg(struct se_wwn *wwn,
1875 		   struct config_group *group,
1876 		   const char *name)
1877 {
1878 	struct scsiback_tport *tport = container_of(wwn,
1879 			struct scsiback_tport, tport_wwn);
1880 
1881 	struct scsiback_tpg *tpg;
1882 	u16 tpgt;
1883 	int ret;
1884 
1885 	if (strstr(name, "tpgt_") != name)
1886 		return ERR_PTR(-EINVAL);
1887 	ret = kstrtou16(name + 5, 10, &tpgt);
1888 	if (ret)
1889 		return ERR_PTR(ret);
1890 
1891 	tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1892 	if (!tpg)
1893 		return ERR_PTR(-ENOMEM);
1894 
1895 	mutex_init(&tpg->tv_tpg_mutex);
1896 	INIT_LIST_HEAD(&tpg->tv_tpg_list);
1897 	INIT_LIST_HEAD(&tpg->info_list);
1898 	tpg->tport = tport;
1899 	tpg->tport_tpgt = tpgt;
1900 
1901 	ret = core_tpg_register(&scsiback_ops, wwn,
1902 				&tpg->se_tpg, tpg, TRANSPORT_TPG_TYPE_NORMAL);
1903 	if (ret < 0) {
1904 		kfree(tpg);
1905 		return NULL;
1906 	}
1907 	mutex_lock(&scsiback_mutex);
1908 	list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1909 	mutex_unlock(&scsiback_mutex);
1910 
1911 	return &tpg->se_tpg;
1912 }
1913 
1914 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1915 {
1916 	struct scsiback_tpg *tpg = container_of(se_tpg,
1917 				struct scsiback_tpg, se_tpg);
1918 
1919 	mutex_lock(&scsiback_mutex);
1920 	list_del(&tpg->tv_tpg_list);
1921 	mutex_unlock(&scsiback_mutex);
1922 	/*
1923 	 * Release the virtual I_T Nexus for this xen-pvscsi TPG
1924 	 */
1925 	scsiback_drop_nexus(tpg);
1926 	/*
1927 	 * Deregister the se_tpg from TCM.
1928 	 */
1929 	core_tpg_deregister(se_tpg);
1930 	kfree(tpg);
1931 }
1932 
1933 static int scsiback_check_true(struct se_portal_group *se_tpg)
1934 {
1935 	return 1;
1936 }
1937 
1938 static int scsiback_check_false(struct se_portal_group *se_tpg)
1939 {
1940 	return 0;
1941 }
1942 
1943 static const struct target_core_fabric_ops scsiback_ops = {
1944 	.module				= THIS_MODULE,
1945 	.name				= "xen-pvscsi",
1946 	.get_fabric_name		= scsiback_get_fabric_name,
1947 	.get_fabric_proto_ident		= scsiback_get_fabric_proto_ident,
1948 	.tpg_get_wwn			= scsiback_get_fabric_wwn,
1949 	.tpg_get_tag			= scsiback_get_tag,
1950 	.tpg_get_default_depth		= scsiback_get_default_depth,
1951 	.tpg_get_pr_transport_id	= scsiback_get_pr_transport_id,
1952 	.tpg_get_pr_transport_id_len	= scsiback_get_pr_transport_id_len,
1953 	.tpg_parse_pr_out_transport_id	= scsiback_parse_pr_out_transport_id,
1954 	.tpg_check_demo_mode		= scsiback_check_true,
1955 	.tpg_check_demo_mode_cache	= scsiback_check_true,
1956 	.tpg_check_demo_mode_write_protect = scsiback_check_false,
1957 	.tpg_check_prod_mode_write_protect = scsiback_check_false,
1958 	.tpg_alloc_fabric_acl		= scsiback_alloc_fabric_acl,
1959 	.tpg_release_fabric_acl		= scsiback_release_fabric_acl,
1960 	.tpg_get_inst_index		= scsiback_tpg_get_inst_index,
1961 	.check_stop_free		= scsiback_check_stop_free,
1962 	.release_cmd			= scsiback_release_cmd,
1963 	.put_session			= NULL,
1964 	.shutdown_session		= scsiback_shutdown_session,
1965 	.close_session			= scsiback_close_session,
1966 	.sess_get_index			= scsiback_sess_get_index,
1967 	.sess_get_initiator_sid		= NULL,
1968 	.write_pending			= scsiback_write_pending,
1969 	.write_pending_status		= scsiback_write_pending_status,
1970 	.set_default_node_attributes	= scsiback_set_default_node_attrs,
1971 	.get_task_tag			= scsiback_get_task_tag,
1972 	.get_cmd_state			= scsiback_get_cmd_state,
1973 	.queue_data_in			= scsiback_queue_data_in,
1974 	.queue_status			= scsiback_queue_status,
1975 	.queue_tm_rsp			= scsiback_queue_tm_rsp,
1976 	.aborted_task			= scsiback_aborted_task,
1977 	/*
1978 	 * Setup callers for generic logic in target_core_fabric_configfs.c
1979 	 */
1980 	.fabric_make_wwn		= scsiback_make_tport,
1981 	.fabric_drop_wwn		= scsiback_drop_tport,
1982 	.fabric_make_tpg		= scsiback_make_tpg,
1983 	.fabric_drop_tpg		= scsiback_drop_tpg,
1984 	.fabric_post_link		= scsiback_port_link,
1985 	.fabric_pre_unlink		= scsiback_port_unlink,
1986 	.fabric_make_np			= NULL,
1987 	.fabric_drop_np			= NULL,
1988 #if 0
1989 	.fabric_make_nodeacl		= scsiback_make_nodeacl,
1990 	.fabric_drop_nodeacl		= scsiback_drop_nodeacl,
1991 #endif
1992 
1993 	.tfc_wwn_attrs			= scsiback_wwn_attrs,
1994 	.tfc_tpg_base_attrs		= scsiback_tpg_attrs,
1995 	.tfc_tpg_param_attrs		= scsiback_param_attrs,
1996 };
1997 
1998 static const struct xenbus_device_id scsiback_ids[] = {
1999 	{ "vscsi" },
2000 	{ "" }
2001 };
2002 
2003 static struct xenbus_driver scsiback_driver = {
2004 	.ids			= scsiback_ids,
2005 	.probe			= scsiback_probe,
2006 	.remove			= scsiback_remove,
2007 	.otherend_changed	= scsiback_frontend_changed
2008 };
2009 
2010 static void scsiback_init_pend(void *p)
2011 {
2012 	struct vscsibk_pend *pend = p;
2013 	int i;
2014 
2015 	memset(pend, 0, sizeof(*pend));
2016 	for (i = 0; i < VSCSI_MAX_GRANTS; i++)
2017 		pend->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
2018 }
2019 
2020 static int __init scsiback_init(void)
2021 {
2022 	int ret;
2023 
2024 	if (!xen_domain())
2025 		return -ENODEV;
2026 
2027 	pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
2028 		 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
2029 
2030 	scsiback_cachep = kmem_cache_create("vscsiif_cache",
2031 		sizeof(struct vscsibk_pend), 0, 0, scsiback_init_pend);
2032 	if (!scsiback_cachep)
2033 		return -ENOMEM;
2034 
2035 	ret = xenbus_register_backend(&scsiback_driver);
2036 	if (ret)
2037 		goto out_cache_destroy;
2038 
2039 	ret = target_register_template(&scsiback_ops);
2040 	if (ret)
2041 		goto out_unregister_xenbus;
2042 
2043 	return 0;
2044 
2045 out_unregister_xenbus:
2046 	xenbus_unregister_driver(&scsiback_driver);
2047 out_cache_destroy:
2048 	kmem_cache_destroy(scsiback_cachep);
2049 	pr_err("%s: error %d\n", __func__, ret);
2050 	return ret;
2051 }
2052 
2053 static void __exit scsiback_exit(void)
2054 {
2055 	struct page *page;
2056 
2057 	while (free_pages_num) {
2058 		if (get_free_page(&page))
2059 			BUG();
2060 		gnttab_free_pages(1, &page);
2061 	}
2062 	target_unregister_template(&scsiback_ops);
2063 	xenbus_unregister_driver(&scsiback_driver);
2064 	kmem_cache_destroy(scsiback_cachep);
2065 }
2066 
2067 module_init(scsiback_init);
2068 module_exit(scsiback_exit);
2069 
2070 MODULE_DESCRIPTION("Xen SCSI backend driver");
2071 MODULE_LICENSE("Dual BSD/GPL");
2072 MODULE_ALIAS("xen-backend:vscsi");
2073 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
2074