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