Merge tag 'for-linus-5.1a-rc1-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         struct completion tmr_done;
139 };
140
141 #define VSCSI_DEFAULT_SESSION_TAGS      128
142
143 struct scsiback_nexus {
144         /* Pointer to TCM session for I_T Nexus */
145         struct se_session *tvn_se_sess;
146 };
147
148 struct 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
159 struct 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
184 static bool log_print_stat;
185 module_param(log_print_stat, bool, 0644);
186
187 static int scsiback_max_buffer_pages = 1024;
188 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
189 MODULE_PARM_DESC(max_buffer_pages,
190 "Maximum number of free pages to keep in backend buffer");
191
192 static DEFINE_SPINLOCK(free_pages_lock);
193 static int free_pages_num;
194 static LIST_HEAD(scsiback_free_pages);
195
196 /* Global spinlock to protect scsiback TPG list */
197 static DEFINE_MUTEX(scsiback_mutex);
198 static LIST_HEAD(scsiback_list);
199
200 static void scsiback_get(struct vscsibk_info *info)
201 {
202         atomic_inc(&info->nr_unreplied_reqs);
203 }
204
205 static 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
211 static 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
230 static 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
246 static 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
253 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
254 {
255         return vaddr_page(req->pages[seg]);
256 }
257
258 static 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
269 static 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
310 static 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
322 static 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
360 static 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
371 static 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
396 static 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
417 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
418         struct page **pg, grant_handle_t *grant, int cnt)
419 {
420         int err, i;
421
422         if (!cnt)
423                 return 0;
424
425         err = gnttab_map_refs(map, NULL, pg, cnt);
426         BUG_ON(err);
427         for (i = 0; i < cnt; i++) {
428                 if (unlikely(map[i].status != GNTST_okay)) {
429                         pr_err("invalid buffer -- could not remap it\n");
430                         map[i].handle = SCSIBACK_INVALID_HANDLE;
431                         err = -ENOMEM;
432                 } else {
433                         get_page(pg[i]);
434                 }
435                 grant[i] = map[i].handle;
436         }
437         return err;
438 }
439
440 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
441                         struct scsiif_request_segment *seg, struct page **pg,
442                         grant_handle_t *grant, int cnt, u32 flags)
443 {
444         int mapcount = 0, i, err = 0;
445         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
446         struct vscsibk_info *info = pending_req->info;
447
448         for (i = 0; i < cnt; i++) {
449                 if (get_free_page(pg + mapcount)) {
450                         put_free_pages(pg, mapcount);
451                         pr_err("no grant page\n");
452                         return -ENOMEM;
453                 }
454                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
455                                   flags, seg[i].gref, info->domid);
456                 mapcount++;
457                 if (mapcount < VSCSI_GRANT_BATCH)
458                         continue;
459                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
460                 pg += mapcount;
461                 grant += mapcount;
462                 pending_req->n_grants += mapcount;
463                 if (err)
464                         return err;
465                 mapcount = 0;
466         }
467         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
468         pending_req->n_grants += mapcount;
469         return err;
470 }
471
472 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
473                                         struct vscsibk_pend *pending_req)
474 {
475         u32 flags;
476         int i, err, n_segs, i_seg = 0;
477         struct page **pg;
478         struct scsiif_request_segment *seg;
479         unsigned long end_seg = 0;
480         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
481         unsigned int nr_sgl = 0;
482         struct scatterlist *sg;
483         grant_handle_t *grant;
484
485         pending_req->n_sg = 0;
486         pending_req->n_grants = 0;
487         pending_req->data_len = 0;
488
489         nr_segments &= ~VSCSIIF_SG_GRANT;
490         if (!nr_segments)
491                 return 0;
492
493         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
494                 pr_debug("invalid parameter nr_seg = %d\n",
495                         ring_req->nr_segments);
496                 return -EINVAL;
497         }
498
499         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
500                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
501                         pending_req->pages, pending_req->grant_handles,
502                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
503                 if (err)
504                         return err;
505                 nr_sgl = nr_segments;
506                 nr_segments = 0;
507                 for (i = 0; i < nr_sgl; i++) {
508                         n_segs = ring_req->seg[i].length /
509                                  sizeof(struct scsiif_request_segment);
510                         if ((unsigned)ring_req->seg[i].offset +
511                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
512                             n_segs * sizeof(struct scsiif_request_segment) !=
513                             ring_req->seg[i].length)
514                                 return -EINVAL;
515                         nr_segments += n_segs;
516                 }
517                 if (nr_segments > SG_ALL) {
518                         pr_debug("invalid nr_seg = %d\n", nr_segments);
519                         return -EINVAL;
520                 }
521         }
522
523         /* free of (sgl) in fast_flush_area() */
524         pending_req->sgl = kmalloc_array(nr_segments,
525                                         sizeof(struct scatterlist), GFP_KERNEL);
526         if (!pending_req->sgl)
527                 return -ENOMEM;
528
529         sg_init_table(pending_req->sgl, nr_segments);
530         pending_req->n_sg = nr_segments;
531
532         flags = GNTMAP_host_map;
533         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
534                 flags |= GNTMAP_readonly;
535
536         pg = pending_req->pages + nr_sgl;
537         grant = pending_req->grant_handles + nr_sgl;
538         if (!nr_sgl) {
539                 seg = ring_req->seg;
540                 err = scsiback_gnttab_data_map_list(pending_req, seg,
541                         pg, grant, nr_segments, flags);
542                 if (err)
543                         return err;
544         } else {
545                 for (i = 0; i < nr_sgl; i++) {
546                         seg = (struct scsiif_request_segment *)(
547                               vaddr(pending_req, i) + ring_req->seg[i].offset);
548                         n_segs = ring_req->seg[i].length /
549                                  sizeof(struct scsiif_request_segment);
550                         err = scsiback_gnttab_data_map_list(pending_req, seg,
551                                 pg, grant, n_segs, flags);
552                         if (err)
553                                 return err;
554                         pg += n_segs;
555                         grant += n_segs;
556                 }
557                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
558                 seg = (struct scsiif_request_segment *)end_seg;
559                 end_seg += ring_req->seg[0].length;
560                 pg = pending_req->pages + nr_sgl;
561         }
562
563         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
564                 sg_set_page(sg, pg[i], seg->length, seg->offset);
565                 pending_req->data_len += seg->length;
566                 seg++;
567                 if (nr_sgl && (unsigned long)seg >= end_seg) {
568                         i_seg++;
569                         end_seg = vaddr(pending_req, i_seg) +
570                                   ring_req->seg[i_seg].offset;
571                         seg = (struct scsiif_request_segment *)end_seg;
572                         end_seg += ring_req->seg[i_seg].length;
573                 }
574                 if (sg->offset >= PAGE_SIZE ||
575                     sg->length > PAGE_SIZE ||
576                     sg->offset + sg->length > PAGE_SIZE)
577                         return -EINVAL;
578         }
579
580         return 0;
581 }
582
583 static void scsiback_disconnect(struct vscsibk_info *info)
584 {
585         wait_event(info->waiting_to_free,
586                 atomic_read(&info->nr_unreplied_reqs) == 0);
587
588         unbind_from_irqhandler(info->irq, info);
589         info->irq = 0;
590         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
591 }
592
593 static void scsiback_device_action(struct vscsibk_pend *pending_req,
594         enum tcm_tmreq_table act, int tag)
595 {
596         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
620 err:
621         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
622 }
623
624 /*
625   Perform virtual to physical translation
626 */
627 static 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
645 out:
646         spin_unlock_irqrestore(&info->v2p_lock, flags);
647         return entry;
648 }
649
650 static 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, cpu, i;
658
659         tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
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         req->se_cmd.map_cpu = cpu;
669
670         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
671                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
672
673         return req;
674 }
675
676 static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
677                                 struct vscsiif_back_ring *ring,
678                                 struct vscsiif_request *ring_req)
679 {
680         struct vscsibk_pend *pending_req;
681         struct v2p_entry *v2p;
682         struct ids_tuple vir;
683
684         /* request range check from frontend */
685         if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
686                 (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
687                 (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
688                 (ring_req->sc_data_direction != DMA_NONE)) {
689                 pr_debug("invalid parameter data_dir = %d\n",
690                         ring_req->sc_data_direction);
691                 return ERR_PTR(-EINVAL);
692         }
693         if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
694                 pr_debug("invalid parameter cmd_len = %d\n",
695                         ring_req->cmd_len);
696                 return ERR_PTR(-EINVAL);
697         }
698
699         vir.chn = ring_req->channel;
700         vir.tgt = ring_req->id;
701         vir.lun = ring_req->lun;
702
703         v2p = scsiback_do_translation(info, &vir);
704         if (!v2p) {
705                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
706                          vir.chn, vir.tgt, vir.lun);
707                 return ERR_PTR(-ENODEV);
708         }
709
710         pending_req = scsiback_get_pend_req(ring, v2p);
711         if (IS_ERR(pending_req)) {
712                 kref_put(&v2p->kref, scsiback_free_translation_entry);
713                 return ERR_PTR(-ENOMEM);
714         }
715         pending_req->rqid = ring_req->rqid;
716         pending_req->info = info;
717         pending_req->v2p = v2p;
718         pending_req->sc_data_direction = ring_req->sc_data_direction;
719         pending_req->cmd_len = ring_req->cmd_len;
720         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
721
722         return pending_req;
723 }
724
725 static int scsiback_do_cmd_fn(struct vscsibk_info *info)
726 {
727         struct vscsiif_back_ring *ring = &info->ring;
728         struct vscsiif_request ring_req;
729         struct vscsibk_pend *pending_req;
730         RING_IDX rc, rp;
731         int more_to_do;
732         uint32_t result;
733
734         rc = ring->req_cons;
735         rp = ring->sring->req_prod;
736         rmb();  /* guest system is accessing ring, too */
737
738         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
739                 rc = ring->rsp_prod_pvt;
740                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
741                            info->domid, rp, rc, rp - rc);
742                 info->ring_error = 1;
743                 return 0;
744         }
745
746         while ((rc != rp)) {
747                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
748                         break;
749
750                 RING_COPY_REQUEST(ring, rc, &ring_req);
751                 ring->req_cons = ++rc;
752
753                 pending_req = prepare_pending_reqs(info, ring, &ring_req);
754                 if (IS_ERR(pending_req)) {
755                         switch (PTR_ERR(pending_req)) {
756                         case -ENODEV:
757                                 result = DID_NO_CONNECT;
758                                 break;
759                         default:
760                                 result = DRIVER_ERROR;
761                                 break;
762                         }
763                         scsiback_send_response(info, NULL, result << 24, 0,
764                                                ring_req.rqid);
765                         return 1;
766                 }
767
768                 switch (ring_req.act) {
769                 case VSCSIIF_ACT_SCSI_CDB:
770                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
771                                 scsiback_fast_flush_area(pending_req);
772                                 scsiback_do_resp_with_sense(NULL,
773                                                 DRIVER_ERROR << 24, 0, pending_req);
774                                 transport_generic_free_cmd(&pending_req->se_cmd, 0);
775                         } else {
776                                 scsiback_cmd_exec(pending_req);
777                         }
778                         break;
779                 case VSCSIIF_ACT_SCSI_ABORT:
780                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
781                                 ring_req.ref_rqid);
782                         break;
783                 case VSCSIIF_ACT_SCSI_RESET:
784                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
785                         break;
786                 default:
787                         pr_err_ratelimited("invalid request\n");
788                         scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24, 0,
789                                                     pending_req);
790                         transport_generic_free_cmd(&pending_req->se_cmd, 0);
791                         break;
792                 }
793
794                 /* Yield point for this unbounded loop. */
795                 cond_resched();
796         }
797
798         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
799         return more_to_do;
800 }
801
802 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
803 {
804         struct vscsibk_info *info = dev_id;
805
806         if (info->ring_error)
807                 return IRQ_HANDLED;
808
809         while (scsiback_do_cmd_fn(info))
810                 cond_resched();
811
812         return IRQ_HANDLED;
813 }
814
815 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
816                         evtchn_port_t evtchn)
817 {
818         void *area;
819         struct vscsiif_sring *sring;
820         int err;
821
822         if (info->irq)
823                 return -1;
824
825         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
826         if (err)
827                 return err;
828
829         sring = (struct vscsiif_sring *)area;
830         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
831
832         err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
833         if (err < 0)
834                 goto unmap_page;
835
836         info->irq = err;
837
838         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
839                                    IRQF_ONESHOT, "vscsiif-backend", info);
840         if (err)
841                 goto free_irq;
842
843         return 0;
844
845 free_irq:
846         unbind_from_irqhandler(info->irq, info);
847         info->irq = 0;
848 unmap_page:
849         xenbus_unmap_ring_vfree(info->dev, area);
850
851         return err;
852 }
853
854 static int scsiback_map(struct vscsibk_info *info)
855 {
856         struct xenbus_device *dev = info->dev;
857         unsigned int ring_ref, evtchn;
858         int err;
859
860         err = xenbus_gather(XBT_NIL, dev->otherend,
861                         "ring-ref", "%u", &ring_ref,
862                         "event-channel", "%u", &evtchn, NULL);
863         if (err) {
864                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
865                 return err;
866         }
867
868         return scsiback_init_sring(info, ring_ref, evtchn);
869 }
870
871 /*
872   Check for a translation entry being present
873 */
874 static struct v2p_entry *scsiback_chk_translation_entry(
875         struct vscsibk_info *info, struct ids_tuple *v)
876 {
877         struct list_head *head = &(info->v2p_entry_lists);
878         struct v2p_entry *entry;
879
880         list_for_each_entry(entry, head, l)
881                 if ((entry->v.chn == v->chn) &&
882                     (entry->v.tgt == v->tgt) &&
883                     (entry->v.lun == v->lun))
884                         return entry;
885
886         return NULL;
887 }
888
889 /*
890   Add a new translation entry
891 */
892 static int scsiback_add_translation_entry(struct vscsibk_info *info,
893                                           char *phy, struct ids_tuple *v)
894 {
895         int err = 0;
896         struct v2p_entry *new;
897         unsigned long flags;
898         char *lunp;
899         unsigned long long unpacked_lun;
900         struct se_lun *se_lun;
901         struct scsiback_tpg *tpg_entry, *tpg = NULL;
902         char *error = "doesn't exist";
903
904         lunp = strrchr(phy, ':');
905         if (!lunp) {
906                 pr_err("illegal format of physical device %s\n", phy);
907                 return -EINVAL;
908         }
909         *lunp = 0;
910         lunp++;
911         err = kstrtoull(lunp, 10, &unpacked_lun);
912         if (err < 0) {
913                 pr_err("lun number not valid: %s\n", lunp);
914                 return err;
915         }
916
917         mutex_lock(&scsiback_mutex);
918         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
919                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
920                     !strcmp(phy, tpg_entry->param_alias)) {
921                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
922                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
923                                 if (se_lun->unpacked_lun == unpacked_lun) {
924                                         if (!tpg_entry->tpg_nexus)
925                                                 error = "nexus undefined";
926                                         else
927                                                 tpg = tpg_entry;
928                                         break;
929                                 }
930                         }
931                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
932                         break;
933                 }
934         }
935         if (tpg) {
936                 mutex_lock(&tpg->tv_tpg_mutex);
937                 tpg->tv_tpg_fe_count++;
938                 mutex_unlock(&tpg->tv_tpg_mutex);
939         }
940         mutex_unlock(&scsiback_mutex);
941
942         if (!tpg) {
943                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
944                 return -ENODEV;
945         }
946
947         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
948         if (new == NULL) {
949                 err = -ENOMEM;
950                 goto out_free;
951         }
952
953         spin_lock_irqsave(&info->v2p_lock, flags);
954
955         /* Check double assignment to identical virtual ID */
956         if (scsiback_chk_translation_entry(info, v)) {
957                 pr_warn("Virtual ID is already used. Assignment was not performed.\n");
958                 err = -EEXIST;
959                 goto out;
960         }
961
962         /* Create a new translation entry and add to the list */
963         kref_init(&new->kref);
964         new->v = *v;
965         new->tpg = tpg;
966         new->lun = unpacked_lun;
967         list_add_tail(&new->l, &info->v2p_entry_lists);
968
969 out:
970         spin_unlock_irqrestore(&info->v2p_lock, flags);
971
972 out_free:
973         if (err) {
974                 mutex_lock(&tpg->tv_tpg_mutex);
975                 tpg->tv_tpg_fe_count--;
976                 mutex_unlock(&tpg->tv_tpg_mutex);
977                 kfree(new);
978         }
979
980         return err;
981 }
982
983 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
984 {
985         list_del(&entry->l);
986         kref_put(&entry->kref, scsiback_free_translation_entry);
987 }
988
989 /*
990   Delete the translation entry specified
991 */
992 static int scsiback_del_translation_entry(struct vscsibk_info *info,
993                                           struct ids_tuple *v)
994 {
995         struct v2p_entry *entry;
996         unsigned long flags;
997         int ret = 0;
998
999         spin_lock_irqsave(&info->v2p_lock, flags);
1000         /* Find out the translation entry specified */
1001         entry = scsiback_chk_translation_entry(info, v);
1002         if (entry)
1003                 __scsiback_del_translation_entry(entry);
1004         else
1005                 ret = -ENOENT;
1006
1007         spin_unlock_irqrestore(&info->v2p_lock, flags);
1008         return ret;
1009 }
1010
1011 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1012                                 char *phy, struct ids_tuple *vir, int try)
1013 {
1014         struct v2p_entry *entry;
1015         unsigned long flags;
1016         int err;
1017
1018         if (try) {
1019                 spin_lock_irqsave(&info->v2p_lock, flags);
1020                 entry = scsiback_chk_translation_entry(info, vir);
1021                 spin_unlock_irqrestore(&info->v2p_lock, flags);
1022                 if (entry)
1023                         return;
1024         }
1025         if (!scsiback_add_translation_entry(info, phy, vir)) {
1026                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1027                                   "%d", XenbusStateInitialised)) {
1028                         pr_err("xenbus_printf error %s\n", state);
1029                         scsiback_del_translation_entry(info, vir);
1030                 }
1031         } else if (!try) {
1032                 err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
1033                               "%d", XenbusStateClosed);
1034                 if (err)
1035                         xenbus_dev_error(info->dev, err,
1036                                 "%s: writing %s", __func__, state);
1037         }
1038 }
1039
1040 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1041                                 struct ids_tuple *vir)
1042 {
1043         if (!scsiback_del_translation_entry(info, vir)) {
1044                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1045                                   "%d", XenbusStateClosed))
1046                         pr_err("xenbus_printf error %s\n", state);
1047         }
1048 }
1049
1050 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1051 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1052
1053 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1054                                      char *ent)
1055 {
1056         int err;
1057         struct ids_tuple vir;
1058         char *val;
1059         int device_state;
1060         char phy[VSCSI_NAMELEN];
1061         char str[64];
1062         char state[64];
1063         struct xenbus_device *dev = info->dev;
1064
1065         /* read status */
1066         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1067         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1068         if (XENBUS_EXIST_ERR(err))
1069                 return;
1070
1071         /* physical SCSI device */
1072         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1073         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1074         if (IS_ERR(val)) {
1075                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1076                               "%d", XenbusStateClosed);
1077                 if (err)
1078                         xenbus_dev_error(info->dev, err,
1079                                 "%s: writing %s", __func__, state);
1080                 return;
1081         }
1082         strlcpy(phy, val, VSCSI_NAMELEN);
1083         kfree(val);
1084
1085         /* virtual SCSI device */
1086         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1087         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1088                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1089         if (XENBUS_EXIST_ERR(err)) {
1090                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1091                               "%d", XenbusStateClosed);
1092                 if (err)
1093                         xenbus_dev_error(info->dev, err,
1094                                 "%s: writing %s", __func__, state);
1095                 return;
1096         }
1097
1098         switch (op) {
1099         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1100                 switch (device_state) {
1101                 case XenbusStateInitialising:
1102                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1103                         break;
1104                 case XenbusStateConnected:
1105                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1106                         break;
1107                 case XenbusStateClosing:
1108                         scsiback_do_del_lun(info, state, &vir);
1109                         break;
1110                 default:
1111                         break;
1112                 }
1113                 break;
1114
1115         case VSCSIBACK_OP_UPDATEDEV_STATE:
1116                 if (device_state == XenbusStateInitialised) {
1117                         /* modify vscsi-devs/dev-x/state */
1118                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1119                                           "%d", XenbusStateConnected)) {
1120                                 pr_err("xenbus_printf error %s\n", str);
1121                                 scsiback_del_translation_entry(info, &vir);
1122                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1123                                               "%d", XenbusStateClosed);
1124                         }
1125                 }
1126                 break;
1127         /* When it is necessary, processing is added here. */
1128         default:
1129                 break;
1130         }
1131 }
1132
1133 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1134 {
1135         int i;
1136         char **dir;
1137         unsigned int ndir = 0;
1138
1139         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1140                                &ndir);
1141         if (IS_ERR(dir))
1142                 return;
1143
1144         for (i = 0; i < ndir; i++)
1145                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1146
1147         kfree(dir);
1148 }
1149
1150 static void scsiback_frontend_changed(struct xenbus_device *dev,
1151                                         enum xenbus_state frontend_state)
1152 {
1153         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1154
1155         switch (frontend_state) {
1156         case XenbusStateInitialising:
1157                 break;
1158
1159         case XenbusStateInitialised:
1160                 if (scsiback_map(info))
1161                         break;
1162
1163                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1164                 xenbus_switch_state(dev, XenbusStateConnected);
1165                 break;
1166
1167         case XenbusStateConnected:
1168                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1169
1170                 if (dev->state == XenbusStateConnected)
1171                         break;
1172
1173                 xenbus_switch_state(dev, XenbusStateConnected);
1174                 break;
1175
1176         case XenbusStateClosing:
1177                 if (info->irq)
1178                         scsiback_disconnect(info);
1179
1180                 xenbus_switch_state(dev, XenbusStateClosing);
1181                 break;
1182
1183         case XenbusStateClosed:
1184                 xenbus_switch_state(dev, XenbusStateClosed);
1185                 if (xenbus_dev_is_online(dev))
1186                         break;
1187                 /* fall through - if not online */
1188         case XenbusStateUnknown:
1189                 device_unregister(&dev->dev);
1190                 break;
1191
1192         case XenbusStateReconfiguring:
1193                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1194                 xenbus_switch_state(dev, XenbusStateReconfigured);
1195
1196                 break;
1197
1198         default:
1199                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1200                                         frontend_state);
1201                 break;
1202         }
1203 }
1204
1205 /*
1206   Release the translation entry specfied
1207 */
1208 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1209 {
1210         struct v2p_entry *entry, *tmp;
1211         struct list_head *head = &(info->v2p_entry_lists);
1212         unsigned long flags;
1213
1214         spin_lock_irqsave(&info->v2p_lock, flags);
1215
1216         list_for_each_entry_safe(entry, tmp, head, l)
1217                 __scsiback_del_translation_entry(entry);
1218
1219         spin_unlock_irqrestore(&info->v2p_lock, flags);
1220 }
1221
1222 static int scsiback_remove(struct xenbus_device *dev)
1223 {
1224         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1225
1226         if (info->irq)
1227                 scsiback_disconnect(info);
1228
1229         scsiback_release_translation_entry(info);
1230
1231         dev_set_drvdata(&dev->dev, NULL);
1232
1233         return 0;
1234 }
1235
1236 static int scsiback_probe(struct xenbus_device *dev,
1237                            const struct xenbus_device_id *id)
1238 {
1239         int err;
1240
1241         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1242                                             GFP_KERNEL);
1243
1244         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1245
1246         if (!info) {
1247                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1248                 return -ENOMEM;
1249         }
1250         info->dev = dev;
1251         dev_set_drvdata(&dev->dev, info);
1252
1253         info->domid = dev->otherend_id;
1254         spin_lock_init(&info->ring_lock);
1255         info->ring_error = 0;
1256         atomic_set(&info->nr_unreplied_reqs, 0);
1257         init_waitqueue_head(&info->waiting_to_free);
1258         info->dev = dev;
1259         info->irq = 0;
1260         INIT_LIST_HEAD(&info->v2p_entry_lists);
1261         spin_lock_init(&info->v2p_lock);
1262
1263         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1264                             SG_ALL);
1265         if (err)
1266                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1267
1268         err = xenbus_switch_state(dev, XenbusStateInitWait);
1269         if (err)
1270                 goto fail;
1271
1272         return 0;
1273
1274 fail:
1275         pr_warn("%s failed\n", __func__);
1276         scsiback_remove(dev);
1277
1278         return err;
1279 }
1280
1281 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1282 {
1283         switch (tport->tport_proto_id) {
1284         case SCSI_PROTOCOL_SAS:
1285                 return "SAS";
1286         case SCSI_PROTOCOL_FCP:
1287                 return "FCP";
1288         case SCSI_PROTOCOL_ISCSI:
1289                 return "iSCSI";
1290         default:
1291                 break;
1292         }
1293
1294         return "Unknown";
1295 }
1296
1297 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1298 {
1299         struct scsiback_tpg *tpg = container_of(se_tpg,
1300                                 struct scsiback_tpg, se_tpg);
1301         struct scsiback_tport *tport = tpg->tport;
1302
1303         return &tport->tport_name[0];
1304 }
1305
1306 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1307 {
1308         struct scsiback_tpg *tpg = container_of(se_tpg,
1309                                 struct scsiback_tpg, se_tpg);
1310         return tpg->tport_tpgt;
1311 }
1312
1313 static struct se_wwn *
1314 scsiback_make_tport(struct target_fabric_configfs *tf,
1315                      struct config_group *group,
1316                      const char *name)
1317 {
1318         struct scsiback_tport *tport;
1319         char *ptr;
1320         u64 wwpn = 0;
1321         int off = 0;
1322
1323         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1324         if (!tport)
1325                 return ERR_PTR(-ENOMEM);
1326
1327         tport->tport_wwpn = wwpn;
1328         /*
1329          * Determine the emulated Protocol Identifier and Target Port Name
1330          * based on the incoming configfs directory name.
1331          */
1332         ptr = strstr(name, "naa.");
1333         if (ptr) {
1334                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1335                 goto check_len;
1336         }
1337         ptr = strstr(name, "fc.");
1338         if (ptr) {
1339                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1340                 off = 3; /* Skip over "fc." */
1341                 goto check_len;
1342         }
1343         ptr = strstr(name, "iqn.");
1344         if (ptr) {
1345                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1346                 goto check_len;
1347         }
1348
1349         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1350         kfree(tport);
1351         return ERR_PTR(-EINVAL);
1352
1353 check_len:
1354         if (strlen(name) >= VSCSI_NAMELEN) {
1355                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1356                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1357                 kfree(tport);
1358                 return ERR_PTR(-EINVAL);
1359         }
1360         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1361
1362         pr_debug("Allocated emulated Target %s Address: %s\n",
1363                  scsiback_dump_proto_id(tport), name);
1364
1365         return &tport->tport_wwn;
1366 }
1367
1368 static void scsiback_drop_tport(struct se_wwn *wwn)
1369 {
1370         struct scsiback_tport *tport = container_of(wwn,
1371                                 struct scsiback_tport, tport_wwn);
1372
1373         pr_debug("Deallocating emulated Target %s Address: %s\n",
1374                  scsiback_dump_proto_id(tport), tport->tport_name);
1375
1376         kfree(tport);
1377 }
1378
1379 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1380 {
1381         return 1;
1382 }
1383
1384 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1385 {
1386         return transport_generic_free_cmd(se_cmd, 0);
1387 }
1388
1389 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1390 {
1391         target_free_tag(se_cmd->se_sess, se_cmd);
1392 }
1393
1394 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1395 {
1396         return 0;
1397 }
1398
1399 static int scsiback_write_pending(struct se_cmd *se_cmd)
1400 {
1401         /* Go ahead and process the write immediately */
1402         target_execute_cmd(se_cmd);
1403
1404         return 0;
1405 }
1406
1407 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1408 {
1409 }
1410
1411 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1412 {
1413         return 0;
1414 }
1415
1416 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1417 {
1418         struct vscsibk_pend *pending_req = container_of(se_cmd,
1419                                 struct vscsibk_pend, se_cmd);
1420
1421         pending_req->result = SAM_STAT_GOOD;
1422         scsiback_cmd_done(pending_req);
1423         return 0;
1424 }
1425
1426 static int scsiback_queue_status(struct se_cmd *se_cmd)
1427 {
1428         struct vscsibk_pend *pending_req = container_of(se_cmd,
1429                                 struct vscsibk_pend, se_cmd);
1430
1431         if (se_cmd->sense_buffer &&
1432             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1433              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1434                 pending_req->result = (DRIVER_SENSE << 24) |
1435                                       SAM_STAT_CHECK_CONDITION;
1436         else
1437                 pending_req->result = se_cmd->scsi_status;
1438
1439         scsiback_cmd_done(pending_req);
1440         return 0;
1441 }
1442
1443 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1444 {
1445         struct vscsibk_pend *pending_req = container_of(se_cmd,
1446                                 struct vscsibk_pend, se_cmd);
1447
1448         complete(&pending_req->tmr_done);
1449 }
1450
1451 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1452 {
1453 }
1454
1455 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1456                                              char *page)
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         ssize_t rb;
1462
1463         mutex_lock(&tpg->tv_tpg_mutex);
1464         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1465         mutex_unlock(&tpg->tv_tpg_mutex);
1466
1467         return rb;
1468 }
1469
1470 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1471                                               const char *page, size_t count)
1472 {
1473         struct se_portal_group *se_tpg = param_to_tpg(item);
1474         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1475                                                 se_tpg);
1476         int len;
1477
1478         if (strlen(page) >= VSCSI_NAMELEN) {
1479                 pr_err("param alias: %s, exceeds max: %d\n", page,
1480                         VSCSI_NAMELEN);
1481                 return -EINVAL;
1482         }
1483
1484         mutex_lock(&tpg->tv_tpg_mutex);
1485         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1486         if (tpg->param_alias[len - 1] == '\n')
1487                 tpg->param_alias[len - 1] = '\0';
1488         mutex_unlock(&tpg->tv_tpg_mutex);
1489
1490         return count;
1491 }
1492
1493 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1494
1495 static struct configfs_attribute *scsiback_param_attrs[] = {
1496         &scsiback_tpg_param_attr_alias,
1497         NULL,
1498 };
1499
1500 static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1501                                   struct se_session *se_sess, void *p)
1502 {
1503         struct scsiback_tpg *tpg = container_of(se_tpg,
1504                                 struct scsiback_tpg, se_tpg);
1505
1506         tpg->tpg_nexus = p;
1507         return 0;
1508 }
1509
1510 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1511                                 const char *name)
1512 {
1513         struct scsiback_nexus *tv_nexus;
1514         int ret = 0;
1515
1516         mutex_lock(&tpg->tv_tpg_mutex);
1517         if (tpg->tpg_nexus) {
1518                 pr_debug("tpg->tpg_nexus already exists\n");
1519                 ret = -EEXIST;
1520                 goto out_unlock;
1521         }
1522
1523         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1524         if (!tv_nexus) {
1525                 ret = -ENOMEM;
1526                 goto out_unlock;
1527         }
1528
1529         tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
1530                                                      VSCSI_DEFAULT_SESSION_TAGS,
1531                                                      sizeof(struct vscsibk_pend),
1532                                                      TARGET_PROT_NORMAL, name,
1533                                                      tv_nexus, scsiback_alloc_sess_cb);
1534         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1535                 kfree(tv_nexus);
1536                 ret = -ENOMEM;
1537                 goto out_unlock;
1538         }
1539
1540 out_unlock:
1541         mutex_unlock(&tpg->tv_tpg_mutex);
1542         return ret;
1543 }
1544
1545 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1546 {
1547         struct se_session *se_sess;
1548         struct scsiback_nexus *tv_nexus;
1549
1550         mutex_lock(&tpg->tv_tpg_mutex);
1551         tv_nexus = tpg->tpg_nexus;
1552         if (!tv_nexus) {
1553                 mutex_unlock(&tpg->tv_tpg_mutex);
1554                 return -ENODEV;
1555         }
1556
1557         se_sess = tv_nexus->tvn_se_sess;
1558         if (!se_sess) {
1559                 mutex_unlock(&tpg->tv_tpg_mutex);
1560                 return -ENODEV;
1561         }
1562
1563         if (tpg->tv_tpg_port_count != 0) {
1564                 mutex_unlock(&tpg->tv_tpg_mutex);
1565                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1566                         tpg->tv_tpg_port_count);
1567                 return -EBUSY;
1568         }
1569
1570         if (tpg->tv_tpg_fe_count != 0) {
1571                 mutex_unlock(&tpg->tv_tpg_mutex);
1572                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1573                         tpg->tv_tpg_fe_count);
1574                 return -EBUSY;
1575         }
1576
1577         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1578                 scsiback_dump_proto_id(tpg->tport),
1579                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1580
1581         /*
1582          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1583          */
1584         target_remove_session(se_sess);
1585         tpg->tpg_nexus = NULL;
1586         mutex_unlock(&tpg->tv_tpg_mutex);
1587
1588         kfree(tv_nexus);
1589         return 0;
1590 }
1591
1592 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1593 {
1594         struct se_portal_group *se_tpg = to_tpg(item);
1595         struct scsiback_tpg *tpg = container_of(se_tpg,
1596                                 struct scsiback_tpg, se_tpg);
1597         struct scsiback_nexus *tv_nexus;
1598         ssize_t ret;
1599
1600         mutex_lock(&tpg->tv_tpg_mutex);
1601         tv_nexus = tpg->tpg_nexus;
1602         if (!tv_nexus) {
1603                 mutex_unlock(&tpg->tv_tpg_mutex);
1604                 return -ENODEV;
1605         }
1606         ret = snprintf(page, PAGE_SIZE, "%s\n",
1607                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1608         mutex_unlock(&tpg->tv_tpg_mutex);
1609
1610         return ret;
1611 }
1612
1613 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1614                 const char *page, size_t count)
1615 {
1616         struct se_portal_group *se_tpg = to_tpg(item);
1617         struct scsiback_tpg *tpg = container_of(se_tpg,
1618                                 struct scsiback_tpg, se_tpg);
1619         struct scsiback_tport *tport_wwn = tpg->tport;
1620         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1621         int ret;
1622         /*
1623          * Shutdown the active I_T nexus if 'NULL' is passed.
1624          */
1625         if (!strncmp(page, "NULL", 4)) {
1626                 ret = scsiback_drop_nexus(tpg);
1627                 return (!ret) ? count : ret;
1628         }
1629         /*
1630          * Otherwise make sure the passed virtual Initiator port WWN matches
1631          * the fabric protocol_id set in scsiback_make_tport(), and call
1632          * scsiback_make_nexus().
1633          */
1634         if (strlen(page) >= VSCSI_NAMELEN) {
1635                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1636                         page, VSCSI_NAMELEN);
1637                 return -EINVAL;
1638         }
1639         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1640
1641         ptr = strstr(i_port, "naa.");
1642         if (ptr) {
1643                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1644                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1645                                 i_port, scsiback_dump_proto_id(tport_wwn));
1646                         return -EINVAL;
1647                 }
1648                 port_ptr = &i_port[0];
1649                 goto check_newline;
1650         }
1651         ptr = strstr(i_port, "fc.");
1652         if (ptr) {
1653                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1654                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1655                                 i_port, scsiback_dump_proto_id(tport_wwn));
1656                         return -EINVAL;
1657                 }
1658                 port_ptr = &i_port[3]; /* Skip over "fc." */
1659                 goto check_newline;
1660         }
1661         ptr = strstr(i_port, "iqn.");
1662         if (ptr) {
1663                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1664                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1665                                 i_port, scsiback_dump_proto_id(tport_wwn));
1666                         return -EINVAL;
1667                 }
1668                 port_ptr = &i_port[0];
1669                 goto check_newline;
1670         }
1671         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1672                 i_port);
1673         return -EINVAL;
1674         /*
1675          * Clear any trailing newline for the NAA WWN
1676          */
1677 check_newline:
1678         if (i_port[strlen(i_port) - 1] == '\n')
1679                 i_port[strlen(i_port) - 1] = '\0';
1680
1681         ret = scsiback_make_nexus(tpg, port_ptr);
1682         if (ret < 0)
1683                 return ret;
1684
1685         return count;
1686 }
1687
1688 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1689
1690 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1691         &scsiback_tpg_attr_nexus,
1692         NULL,
1693 };
1694
1695 static ssize_t
1696 scsiback_wwn_version_show(struct config_item *item, char *page)
1697 {
1698         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1699                 UTS_RELEASE"\n",
1700                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1701 }
1702
1703 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1704
1705 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1706         &scsiback_wwn_attr_version,
1707         NULL,
1708 };
1709
1710 static int scsiback_port_link(struct se_portal_group *se_tpg,
1711                                struct se_lun *lun)
1712 {
1713         struct scsiback_tpg *tpg = container_of(se_tpg,
1714                                 struct scsiback_tpg, se_tpg);
1715
1716         mutex_lock(&tpg->tv_tpg_mutex);
1717         tpg->tv_tpg_port_count++;
1718         mutex_unlock(&tpg->tv_tpg_mutex);
1719
1720         return 0;
1721 }
1722
1723 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1724                                   struct se_lun *lun)
1725 {
1726         struct scsiback_tpg *tpg = container_of(se_tpg,
1727                                 struct scsiback_tpg, se_tpg);
1728
1729         mutex_lock(&tpg->tv_tpg_mutex);
1730         tpg->tv_tpg_port_count--;
1731         mutex_unlock(&tpg->tv_tpg_mutex);
1732 }
1733
1734 static struct se_portal_group *
1735 scsiback_make_tpg(struct se_wwn *wwn, const char *name)
1736 {
1737         struct scsiback_tport *tport = container_of(wwn,
1738                         struct scsiback_tport, tport_wwn);
1739
1740         struct scsiback_tpg *tpg;
1741         u16 tpgt;
1742         int ret;
1743
1744         if (strstr(name, "tpgt_") != name)
1745                 return ERR_PTR(-EINVAL);
1746         ret = kstrtou16(name + 5, 10, &tpgt);
1747         if (ret)
1748                 return ERR_PTR(ret);
1749
1750         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1751         if (!tpg)
1752                 return ERR_PTR(-ENOMEM);
1753
1754         mutex_init(&tpg->tv_tpg_mutex);
1755         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1756         INIT_LIST_HEAD(&tpg->info_list);
1757         tpg->tport = tport;
1758         tpg->tport_tpgt = tpgt;
1759
1760         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1761         if (ret < 0) {
1762                 kfree(tpg);
1763                 return NULL;
1764         }
1765         mutex_lock(&scsiback_mutex);
1766         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1767         mutex_unlock(&scsiback_mutex);
1768
1769         return &tpg->se_tpg;
1770 }
1771
1772 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1773 {
1774         struct scsiback_tpg *tpg = container_of(se_tpg,
1775                                 struct scsiback_tpg, se_tpg);
1776
1777         mutex_lock(&scsiback_mutex);
1778         list_del(&tpg->tv_tpg_list);
1779         mutex_unlock(&scsiback_mutex);
1780         /*
1781          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1782          */
1783         scsiback_drop_nexus(tpg);
1784         /*
1785          * Deregister the se_tpg from TCM.
1786          */
1787         core_tpg_deregister(se_tpg);
1788         kfree(tpg);
1789 }
1790
1791 static int scsiback_check_true(struct se_portal_group *se_tpg)
1792 {
1793         return 1;
1794 }
1795
1796 static int scsiback_check_false(struct se_portal_group *se_tpg)
1797 {
1798         return 0;
1799 }
1800
1801 static const struct target_core_fabric_ops scsiback_ops = {
1802         .module                         = THIS_MODULE,
1803         .fabric_name                    = "xen-pvscsi",
1804         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1805         .tpg_get_tag                    = scsiback_get_tag,
1806         .tpg_check_demo_mode            = scsiback_check_true,
1807         .tpg_check_demo_mode_cache      = scsiback_check_true,
1808         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1809         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1810         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1811         .check_stop_free                = scsiback_check_stop_free,
1812         .release_cmd                    = scsiback_release_cmd,
1813         .sess_get_index                 = scsiback_sess_get_index,
1814         .sess_get_initiator_sid         = NULL,
1815         .write_pending                  = scsiback_write_pending,
1816         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1817         .get_cmd_state                  = scsiback_get_cmd_state,
1818         .queue_data_in                  = scsiback_queue_data_in,
1819         .queue_status                   = scsiback_queue_status,
1820         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1821         .aborted_task                   = scsiback_aborted_task,
1822         /*
1823          * Setup callers for generic logic in target_core_fabric_configfs.c
1824          */
1825         .fabric_make_wwn                = scsiback_make_tport,
1826         .fabric_drop_wwn                = scsiback_drop_tport,
1827         .fabric_make_tpg                = scsiback_make_tpg,
1828         .fabric_drop_tpg                = scsiback_drop_tpg,
1829         .fabric_post_link               = scsiback_port_link,
1830         .fabric_pre_unlink              = scsiback_port_unlink,
1831
1832         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1833         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1834         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1835 };
1836
1837 static const struct xenbus_device_id scsiback_ids[] = {
1838         { "vscsi" },
1839         { "" }
1840 };
1841
1842 static struct xenbus_driver scsiback_driver = {
1843         .ids                    = scsiback_ids,
1844         .probe                  = scsiback_probe,
1845         .remove                 = scsiback_remove,
1846         .otherend_changed       = scsiback_frontend_changed
1847 };
1848
1849 static int __init scsiback_init(void)
1850 {
1851         int ret;
1852
1853         if (!xen_domain())
1854                 return -ENODEV;
1855
1856         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1857                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1858
1859         ret = xenbus_register_backend(&scsiback_driver);
1860         if (ret)
1861                 goto out;
1862
1863         ret = target_register_template(&scsiback_ops);
1864         if (ret)
1865                 goto out_unregister_xenbus;
1866
1867         return 0;
1868
1869 out_unregister_xenbus:
1870         xenbus_unregister_driver(&scsiback_driver);
1871 out:
1872         pr_err("%s: error %d\n", __func__, ret);
1873         return ret;
1874 }
1875
1876 static void __exit scsiback_exit(void)
1877 {
1878         struct page *page;
1879
1880         while (free_pages_num) {
1881                 if (get_free_page(&page))
1882                         BUG();
1883                 gnttab_free_pages(1, &page);
1884         }
1885         target_unregister_template(&scsiback_ops);
1886         xenbus_unregister_driver(&scsiback_driver);
1887 }
1888
1889 module_init(scsiback_init);
1890 module_exit(scsiback_exit);
1891
1892 MODULE_DESCRIPTION("Xen SCSI backend driver");
1893 MODULE_LICENSE("Dual BSD/GPL");
1894 MODULE_ALIAS("xen-backend:vscsi");
1895 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");