xref: /openbmc/linux/drivers/xen/xen-scsiback.c (revision b2c042cc)
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 <linux/module.h>
37 #include <linux/utsname.h>
38 #include <linux/interrupt.h>
39 #include <linux/slab.h>
40 #include <linux/wait.h>
41 #include <linux/sched.h>
42 #include <linux/list.h>
43 #include <linux/gfp.h>
44 #include <linux/delay.h>
45 #include <linux/spinlock.h>
46 #include <linux/configfs.h>
47 
48 #include <generated/utsrelease.h>
49 
50 #include <scsi/scsi_host.h> /* SG_ALL */
51 
52 #include <target/target_core_base.h>
53 #include <target/target_core_fabric.h>
54 
55 #include <asm/hypervisor.h>
56 
57 #include <xen/xen.h>
58 #include <xen/balloon.h>
59 #include <xen/events.h>
60 #include <xen/xenbus.h>
61 #include <xen/grant_table.h>
62 #include <xen/page.h>
63 
64 #include <xen/interface/grant_table.h>
65 #include <xen/interface/io/vscsiif.h>
66 
67 #define VSCSI_VERSION	"v0.1"
68 #define VSCSI_NAMELEN	32
69 
70 struct ids_tuple {
71 	unsigned int hst;		/* host    */
72 	unsigned int chn;		/* channel */
73 	unsigned int tgt;		/* target  */
74 	unsigned int lun;		/* LUN     */
75 };
76 
77 struct v2p_entry {
78 	struct ids_tuple v;		/* translate from */
79 	struct scsiback_tpg *tpg;	/* translate to   */
80 	unsigned int lun;
81 	struct kref kref;
82 	struct list_head l;
83 };
84 
85 struct vscsibk_info {
86 	struct xenbus_device *dev;
87 
88 	domid_t domid;
89 	unsigned int irq;
90 
91 	struct vscsiif_back_ring ring;
92 
93 	spinlock_t ring_lock;
94 	atomic_t nr_unreplied_reqs;
95 
96 	spinlock_t v2p_lock;
97 	struct list_head v2p_entry_lists;
98 
99 	wait_queue_head_t waiting_to_free;
100 
101 	struct gnttab_page_cache free_pages;
102 };
103 
104 /* theoretical maximum of grants for one request */
105 #define VSCSI_MAX_GRANTS	(SG_ALL + VSCSIIF_SG_TABLESIZE)
106 
107 /*
108  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
109  * call to map/unmap grants. Don't choose it too large, as there are arrays
110  * with VSCSI_GRANT_BATCH elements allocated on the stack.
111  */
112 #define VSCSI_GRANT_BATCH	16
113 
114 struct vscsibk_pend {
115 	uint16_t rqid;
116 
117 	uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
118 	uint8_t cmd_len;
119 
120 	uint8_t sc_data_direction;
121 	uint16_t n_sg;		/* real length of SG list */
122 	uint16_t n_grants;	/* SG pages and potentially SG list */
123 	uint32_t data_len;
124 	uint32_t result;
125 
126 	struct vscsibk_info *info;
127 	struct v2p_entry *v2p;
128 	struct scatterlist *sgl;
129 
130 	uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
131 
132 	grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
133 	struct page *pages[VSCSI_MAX_GRANTS];
134 
135 	struct se_cmd se_cmd;
136 
137 	struct completion tmr_done;
138 };
139 
140 #define VSCSI_DEFAULT_SESSION_TAGS	128
141 
142 struct scsiback_nexus {
143 	/* Pointer to TCM session for I_T Nexus */
144 	struct se_session *tvn_se_sess;
145 };
146 
147 struct scsiback_tport {
148 	/* SCSI protocol the tport is providing */
149 	u8 tport_proto_id;
150 	/* Binary World Wide unique Port Name for pvscsi Target port */
151 	u64 tport_wwpn;
152 	/* ASCII formatted WWPN for pvscsi Target port */
153 	char tport_name[VSCSI_NAMELEN];
154 	/* Returned by scsiback_make_tport() */
155 	struct se_wwn tport_wwn;
156 };
157 
158 struct scsiback_tpg {
159 	/* scsiback port target portal group tag for TCM */
160 	u16 tport_tpgt;
161 	/* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
162 	int tv_tpg_port_count;
163 	/* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
164 	int tv_tpg_fe_count;
165 	/* list for scsiback_list */
166 	struct list_head tv_tpg_list;
167 	/* Used to protect access for tpg_nexus */
168 	struct mutex tv_tpg_mutex;
169 	/* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
170 	struct scsiback_nexus *tpg_nexus;
171 	/* Pointer back to scsiback_tport */
172 	struct scsiback_tport *tport;
173 	/* Returned by scsiback_make_tpg() */
174 	struct se_portal_group se_tpg;
175 	/* alias used in xenstore */
176 	char param_alias[VSCSI_NAMELEN];
177 	/* list of info structures related to this target portal group */
178 	struct list_head info_list;
179 };
180 
181 #define SCSIBACK_INVALID_HANDLE (~0)
182 
183 static bool log_print_stat;
184 module_param(log_print_stat, bool, 0644);
185 
186 static int scsiback_max_buffer_pages = 1024;
187 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
188 MODULE_PARM_DESC(max_buffer_pages,
189 "Maximum number of free pages to keep in backend buffer");
190 
191 /* Global spinlock to protect scsiback TPG list */
192 static DEFINE_MUTEX(scsiback_mutex);
193 static LIST_HEAD(scsiback_list);
194 
scsiback_get(struct vscsibk_info * info)195 static void scsiback_get(struct vscsibk_info *info)
196 {
197 	atomic_inc(&info->nr_unreplied_reqs);
198 }
199 
scsiback_put(struct vscsibk_info * info)200 static void scsiback_put(struct vscsibk_info *info)
201 {
202 	if (atomic_dec_and_test(&info->nr_unreplied_reqs))
203 		wake_up(&info->waiting_to_free);
204 }
205 
vaddr_page(struct page * page)206 static unsigned long vaddr_page(struct page *page)
207 {
208 	unsigned long pfn = page_to_pfn(page);
209 
210 	return (unsigned long)pfn_to_kaddr(pfn);
211 }
212 
vaddr(struct vscsibk_pend * req,int seg)213 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
214 {
215 	return vaddr_page(req->pages[seg]);
216 }
217 
scsiback_print_status(char * sense_buffer,int errors,struct vscsibk_pend * pending_req)218 static void scsiback_print_status(char *sense_buffer, int errors,
219 					struct vscsibk_pend *pending_req)
220 {
221 	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
222 
223 	pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x\n",
224 	       tpg->tport->tport_name, pending_req->v2p->lun,
225 	       pending_req->cmnd[0], errors & 0xff, COMMAND_COMPLETE,
226 	       host_byte(errors));
227 }
228 
scsiback_fast_flush_area(struct vscsibk_pend * req)229 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
230 {
231 	struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
232 	struct page *pages[VSCSI_GRANT_BATCH];
233 	unsigned int i, invcount = 0;
234 	grant_handle_t handle;
235 	int err;
236 
237 	kfree(req->sgl);
238 	req->sgl = NULL;
239 	req->n_sg = 0;
240 
241 	if (!req->n_grants)
242 		return;
243 
244 	for (i = 0; i < req->n_grants; i++) {
245 		handle = req->grant_handles[i];
246 		if (handle == SCSIBACK_INVALID_HANDLE)
247 			continue;
248 		gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
249 				    GNTMAP_host_map, handle);
250 		req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
251 		pages[invcount] = req->pages[i];
252 		put_page(pages[invcount]);
253 		invcount++;
254 		if (invcount < VSCSI_GRANT_BATCH)
255 			continue;
256 		err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
257 		BUG_ON(err);
258 		invcount = 0;
259 	}
260 
261 	if (invcount) {
262 		err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
263 		BUG_ON(err);
264 	}
265 
266 	gnttab_page_cache_put(&req->info->free_pages, req->pages,
267 			      req->n_grants);
268 	req->n_grants = 0;
269 }
270 
scsiback_free_translation_entry(struct kref * kref)271 static void scsiback_free_translation_entry(struct kref *kref)
272 {
273 	struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
274 	struct scsiback_tpg *tpg = entry->tpg;
275 
276 	mutex_lock(&tpg->tv_tpg_mutex);
277 	tpg->tv_tpg_fe_count--;
278 	mutex_unlock(&tpg->tv_tpg_mutex);
279 
280 	kfree(entry);
281 }
282 
scsiback_result(int32_t result)283 static int32_t scsiback_result(int32_t result)
284 {
285 	int32_t host_status;
286 
287 	switch (XEN_VSCSIIF_RSLT_HOST(result)) {
288 	case DID_OK:
289 		host_status = XEN_VSCSIIF_RSLT_HOST_OK;
290 		break;
291 	case DID_NO_CONNECT:
292 		host_status = XEN_VSCSIIF_RSLT_HOST_NO_CONNECT;
293 		break;
294 	case DID_BUS_BUSY:
295 		host_status = XEN_VSCSIIF_RSLT_HOST_BUS_BUSY;
296 		break;
297 	case DID_TIME_OUT:
298 		host_status = XEN_VSCSIIF_RSLT_HOST_TIME_OUT;
299 		break;
300 	case DID_BAD_TARGET:
301 		host_status = XEN_VSCSIIF_RSLT_HOST_BAD_TARGET;
302 		break;
303 	case DID_ABORT:
304 		host_status = XEN_VSCSIIF_RSLT_HOST_ABORT;
305 		break;
306 	case DID_PARITY:
307 		host_status = XEN_VSCSIIF_RSLT_HOST_PARITY;
308 		break;
309 	case DID_ERROR:
310 		host_status = XEN_VSCSIIF_RSLT_HOST_ERROR;
311 		break;
312 	case DID_RESET:
313 		host_status = XEN_VSCSIIF_RSLT_HOST_RESET;
314 		break;
315 	case DID_BAD_INTR:
316 		host_status = XEN_VSCSIIF_RSLT_HOST_BAD_INTR;
317 		break;
318 	case DID_PASSTHROUGH:
319 		host_status = XEN_VSCSIIF_RSLT_HOST_PASSTHROUGH;
320 		break;
321 	case DID_SOFT_ERROR:
322 		host_status = XEN_VSCSIIF_RSLT_HOST_SOFT_ERROR;
323 		break;
324 	case DID_IMM_RETRY:
325 		host_status = XEN_VSCSIIF_RSLT_HOST_IMM_RETRY;
326 		break;
327 	case DID_REQUEUE:
328 		host_status = XEN_VSCSIIF_RSLT_HOST_REQUEUE;
329 		break;
330 	case DID_TRANSPORT_DISRUPTED:
331 		host_status = XEN_VSCSIIF_RSLT_HOST_TRANSPORT_DISRUPTED;
332 		break;
333 	case DID_TRANSPORT_FAILFAST:
334 		host_status = XEN_VSCSIIF_RSLT_HOST_TRANSPORT_FAILFAST;
335 		break;
336 	case DID_TRANSPORT_MARGINAL:
337 		host_status = XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL;
338 		break;
339 	default:
340 		host_status = XEN_VSCSIIF_RSLT_HOST_ERROR;
341 		break;
342 	}
343 
344 	return (host_status << 16) | (result & 0x00ffff);
345 }
346 
scsiback_send_response(struct vscsibk_info * info,char * sense_buffer,int32_t result,uint32_t resid,uint16_t rqid)347 static void scsiback_send_response(struct vscsibk_info *info,
348 			char *sense_buffer, int32_t result, uint32_t resid,
349 			uint16_t rqid)
350 {
351 	struct vscsiif_response *ring_res;
352 	int notify;
353 	struct scsi_sense_hdr sshdr;
354 	unsigned long flags;
355 	unsigned len;
356 
357 	spin_lock_irqsave(&info->ring_lock, flags);
358 
359 	ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
360 	info->ring.rsp_prod_pvt++;
361 
362 	ring_res->rslt   = scsiback_result(result);
363 	ring_res->rqid   = rqid;
364 
365 	if (sense_buffer != NULL &&
366 	    scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
367 				 &sshdr)) {
368 		len = min_t(unsigned, 8 + sense_buffer[7],
369 			    VSCSIIF_SENSE_BUFFERSIZE);
370 		memcpy(ring_res->sense_buffer, sense_buffer, len);
371 		ring_res->sense_len = len;
372 	} else {
373 		ring_res->sense_len = 0;
374 	}
375 
376 	ring_res->residual_len = resid;
377 
378 	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
379 	spin_unlock_irqrestore(&info->ring_lock, flags);
380 
381 	if (notify)
382 		notify_remote_via_irq(info->irq);
383 }
384 
scsiback_do_resp_with_sense(char * sense_buffer,int32_t result,uint32_t resid,struct vscsibk_pend * pending_req)385 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
386 			uint32_t resid, struct vscsibk_pend *pending_req)
387 {
388 	scsiback_send_response(pending_req->info, sense_buffer, result,
389 			       resid, pending_req->rqid);
390 
391 	if (pending_req->v2p)
392 		kref_put(&pending_req->v2p->kref,
393 			 scsiback_free_translation_entry);
394 }
395 
scsiback_cmd_done(struct vscsibk_pend * pending_req)396 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
397 {
398 	struct vscsibk_info *info = pending_req->info;
399 	unsigned char *sense_buffer;
400 	unsigned int resid;
401 	int errors;
402 
403 	sense_buffer = pending_req->sense_buffer;
404 	resid        = pending_req->se_cmd.residual_count;
405 	errors       = pending_req->result;
406 
407 	if (errors && log_print_stat)
408 		scsiback_print_status(sense_buffer, errors, pending_req);
409 
410 	scsiback_fast_flush_area(pending_req);
411 	scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
412 	scsiback_put(info);
413 	/*
414 	 * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
415 	 * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
416 	 * final se_cmd->cmd_kref put.
417 	 */
418 	target_put_sess_cmd(&pending_req->se_cmd);
419 }
420 
scsiback_cmd_exec(struct vscsibk_pend * pending_req)421 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
422 {
423 	struct se_cmd *se_cmd = &pending_req->se_cmd;
424 	struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
425 
426 	scsiback_get(pending_req->info);
427 	se_cmd->tag = pending_req->rqid;
428 	target_init_cmd(se_cmd, sess, pending_req->sense_buffer,
429 			pending_req->v2p->lun, pending_req->data_len, 0,
430 			pending_req->sc_data_direction, TARGET_SCF_ACK_KREF);
431 
432 	if (target_submit_prep(se_cmd, pending_req->cmnd, pending_req->sgl,
433 			       pending_req->n_sg, NULL, 0, NULL, 0, GFP_KERNEL))
434 		return;
435 
436 	target_submit(se_cmd);
437 }
438 
scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref * map,struct page ** pg,grant_handle_t * grant,int cnt)439 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
440 	struct page **pg, grant_handle_t *grant, int cnt)
441 {
442 	int err, i;
443 
444 	if (!cnt)
445 		return 0;
446 
447 	err = gnttab_map_refs(map, NULL, pg, cnt);
448 	for (i = 0; i < cnt; i++) {
449 		if (unlikely(map[i].status != GNTST_okay)) {
450 			pr_err("invalid buffer -- could not remap it\n");
451 			map[i].handle = SCSIBACK_INVALID_HANDLE;
452 			if (!err)
453 				err = -ENOMEM;
454 		} else {
455 			get_page(pg[i]);
456 		}
457 		grant[i] = map[i].handle;
458 	}
459 	return err;
460 }
461 
scsiback_gnttab_data_map_list(struct vscsibk_pend * pending_req,struct scsiif_request_segment * seg,struct page ** pg,grant_handle_t * grant,int cnt,u32 flags)462 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
463 			struct scsiif_request_segment *seg, struct page **pg,
464 			grant_handle_t *grant, int cnt, u32 flags)
465 {
466 	int mapcount = 0, i, err = 0;
467 	struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
468 	struct vscsibk_info *info = pending_req->info;
469 
470 	for (i = 0; i < cnt; i++) {
471 		if (gnttab_page_cache_get(&info->free_pages, pg + mapcount)) {
472 			gnttab_page_cache_put(&info->free_pages, pg, mapcount);
473 			pr_err("no grant page\n");
474 			return -ENOMEM;
475 		}
476 		gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
477 				  flags, seg[i].gref, info->domid);
478 		mapcount++;
479 		if (mapcount < VSCSI_GRANT_BATCH)
480 			continue;
481 		err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
482 		pg += mapcount;
483 		grant += mapcount;
484 		pending_req->n_grants += mapcount;
485 		if (err)
486 			return err;
487 		mapcount = 0;
488 	}
489 	err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
490 	pending_req->n_grants += mapcount;
491 	return err;
492 }
493 
scsiback_gnttab_data_map(struct vscsiif_request * ring_req,struct vscsibk_pend * pending_req)494 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
495 					struct vscsibk_pend *pending_req)
496 {
497 	u32 flags;
498 	int i, err, n_segs, i_seg = 0;
499 	struct page **pg;
500 	struct scsiif_request_segment *seg;
501 	unsigned long end_seg = 0;
502 	unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
503 	unsigned int nr_sgl = 0;
504 	struct scatterlist *sg;
505 	grant_handle_t *grant;
506 
507 	pending_req->n_sg = 0;
508 	pending_req->n_grants = 0;
509 	pending_req->data_len = 0;
510 
511 	nr_segments &= ~VSCSIIF_SG_GRANT;
512 	if (!nr_segments)
513 		return 0;
514 
515 	if (nr_segments > VSCSIIF_SG_TABLESIZE) {
516 		pr_debug("invalid parameter nr_seg = %d\n",
517 			ring_req->nr_segments);
518 		return -EINVAL;
519 	}
520 
521 	if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
522 		err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
523 			pending_req->pages, pending_req->grant_handles,
524 			nr_segments, GNTMAP_host_map | GNTMAP_readonly);
525 		if (err)
526 			return err;
527 		nr_sgl = nr_segments;
528 		nr_segments = 0;
529 		for (i = 0; i < nr_sgl; i++) {
530 			n_segs = ring_req->seg[i].length /
531 				 sizeof(struct scsiif_request_segment);
532 			if ((unsigned)ring_req->seg[i].offset +
533 			    (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
534 			    n_segs * sizeof(struct scsiif_request_segment) !=
535 			    ring_req->seg[i].length)
536 				return -EINVAL;
537 			nr_segments += n_segs;
538 		}
539 		if (nr_segments > SG_ALL) {
540 			pr_debug("invalid nr_seg = %d\n", nr_segments);
541 			return -EINVAL;
542 		}
543 	}
544 
545 	/* free of (sgl) in fast_flush_area() */
546 	pending_req->sgl = kmalloc_array(nr_segments,
547 					sizeof(struct scatterlist), GFP_KERNEL);
548 	if (!pending_req->sgl)
549 		return -ENOMEM;
550 
551 	sg_init_table(pending_req->sgl, nr_segments);
552 	pending_req->n_sg = nr_segments;
553 
554 	flags = GNTMAP_host_map;
555 	if (pending_req->sc_data_direction == DMA_TO_DEVICE)
556 		flags |= GNTMAP_readonly;
557 
558 	pg = pending_req->pages + nr_sgl;
559 	grant = pending_req->grant_handles + nr_sgl;
560 	if (!nr_sgl) {
561 		seg = ring_req->seg;
562 		err = scsiback_gnttab_data_map_list(pending_req, seg,
563 			pg, grant, nr_segments, flags);
564 		if (err)
565 			return err;
566 	} else {
567 		for (i = 0; i < nr_sgl; i++) {
568 			seg = (struct scsiif_request_segment *)(
569 			      vaddr(pending_req, i) + ring_req->seg[i].offset);
570 			n_segs = ring_req->seg[i].length /
571 				 sizeof(struct scsiif_request_segment);
572 			err = scsiback_gnttab_data_map_list(pending_req, seg,
573 				pg, grant, n_segs, flags);
574 			if (err)
575 				return err;
576 			pg += n_segs;
577 			grant += n_segs;
578 		}
579 		end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
580 		seg = (struct scsiif_request_segment *)end_seg;
581 		end_seg += ring_req->seg[0].length;
582 		pg = pending_req->pages + nr_sgl;
583 	}
584 
585 	for_each_sg(pending_req->sgl, sg, nr_segments, i) {
586 		sg_set_page(sg, pg[i], seg->length, seg->offset);
587 		pending_req->data_len += seg->length;
588 		seg++;
589 		if (nr_sgl && (unsigned long)seg >= end_seg) {
590 			i_seg++;
591 			end_seg = vaddr(pending_req, i_seg) +
592 				  ring_req->seg[i_seg].offset;
593 			seg = (struct scsiif_request_segment *)end_seg;
594 			end_seg += ring_req->seg[i_seg].length;
595 		}
596 		if (sg->offset >= PAGE_SIZE ||
597 		    sg->length > PAGE_SIZE ||
598 		    sg->offset + sg->length > PAGE_SIZE)
599 			return -EINVAL;
600 	}
601 
602 	return 0;
603 }
604 
scsiback_disconnect(struct vscsibk_info * info)605 static void scsiback_disconnect(struct vscsibk_info *info)
606 {
607 	wait_event(info->waiting_to_free,
608 		atomic_read(&info->nr_unreplied_reqs) == 0);
609 
610 	unbind_from_irqhandler(info->irq, info);
611 	info->irq = 0;
612 	xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
613 }
614 
scsiback_device_action(struct vscsibk_pend * pending_req,enum tcm_tmreq_table act,int tag)615 static void scsiback_device_action(struct vscsibk_pend *pending_req,
616 	enum tcm_tmreq_table act, int tag)
617 {
618 	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
619 	struct scsiback_nexus *nexus = tpg->tpg_nexus;
620 	struct se_cmd *se_cmd = &pending_req->se_cmd;
621 	u64 unpacked_lun = pending_req->v2p->lun;
622 	int rc, err = XEN_VSCSIIF_RSLT_RESET_FAILED;
623 
624 	init_completion(&pending_req->tmr_done);
625 
626 	rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
627 			       &pending_req->sense_buffer[0],
628 			       unpacked_lun, NULL, act, GFP_KERNEL,
629 			       tag, TARGET_SCF_ACK_KREF);
630 	if (rc)
631 		goto err;
632 
633 	wait_for_completion(&pending_req->tmr_done);
634 
635 	err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
636 		XEN_VSCSIIF_RSLT_RESET_SUCCESS : XEN_VSCSIIF_RSLT_RESET_FAILED;
637 
638 	scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
639 	transport_generic_free_cmd(&pending_req->se_cmd, 0);
640 	return;
641 
642 err:
643 	scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
644 }
645 
646 /*
647   Perform virtual to physical translation
648 */
scsiback_do_translation(struct vscsibk_info * info,struct ids_tuple * v)649 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
650 			struct ids_tuple *v)
651 {
652 	struct v2p_entry *entry;
653 	struct list_head *head = &(info->v2p_entry_lists);
654 	unsigned long flags;
655 
656 	spin_lock_irqsave(&info->v2p_lock, flags);
657 	list_for_each_entry(entry, head, l) {
658 		if ((entry->v.chn == v->chn) &&
659 		    (entry->v.tgt == v->tgt) &&
660 		    (entry->v.lun == v->lun)) {
661 			kref_get(&entry->kref);
662 			goto out;
663 		}
664 	}
665 	entry = NULL;
666 
667 out:
668 	spin_unlock_irqrestore(&info->v2p_lock, flags);
669 	return entry;
670 }
671 
scsiback_get_pend_req(struct vscsiif_back_ring * ring,struct v2p_entry * v2p)672 static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
673 				struct v2p_entry *v2p)
674 {
675 	struct scsiback_tpg *tpg = v2p->tpg;
676 	struct scsiback_nexus *nexus = tpg->tpg_nexus;
677 	struct se_session *se_sess = nexus->tvn_se_sess;
678 	struct vscsibk_pend *req;
679 	int tag, cpu, i;
680 
681 	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
682 	if (tag < 0) {
683 		pr_err("Unable to obtain tag for vscsiif_request\n");
684 		return ERR_PTR(-ENOMEM);
685 	}
686 
687 	req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
688 	memset(req, 0, sizeof(*req));
689 	req->se_cmd.map_tag = tag;
690 	req->se_cmd.map_cpu = cpu;
691 
692 	for (i = 0; i < VSCSI_MAX_GRANTS; i++)
693 		req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
694 
695 	return req;
696 }
697 
prepare_pending_reqs(struct vscsibk_info * info,struct vscsiif_back_ring * ring,struct vscsiif_request * ring_req)698 static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
699 				struct vscsiif_back_ring *ring,
700 				struct vscsiif_request *ring_req)
701 {
702 	struct vscsibk_pend *pending_req;
703 	struct v2p_entry *v2p;
704 	struct ids_tuple vir;
705 
706 	/* request range check from frontend */
707 	if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
708 		(ring_req->sc_data_direction != DMA_TO_DEVICE) &&
709 		(ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
710 		(ring_req->sc_data_direction != DMA_NONE)) {
711 		pr_debug("invalid parameter data_dir = %d\n",
712 			ring_req->sc_data_direction);
713 		return ERR_PTR(-EINVAL);
714 	}
715 	if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
716 		pr_debug("invalid parameter cmd_len = %d\n",
717 			ring_req->cmd_len);
718 		return ERR_PTR(-EINVAL);
719 	}
720 
721 	vir.chn = ring_req->channel;
722 	vir.tgt = ring_req->id;
723 	vir.lun = ring_req->lun;
724 
725 	v2p = scsiback_do_translation(info, &vir);
726 	if (!v2p) {
727 		pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
728 			 vir.chn, vir.tgt, vir.lun);
729 		return ERR_PTR(-ENODEV);
730 	}
731 
732 	pending_req = scsiback_get_pend_req(ring, v2p);
733 	if (IS_ERR(pending_req)) {
734 		kref_put(&v2p->kref, scsiback_free_translation_entry);
735 		return ERR_PTR(-ENOMEM);
736 	}
737 	pending_req->rqid = ring_req->rqid;
738 	pending_req->info = info;
739 	pending_req->v2p = v2p;
740 	pending_req->sc_data_direction = ring_req->sc_data_direction;
741 	pending_req->cmd_len = ring_req->cmd_len;
742 	memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
743 
744 	return pending_req;
745 }
746 
scsiback_do_cmd_fn(struct vscsibk_info * info,unsigned int * eoi_flags)747 static int scsiback_do_cmd_fn(struct vscsibk_info *info,
748 			      unsigned int *eoi_flags)
749 {
750 	struct vscsiif_back_ring *ring = &info->ring;
751 	struct vscsiif_request ring_req;
752 	struct vscsibk_pend *pending_req;
753 	RING_IDX rc, rp;
754 	int more_to_do;
755 	uint32_t result;
756 
757 	rc = ring->req_cons;
758 	rp = ring->sring->req_prod;
759 	rmb();	/* guest system is accessing ring, too */
760 
761 	if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
762 		rc = ring->rsp_prod_pvt;
763 		pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
764 			   info->domid, rp, rc, rp - rc);
765 		return -EINVAL;
766 	}
767 
768 	while ((rc != rp)) {
769 		*eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
770 
771 		if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
772 			break;
773 
774 		RING_COPY_REQUEST(ring, rc, &ring_req);
775 		ring->req_cons = ++rc;
776 
777 		pending_req = prepare_pending_reqs(info, ring, &ring_req);
778 		if (IS_ERR(pending_req)) {
779 			switch (PTR_ERR(pending_req)) {
780 			case -ENODEV:
781 				result = DID_NO_CONNECT;
782 				break;
783 			default:
784 				result = DID_ERROR;
785 				break;
786 			}
787 			scsiback_send_response(info, NULL, result << 16, 0,
788 					       ring_req.rqid);
789 			return 1;
790 		}
791 
792 		switch (ring_req.act) {
793 		case VSCSIIF_ACT_SCSI_CDB:
794 			if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
795 				scsiback_fast_flush_area(pending_req);
796 				scsiback_do_resp_with_sense(NULL,
797 						DID_ERROR << 16, 0, pending_req);
798 				transport_generic_free_cmd(&pending_req->se_cmd, 0);
799 			} else {
800 				scsiback_cmd_exec(pending_req);
801 			}
802 			break;
803 		case VSCSIIF_ACT_SCSI_ABORT:
804 			scsiback_device_action(pending_req, TMR_ABORT_TASK,
805 				ring_req.ref_rqid);
806 			break;
807 		case VSCSIIF_ACT_SCSI_RESET:
808 			scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
809 			break;
810 		default:
811 			pr_err_ratelimited("invalid request\n");
812 			scsiback_do_resp_with_sense(NULL, DID_ERROR << 16, 0,
813 						    pending_req);
814 			transport_generic_free_cmd(&pending_req->se_cmd, 0);
815 			break;
816 		}
817 
818 		/* Yield point for this unbounded loop. */
819 		cond_resched();
820 	}
821 
822 	gnttab_page_cache_shrink(&info->free_pages, scsiback_max_buffer_pages);
823 
824 	RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
825 	return more_to_do;
826 }
827 
scsiback_irq_fn(int irq,void * dev_id)828 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
829 {
830 	struct vscsibk_info *info = dev_id;
831 	int rc;
832 	unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
833 
834 	while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
835 		cond_resched();
836 
837 	/* In case of a ring error we keep the event channel masked. */
838 	if (!rc)
839 		xen_irq_lateeoi(irq, eoi_flags);
840 
841 	return IRQ_HANDLED;
842 }
843 
scsiback_init_sring(struct vscsibk_info * info,grant_ref_t ring_ref,evtchn_port_t evtchn)844 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
845 			evtchn_port_t evtchn)
846 {
847 	void *area;
848 	struct vscsiif_sring *sring;
849 	int err;
850 
851 	if (info->irq)
852 		return -1;
853 
854 	err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
855 	if (err)
856 		return err;
857 
858 	sring = (struct vscsiif_sring *)area;
859 	BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
860 
861 	err = bind_interdomain_evtchn_to_irq_lateeoi(info->dev, evtchn);
862 	if (err < 0)
863 		goto unmap_page;
864 
865 	info->irq = err;
866 
867 	err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
868 				   IRQF_ONESHOT, "vscsiif-backend", info);
869 	if (err)
870 		goto free_irq;
871 
872 	return 0;
873 
874 free_irq:
875 	unbind_from_irqhandler(info->irq, info);
876 	info->irq = 0;
877 unmap_page:
878 	xenbus_unmap_ring_vfree(info->dev, area);
879 
880 	return err;
881 }
882 
scsiback_map(struct vscsibk_info * info)883 static int scsiback_map(struct vscsibk_info *info)
884 {
885 	struct xenbus_device *dev = info->dev;
886 	unsigned int ring_ref;
887 	evtchn_port_t evtchn;
888 	int err;
889 
890 	err = xenbus_gather(XBT_NIL, dev->otherend,
891 			"ring-ref", "%u", &ring_ref,
892 			"event-channel", "%u", &evtchn, NULL);
893 	if (err) {
894 		xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
895 		return err;
896 	}
897 
898 	return scsiback_init_sring(info, ring_ref, evtchn);
899 }
900 
901 /*
902   Check for a translation entry being present
903 */
scsiback_chk_translation_entry(struct vscsibk_info * info,struct ids_tuple * v)904 static struct v2p_entry *scsiback_chk_translation_entry(
905 	struct vscsibk_info *info, struct ids_tuple *v)
906 {
907 	struct list_head *head = &(info->v2p_entry_lists);
908 	struct v2p_entry *entry;
909 
910 	list_for_each_entry(entry, head, l)
911 		if ((entry->v.chn == v->chn) &&
912 		    (entry->v.tgt == v->tgt) &&
913 		    (entry->v.lun == v->lun))
914 			return entry;
915 
916 	return NULL;
917 }
918 
919 /*
920   Add a new translation entry
921 */
scsiback_add_translation_entry(struct vscsibk_info * info,char * phy,struct ids_tuple * v)922 static int scsiback_add_translation_entry(struct vscsibk_info *info,
923 					  char *phy, struct ids_tuple *v)
924 {
925 	int err = 0;
926 	struct v2p_entry *new;
927 	unsigned long flags;
928 	char *lunp;
929 	unsigned long long unpacked_lun;
930 	struct se_lun *se_lun;
931 	struct scsiback_tpg *tpg_entry, *tpg = NULL;
932 	char *error = "doesn't exist";
933 
934 	lunp = strrchr(phy, ':');
935 	if (!lunp) {
936 		pr_err("illegal format of physical device %s\n", phy);
937 		return -EINVAL;
938 	}
939 	*lunp = 0;
940 	lunp++;
941 	err = kstrtoull(lunp, 10, &unpacked_lun);
942 	if (err < 0) {
943 		pr_err("lun number not valid: %s\n", lunp);
944 		return err;
945 	}
946 
947 	mutex_lock(&scsiback_mutex);
948 	list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
949 		if (!strcmp(phy, tpg_entry->tport->tport_name) ||
950 		    !strcmp(phy, tpg_entry->param_alias)) {
951 			mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
952 			hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
953 				if (se_lun->unpacked_lun == unpacked_lun) {
954 					if (!tpg_entry->tpg_nexus)
955 						error = "nexus undefined";
956 					else
957 						tpg = tpg_entry;
958 					break;
959 				}
960 			}
961 			mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
962 			break;
963 		}
964 	}
965 	if (tpg) {
966 		mutex_lock(&tpg->tv_tpg_mutex);
967 		tpg->tv_tpg_fe_count++;
968 		mutex_unlock(&tpg->tv_tpg_mutex);
969 	}
970 	mutex_unlock(&scsiback_mutex);
971 
972 	if (!tpg) {
973 		pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
974 		return -ENODEV;
975 	}
976 
977 	new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
978 	if (new == NULL) {
979 		err = -ENOMEM;
980 		goto out_free;
981 	}
982 
983 	spin_lock_irqsave(&info->v2p_lock, flags);
984 
985 	/* Check double assignment to identical virtual ID */
986 	if (scsiback_chk_translation_entry(info, v)) {
987 		pr_warn("Virtual ID is already used. Assignment was not performed.\n");
988 		err = -EEXIST;
989 		goto out;
990 	}
991 
992 	/* Create a new translation entry and add to the list */
993 	kref_init(&new->kref);
994 	new->v = *v;
995 	new->tpg = tpg;
996 	new->lun = unpacked_lun;
997 	list_add_tail(&new->l, &info->v2p_entry_lists);
998 
999 out:
1000 	spin_unlock_irqrestore(&info->v2p_lock, flags);
1001 
1002 out_free:
1003 	if (err) {
1004 		mutex_lock(&tpg->tv_tpg_mutex);
1005 		tpg->tv_tpg_fe_count--;
1006 		mutex_unlock(&tpg->tv_tpg_mutex);
1007 		kfree(new);
1008 	}
1009 
1010 	return err;
1011 }
1012 
1013 /*
1014   Delete the translation entry specified
1015 */
scsiback_del_translation_entry(struct vscsibk_info * info,struct ids_tuple * v)1016 static int scsiback_del_translation_entry(struct vscsibk_info *info,
1017 					  struct ids_tuple *v)
1018 {
1019 	struct v2p_entry *entry;
1020 	unsigned long flags;
1021 
1022 	spin_lock_irqsave(&info->v2p_lock, flags);
1023 	/* Find out the translation entry specified */
1024 	entry = scsiback_chk_translation_entry(info, v);
1025 	if (entry)
1026 		list_del(&entry->l);
1027 
1028 	spin_unlock_irqrestore(&info->v2p_lock, flags);
1029 
1030 	if (!entry)
1031 		return -ENOENT;
1032 
1033 	kref_put(&entry->kref, scsiback_free_translation_entry);
1034 	return 0;
1035 }
1036 
scsiback_do_add_lun(struct vscsibk_info * info,const char * state,char * phy,struct ids_tuple * vir,int try)1037 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1038 				char *phy, struct ids_tuple *vir, int try)
1039 {
1040 	struct v2p_entry *entry;
1041 	unsigned long flags;
1042 	int err;
1043 
1044 	if (try) {
1045 		spin_lock_irqsave(&info->v2p_lock, flags);
1046 		entry = scsiback_chk_translation_entry(info, vir);
1047 		spin_unlock_irqrestore(&info->v2p_lock, flags);
1048 		if (entry)
1049 			return;
1050 	}
1051 	if (!scsiback_add_translation_entry(info, phy, vir)) {
1052 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1053 				  "%d", XenbusStateInitialised)) {
1054 			pr_err("xenbus_printf error %s\n", state);
1055 			scsiback_del_translation_entry(info, vir);
1056 		}
1057 	} else if (!try) {
1058 		err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
1059 			      "%d", XenbusStateClosed);
1060 		if (err)
1061 			xenbus_dev_error(info->dev, err,
1062 				"%s: writing %s", __func__, state);
1063 	}
1064 }
1065 
scsiback_do_del_lun(struct vscsibk_info * info,const char * state,struct ids_tuple * vir)1066 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1067 				struct ids_tuple *vir)
1068 {
1069 	if (!scsiback_del_translation_entry(info, vir)) {
1070 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1071 				  "%d", XenbusStateClosed))
1072 			pr_err("xenbus_printf error %s\n", state);
1073 	}
1074 }
1075 
1076 #define VSCSIBACK_OP_ADD_OR_DEL_LUN	1
1077 #define VSCSIBACK_OP_UPDATEDEV_STATE	2
1078 
scsiback_do_1lun_hotplug(struct vscsibk_info * info,int op,char * ent)1079 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1080 				     char *ent)
1081 {
1082 	int err;
1083 	struct ids_tuple vir;
1084 	char *val;
1085 	int device_state;
1086 	char phy[VSCSI_NAMELEN];
1087 	char str[64];
1088 	char state[64];
1089 	struct xenbus_device *dev = info->dev;
1090 
1091 	/* read status */
1092 	snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1093 	err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1094 	if (XENBUS_EXIST_ERR(err))
1095 		return;
1096 
1097 	/* physical SCSI device */
1098 	snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1099 	val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1100 	if (IS_ERR(val)) {
1101 		err = xenbus_printf(XBT_NIL, dev->nodename, state,
1102 			      "%d", XenbusStateClosed);
1103 		if (err)
1104 			xenbus_dev_error(info->dev, err,
1105 				"%s: writing %s", __func__, state);
1106 		return;
1107 	}
1108 	strscpy(phy, val, VSCSI_NAMELEN);
1109 	kfree(val);
1110 
1111 	/* virtual SCSI device */
1112 	snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1113 	err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1114 			   &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1115 	if (XENBUS_EXIST_ERR(err)) {
1116 		err = xenbus_printf(XBT_NIL, dev->nodename, state,
1117 			      "%d", XenbusStateClosed);
1118 		if (err)
1119 			xenbus_dev_error(info->dev, err,
1120 				"%s: writing %s", __func__, state);
1121 		return;
1122 	}
1123 
1124 	switch (op) {
1125 	case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1126 		switch (device_state) {
1127 		case XenbusStateInitialising:
1128 			scsiback_do_add_lun(info, state, phy, &vir, 0);
1129 			break;
1130 		case XenbusStateConnected:
1131 			scsiback_do_add_lun(info, state, phy, &vir, 1);
1132 			break;
1133 		case XenbusStateClosing:
1134 			scsiback_do_del_lun(info, state, &vir);
1135 			break;
1136 		default:
1137 			break;
1138 		}
1139 		break;
1140 
1141 	case VSCSIBACK_OP_UPDATEDEV_STATE:
1142 		if (device_state == XenbusStateInitialised) {
1143 			/* modify vscsi-devs/dev-x/state */
1144 			if (xenbus_printf(XBT_NIL, dev->nodename, state,
1145 					  "%d", XenbusStateConnected)) {
1146 				pr_err("xenbus_printf error %s\n", str);
1147 				scsiback_del_translation_entry(info, &vir);
1148 				xenbus_printf(XBT_NIL, dev->nodename, state,
1149 					      "%d", XenbusStateClosed);
1150 			}
1151 		}
1152 		break;
1153 	/* When it is necessary, processing is added here. */
1154 	default:
1155 		break;
1156 	}
1157 }
1158 
scsiback_do_lun_hotplug(struct vscsibk_info * info,int op)1159 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1160 {
1161 	int i;
1162 	char **dir;
1163 	unsigned int ndir = 0;
1164 
1165 	dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1166 			       &ndir);
1167 	if (IS_ERR(dir))
1168 		return;
1169 
1170 	for (i = 0; i < ndir; i++)
1171 		scsiback_do_1lun_hotplug(info, op, dir[i]);
1172 
1173 	kfree(dir);
1174 }
1175 
scsiback_frontend_changed(struct xenbus_device * dev,enum xenbus_state frontend_state)1176 static void scsiback_frontend_changed(struct xenbus_device *dev,
1177 					enum xenbus_state frontend_state)
1178 {
1179 	struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1180 
1181 	switch (frontend_state) {
1182 	case XenbusStateInitialising:
1183 		break;
1184 
1185 	case XenbusStateInitialised:
1186 		if (scsiback_map(info))
1187 			break;
1188 
1189 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1190 		xenbus_switch_state(dev, XenbusStateConnected);
1191 		break;
1192 
1193 	case XenbusStateConnected:
1194 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1195 
1196 		if (dev->state == XenbusStateConnected)
1197 			break;
1198 
1199 		xenbus_switch_state(dev, XenbusStateConnected);
1200 		break;
1201 
1202 	case XenbusStateClosing:
1203 		if (info->irq)
1204 			scsiback_disconnect(info);
1205 
1206 		xenbus_switch_state(dev, XenbusStateClosing);
1207 		break;
1208 
1209 	case XenbusStateClosed:
1210 		xenbus_switch_state(dev, XenbusStateClosed);
1211 		if (xenbus_dev_is_online(dev))
1212 			break;
1213 		fallthrough;	/* if not online */
1214 	case XenbusStateUnknown:
1215 		device_unregister(&dev->dev);
1216 		break;
1217 
1218 	case XenbusStateReconfiguring:
1219 		scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1220 		xenbus_switch_state(dev, XenbusStateReconfigured);
1221 
1222 		break;
1223 
1224 	default:
1225 		xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1226 					frontend_state);
1227 		break;
1228 	}
1229 }
1230 
1231 /*
1232   Release the translation entry specfied
1233 */
scsiback_release_translation_entry(struct vscsibk_info * info)1234 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1235 {
1236 	struct v2p_entry *entry, *tmp;
1237 	struct list_head *head = &(info->v2p_entry_lists);
1238 	struct list_head tmp_list;
1239 	unsigned long flags;
1240 
1241 	spin_lock_irqsave(&info->v2p_lock, flags);
1242 
1243 	list_cut_before(&tmp_list, head, head);
1244 
1245 	spin_unlock_irqrestore(&info->v2p_lock, flags);
1246 
1247 	list_for_each_entry_safe(entry, tmp, &tmp_list, l) {
1248 		list_del(&entry->l);
1249 		kref_put(&entry->kref, scsiback_free_translation_entry);
1250 	}
1251 }
1252 
scsiback_remove(struct xenbus_device * dev)1253 static void scsiback_remove(struct xenbus_device *dev)
1254 {
1255 	struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1256 
1257 	if (info->irq)
1258 		scsiback_disconnect(info);
1259 
1260 	scsiback_release_translation_entry(info);
1261 
1262 	gnttab_page_cache_shrink(&info->free_pages, 0);
1263 
1264 	dev_set_drvdata(&dev->dev, NULL);
1265 }
1266 
scsiback_probe(struct xenbus_device * dev,const struct xenbus_device_id * id)1267 static int scsiback_probe(struct xenbus_device *dev,
1268 			   const struct xenbus_device_id *id)
1269 {
1270 	int err;
1271 
1272 	struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1273 					    GFP_KERNEL);
1274 
1275 	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1276 
1277 	if (!info) {
1278 		xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1279 		return -ENOMEM;
1280 	}
1281 	info->dev = dev;
1282 	dev_set_drvdata(&dev->dev, info);
1283 
1284 	info->domid = dev->otherend_id;
1285 	spin_lock_init(&info->ring_lock);
1286 	atomic_set(&info->nr_unreplied_reqs, 0);
1287 	init_waitqueue_head(&info->waiting_to_free);
1288 	info->dev = dev;
1289 	info->irq = 0;
1290 	INIT_LIST_HEAD(&info->v2p_entry_lists);
1291 	spin_lock_init(&info->v2p_lock);
1292 	gnttab_page_cache_init(&info->free_pages);
1293 
1294 	err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1295 			    SG_ALL);
1296 	if (err)
1297 		xenbus_dev_error(dev, err, "writing feature-sg-grant");
1298 
1299 	err = xenbus_switch_state(dev, XenbusStateInitWait);
1300 	if (err)
1301 		goto fail;
1302 
1303 	return 0;
1304 
1305 fail:
1306 	pr_warn("%s failed\n", __func__);
1307 	scsiback_remove(dev);
1308 
1309 	return err;
1310 }
1311 
scsiback_dump_proto_id(struct scsiback_tport * tport)1312 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1313 {
1314 	switch (tport->tport_proto_id) {
1315 	case SCSI_PROTOCOL_SAS:
1316 		return "SAS";
1317 	case SCSI_PROTOCOL_FCP:
1318 		return "FCP";
1319 	case SCSI_PROTOCOL_ISCSI:
1320 		return "iSCSI";
1321 	default:
1322 		break;
1323 	}
1324 
1325 	return "Unknown";
1326 }
1327 
scsiback_get_fabric_wwn(struct se_portal_group * se_tpg)1328 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1329 {
1330 	struct scsiback_tpg *tpg = container_of(se_tpg,
1331 				struct scsiback_tpg, se_tpg);
1332 	struct scsiback_tport *tport = tpg->tport;
1333 
1334 	return &tport->tport_name[0];
1335 }
1336 
scsiback_get_tag(struct se_portal_group * se_tpg)1337 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1338 {
1339 	struct scsiback_tpg *tpg = container_of(se_tpg,
1340 				struct scsiback_tpg, se_tpg);
1341 	return tpg->tport_tpgt;
1342 }
1343 
1344 static struct se_wwn *
scsiback_make_tport(struct target_fabric_configfs * tf,struct config_group * group,const char * name)1345 scsiback_make_tport(struct target_fabric_configfs *tf,
1346 		     struct config_group *group,
1347 		     const char *name)
1348 {
1349 	struct scsiback_tport *tport;
1350 	char *ptr;
1351 	u64 wwpn = 0;
1352 	int off = 0;
1353 
1354 	tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1355 	if (!tport)
1356 		return ERR_PTR(-ENOMEM);
1357 
1358 	tport->tport_wwpn = wwpn;
1359 	/*
1360 	 * Determine the emulated Protocol Identifier and Target Port Name
1361 	 * based on the incoming configfs directory name.
1362 	 */
1363 	ptr = strstr(name, "naa.");
1364 	if (ptr) {
1365 		tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1366 		goto check_len;
1367 	}
1368 	ptr = strstr(name, "fc.");
1369 	if (ptr) {
1370 		tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1371 		off = 3; /* Skip over "fc." */
1372 		goto check_len;
1373 	}
1374 	ptr = strstr(name, "iqn.");
1375 	if (ptr) {
1376 		tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1377 		goto check_len;
1378 	}
1379 
1380 	pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1381 	kfree(tport);
1382 	return ERR_PTR(-EINVAL);
1383 
1384 check_len:
1385 	if (strlen(name) >= VSCSI_NAMELEN) {
1386 		pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1387 			scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1388 		kfree(tport);
1389 		return ERR_PTR(-EINVAL);
1390 	}
1391 	snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1392 
1393 	pr_debug("Allocated emulated Target %s Address: %s\n",
1394 		 scsiback_dump_proto_id(tport), name);
1395 
1396 	return &tport->tport_wwn;
1397 }
1398 
scsiback_drop_tport(struct se_wwn * wwn)1399 static void scsiback_drop_tport(struct se_wwn *wwn)
1400 {
1401 	struct scsiback_tport *tport = container_of(wwn,
1402 				struct scsiback_tport, tport_wwn);
1403 
1404 	pr_debug("Deallocating emulated Target %s Address: %s\n",
1405 		 scsiback_dump_proto_id(tport), tport->tport_name);
1406 
1407 	kfree(tport);
1408 }
1409 
scsiback_check_stop_free(struct se_cmd * se_cmd)1410 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1411 {
1412 	return transport_generic_free_cmd(se_cmd, 0);
1413 }
1414 
scsiback_release_cmd(struct se_cmd * se_cmd)1415 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1416 {
1417 	target_free_tag(se_cmd->se_sess, se_cmd);
1418 }
1419 
scsiback_write_pending(struct se_cmd * se_cmd)1420 static int scsiback_write_pending(struct se_cmd *se_cmd)
1421 {
1422 	/* Go ahead and process the write immediately */
1423 	target_execute_cmd(se_cmd);
1424 
1425 	return 0;
1426 }
1427 
scsiback_queue_data_in(struct se_cmd * se_cmd)1428 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1429 {
1430 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1431 				struct vscsibk_pend, se_cmd);
1432 
1433 	pending_req->result = SAM_STAT_GOOD;
1434 	scsiback_cmd_done(pending_req);
1435 	return 0;
1436 }
1437 
scsiback_queue_status(struct se_cmd * se_cmd)1438 static int scsiback_queue_status(struct se_cmd *se_cmd)
1439 {
1440 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1441 				struct vscsibk_pend, se_cmd);
1442 
1443 	if (se_cmd->sense_buffer &&
1444 	    ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1445 	     (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1446 		pending_req->result = SAM_STAT_CHECK_CONDITION;
1447 	else
1448 		pending_req->result = se_cmd->scsi_status;
1449 
1450 	scsiback_cmd_done(pending_req);
1451 	return 0;
1452 }
1453 
scsiback_queue_tm_rsp(struct se_cmd * se_cmd)1454 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1455 {
1456 	struct vscsibk_pend *pending_req = container_of(se_cmd,
1457 				struct vscsibk_pend, se_cmd);
1458 
1459 	complete(&pending_req->tmr_done);
1460 }
1461 
scsiback_aborted_task(struct se_cmd * se_cmd)1462 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1463 {
1464 }
1465 
scsiback_tpg_param_alias_show(struct config_item * item,char * page)1466 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1467 					     char *page)
1468 {
1469 	struct se_portal_group *se_tpg = param_to_tpg(item);
1470 	struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1471 						se_tpg);
1472 	ssize_t rb;
1473 
1474 	mutex_lock(&tpg->tv_tpg_mutex);
1475 	rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1476 	mutex_unlock(&tpg->tv_tpg_mutex);
1477 
1478 	return rb;
1479 }
1480 
scsiback_tpg_param_alias_store(struct config_item * item,const char * page,size_t count)1481 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1482 					      const char *page, size_t count)
1483 {
1484 	struct se_portal_group *se_tpg = param_to_tpg(item);
1485 	struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1486 						se_tpg);
1487 	int len;
1488 
1489 	if (strlen(page) >= VSCSI_NAMELEN) {
1490 		pr_err("param alias: %s, exceeds max: %d\n", page,
1491 			VSCSI_NAMELEN);
1492 		return -EINVAL;
1493 	}
1494 
1495 	mutex_lock(&tpg->tv_tpg_mutex);
1496 	len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1497 	if (tpg->param_alias[len - 1] == '\n')
1498 		tpg->param_alias[len - 1] = '\0';
1499 	mutex_unlock(&tpg->tv_tpg_mutex);
1500 
1501 	return count;
1502 }
1503 
1504 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1505 
1506 static struct configfs_attribute *scsiback_param_attrs[] = {
1507 	&scsiback_tpg_param_attr_alias,
1508 	NULL,
1509 };
1510 
scsiback_alloc_sess_cb(struct se_portal_group * se_tpg,struct se_session * se_sess,void * p)1511 static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1512 				  struct se_session *se_sess, void *p)
1513 {
1514 	struct scsiback_tpg *tpg = container_of(se_tpg,
1515 				struct scsiback_tpg, se_tpg);
1516 
1517 	tpg->tpg_nexus = p;
1518 	return 0;
1519 }
1520 
scsiback_make_nexus(struct scsiback_tpg * tpg,const char * name)1521 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1522 				const char *name)
1523 {
1524 	struct scsiback_nexus *tv_nexus;
1525 	int ret = 0;
1526 
1527 	mutex_lock(&tpg->tv_tpg_mutex);
1528 	if (tpg->tpg_nexus) {
1529 		pr_debug("tpg->tpg_nexus already exists\n");
1530 		ret = -EEXIST;
1531 		goto out_unlock;
1532 	}
1533 
1534 	tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1535 	if (!tv_nexus) {
1536 		ret = -ENOMEM;
1537 		goto out_unlock;
1538 	}
1539 
1540 	tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
1541 						     VSCSI_DEFAULT_SESSION_TAGS,
1542 						     sizeof(struct vscsibk_pend),
1543 						     TARGET_PROT_NORMAL, name,
1544 						     tv_nexus, scsiback_alloc_sess_cb);
1545 	if (IS_ERR(tv_nexus->tvn_se_sess)) {
1546 		kfree(tv_nexus);
1547 		ret = -ENOMEM;
1548 		goto out_unlock;
1549 	}
1550 
1551 out_unlock:
1552 	mutex_unlock(&tpg->tv_tpg_mutex);
1553 	return ret;
1554 }
1555 
scsiback_drop_nexus(struct scsiback_tpg * tpg)1556 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1557 {
1558 	struct se_session *se_sess;
1559 	struct scsiback_nexus *tv_nexus;
1560 
1561 	mutex_lock(&tpg->tv_tpg_mutex);
1562 	tv_nexus = tpg->tpg_nexus;
1563 	if (!tv_nexus) {
1564 		mutex_unlock(&tpg->tv_tpg_mutex);
1565 		return -ENODEV;
1566 	}
1567 
1568 	se_sess = tv_nexus->tvn_se_sess;
1569 	if (!se_sess) {
1570 		mutex_unlock(&tpg->tv_tpg_mutex);
1571 		return -ENODEV;
1572 	}
1573 
1574 	if (tpg->tv_tpg_port_count != 0) {
1575 		mutex_unlock(&tpg->tv_tpg_mutex);
1576 		pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1577 			tpg->tv_tpg_port_count);
1578 		return -EBUSY;
1579 	}
1580 
1581 	if (tpg->tv_tpg_fe_count != 0) {
1582 		mutex_unlock(&tpg->tv_tpg_mutex);
1583 		pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1584 			tpg->tv_tpg_fe_count);
1585 		return -EBUSY;
1586 	}
1587 
1588 	pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1589 		scsiback_dump_proto_id(tpg->tport),
1590 		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1591 
1592 	/*
1593 	 * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1594 	 */
1595 	target_remove_session(se_sess);
1596 	tpg->tpg_nexus = NULL;
1597 	mutex_unlock(&tpg->tv_tpg_mutex);
1598 
1599 	kfree(tv_nexus);
1600 	return 0;
1601 }
1602 
scsiback_tpg_nexus_show(struct config_item * item,char * page)1603 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1604 {
1605 	struct se_portal_group *se_tpg = to_tpg(item);
1606 	struct scsiback_tpg *tpg = container_of(se_tpg,
1607 				struct scsiback_tpg, se_tpg);
1608 	struct scsiback_nexus *tv_nexus;
1609 	ssize_t ret;
1610 
1611 	mutex_lock(&tpg->tv_tpg_mutex);
1612 	tv_nexus = tpg->tpg_nexus;
1613 	if (!tv_nexus) {
1614 		mutex_unlock(&tpg->tv_tpg_mutex);
1615 		return -ENODEV;
1616 	}
1617 	ret = snprintf(page, PAGE_SIZE, "%s\n",
1618 			tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1619 	mutex_unlock(&tpg->tv_tpg_mutex);
1620 
1621 	return ret;
1622 }
1623 
scsiback_tpg_nexus_store(struct config_item * item,const char * page,size_t count)1624 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1625 		const char *page, size_t count)
1626 {
1627 	struct se_portal_group *se_tpg = to_tpg(item);
1628 	struct scsiback_tpg *tpg = container_of(se_tpg,
1629 				struct scsiback_tpg, se_tpg);
1630 	struct scsiback_tport *tport_wwn = tpg->tport;
1631 	unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1632 	int ret;
1633 	/*
1634 	 * Shutdown the active I_T nexus if 'NULL' is passed.
1635 	 */
1636 	if (!strncmp(page, "NULL", 4)) {
1637 		ret = scsiback_drop_nexus(tpg);
1638 		return (!ret) ? count : ret;
1639 	}
1640 	/*
1641 	 * Otherwise make sure the passed virtual Initiator port WWN matches
1642 	 * the fabric protocol_id set in scsiback_make_tport(), and call
1643 	 * scsiback_make_nexus().
1644 	 */
1645 	if (strlen(page) >= VSCSI_NAMELEN) {
1646 		pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1647 			page, VSCSI_NAMELEN);
1648 		return -EINVAL;
1649 	}
1650 	snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1651 
1652 	ptr = strstr(i_port, "naa.");
1653 	if (ptr) {
1654 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1655 			pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1656 				i_port, scsiback_dump_proto_id(tport_wwn));
1657 			return -EINVAL;
1658 		}
1659 		port_ptr = &i_port[0];
1660 		goto check_newline;
1661 	}
1662 	ptr = strstr(i_port, "fc.");
1663 	if (ptr) {
1664 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1665 			pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1666 				i_port, scsiback_dump_proto_id(tport_wwn));
1667 			return -EINVAL;
1668 		}
1669 		port_ptr = &i_port[3]; /* Skip over "fc." */
1670 		goto check_newline;
1671 	}
1672 	ptr = strstr(i_port, "iqn.");
1673 	if (ptr) {
1674 		if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1675 			pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1676 				i_port, scsiback_dump_proto_id(tport_wwn));
1677 			return -EINVAL;
1678 		}
1679 		port_ptr = &i_port[0];
1680 		goto check_newline;
1681 	}
1682 	pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1683 		i_port);
1684 	return -EINVAL;
1685 	/*
1686 	 * Clear any trailing newline for the NAA WWN
1687 	 */
1688 check_newline:
1689 	if (i_port[strlen(i_port) - 1] == '\n')
1690 		i_port[strlen(i_port) - 1] = '\0';
1691 
1692 	ret = scsiback_make_nexus(tpg, port_ptr);
1693 	if (ret < 0)
1694 		return ret;
1695 
1696 	return count;
1697 }
1698 
1699 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1700 
1701 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1702 	&scsiback_tpg_attr_nexus,
1703 	NULL,
1704 };
1705 
1706 static ssize_t
scsiback_wwn_version_show(struct config_item * item,char * page)1707 scsiback_wwn_version_show(struct config_item *item, char *page)
1708 {
1709 	return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1710 		UTS_RELEASE"\n",
1711 		VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1712 }
1713 
1714 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1715 
1716 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1717 	&scsiback_wwn_attr_version,
1718 	NULL,
1719 };
1720 
scsiback_port_link(struct se_portal_group * se_tpg,struct se_lun * lun)1721 static int scsiback_port_link(struct se_portal_group *se_tpg,
1722 			       struct se_lun *lun)
1723 {
1724 	struct scsiback_tpg *tpg = container_of(se_tpg,
1725 				struct scsiback_tpg, se_tpg);
1726 
1727 	mutex_lock(&tpg->tv_tpg_mutex);
1728 	tpg->tv_tpg_port_count++;
1729 	mutex_unlock(&tpg->tv_tpg_mutex);
1730 
1731 	return 0;
1732 }
1733 
scsiback_port_unlink(struct se_portal_group * se_tpg,struct se_lun * lun)1734 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1735 				  struct se_lun *lun)
1736 {
1737 	struct scsiback_tpg *tpg = container_of(se_tpg,
1738 				struct scsiback_tpg, se_tpg);
1739 
1740 	mutex_lock(&tpg->tv_tpg_mutex);
1741 	tpg->tv_tpg_port_count--;
1742 	mutex_unlock(&tpg->tv_tpg_mutex);
1743 }
1744 
1745 static struct se_portal_group *
scsiback_make_tpg(struct se_wwn * wwn,const char * name)1746 scsiback_make_tpg(struct se_wwn *wwn, const char *name)
1747 {
1748 	struct scsiback_tport *tport = container_of(wwn,
1749 			struct scsiback_tport, tport_wwn);
1750 
1751 	struct scsiback_tpg *tpg;
1752 	u16 tpgt;
1753 	int ret;
1754 
1755 	if (strstr(name, "tpgt_") != name)
1756 		return ERR_PTR(-EINVAL);
1757 	ret = kstrtou16(name + 5, 10, &tpgt);
1758 	if (ret)
1759 		return ERR_PTR(ret);
1760 
1761 	tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1762 	if (!tpg)
1763 		return ERR_PTR(-ENOMEM);
1764 
1765 	mutex_init(&tpg->tv_tpg_mutex);
1766 	INIT_LIST_HEAD(&tpg->tv_tpg_list);
1767 	INIT_LIST_HEAD(&tpg->info_list);
1768 	tpg->tport = tport;
1769 	tpg->tport_tpgt = tpgt;
1770 
1771 	ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1772 	if (ret < 0) {
1773 		kfree(tpg);
1774 		return NULL;
1775 	}
1776 	mutex_lock(&scsiback_mutex);
1777 	list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1778 	mutex_unlock(&scsiback_mutex);
1779 
1780 	return &tpg->se_tpg;
1781 }
1782 
scsiback_drop_tpg(struct se_portal_group * se_tpg)1783 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1784 {
1785 	struct scsiback_tpg *tpg = container_of(se_tpg,
1786 				struct scsiback_tpg, se_tpg);
1787 
1788 	mutex_lock(&scsiback_mutex);
1789 	list_del(&tpg->tv_tpg_list);
1790 	mutex_unlock(&scsiback_mutex);
1791 	/*
1792 	 * Release the virtual I_T Nexus for this xen-pvscsi TPG
1793 	 */
1794 	scsiback_drop_nexus(tpg);
1795 	/*
1796 	 * Deregister the se_tpg from TCM.
1797 	 */
1798 	core_tpg_deregister(se_tpg);
1799 	kfree(tpg);
1800 }
1801 
scsiback_check_true(struct se_portal_group * se_tpg)1802 static int scsiback_check_true(struct se_portal_group *se_tpg)
1803 {
1804 	return 1;
1805 }
1806 
1807 static const struct target_core_fabric_ops scsiback_ops = {
1808 	.module				= THIS_MODULE,
1809 	.fabric_name			= "xen-pvscsi",
1810 	.tpg_get_wwn			= scsiback_get_fabric_wwn,
1811 	.tpg_get_tag			= scsiback_get_tag,
1812 	.tpg_check_demo_mode		= scsiback_check_true,
1813 	.tpg_check_demo_mode_cache	= scsiback_check_true,
1814 	.check_stop_free		= scsiback_check_stop_free,
1815 	.release_cmd			= scsiback_release_cmd,
1816 	.sess_get_initiator_sid		= NULL,
1817 	.write_pending			= scsiback_write_pending,
1818 	.queue_data_in			= scsiback_queue_data_in,
1819 	.queue_status			= scsiback_queue_status,
1820 	.queue_tm_rsp			= scsiback_queue_tm_rsp,
1821 	.aborted_task			= scsiback_aborted_task,
1822 	/*
1823 	 * Setup callers for generic logic in target_core_fabric_configfs.c
1824 	 */
1825 	.fabric_make_wwn		= scsiback_make_tport,
1826 	.fabric_drop_wwn		= scsiback_drop_tport,
1827 	.fabric_make_tpg		= scsiback_make_tpg,
1828 	.fabric_drop_tpg		= scsiback_drop_tpg,
1829 	.fabric_post_link		= scsiback_port_link,
1830 	.fabric_pre_unlink		= scsiback_port_unlink,
1831 
1832 	.tfc_wwn_attrs			= scsiback_wwn_attrs,
1833 	.tfc_tpg_base_attrs		= scsiback_tpg_attrs,
1834 	.tfc_tpg_param_attrs		= scsiback_param_attrs,
1835 };
1836 
1837 static const struct xenbus_device_id scsiback_ids[] = {
1838 	{ "vscsi" },
1839 	{ "" }
1840 };
1841 
1842 static struct xenbus_driver scsiback_driver = {
1843 	.ids			= scsiback_ids,
1844 	.probe			= scsiback_probe,
1845 	.remove			= scsiback_remove,
1846 	.otherend_changed	= scsiback_frontend_changed
1847 };
1848 
scsiback_init(void)1849 static int __init scsiback_init(void)
1850 {
1851 	int ret;
1852 
1853 	if (!xen_domain())
1854 		return -ENODEV;
1855 
1856 	pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1857 		 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1858 
1859 	ret = xenbus_register_backend(&scsiback_driver);
1860 	if (ret)
1861 		goto out;
1862 
1863 	ret = target_register_template(&scsiback_ops);
1864 	if (ret)
1865 		goto out_unregister_xenbus;
1866 
1867 	return 0;
1868 
1869 out_unregister_xenbus:
1870 	xenbus_unregister_driver(&scsiback_driver);
1871 out:
1872 	pr_err("%s: error %d\n", __func__, ret);
1873 	return ret;
1874 }
1875 
scsiback_exit(void)1876 static void __exit scsiback_exit(void)
1877 {
1878 	target_unregister_template(&scsiback_ops);
1879 	xenbus_unregister_driver(&scsiback_driver);
1880 }
1881 
1882 module_init(scsiback_init);
1883 module_exit(scsiback_exit);
1884 
1885 MODULE_DESCRIPTION("Xen SCSI backend driver");
1886 MODULE_LICENSE("Dual BSD/GPL");
1887 MODULE_ALIAS("xen-backend:vscsi");
1888 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
1889