Merge tag 'for-linus-4.4-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git...
[sfrench/cifs-2.6.git] / drivers / xen / xen-scsiback.c
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
72 struct ids_tuple {
73         unsigned int hst;               /* host    */
74         unsigned int chn;               /* channel */
75         unsigned int tgt;               /* target  */
76         unsigned int lun;               /* LUN     */
77 };
78
79 struct 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
87 struct 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
115 struct 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
139 struct scsiback_tmr {
140         atomic_t tmr_complete;
141         wait_queue_head_t tmr_wait;
142 };
143
144 struct scsiback_nexus {
145         /* Pointer to TCM session for I_T Nexus */
146         struct se_session *tvn_se_sess;
147 };
148
149 struct scsiback_tport {
150         /* SCSI protocol the tport is providing */
151         u8 tport_proto_id;
152         /* Binary World Wide unique Port Name for pvscsi Target port */
153         u64 tport_wwpn;
154         /* ASCII formatted WWPN for pvscsi Target port */
155         char tport_name[VSCSI_NAMELEN];
156         /* Returned by scsiback_make_tport() */
157         struct se_wwn tport_wwn;
158 };
159
160 struct scsiback_tpg {
161         /* scsiback port target portal group tag for TCM */
162         u16 tport_tpgt;
163         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
164         int tv_tpg_port_count;
165         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
166         int tv_tpg_fe_count;
167         /* list for scsiback_list */
168         struct list_head tv_tpg_list;
169         /* Used to protect access for tpg_nexus */
170         struct mutex tv_tpg_mutex;
171         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
172         struct scsiback_nexus *tpg_nexus;
173         /* Pointer back to scsiback_tport */
174         struct scsiback_tport *tport;
175         /* Returned by scsiback_make_tpg() */
176         struct se_portal_group se_tpg;
177         /* alias used in xenstore */
178         char param_alias[VSCSI_NAMELEN];
179         /* list of info structures related to this target portal group */
180         struct list_head info_list;
181 };
182
183 #define SCSIBACK_INVALID_HANDLE (~0)
184
185 static bool log_print_stat;
186 module_param(log_print_stat, bool, 0644);
187
188 static int scsiback_max_buffer_pages = 1024;
189 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
190 MODULE_PARM_DESC(max_buffer_pages,
191 "Maximum number of free pages to keep in backend buffer");
192
193 static struct kmem_cache *scsiback_cachep;
194 static DEFINE_SPINLOCK(free_pages_lock);
195 static int free_pages_num;
196 static LIST_HEAD(scsiback_free_pages);
197
198 /* Global spinlock to protect scsiback TPG list */
199 static DEFINE_MUTEX(scsiback_mutex);
200 static LIST_HEAD(scsiback_list);
201
202 static void scsiback_get(struct vscsibk_info *info)
203 {
204         atomic_inc(&info->nr_unreplied_reqs);
205 }
206
207 static void scsiback_put(struct vscsibk_info *info)
208 {
209         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
210                 wake_up(&info->waiting_to_free);
211 }
212
213 static void put_free_pages(struct page **page, int num)
214 {
215         unsigned long flags;
216         int i = free_pages_num + num, n = num;
217
218         if (num == 0)
219                 return;
220         if (i > scsiback_max_buffer_pages) {
221                 n = min(num, i - scsiback_max_buffer_pages);
222                 gnttab_free_pages(n, page + num - n);
223                 n = num - n;
224         }
225         spin_lock_irqsave(&free_pages_lock, flags);
226         for (i = 0; i < n; i++)
227                 list_add(&page[i]->lru, &scsiback_free_pages);
228         free_pages_num += n;
229         spin_unlock_irqrestore(&free_pages_lock, flags);
230 }
231
232 static int get_free_page(struct page **page)
233 {
234         unsigned long flags;
235
236         spin_lock_irqsave(&free_pages_lock, flags);
237         if (list_empty(&scsiback_free_pages)) {
238                 spin_unlock_irqrestore(&free_pages_lock, flags);
239                 return gnttab_alloc_pages(1, page);
240         }
241         page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
242         list_del(&page[0]->lru);
243         free_pages_num--;
244         spin_unlock_irqrestore(&free_pages_lock, flags);
245         return 0;
246 }
247
248 static unsigned long vaddr_page(struct page *page)
249 {
250         unsigned long pfn = page_to_pfn(page);
251
252         return (unsigned long)pfn_to_kaddr(pfn);
253 }
254
255 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
256 {
257         return vaddr_page(req->pages[seg]);
258 }
259
260 static void scsiback_print_status(char *sense_buffer, int errors,
261                                         struct vscsibk_pend *pending_req)
262 {
263         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
264
265         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
266                tpg->tport->tport_name, pending_req->v2p->lun,
267                pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
268                host_byte(errors), driver_byte(errors));
269 }
270
271 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
272 {
273         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
274         struct page *pages[VSCSI_GRANT_BATCH];
275         unsigned int i, invcount = 0;
276         grant_handle_t handle;
277         int err;
278
279         kfree(req->sgl);
280         req->sgl = NULL;
281         req->n_sg = 0;
282
283         if (!req->n_grants)
284                 return;
285
286         for (i = 0; i < req->n_grants; i++) {
287                 handle = req->grant_handles[i];
288                 if (handle == SCSIBACK_INVALID_HANDLE)
289                         continue;
290                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
291                                     GNTMAP_host_map, handle);
292                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
293                 pages[invcount] = req->pages[i];
294                 put_page(pages[invcount]);
295                 invcount++;
296                 if (invcount < VSCSI_GRANT_BATCH)
297                         continue;
298                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
299                 BUG_ON(err);
300                 invcount = 0;
301         }
302
303         if (invcount) {
304                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
305                 BUG_ON(err);
306         }
307
308         put_free_pages(req->pages, req->n_grants);
309         req->n_grants = 0;
310 }
311
312 static void scsiback_free_translation_entry(struct kref *kref)
313 {
314         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
315         struct scsiback_tpg *tpg = entry->tpg;
316
317         mutex_lock(&tpg->tv_tpg_mutex);
318         tpg->tv_tpg_fe_count--;
319         mutex_unlock(&tpg->tv_tpg_mutex);
320
321         kfree(entry);
322 }
323
324 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
325                         uint32_t resid, struct vscsibk_pend *pending_req)
326 {
327         struct vscsiif_response *ring_res;
328         struct vscsibk_info *info = pending_req->info;
329         int notify;
330         struct scsi_sense_hdr sshdr;
331         unsigned long flags;
332         unsigned len;
333
334         spin_lock_irqsave(&info->ring_lock, flags);
335
336         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
337         info->ring.rsp_prod_pvt++;
338
339         ring_res->rslt   = result;
340         ring_res->rqid   = pending_req->rqid;
341
342         if (sense_buffer != NULL &&
343             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
344                                  &sshdr)) {
345                 len = min_t(unsigned, 8 + sense_buffer[7],
346                             VSCSIIF_SENSE_BUFFERSIZE);
347                 memcpy(ring_res->sense_buffer, sense_buffer, len);
348                 ring_res->sense_len = len;
349         } else {
350                 ring_res->sense_len = 0;
351         }
352
353         ring_res->residual_len = resid;
354
355         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
356         spin_unlock_irqrestore(&info->ring_lock, flags);
357
358         if (notify)
359                 notify_remote_via_irq(info->irq);
360
361         if (pending_req->v2p)
362                 kref_put(&pending_req->v2p->kref,
363                          scsiback_free_translation_entry);
364 }
365
366 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
367 {
368         struct vscsibk_info *info = pending_req->info;
369         unsigned char *sense_buffer;
370         unsigned int resid;
371         int errors;
372
373         sense_buffer = pending_req->sense_buffer;
374         resid        = pending_req->se_cmd.residual_count;
375         errors       = pending_req->result;
376
377         if (errors && log_print_stat)
378                 scsiback_print_status(sense_buffer, errors, pending_req);
379
380         scsiback_fast_flush_area(pending_req);
381         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
382         scsiback_put(info);
383 }
384
385 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
386 {
387         struct se_cmd *se_cmd = &pending_req->se_cmd;
388         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
389         int rc;
390
391         memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
392
393         memset(se_cmd, 0, sizeof(*se_cmd));
394
395         scsiback_get(pending_req->info);
396         se_cmd->tag = pending_req->rqid;
397         rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
398                         pending_req->sense_buffer, pending_req->v2p->lun,
399                         pending_req->data_len, 0,
400                         pending_req->sc_data_direction, 0,
401                         pending_req->sgl, pending_req->n_sg,
402                         NULL, 0, NULL, 0);
403         if (rc < 0) {
404                 transport_send_check_condition_and_sense(se_cmd,
405                                 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
406                 transport_generic_free_cmd(se_cmd, 0);
407         }
408 }
409
410 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
411         struct page **pg, grant_handle_t *grant, int cnt)
412 {
413         int err, i;
414
415         if (!cnt)
416                 return 0;
417
418         err = gnttab_map_refs(map, NULL, pg, cnt);
419         BUG_ON(err);
420         for (i = 0; i < cnt; i++) {
421                 if (unlikely(map[i].status != GNTST_okay)) {
422                         pr_err("invalid buffer -- could not remap it\n");
423                         map[i].handle = SCSIBACK_INVALID_HANDLE;
424                         err = -ENOMEM;
425                 } else {
426                         get_page(pg[i]);
427                 }
428                 grant[i] = map[i].handle;
429         }
430         return err;
431 }
432
433 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
434                         struct scsiif_request_segment *seg, struct page **pg,
435                         grant_handle_t *grant, int cnt, u32 flags)
436 {
437         int mapcount = 0, i, err = 0;
438         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
439         struct vscsibk_info *info = pending_req->info;
440
441         for (i = 0; i < cnt; i++) {
442                 if (get_free_page(pg + mapcount)) {
443                         put_free_pages(pg, mapcount);
444                         pr_err("no grant page\n");
445                         return -ENOMEM;
446                 }
447                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
448                                   flags, seg[i].gref, info->domid);
449                 mapcount++;
450                 if (mapcount < VSCSI_GRANT_BATCH)
451                         continue;
452                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
453                 pg += mapcount;
454                 grant += mapcount;
455                 pending_req->n_grants += mapcount;
456                 if (err)
457                         return err;
458                 mapcount = 0;
459         }
460         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
461         pending_req->n_grants += mapcount;
462         return err;
463 }
464
465 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
466                                         struct vscsibk_pend *pending_req)
467 {
468         u32 flags;
469         int i, err, n_segs, i_seg = 0;
470         struct page **pg;
471         struct scsiif_request_segment *seg;
472         unsigned long end_seg = 0;
473         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
474         unsigned int nr_sgl = 0;
475         struct scatterlist *sg;
476         grant_handle_t *grant;
477
478         pending_req->n_sg = 0;
479         pending_req->n_grants = 0;
480         pending_req->data_len = 0;
481
482         nr_segments &= ~VSCSIIF_SG_GRANT;
483         if (!nr_segments)
484                 return 0;
485
486         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
487                 pr_debug("invalid parameter nr_seg = %d\n",
488                         ring_req->nr_segments);
489                 return -EINVAL;
490         }
491
492         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
493                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
494                         pending_req->pages, pending_req->grant_handles,
495                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
496                 if (err)
497                         return err;
498                 nr_sgl = nr_segments;
499                 nr_segments = 0;
500                 for (i = 0; i < nr_sgl; i++) {
501                         n_segs = ring_req->seg[i].length /
502                                  sizeof(struct scsiif_request_segment);
503                         if ((unsigned)ring_req->seg[i].offset +
504                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
505                             n_segs * sizeof(struct scsiif_request_segment) !=
506                             ring_req->seg[i].length)
507                                 return -EINVAL;
508                         nr_segments += n_segs;
509                 }
510                 if (nr_segments > SG_ALL) {
511                         pr_debug("invalid nr_seg = %d\n", nr_segments);
512                         return -EINVAL;
513                 }
514         }
515
516         /* free of (sgl) in fast_flush_area() */
517         pending_req->sgl = kmalloc_array(nr_segments,
518                                         sizeof(struct scatterlist), GFP_KERNEL);
519         if (!pending_req->sgl)
520                 return -ENOMEM;
521
522         sg_init_table(pending_req->sgl, nr_segments);
523         pending_req->n_sg = nr_segments;
524
525         flags = GNTMAP_host_map;
526         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
527                 flags |= GNTMAP_readonly;
528
529         pg = pending_req->pages + nr_sgl;
530         grant = pending_req->grant_handles + nr_sgl;
531         if (!nr_sgl) {
532                 seg = ring_req->seg;
533                 err = scsiback_gnttab_data_map_list(pending_req, seg,
534                         pg, grant, nr_segments, flags);
535                 if (err)
536                         return err;
537         } else {
538                 for (i = 0; i < nr_sgl; i++) {
539                         seg = (struct scsiif_request_segment *)(
540                               vaddr(pending_req, i) + ring_req->seg[i].offset);
541                         n_segs = ring_req->seg[i].length /
542                                  sizeof(struct scsiif_request_segment);
543                         err = scsiback_gnttab_data_map_list(pending_req, seg,
544                                 pg, grant, n_segs, flags);
545                         if (err)
546                                 return err;
547                         pg += n_segs;
548                         grant += n_segs;
549                 }
550                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
551                 seg = (struct scsiif_request_segment *)end_seg;
552                 end_seg += ring_req->seg[0].length;
553                 pg = pending_req->pages + nr_sgl;
554         }
555
556         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
557                 sg_set_page(sg, pg[i], seg->length, seg->offset);
558                 pending_req->data_len += seg->length;
559                 seg++;
560                 if (nr_sgl && (unsigned long)seg >= end_seg) {
561                         i_seg++;
562                         end_seg = vaddr(pending_req, i_seg) +
563                                   ring_req->seg[i_seg].offset;
564                         seg = (struct scsiif_request_segment *)end_seg;
565                         end_seg += ring_req->seg[i_seg].length;
566                 }
567                 if (sg->offset >= PAGE_SIZE ||
568                     sg->length > PAGE_SIZE ||
569                     sg->offset + sg->length > PAGE_SIZE)
570                         return -EINVAL;
571         }
572
573         return 0;
574 }
575
576 static void scsiback_disconnect(struct vscsibk_info *info)
577 {
578         wait_event(info->waiting_to_free,
579                 atomic_read(&info->nr_unreplied_reqs) == 0);
580
581         unbind_from_irqhandler(info->irq, info);
582         info->irq = 0;
583         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
584 }
585
586 static void scsiback_device_action(struct vscsibk_pend *pending_req,
587         enum tcm_tmreq_table act, int tag)
588 {
589         int rc, err = FAILED;
590         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
591         struct se_cmd *se_cmd = &pending_req->se_cmd;
592         struct scsiback_tmr *tmr;
593
594         tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
595         if (!tmr)
596                 goto out;
597
598         init_waitqueue_head(&tmr->tmr_wait);
599
600         transport_init_se_cmd(se_cmd, tpg->se_tpg.se_tpg_tfo,
601                 tpg->tpg_nexus->tvn_se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG,
602                 &pending_req->sense_buffer[0]);
603
604         rc = core_tmr_alloc_req(se_cmd, tmr, act, GFP_KERNEL);
605         if (rc < 0)
606                 goto out;
607
608         se_cmd->se_tmr_req->ref_task_tag = tag;
609
610         if (transport_lookup_tmr_lun(se_cmd, pending_req->v2p->lun) < 0)
611                 goto out;
612
613         transport_generic_handle_tmr(se_cmd);
614         wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));
615
616         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
617                 SUCCESS : FAILED;
618
619 out:
620         if (tmr) {
621                 transport_generic_free_cmd(&pending_req->se_cmd, 1);
622                 kfree(tmr);
623         }
624
625         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
626
627         kmem_cache_free(scsiback_cachep, pending_req);
628 }
629
630 /*
631   Perform virtual to physical translation
632 */
633 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
634                         struct ids_tuple *v)
635 {
636         struct v2p_entry *entry;
637         struct list_head *head = &(info->v2p_entry_lists);
638         unsigned long flags;
639
640         spin_lock_irqsave(&info->v2p_lock, flags);
641         list_for_each_entry(entry, head, l) {
642                 if ((entry->v.chn == v->chn) &&
643                     (entry->v.tgt == v->tgt) &&
644                     (entry->v.lun == v->lun)) {
645                         kref_get(&entry->kref);
646                         goto out;
647                 }
648         }
649         entry = NULL;
650
651 out:
652         spin_unlock_irqrestore(&info->v2p_lock, flags);
653         return entry;
654 }
655
656 static int prepare_pending_reqs(struct vscsibk_info *info,
657                                 struct vscsiif_request *ring_req,
658                                 struct vscsibk_pend *pending_req)
659 {
660         struct v2p_entry *v2p;
661         struct ids_tuple vir;
662
663         pending_req->rqid       = ring_req->rqid;
664         pending_req->info       = info;
665
666         vir.chn = ring_req->channel;
667         vir.tgt = ring_req->id;
668         vir.lun = ring_req->lun;
669
670         v2p = scsiback_do_translation(info, &vir);
671         if (!v2p) {
672                 pending_req->v2p = NULL;
673                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
674                         vir.chn, vir.tgt, vir.lun);
675                 return -ENODEV;
676         }
677         pending_req->v2p = v2p;
678
679         /* request range check from frontend */
680         pending_req->sc_data_direction = ring_req->sc_data_direction;
681         if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
682                 (pending_req->sc_data_direction != DMA_TO_DEVICE) &&
683                 (pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
684                 (pending_req->sc_data_direction != DMA_NONE)) {
685                 pr_debug("invalid parameter data_dir = %d\n",
686                         pending_req->sc_data_direction);
687                 return -EINVAL;
688         }
689
690         pending_req->cmd_len = ring_req->cmd_len;
691         if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
692                 pr_debug("invalid parameter cmd_len = %d\n",
693                         pending_req->cmd_len);
694                 return -EINVAL;
695         }
696         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
697
698         return 0;
699 }
700
701 static int scsiback_do_cmd_fn(struct vscsibk_info *info)
702 {
703         struct vscsiif_back_ring *ring = &info->ring;
704         struct vscsiif_request ring_req;
705         struct vscsibk_pend *pending_req;
706         RING_IDX rc, rp;
707         int err, more_to_do;
708         uint32_t result;
709
710         rc = ring->req_cons;
711         rp = ring->sring->req_prod;
712         rmb();  /* guest system is accessing ring, too */
713
714         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
715                 rc = ring->rsp_prod_pvt;
716                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
717                            info->domid, rp, rc, rp - rc);
718                 info->ring_error = 1;
719                 return 0;
720         }
721
722         while ((rc != rp)) {
723                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
724                         break;
725                 pending_req = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
726                 if (!pending_req)
727                         return 1;
728
729                 RING_COPY_REQUEST(ring, rc, &ring_req);
730                 ring->req_cons = ++rc;
731
732                 err = prepare_pending_reqs(info, &ring_req, pending_req);
733                 if (err) {
734                         switch (err) {
735                         case -ENODEV:
736                                 result = DID_NO_CONNECT;
737                                 break;
738                         default:
739                                 result = DRIVER_ERROR;
740                                 break;
741                         }
742                         scsiback_do_resp_with_sense(NULL, result << 24, 0,
743                                                     pending_req);
744                         kmem_cache_free(scsiback_cachep, pending_req);
745                         return 1;
746                 }
747
748                 switch (ring_req.act) {
749                 case VSCSIIF_ACT_SCSI_CDB:
750                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
751                                 scsiback_fast_flush_area(pending_req);
752                                 scsiback_do_resp_with_sense(NULL,
753                                         DRIVER_ERROR << 24, 0, pending_req);
754                                 kmem_cache_free(scsiback_cachep, pending_req);
755                         } else {
756                                 scsiback_cmd_exec(pending_req);
757                         }
758                         break;
759                 case VSCSIIF_ACT_SCSI_ABORT:
760                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
761                                 ring_req.ref_rqid);
762                         break;
763                 case VSCSIIF_ACT_SCSI_RESET:
764                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
765                         break;
766                 default:
767                         pr_err_ratelimited("invalid request\n");
768                         scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
769                                                     0, pending_req);
770                         kmem_cache_free(scsiback_cachep, pending_req);
771                         break;
772                 }
773
774                 /* Yield point for this unbounded loop. */
775                 cond_resched();
776         }
777
778         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
779         return more_to_do;
780 }
781
782 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
783 {
784         struct vscsibk_info *info = dev_id;
785
786         if (info->ring_error)
787                 return IRQ_HANDLED;
788
789         while (scsiback_do_cmd_fn(info))
790                 cond_resched();
791
792         return IRQ_HANDLED;
793 }
794
795 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
796                         evtchn_port_t evtchn)
797 {
798         void *area;
799         struct vscsiif_sring *sring;
800         int err;
801
802         if (info->irq)
803                 return -1;
804
805         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
806         if (err)
807                 return err;
808
809         sring = (struct vscsiif_sring *)area;
810         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
811
812         err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
813         if (err < 0)
814                 goto unmap_page;
815
816         info->irq = err;
817
818         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
819                                    IRQF_ONESHOT, "vscsiif-backend", info);
820         if (err)
821                 goto free_irq;
822
823         return 0;
824
825 free_irq:
826         unbind_from_irqhandler(info->irq, info);
827         info->irq = 0;
828 unmap_page:
829         xenbus_unmap_ring_vfree(info->dev, area);
830
831         return err;
832 }
833
834 static int scsiback_map(struct vscsibk_info *info)
835 {
836         struct xenbus_device *dev = info->dev;
837         unsigned int ring_ref, evtchn;
838         int err;
839
840         err = xenbus_gather(XBT_NIL, dev->otherend,
841                         "ring-ref", "%u", &ring_ref,
842                         "event-channel", "%u", &evtchn, NULL);
843         if (err) {
844                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
845                 return err;
846         }
847
848         return scsiback_init_sring(info, ring_ref, evtchn);
849 }
850
851 /*
852   Add a new translation entry
853 */
854 static int scsiback_add_translation_entry(struct vscsibk_info *info,
855                                           char *phy, struct ids_tuple *v)
856 {
857         int err = 0;
858         struct v2p_entry *entry;
859         struct v2p_entry *new;
860         struct list_head *head = &(info->v2p_entry_lists);
861         unsigned long flags;
862         char *lunp;
863         unsigned long long unpacked_lun;
864         struct se_lun *se_lun;
865         struct scsiback_tpg *tpg_entry, *tpg = NULL;
866         char *error = "doesn't exist";
867
868         lunp = strrchr(phy, ':');
869         if (!lunp) {
870                 pr_err("illegal format of physical device %s\n", phy);
871                 return -EINVAL;
872         }
873         *lunp = 0;
874         lunp++;
875         err = kstrtoull(lunp, 10, &unpacked_lun);
876         if (err < 0) {
877                 pr_err("lun number not valid: %s\n", lunp);
878                 return err;
879         }
880
881         mutex_lock(&scsiback_mutex);
882         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
883                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
884                     !strcmp(phy, tpg_entry->param_alias)) {
885                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
886                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
887                                 if (se_lun->unpacked_lun == unpacked_lun) {
888                                         if (!tpg_entry->tpg_nexus)
889                                                 error = "nexus undefined";
890                                         else
891                                                 tpg = tpg_entry;
892                                         break;
893                                 }
894                         }
895                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
896                         break;
897                 }
898         }
899         if (tpg) {
900                 mutex_lock(&tpg->tv_tpg_mutex);
901                 tpg->tv_tpg_fe_count++;
902                 mutex_unlock(&tpg->tv_tpg_mutex);
903         }
904         mutex_unlock(&scsiback_mutex);
905
906         if (!tpg) {
907                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
908                 return -ENODEV;
909         }
910
911         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
912         if (new == NULL) {
913                 err = -ENOMEM;
914                 goto out_free;
915         }
916
917         spin_lock_irqsave(&info->v2p_lock, flags);
918
919         /* Check double assignment to identical virtual ID */
920         list_for_each_entry(entry, head, l) {
921                 if ((entry->v.chn == v->chn) &&
922                     (entry->v.tgt == v->tgt) &&
923                     (entry->v.lun == v->lun)) {
924                         pr_warn("Virtual ID is already used. Assignment was not performed.\n");
925                         err = -EEXIST;
926                         goto out;
927                 }
928
929         }
930
931         /* Create a new translation entry and add to the list */
932         kref_init(&new->kref);
933         new->v = *v;
934         new->tpg = tpg;
935         new->lun = unpacked_lun;
936         list_add_tail(&new->l, head);
937
938 out:
939         spin_unlock_irqrestore(&info->v2p_lock, flags);
940
941 out_free:
942         mutex_lock(&tpg->tv_tpg_mutex);
943         tpg->tv_tpg_fe_count--;
944         mutex_unlock(&tpg->tv_tpg_mutex);
945
946         if (err)
947                 kfree(new);
948
949         return err;
950 }
951
952 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
953 {
954         list_del(&entry->l);
955         kref_put(&entry->kref, scsiback_free_translation_entry);
956 }
957
958 /*
959   Delete the translation entry specfied
960 */
961 static int scsiback_del_translation_entry(struct vscsibk_info *info,
962                                           struct ids_tuple *v)
963 {
964         struct v2p_entry *entry;
965         struct list_head *head = &(info->v2p_entry_lists);
966         unsigned long flags;
967
968         spin_lock_irqsave(&info->v2p_lock, flags);
969         /* Find out the translation entry specified */
970         list_for_each_entry(entry, head, l) {
971                 if ((entry->v.chn == v->chn) &&
972                     (entry->v.tgt == v->tgt) &&
973                     (entry->v.lun == v->lun)) {
974                         goto found;
975                 }
976         }
977
978         spin_unlock_irqrestore(&info->v2p_lock, flags);
979         return 1;
980
981 found:
982         /* Delete the translation entry specfied */
983         __scsiback_del_translation_entry(entry);
984
985         spin_unlock_irqrestore(&info->v2p_lock, flags);
986         return 0;
987 }
988
989 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
990                                 char *phy, struct ids_tuple *vir, int try)
991 {
992         if (!scsiback_add_translation_entry(info, phy, vir)) {
993                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
994                                   "%d", XenbusStateInitialised)) {
995                         pr_err("xenbus_printf error %s\n", state);
996                         scsiback_del_translation_entry(info, vir);
997                 }
998         } else if (!try) {
999                 xenbus_printf(XBT_NIL, info->dev->nodename, state,
1000                               "%d", XenbusStateClosed);
1001         }
1002 }
1003
1004 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1005                                 struct ids_tuple *vir)
1006 {
1007         if (!scsiback_del_translation_entry(info, vir)) {
1008                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1009                                   "%d", XenbusStateClosed))
1010                         pr_err("xenbus_printf error %s\n", state);
1011         }
1012 }
1013
1014 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1015 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1016
1017 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1018                                      char *ent)
1019 {
1020         int err;
1021         struct ids_tuple vir;
1022         char *val;
1023         int device_state;
1024         char phy[VSCSI_NAMELEN];
1025         char str[64];
1026         char state[64];
1027         struct xenbus_device *dev = info->dev;
1028
1029         /* read status */
1030         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1031         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1032         if (XENBUS_EXIST_ERR(err))
1033                 return;
1034
1035         /* physical SCSI device */
1036         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1037         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1038         if (IS_ERR(val)) {
1039                 xenbus_printf(XBT_NIL, dev->nodename, state,
1040                               "%d", XenbusStateClosed);
1041                 return;
1042         }
1043         strlcpy(phy, val, VSCSI_NAMELEN);
1044         kfree(val);
1045
1046         /* virtual SCSI device */
1047         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1048         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1049                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1050         if (XENBUS_EXIST_ERR(err)) {
1051                 xenbus_printf(XBT_NIL, dev->nodename, state,
1052                               "%d", XenbusStateClosed);
1053                 return;
1054         }
1055
1056         switch (op) {
1057         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1058                 switch (device_state) {
1059                 case XenbusStateInitialising:
1060                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1061                         break;
1062                 case XenbusStateConnected:
1063                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1064                         break;
1065                 case XenbusStateClosing:
1066                         scsiback_do_del_lun(info, state, &vir);
1067                         break;
1068                 default:
1069                         break;
1070                 }
1071                 break;
1072
1073         case VSCSIBACK_OP_UPDATEDEV_STATE:
1074                 if (device_state == XenbusStateInitialised) {
1075                         /* modify vscsi-devs/dev-x/state */
1076                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1077                                           "%d", XenbusStateConnected)) {
1078                                 pr_err("xenbus_printf error %s\n", str);
1079                                 scsiback_del_translation_entry(info, &vir);
1080                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1081                                               "%d", XenbusStateClosed);
1082                         }
1083                 }
1084                 break;
1085         /* When it is necessary, processing is added here. */
1086         default:
1087                 break;
1088         }
1089 }
1090
1091 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1092 {
1093         int i;
1094         char **dir;
1095         unsigned int ndir = 0;
1096
1097         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1098                                &ndir);
1099         if (IS_ERR(dir))
1100                 return;
1101
1102         for (i = 0; i < ndir; i++)
1103                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1104
1105         kfree(dir);
1106 }
1107
1108 static void scsiback_frontend_changed(struct xenbus_device *dev,
1109                                         enum xenbus_state frontend_state)
1110 {
1111         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1112
1113         switch (frontend_state) {
1114         case XenbusStateInitialising:
1115                 break;
1116
1117         case XenbusStateInitialised:
1118                 if (scsiback_map(info))
1119                         break;
1120
1121                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1122                 xenbus_switch_state(dev, XenbusStateConnected);
1123                 break;
1124
1125         case XenbusStateConnected:
1126                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1127
1128                 if (dev->state == XenbusStateConnected)
1129                         break;
1130
1131                 xenbus_switch_state(dev, XenbusStateConnected);
1132                 break;
1133
1134         case XenbusStateClosing:
1135                 if (info->irq)
1136                         scsiback_disconnect(info);
1137
1138                 xenbus_switch_state(dev, XenbusStateClosing);
1139                 break;
1140
1141         case XenbusStateClosed:
1142                 xenbus_switch_state(dev, XenbusStateClosed);
1143                 if (xenbus_dev_is_online(dev))
1144                         break;
1145                 /* fall through if not online */
1146         case XenbusStateUnknown:
1147                 device_unregister(&dev->dev);
1148                 break;
1149
1150         case XenbusStateReconfiguring:
1151                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1152                 xenbus_switch_state(dev, XenbusStateReconfigured);
1153
1154                 break;
1155
1156         default:
1157                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1158                                         frontend_state);
1159                 break;
1160         }
1161 }
1162
1163 /*
1164   Release the translation entry specfied
1165 */
1166 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1167 {
1168         struct v2p_entry *entry, *tmp;
1169         struct list_head *head = &(info->v2p_entry_lists);
1170         unsigned long flags;
1171
1172         spin_lock_irqsave(&info->v2p_lock, flags);
1173
1174         list_for_each_entry_safe(entry, tmp, head, l)
1175                 __scsiback_del_translation_entry(entry);
1176
1177         spin_unlock_irqrestore(&info->v2p_lock, flags);
1178 }
1179
1180 static int scsiback_remove(struct xenbus_device *dev)
1181 {
1182         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1183
1184         if (info->irq)
1185                 scsiback_disconnect(info);
1186
1187         scsiback_release_translation_entry(info);
1188
1189         dev_set_drvdata(&dev->dev, NULL);
1190
1191         return 0;
1192 }
1193
1194 static int scsiback_probe(struct xenbus_device *dev,
1195                            const struct xenbus_device_id *id)
1196 {
1197         int err;
1198
1199         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1200                                             GFP_KERNEL);
1201
1202         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1203
1204         if (!info) {
1205                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1206                 return -ENOMEM;
1207         }
1208         info->dev = dev;
1209         dev_set_drvdata(&dev->dev, info);
1210
1211         info->domid = dev->otherend_id;
1212         spin_lock_init(&info->ring_lock);
1213         info->ring_error = 0;
1214         atomic_set(&info->nr_unreplied_reqs, 0);
1215         init_waitqueue_head(&info->waiting_to_free);
1216         info->dev = dev;
1217         info->irq = 0;
1218         INIT_LIST_HEAD(&info->v2p_entry_lists);
1219         spin_lock_init(&info->v2p_lock);
1220
1221         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1222                             SG_ALL);
1223         if (err)
1224                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1225
1226         err = xenbus_switch_state(dev, XenbusStateInitWait);
1227         if (err)
1228                 goto fail;
1229
1230         return 0;
1231
1232 fail:
1233         pr_warn("%s failed\n", __func__);
1234         scsiback_remove(dev);
1235
1236         return err;
1237 }
1238
1239 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1240 {
1241         switch (tport->tport_proto_id) {
1242         case SCSI_PROTOCOL_SAS:
1243                 return "SAS";
1244         case SCSI_PROTOCOL_FCP:
1245                 return "FCP";
1246         case SCSI_PROTOCOL_ISCSI:
1247                 return "iSCSI";
1248         default:
1249                 break;
1250         }
1251
1252         return "Unknown";
1253 }
1254
1255 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1256 {
1257         struct scsiback_tpg *tpg = container_of(se_tpg,
1258                                 struct scsiback_tpg, se_tpg);
1259         struct scsiback_tport *tport = tpg->tport;
1260
1261         return &tport->tport_name[0];
1262 }
1263
1264 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1265 {
1266         struct scsiback_tpg *tpg = container_of(se_tpg,
1267                                 struct scsiback_tpg, se_tpg);
1268         return tpg->tport_tpgt;
1269 }
1270
1271 static struct se_wwn *
1272 scsiback_make_tport(struct target_fabric_configfs *tf,
1273                      struct config_group *group,
1274                      const char *name)
1275 {
1276         struct scsiback_tport *tport;
1277         char *ptr;
1278         u64 wwpn = 0;
1279         int off = 0;
1280
1281         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1282         if (!tport)
1283                 return ERR_PTR(-ENOMEM);
1284
1285         tport->tport_wwpn = wwpn;
1286         /*
1287          * Determine the emulated Protocol Identifier and Target Port Name
1288          * based on the incoming configfs directory name.
1289          */
1290         ptr = strstr(name, "naa.");
1291         if (ptr) {
1292                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1293                 goto check_len;
1294         }
1295         ptr = strstr(name, "fc.");
1296         if (ptr) {
1297                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1298                 off = 3; /* Skip over "fc." */
1299                 goto check_len;
1300         }
1301         ptr = strstr(name, "iqn.");
1302         if (ptr) {
1303                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1304                 goto check_len;
1305         }
1306
1307         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1308         kfree(tport);
1309         return ERR_PTR(-EINVAL);
1310
1311 check_len:
1312         if (strlen(name) >= VSCSI_NAMELEN) {
1313                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1314                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1315                 kfree(tport);
1316                 return ERR_PTR(-EINVAL);
1317         }
1318         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1319
1320         pr_debug("Allocated emulated Target %s Address: %s\n",
1321                  scsiback_dump_proto_id(tport), name);
1322
1323         return &tport->tport_wwn;
1324 }
1325
1326 static void scsiback_drop_tport(struct se_wwn *wwn)
1327 {
1328         struct scsiback_tport *tport = container_of(wwn,
1329                                 struct scsiback_tport, tport_wwn);
1330
1331         pr_debug("Deallocating emulated Target %s Address: %s\n",
1332                  scsiback_dump_proto_id(tport), tport->tport_name);
1333
1334         kfree(tport);
1335 }
1336
1337 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1338 {
1339         return 1;
1340 }
1341
1342 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1343 {
1344         /*
1345          * Do not release struct se_cmd's containing a valid TMR pointer.
1346          * These will be released directly in scsiback_device_action()
1347          * with transport_generic_free_cmd().
1348          */
1349         if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1350                 return 0;
1351
1352         transport_generic_free_cmd(se_cmd, 0);
1353         return 1;
1354 }
1355
1356 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1357 {
1358         struct vscsibk_pend *pending_req = container_of(se_cmd,
1359                                 struct vscsibk_pend, se_cmd);
1360
1361         kmem_cache_free(scsiback_cachep, pending_req);
1362 }
1363
1364 static int scsiback_shutdown_session(struct se_session *se_sess)
1365 {
1366         return 0;
1367 }
1368
1369 static void scsiback_close_session(struct se_session *se_sess)
1370 {
1371 }
1372
1373 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1374 {
1375         return 0;
1376 }
1377
1378 static int scsiback_write_pending(struct se_cmd *se_cmd)
1379 {
1380         /* Go ahead and process the write immediately */
1381         target_execute_cmd(se_cmd);
1382
1383         return 0;
1384 }
1385
1386 static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1387 {
1388         return 0;
1389 }
1390
1391 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1392 {
1393 }
1394
1395 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1396 {
1397         return 0;
1398 }
1399
1400 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1401 {
1402         struct vscsibk_pend *pending_req = container_of(se_cmd,
1403                                 struct vscsibk_pend, se_cmd);
1404
1405         pending_req->result = SAM_STAT_GOOD;
1406         scsiback_cmd_done(pending_req);
1407         return 0;
1408 }
1409
1410 static int scsiback_queue_status(struct se_cmd *se_cmd)
1411 {
1412         struct vscsibk_pend *pending_req = container_of(se_cmd,
1413                                 struct vscsibk_pend, se_cmd);
1414
1415         if (se_cmd->sense_buffer &&
1416             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1417              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1418                 pending_req->result = (DRIVER_SENSE << 24) |
1419                                       SAM_STAT_CHECK_CONDITION;
1420         else
1421                 pending_req->result = se_cmd->scsi_status;
1422
1423         scsiback_cmd_done(pending_req);
1424         return 0;
1425 }
1426
1427 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1428 {
1429         struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1430         struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1431
1432         atomic_set(&tmr->tmr_complete, 1);
1433         wake_up(&tmr->tmr_wait);
1434 }
1435
1436 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1437 {
1438 }
1439
1440 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1441                                              char *page)
1442 {
1443         struct se_portal_group *se_tpg = param_to_tpg(item);
1444         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1445                                                 se_tpg);
1446         ssize_t rb;
1447
1448         mutex_lock(&tpg->tv_tpg_mutex);
1449         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1450         mutex_unlock(&tpg->tv_tpg_mutex);
1451
1452         return rb;
1453 }
1454
1455 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1456                                               const char *page, size_t count)
1457 {
1458         struct se_portal_group *se_tpg = param_to_tpg(item);
1459         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1460                                                 se_tpg);
1461         int len;
1462
1463         if (strlen(page) >= VSCSI_NAMELEN) {
1464                 pr_err("param alias: %s, exceeds max: %d\n", page,
1465                         VSCSI_NAMELEN);
1466                 return -EINVAL;
1467         }
1468
1469         mutex_lock(&tpg->tv_tpg_mutex);
1470         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1471         if (tpg->param_alias[len - 1] == '\n')
1472                 tpg->param_alias[len - 1] = '\0';
1473         mutex_unlock(&tpg->tv_tpg_mutex);
1474
1475         return count;
1476 }
1477
1478 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1479
1480 static struct configfs_attribute *scsiback_param_attrs[] = {
1481         &scsiback_tpg_param_attr_alias,
1482         NULL,
1483 };
1484
1485 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1486                                 const char *name)
1487 {
1488         struct se_portal_group *se_tpg;
1489         struct se_session *se_sess;
1490         struct scsiback_nexus *tv_nexus;
1491
1492         mutex_lock(&tpg->tv_tpg_mutex);
1493         if (tpg->tpg_nexus) {
1494                 mutex_unlock(&tpg->tv_tpg_mutex);
1495                 pr_debug("tpg->tpg_nexus already exists\n");
1496                 return -EEXIST;
1497         }
1498         se_tpg = &tpg->se_tpg;
1499
1500         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1501         if (!tv_nexus) {
1502                 mutex_unlock(&tpg->tv_tpg_mutex);
1503                 return -ENOMEM;
1504         }
1505         /*
1506          * Initialize the struct se_session pointer
1507          */
1508         tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
1509         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1510                 mutex_unlock(&tpg->tv_tpg_mutex);
1511                 kfree(tv_nexus);
1512                 return -ENOMEM;
1513         }
1514         se_sess = tv_nexus->tvn_se_sess;
1515         /*
1516          * Since we are running in 'demo mode' this call with generate a
1517          * struct se_node_acl for the scsiback struct se_portal_group with
1518          * the SCSI Initiator port name of the passed configfs group 'name'.
1519          */
1520         tv_nexus->tvn_se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1521                                 se_tpg, (unsigned char *)name);
1522         if (!tv_nexus->tvn_se_sess->se_node_acl) {
1523                 mutex_unlock(&tpg->tv_tpg_mutex);
1524                 pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
1525                          name);
1526                 goto out;
1527         }
1528         /* Now register the TCM pvscsi virtual I_T Nexus as active. */
1529         transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
1530                         tv_nexus->tvn_se_sess, tv_nexus);
1531         tpg->tpg_nexus = tv_nexus;
1532
1533         mutex_unlock(&tpg->tv_tpg_mutex);
1534         return 0;
1535
1536 out:
1537         transport_free_session(se_sess);
1538         kfree(tv_nexus);
1539         return -ENOMEM;
1540 }
1541
1542 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1543 {
1544         struct se_session *se_sess;
1545         struct scsiback_nexus *tv_nexus;
1546
1547         mutex_lock(&tpg->tv_tpg_mutex);
1548         tv_nexus = tpg->tpg_nexus;
1549         if (!tv_nexus) {
1550                 mutex_unlock(&tpg->tv_tpg_mutex);
1551                 return -ENODEV;
1552         }
1553
1554         se_sess = tv_nexus->tvn_se_sess;
1555         if (!se_sess) {
1556                 mutex_unlock(&tpg->tv_tpg_mutex);
1557                 return -ENODEV;
1558         }
1559
1560         if (tpg->tv_tpg_port_count != 0) {
1561                 mutex_unlock(&tpg->tv_tpg_mutex);
1562                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1563                         tpg->tv_tpg_port_count);
1564                 return -EBUSY;
1565         }
1566
1567         if (tpg->tv_tpg_fe_count != 0) {
1568                 mutex_unlock(&tpg->tv_tpg_mutex);
1569                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1570                         tpg->tv_tpg_fe_count);
1571                 return -EBUSY;
1572         }
1573
1574         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1575                 scsiback_dump_proto_id(tpg->tport),
1576                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1577
1578         /*
1579          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1580          */
1581         transport_deregister_session(tv_nexus->tvn_se_sess);
1582         tpg->tpg_nexus = NULL;
1583         mutex_unlock(&tpg->tv_tpg_mutex);
1584
1585         kfree(tv_nexus);
1586         return 0;
1587 }
1588
1589 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1590 {
1591         struct se_portal_group *se_tpg = to_tpg(item);
1592         struct scsiback_tpg *tpg = container_of(se_tpg,
1593                                 struct scsiback_tpg, se_tpg);
1594         struct scsiback_nexus *tv_nexus;
1595         ssize_t ret;
1596
1597         mutex_lock(&tpg->tv_tpg_mutex);
1598         tv_nexus = tpg->tpg_nexus;
1599         if (!tv_nexus) {
1600                 mutex_unlock(&tpg->tv_tpg_mutex);
1601                 return -ENODEV;
1602         }
1603         ret = snprintf(page, PAGE_SIZE, "%s\n",
1604                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1605         mutex_unlock(&tpg->tv_tpg_mutex);
1606
1607         return ret;
1608 }
1609
1610 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1611                 const char *page, size_t count)
1612 {
1613         struct se_portal_group *se_tpg = to_tpg(item);
1614         struct scsiback_tpg *tpg = container_of(se_tpg,
1615                                 struct scsiback_tpg, se_tpg);
1616         struct scsiback_tport *tport_wwn = tpg->tport;
1617         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1618         int ret;
1619         /*
1620          * Shutdown the active I_T nexus if 'NULL' is passed.
1621          */
1622         if (!strncmp(page, "NULL", 4)) {
1623                 ret = scsiback_drop_nexus(tpg);
1624                 return (!ret) ? count : ret;
1625         }
1626         /*
1627          * Otherwise make sure the passed virtual Initiator port WWN matches
1628          * the fabric protocol_id set in scsiback_make_tport(), and call
1629          * scsiback_make_nexus().
1630          */
1631         if (strlen(page) >= VSCSI_NAMELEN) {
1632                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1633                         page, VSCSI_NAMELEN);
1634                 return -EINVAL;
1635         }
1636         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1637
1638         ptr = strstr(i_port, "naa.");
1639         if (ptr) {
1640                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1641                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1642                                 i_port, scsiback_dump_proto_id(tport_wwn));
1643                         return -EINVAL;
1644                 }
1645                 port_ptr = &i_port[0];
1646                 goto check_newline;
1647         }
1648         ptr = strstr(i_port, "fc.");
1649         if (ptr) {
1650                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1651                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1652                                 i_port, scsiback_dump_proto_id(tport_wwn));
1653                         return -EINVAL;
1654                 }
1655                 port_ptr = &i_port[3]; /* Skip over "fc." */
1656                 goto check_newline;
1657         }
1658         ptr = strstr(i_port, "iqn.");
1659         if (ptr) {
1660                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1661                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1662                                 i_port, scsiback_dump_proto_id(tport_wwn));
1663                         return -EINVAL;
1664                 }
1665                 port_ptr = &i_port[0];
1666                 goto check_newline;
1667         }
1668         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1669                 i_port);
1670         return -EINVAL;
1671         /*
1672          * Clear any trailing newline for the NAA WWN
1673          */
1674 check_newline:
1675         if (i_port[strlen(i_port) - 1] == '\n')
1676                 i_port[strlen(i_port) - 1] = '\0';
1677
1678         ret = scsiback_make_nexus(tpg, port_ptr);
1679         if (ret < 0)
1680                 return ret;
1681
1682         return count;
1683 }
1684
1685 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1686
1687 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1688         &scsiback_tpg_attr_nexus,
1689         NULL,
1690 };
1691
1692 static ssize_t
1693 scsiback_wwn_version_show(struct config_item *item, char *page)
1694 {
1695         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1696                 UTS_RELEASE"\n",
1697                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1698 }
1699
1700 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1701
1702 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1703         &scsiback_wwn_attr_version,
1704         NULL,
1705 };
1706
1707 static char *scsiback_get_fabric_name(void)
1708 {
1709         return "xen-pvscsi";
1710 }
1711
1712 static int scsiback_port_link(struct se_portal_group *se_tpg,
1713                                struct se_lun *lun)
1714 {
1715         struct scsiback_tpg *tpg = container_of(se_tpg,
1716                                 struct scsiback_tpg, se_tpg);
1717
1718         mutex_lock(&tpg->tv_tpg_mutex);
1719         tpg->tv_tpg_port_count++;
1720         mutex_unlock(&tpg->tv_tpg_mutex);
1721
1722         return 0;
1723 }
1724
1725 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1726                                   struct se_lun *lun)
1727 {
1728         struct scsiback_tpg *tpg = container_of(se_tpg,
1729                                 struct scsiback_tpg, se_tpg);
1730
1731         mutex_lock(&tpg->tv_tpg_mutex);
1732         tpg->tv_tpg_port_count--;
1733         mutex_unlock(&tpg->tv_tpg_mutex);
1734 }
1735
1736 static struct se_portal_group *
1737 scsiback_make_tpg(struct se_wwn *wwn,
1738                    struct config_group *group,
1739                    const char *name)
1740 {
1741         struct scsiback_tport *tport = container_of(wwn,
1742                         struct scsiback_tport, tport_wwn);
1743
1744         struct scsiback_tpg *tpg;
1745         u16 tpgt;
1746         int ret;
1747
1748         if (strstr(name, "tpgt_") != name)
1749                 return ERR_PTR(-EINVAL);
1750         ret = kstrtou16(name + 5, 10, &tpgt);
1751         if (ret)
1752                 return ERR_PTR(ret);
1753
1754         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1755         if (!tpg)
1756                 return ERR_PTR(-ENOMEM);
1757
1758         mutex_init(&tpg->tv_tpg_mutex);
1759         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1760         INIT_LIST_HEAD(&tpg->info_list);
1761         tpg->tport = tport;
1762         tpg->tport_tpgt = tpgt;
1763
1764         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1765         if (ret < 0) {
1766                 kfree(tpg);
1767                 return NULL;
1768         }
1769         mutex_lock(&scsiback_mutex);
1770         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1771         mutex_unlock(&scsiback_mutex);
1772
1773         return &tpg->se_tpg;
1774 }
1775
1776 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1777 {
1778         struct scsiback_tpg *tpg = container_of(se_tpg,
1779                                 struct scsiback_tpg, se_tpg);
1780
1781         mutex_lock(&scsiback_mutex);
1782         list_del(&tpg->tv_tpg_list);
1783         mutex_unlock(&scsiback_mutex);
1784         /*
1785          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1786          */
1787         scsiback_drop_nexus(tpg);
1788         /*
1789          * Deregister the se_tpg from TCM.
1790          */
1791         core_tpg_deregister(se_tpg);
1792         kfree(tpg);
1793 }
1794
1795 static int scsiback_check_true(struct se_portal_group *se_tpg)
1796 {
1797         return 1;
1798 }
1799
1800 static int scsiback_check_false(struct se_portal_group *se_tpg)
1801 {
1802         return 0;
1803 }
1804
1805 static const struct target_core_fabric_ops scsiback_ops = {
1806         .module                         = THIS_MODULE,
1807         .name                           = "xen-pvscsi",
1808         .get_fabric_name                = scsiback_get_fabric_name,
1809         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1810         .tpg_get_tag                    = scsiback_get_tag,
1811         .tpg_check_demo_mode            = scsiback_check_true,
1812         .tpg_check_demo_mode_cache      = scsiback_check_true,
1813         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1814         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1815         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1816         .check_stop_free                = scsiback_check_stop_free,
1817         .release_cmd                    = scsiback_release_cmd,
1818         .shutdown_session               = scsiback_shutdown_session,
1819         .close_session                  = scsiback_close_session,
1820         .sess_get_index                 = scsiback_sess_get_index,
1821         .sess_get_initiator_sid         = NULL,
1822         .write_pending                  = scsiback_write_pending,
1823         .write_pending_status           = scsiback_write_pending_status,
1824         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1825         .get_cmd_state                  = scsiback_get_cmd_state,
1826         .queue_data_in                  = scsiback_queue_data_in,
1827         .queue_status                   = scsiback_queue_status,
1828         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1829         .aborted_task                   = scsiback_aborted_task,
1830         /*
1831          * Setup callers for generic logic in target_core_fabric_configfs.c
1832          */
1833         .fabric_make_wwn                = scsiback_make_tport,
1834         .fabric_drop_wwn                = scsiback_drop_tport,
1835         .fabric_make_tpg                = scsiback_make_tpg,
1836         .fabric_drop_tpg                = scsiback_drop_tpg,
1837         .fabric_post_link               = scsiback_port_link,
1838         .fabric_pre_unlink              = scsiback_port_unlink,
1839
1840         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1841         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1842         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1843 };
1844
1845 static const struct xenbus_device_id scsiback_ids[] = {
1846         { "vscsi" },
1847         { "" }
1848 };
1849
1850 static struct xenbus_driver scsiback_driver = {
1851         .ids                    = scsiback_ids,
1852         .probe                  = scsiback_probe,
1853         .remove                 = scsiback_remove,
1854         .otherend_changed       = scsiback_frontend_changed
1855 };
1856
1857 static void scsiback_init_pend(void *p)
1858 {
1859         struct vscsibk_pend *pend = p;
1860         int i;
1861
1862         memset(pend, 0, sizeof(*pend));
1863         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
1864                 pend->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
1865 }
1866
1867 static int __init scsiback_init(void)
1868 {
1869         int ret;
1870
1871         if (!xen_domain())
1872                 return -ENODEV;
1873
1874         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1875                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1876
1877         scsiback_cachep = kmem_cache_create("vscsiif_cache",
1878                 sizeof(struct vscsibk_pend), 0, 0, scsiback_init_pend);
1879         if (!scsiback_cachep)
1880                 return -ENOMEM;
1881
1882         ret = xenbus_register_backend(&scsiback_driver);
1883         if (ret)
1884                 goto out_cache_destroy;
1885
1886         ret = target_register_template(&scsiback_ops);
1887         if (ret)
1888                 goto out_unregister_xenbus;
1889
1890         return 0;
1891
1892 out_unregister_xenbus:
1893         xenbus_unregister_driver(&scsiback_driver);
1894 out_cache_destroy:
1895         kmem_cache_destroy(scsiback_cachep);
1896         pr_err("%s: error %d\n", __func__, ret);
1897         return ret;
1898 }
1899
1900 static void __exit scsiback_exit(void)
1901 {
1902         struct page *page;
1903
1904         while (free_pages_num) {
1905                 if (get_free_page(&page))
1906                         BUG();
1907                 gnttab_free_pages(1, &page);
1908         }
1909         target_unregister_template(&scsiback_ops);
1910         xenbus_unregister_driver(&scsiback_driver);
1911         kmem_cache_destroy(scsiback_cachep);
1912 }
1913
1914 module_init(scsiback_init);
1915 module_exit(scsiback_exit);
1916
1917 MODULE_DESCRIPTION("Xen SCSI backend driver");
1918 MODULE_LICENSE("Dual BSD/GPL");
1919 MODULE_ALIAS("xen-backend:vscsi");
1920 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");