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8beb8d4c JG |
1 | /* |
2 | * Xen SCSI frontend driver | |
3 | * | |
4 | * Copyright (c) 2008, FUJITSU Limited | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License version 2 | |
8 | * as published by the Free Software Foundation; or, when distributed | |
9 | * separately from the Linux kernel or incorporated into other | |
10 | * software packages, subject to the following license: | |
11 | * | |
12 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
13 | * of this source file (the "Software"), to deal in the Software without | |
14 | * restriction, including without limitation the rights to use, copy, modify, | |
15 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | |
16 | * and to permit persons to whom the Software is furnished to do so, subject to | |
17 | * the following conditions: | |
18 | * | |
19 | * The above copyright notice and this permission notice shall be included in | |
20 | * all copies or substantial portions of the Software. | |
21 | * | |
22 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
23 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
24 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
25 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
26 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
27 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
28 | * IN THE SOFTWARE. | |
29 | */ | |
30 | ||
31 | #include <linux/module.h> | |
32 | #include <linux/kernel.h> | |
33 | #include <linux/device.h> | |
34 | #include <linux/wait.h> | |
35 | #include <linux/interrupt.h> | |
36 | #include <linux/mutex.h> | |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/sched.h> | |
39 | #include <linux/blkdev.h> | |
40 | #include <linux/pfn.h> | |
41 | #include <linux/slab.h> | |
42 | #include <linux/bitops.h> | |
43 | ||
44 | #include <scsi/scsi_cmnd.h> | |
45 | #include <scsi/scsi_device.h> | |
46 | #include <scsi/scsi.h> | |
47 | #include <scsi/scsi_host.h> | |
48 | ||
49 | #include <xen/xen.h> | |
50 | #include <xen/xenbus.h> | |
51 | #include <xen/grant_table.h> | |
52 | #include <xen/events.h> | |
53 | #include <xen/page.h> | |
54 | ||
55 | #include <xen/interface/grant_table.h> | |
56 | #include <xen/interface/io/vscsiif.h> | |
57 | #include <xen/interface/io/protocols.h> | |
58 | ||
59 | #include <asm/xen/hypervisor.h> | |
60 | ||
61 | ||
62 | #define GRANT_INVALID_REF 0 | |
63 | ||
64 | #define VSCSIFRONT_OP_ADD_LUN 1 | |
65 | #define VSCSIFRONT_OP_DEL_LUN 2 | |
66 | ||
67 | /* Tuning point. */ | |
68 | #define VSCSIIF_DEFAULT_CMD_PER_LUN 10 | |
69 | #define VSCSIIF_MAX_TARGET 64 | |
70 | #define VSCSIIF_MAX_LUN 255 | |
71 | ||
72 | #define VSCSIIF_RING_SIZE __CONST_RING_SIZE(vscsiif, PAGE_SIZE) | |
73 | #define VSCSIIF_MAX_REQS VSCSIIF_RING_SIZE | |
74 | ||
75 | #define vscsiif_grants_sg(_sg) (PFN_UP((_sg) * \ | |
76 | sizeof(struct scsiif_request_segment))) | |
77 | ||
78 | struct vscsifrnt_shadow { | |
79 | /* command between backend and frontend */ | |
80 | unsigned char act; | |
81 | uint16_t rqid; | |
82 | ||
83 | unsigned int nr_grants; /* number of grants in gref[] */ | |
84 | struct scsiif_request_segment *sg; /* scatter/gather elements */ | |
85 | ||
86 | /* Do reset or abort function. */ | |
87 | wait_queue_head_t wq_reset; /* reset work queue */ | |
88 | int wait_reset; /* reset work queue condition */ | |
89 | int32_t rslt_reset; /* reset response status: */ | |
90 | /* SUCCESS or FAILED or: */ | |
91 | #define RSLT_RESET_WAITING 0 | |
92 | #define RSLT_RESET_ERR -1 | |
93 | ||
94 | /* Requested struct scsi_cmnd is stored from kernel. */ | |
95 | struct scsi_cmnd *sc; | |
96 | int gref[vscsiif_grants_sg(SG_ALL) + SG_ALL]; | |
97 | }; | |
98 | ||
99 | struct vscsifrnt_info { | |
100 | struct xenbus_device *dev; | |
101 | ||
102 | struct Scsi_Host *host; | |
103 | int host_active; | |
104 | ||
105 | unsigned int evtchn; | |
106 | unsigned int irq; | |
107 | ||
108 | grant_ref_t ring_ref; | |
109 | struct vscsiif_front_ring ring; | |
110 | struct vscsiif_response ring_rsp; | |
111 | ||
112 | spinlock_t shadow_lock; | |
113 | DECLARE_BITMAP(shadow_free_bitmap, VSCSIIF_MAX_REQS); | |
114 | struct vscsifrnt_shadow *shadow[VSCSIIF_MAX_REQS]; | |
115 | ||
116 | wait_queue_head_t wq_sync; | |
117 | unsigned int wait_ring_available:1; | |
118 | ||
119 | char dev_state_path[64]; | |
120 | struct task_struct *curr; | |
121 | }; | |
122 | ||
123 | static DEFINE_MUTEX(scsifront_mutex); | |
124 | ||
125 | static void scsifront_wake_up(struct vscsifrnt_info *info) | |
126 | { | |
127 | info->wait_ring_available = 0; | |
128 | wake_up(&info->wq_sync); | |
129 | } | |
130 | ||
131 | static int scsifront_get_rqid(struct vscsifrnt_info *info) | |
132 | { | |
133 | unsigned long flags; | |
134 | int free; | |
135 | ||
136 | spin_lock_irqsave(&info->shadow_lock, flags); | |
137 | ||
138 | free = find_first_bit(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); | |
139 | __clear_bit(free, info->shadow_free_bitmap); | |
140 | ||
141 | spin_unlock_irqrestore(&info->shadow_lock, flags); | |
142 | ||
143 | return free; | |
144 | } | |
145 | ||
146 | static int _scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id) | |
147 | { | |
148 | int empty = bitmap_empty(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); | |
149 | ||
150 | __set_bit(id, info->shadow_free_bitmap); | |
151 | info->shadow[id] = NULL; | |
152 | ||
153 | return empty || info->wait_ring_available; | |
154 | } | |
155 | ||
156 | static void scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id) | |
157 | { | |
158 | unsigned long flags; | |
159 | int kick; | |
160 | ||
161 | spin_lock_irqsave(&info->shadow_lock, flags); | |
162 | kick = _scsifront_put_rqid(info, id); | |
163 | spin_unlock_irqrestore(&info->shadow_lock, flags); | |
164 | ||
165 | if (kick) | |
166 | scsifront_wake_up(info); | |
167 | } | |
168 | ||
169 | static struct vscsiif_request *scsifront_pre_req(struct vscsifrnt_info *info) | |
170 | { | |
171 | struct vscsiif_front_ring *ring = &(info->ring); | |
172 | struct vscsiif_request *ring_req; | |
173 | uint32_t id; | |
174 | ||
175 | id = scsifront_get_rqid(info); /* use id in response */ | |
176 | if (id >= VSCSIIF_MAX_REQS) | |
177 | return NULL; | |
178 | ||
179 | ring_req = RING_GET_REQUEST(&(info->ring), ring->req_prod_pvt); | |
180 | ||
181 | ring->req_prod_pvt++; | |
182 | ||
183 | ring_req->rqid = (uint16_t)id; | |
184 | ||
185 | return ring_req; | |
186 | } | |
187 | ||
188 | static void scsifront_do_request(struct vscsifrnt_info *info) | |
189 | { | |
190 | struct vscsiif_front_ring *ring = &(info->ring); | |
191 | int notify; | |
192 | ||
193 | RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(ring, notify); | |
194 | if (notify) | |
195 | notify_remote_via_irq(info->irq); | |
196 | } | |
197 | ||
198 | static void scsifront_gnttab_done(struct vscsifrnt_info *info, uint32_t id) | |
199 | { | |
200 | struct vscsifrnt_shadow *s = info->shadow[id]; | |
201 | int i; | |
202 | ||
203 | if (s->sc->sc_data_direction == DMA_NONE) | |
204 | return; | |
205 | ||
206 | for (i = 0; i < s->nr_grants; i++) { | |
207 | if (unlikely(gnttab_query_foreign_access(s->gref[i]) != 0)) { | |
208 | shost_printk(KERN_ALERT, info->host, KBUILD_MODNAME | |
209 | "grant still in use by backend\n"); | |
210 | BUG(); | |
211 | } | |
212 | gnttab_end_foreign_access(s->gref[i], 0, 0UL); | |
213 | } | |
214 | ||
215 | kfree(s->sg); | |
216 | } | |
217 | ||
218 | static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info, | |
219 | struct vscsiif_response *ring_rsp) | |
220 | { | |
221 | struct scsi_cmnd *sc; | |
222 | uint32_t id; | |
223 | uint8_t sense_len; | |
224 | ||
225 | id = ring_rsp->rqid; | |
226 | sc = info->shadow[id]->sc; | |
227 | ||
228 | BUG_ON(sc == NULL); | |
229 | ||
230 | scsifront_gnttab_done(info, id); | |
231 | scsifront_put_rqid(info, id); | |
232 | ||
233 | sc->result = ring_rsp->rslt; | |
234 | scsi_set_resid(sc, ring_rsp->residual_len); | |
235 | ||
236 | sense_len = min_t(uint8_t, VSCSIIF_SENSE_BUFFERSIZE, | |
237 | ring_rsp->sense_len); | |
238 | ||
239 | if (sense_len) | |
240 | memcpy(sc->sense_buffer, ring_rsp->sense_buffer, sense_len); | |
241 | ||
242 | sc->scsi_done(sc); | |
243 | } | |
244 | ||
245 | static void scsifront_sync_cmd_done(struct vscsifrnt_info *info, | |
246 | struct vscsiif_response *ring_rsp) | |
247 | { | |
248 | uint16_t id = ring_rsp->rqid; | |
249 | unsigned long flags; | |
250 | struct vscsifrnt_shadow *shadow = info->shadow[id]; | |
251 | int kick; | |
252 | ||
253 | spin_lock_irqsave(&info->shadow_lock, flags); | |
254 | shadow->wait_reset = 1; | |
255 | switch (shadow->rslt_reset) { | |
256 | case RSLT_RESET_WAITING: | |
257 | shadow->rslt_reset = ring_rsp->rslt; | |
258 | break; | |
259 | case RSLT_RESET_ERR: | |
260 | kick = _scsifront_put_rqid(info, id); | |
261 | spin_unlock_irqrestore(&info->shadow_lock, flags); | |
262 | kfree(shadow); | |
263 | if (kick) | |
264 | scsifront_wake_up(info); | |
265 | return; | |
266 | default: | |
267 | shost_printk(KERN_ERR, info->host, KBUILD_MODNAME | |
268 | "bad reset state %d, possibly leaking %u\n", | |
269 | shadow->rslt_reset, id); | |
270 | break; | |
271 | } | |
272 | spin_unlock_irqrestore(&info->shadow_lock, flags); | |
273 | ||
274 | wake_up(&shadow->wq_reset); | |
275 | } | |
276 | ||
277 | static int scsifront_cmd_done(struct vscsifrnt_info *info) | |
278 | { | |
279 | struct vscsiif_response *ring_rsp; | |
280 | RING_IDX i, rp; | |
281 | int more_to_do = 0; | |
282 | unsigned long flags; | |
283 | ||
284 | spin_lock_irqsave(info->host->host_lock, flags); | |
285 | ||
286 | rp = info->ring.sring->rsp_prod; | |
287 | rmb(); /* ordering required respective to dom0 */ | |
288 | for (i = info->ring.rsp_cons; i != rp; i++) { | |
289 | ||
290 | ring_rsp = RING_GET_RESPONSE(&info->ring, i); | |
291 | ||
292 | if (WARN(ring_rsp->rqid >= VSCSIIF_MAX_REQS || | |
293 | test_bit(ring_rsp->rqid, info->shadow_free_bitmap), | |
294 | "illegal rqid %u returned by backend!\n", | |
295 | ring_rsp->rqid)) | |
296 | continue; | |
297 | ||
298 | if (info->shadow[ring_rsp->rqid]->act == VSCSIIF_ACT_SCSI_CDB) | |
299 | scsifront_cdb_cmd_done(info, ring_rsp); | |
300 | else | |
301 | scsifront_sync_cmd_done(info, ring_rsp); | |
302 | } | |
303 | ||
304 | info->ring.rsp_cons = i; | |
305 | ||
306 | if (i != info->ring.req_prod_pvt) | |
307 | RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do); | |
308 | else | |
309 | info->ring.sring->rsp_event = i + 1; | |
310 | ||
311 | info->wait_ring_available = 0; | |
312 | ||
313 | spin_unlock_irqrestore(info->host->host_lock, flags); | |
314 | ||
315 | wake_up(&info->wq_sync); | |
316 | ||
317 | return more_to_do; | |
318 | } | |
319 | ||
320 | static irqreturn_t scsifront_irq_fn(int irq, void *dev_id) | |
321 | { | |
322 | struct vscsifrnt_info *info = dev_id; | |
323 | ||
324 | while (scsifront_cmd_done(info)) | |
325 | /* Yield point for this unbounded loop. */ | |
326 | cond_resched(); | |
327 | ||
328 | return IRQ_HANDLED; | |
329 | } | |
330 | ||
331 | static int map_data_for_request(struct vscsifrnt_info *info, | |
332 | struct scsi_cmnd *sc, | |
333 | struct vscsiif_request *ring_req, | |
334 | struct vscsifrnt_shadow *shadow) | |
335 | { | |
336 | grant_ref_t gref_head; | |
337 | struct page *page; | |
338 | int err, ref, ref_cnt = 0; | |
339 | int grant_ro = (sc->sc_data_direction == DMA_TO_DEVICE); | |
340 | unsigned int i, off, len, bytes; | |
341 | unsigned int data_len = scsi_bufflen(sc); | |
342 | unsigned int data_grants = 0, seg_grants = 0; | |
343 | struct scatterlist *sg; | |
344 | unsigned long mfn; | |
345 | struct scsiif_request_segment *seg; | |
346 | ||
347 | ring_req->nr_segments = 0; | |
348 | if (sc->sc_data_direction == DMA_NONE || !data_len) | |
349 | return 0; | |
350 | ||
351 | scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) | |
352 | data_grants += PFN_UP(sg->offset + sg->length); | |
353 | ||
354 | if (data_grants > VSCSIIF_SG_TABLESIZE) { | |
355 | if (data_grants > info->host->sg_tablesize) { | |
356 | shost_printk(KERN_ERR, info->host, KBUILD_MODNAME | |
357 | "Unable to map request_buffer for command!\n"); | |
358 | return -E2BIG; | |
359 | } | |
360 | seg_grants = vscsiif_grants_sg(data_grants); | |
361 | shadow->sg = kcalloc(data_grants, | |
362 | sizeof(struct scsiif_request_segment), GFP_NOIO); | |
363 | if (!shadow->sg) | |
364 | return -ENOMEM; | |
365 | } | |
366 | seg = shadow->sg ? : ring_req->seg; | |
367 | ||
368 | err = gnttab_alloc_grant_references(seg_grants + data_grants, | |
369 | &gref_head); | |
370 | if (err) { | |
371 | kfree(shadow->sg); | |
372 | shost_printk(KERN_ERR, info->host, KBUILD_MODNAME | |
373 | "gnttab_alloc_grant_references() error\n"); | |
374 | return -ENOMEM; | |
375 | } | |
376 | ||
377 | if (seg_grants) { | |
378 | page = virt_to_page(seg); | |
379 | off = (unsigned long)seg & ~PAGE_MASK; | |
380 | len = sizeof(struct scsiif_request_segment) * data_grants; | |
381 | while (len > 0) { | |
382 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); | |
383 | ||
384 | ref = gnttab_claim_grant_reference(&gref_head); | |
385 | BUG_ON(ref == -ENOSPC); | |
386 | ||
387 | mfn = pfn_to_mfn(page_to_pfn(page)); | |
388 | gnttab_grant_foreign_access_ref(ref, | |
389 | info->dev->otherend_id, mfn, 1); | |
390 | shadow->gref[ref_cnt] = ref; | |
391 | ring_req->seg[ref_cnt].gref = ref; | |
392 | ring_req->seg[ref_cnt].offset = (uint16_t)off; | |
393 | ring_req->seg[ref_cnt].length = (uint16_t)bytes; | |
394 | ||
395 | page++; | |
396 | len -= bytes; | |
397 | off = 0; | |
398 | ref_cnt++; | |
399 | } | |
400 | BUG_ON(seg_grants < ref_cnt); | |
401 | seg_grants = ref_cnt; | |
402 | } | |
403 | ||
404 | scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) { | |
405 | page = sg_page(sg); | |
406 | off = sg->offset; | |
407 | len = sg->length; | |
408 | ||
409 | while (len > 0 && data_len > 0) { | |
410 | /* | |
411 | * sg sends a scatterlist that is larger than | |
412 | * the data_len it wants transferred for certain | |
413 | * IO sizes. | |
414 | */ | |
415 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); | |
416 | bytes = min(bytes, data_len); | |
417 | ||
418 | ref = gnttab_claim_grant_reference(&gref_head); | |
419 | BUG_ON(ref == -ENOSPC); | |
420 | ||
421 | mfn = pfn_to_mfn(page_to_pfn(page)); | |
422 | gnttab_grant_foreign_access_ref(ref, | |
423 | info->dev->otherend_id, mfn, grant_ro); | |
424 | ||
425 | shadow->gref[ref_cnt] = ref; | |
426 | seg->gref = ref; | |
427 | seg->offset = (uint16_t)off; | |
428 | seg->length = (uint16_t)bytes; | |
429 | ||
430 | page++; | |
431 | seg++; | |
432 | len -= bytes; | |
433 | data_len -= bytes; | |
434 | off = 0; | |
435 | ref_cnt++; | |
436 | } | |
437 | } | |
438 | ||
439 | if (seg_grants) | |
440 | ring_req->nr_segments = VSCSIIF_SG_GRANT | seg_grants; | |
441 | else | |
442 | ring_req->nr_segments = (uint8_t)ref_cnt; | |
443 | shadow->nr_grants = ref_cnt; | |
444 | ||
445 | return 0; | |
446 | } | |
447 | ||
448 | static struct vscsiif_request *scsifront_command2ring( | |
449 | struct vscsifrnt_info *info, struct scsi_cmnd *sc, | |
450 | struct vscsifrnt_shadow *shadow) | |
451 | { | |
452 | struct vscsiif_request *ring_req; | |
453 | ||
454 | memset(shadow, 0, sizeof(*shadow)); | |
455 | ||
456 | ring_req = scsifront_pre_req(info); | |
457 | if (!ring_req) | |
458 | return NULL; | |
459 | ||
460 | info->shadow[ring_req->rqid] = shadow; | |
461 | shadow->rqid = ring_req->rqid; | |
462 | ||
463 | ring_req->id = sc->device->id; | |
464 | ring_req->lun = sc->device->lun; | |
465 | ring_req->channel = sc->device->channel; | |
466 | ring_req->cmd_len = sc->cmd_len; | |
467 | ||
468 | BUG_ON(sc->cmd_len > VSCSIIF_MAX_COMMAND_SIZE); | |
469 | ||
470 | memcpy(ring_req->cmnd, sc->cmnd, sc->cmd_len); | |
471 | ||
472 | ring_req->sc_data_direction = (uint8_t)sc->sc_data_direction; | |
473 | ring_req->timeout_per_command = sc->request->timeout / HZ; | |
474 | ||
475 | return ring_req; | |
476 | } | |
477 | ||
478 | static int scsifront_queuecommand(struct Scsi_Host *shost, | |
479 | struct scsi_cmnd *sc) | |
480 | { | |
481 | struct vscsifrnt_info *info = shost_priv(shost); | |
482 | struct vscsiif_request *ring_req; | |
483 | struct vscsifrnt_shadow *shadow = scsi_cmd_priv(sc); | |
484 | unsigned long flags; | |
485 | int err; | |
486 | uint16_t rqid; | |
487 | ||
488 | spin_lock_irqsave(shost->host_lock, flags); | |
489 | if (RING_FULL(&info->ring)) | |
490 | goto busy; | |
491 | ||
492 | ring_req = scsifront_command2ring(info, sc, shadow); | |
493 | if (!ring_req) | |
494 | goto busy; | |
495 | ||
496 | sc->result = 0; | |
497 | ||
498 | rqid = ring_req->rqid; | |
499 | ring_req->act = VSCSIIF_ACT_SCSI_CDB; | |
500 | ||
501 | shadow->sc = sc; | |
502 | shadow->act = VSCSIIF_ACT_SCSI_CDB; | |
503 | ||
504 | err = map_data_for_request(info, sc, ring_req, shadow); | |
505 | if (err < 0) { | |
506 | pr_debug("%s: err %d\n", __func__, err); | |
507 | scsifront_put_rqid(info, rqid); | |
508 | spin_unlock_irqrestore(shost->host_lock, flags); | |
509 | if (err == -ENOMEM) | |
510 | return SCSI_MLQUEUE_HOST_BUSY; | |
511 | sc->result = DID_ERROR << 16; | |
512 | sc->scsi_done(sc); | |
513 | return 0; | |
514 | } | |
515 | ||
516 | scsifront_do_request(info); | |
517 | spin_unlock_irqrestore(shost->host_lock, flags); | |
518 | ||
519 | return 0; | |
520 | ||
521 | busy: | |
522 | spin_unlock_irqrestore(shost->host_lock, flags); | |
523 | pr_debug("%s: busy\n", __func__); | |
524 | return SCSI_MLQUEUE_HOST_BUSY; | |
525 | } | |
526 | ||
527 | /* | |
528 | * Any exception handling (reset or abort) must be forwarded to the backend. | |
529 | * We have to wait until an answer is returned. This answer contains the | |
530 | * result to be returned to the requestor. | |
531 | */ | |
532 | static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act) | |
533 | { | |
534 | struct Scsi_Host *host = sc->device->host; | |
535 | struct vscsifrnt_info *info = shost_priv(host); | |
536 | struct vscsifrnt_shadow *shadow, *s = scsi_cmd_priv(sc); | |
537 | struct vscsiif_request *ring_req; | |
538 | int err = 0; | |
539 | ||
540 | shadow = kmalloc(sizeof(*shadow), GFP_NOIO); | |
541 | if (!shadow) | |
542 | return FAILED; | |
543 | ||
544 | for (;;) { | |
545 | spin_lock_irq(host->host_lock); | |
546 | if (!RING_FULL(&info->ring)) { | |
547 | ring_req = scsifront_command2ring(info, sc, shadow); | |
548 | if (ring_req) | |
549 | break; | |
550 | } | |
551 | if (err) { | |
552 | spin_unlock_irq(host->host_lock); | |
553 | kfree(shadow); | |
554 | return FAILED; | |
555 | } | |
556 | info->wait_ring_available = 1; | |
557 | spin_unlock_irq(host->host_lock); | |
558 | err = wait_event_interruptible(info->wq_sync, | |
559 | !info->wait_ring_available); | |
560 | spin_lock_irq(host->host_lock); | |
561 | } | |
562 | ||
563 | ring_req->act = act; | |
564 | ring_req->ref_rqid = s->rqid; | |
565 | ||
566 | shadow->act = act; | |
567 | shadow->rslt_reset = RSLT_RESET_WAITING; | |
568 | init_waitqueue_head(&shadow->wq_reset); | |
569 | ||
570 | ring_req->nr_segments = 0; | |
571 | ||
572 | scsifront_do_request(info); | |
573 | ||
574 | spin_unlock_irq(host->host_lock); | |
575 | err = wait_event_interruptible(shadow->wq_reset, shadow->wait_reset); | |
576 | spin_lock_irq(host->host_lock); | |
577 | ||
578 | if (!err) { | |
579 | err = shadow->rslt_reset; | |
580 | scsifront_put_rqid(info, shadow->rqid); | |
581 | kfree(shadow); | |
582 | } else { | |
583 | spin_lock(&info->shadow_lock); | |
584 | shadow->rslt_reset = RSLT_RESET_ERR; | |
585 | spin_unlock(&info->shadow_lock); | |
586 | err = FAILED; | |
587 | } | |
588 | ||
589 | spin_unlock_irq(host->host_lock); | |
590 | return err; | |
591 | } | |
592 | ||
593 | static int scsifront_eh_abort_handler(struct scsi_cmnd *sc) | |
594 | { | |
595 | pr_debug("%s\n", __func__); | |
596 | return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_ABORT); | |
597 | } | |
598 | ||
599 | static int scsifront_dev_reset_handler(struct scsi_cmnd *sc) | |
600 | { | |
601 | pr_debug("%s\n", __func__); | |
602 | return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_RESET); | |
603 | } | |
604 | ||
605 | static int scsifront_sdev_configure(struct scsi_device *sdev) | |
606 | { | |
607 | struct vscsifrnt_info *info = shost_priv(sdev->host); | |
608 | ||
609 | if (info && current == info->curr) | |
610 | xenbus_printf(XBT_NIL, info->dev->nodename, | |
611 | info->dev_state_path, "%d", XenbusStateConnected); | |
612 | ||
613 | return 0; | |
614 | } | |
615 | ||
616 | static void scsifront_sdev_destroy(struct scsi_device *sdev) | |
617 | { | |
618 | struct vscsifrnt_info *info = shost_priv(sdev->host); | |
619 | ||
620 | if (info && current == info->curr) | |
621 | xenbus_printf(XBT_NIL, info->dev->nodename, | |
622 | info->dev_state_path, "%d", XenbusStateClosed); | |
623 | } | |
624 | ||
625 | static struct scsi_host_template scsifront_sht = { | |
626 | .module = THIS_MODULE, | |
627 | .name = "Xen SCSI frontend driver", | |
628 | .queuecommand = scsifront_queuecommand, | |
629 | .eh_abort_handler = scsifront_eh_abort_handler, | |
630 | .eh_device_reset_handler = scsifront_dev_reset_handler, | |
631 | .slave_configure = scsifront_sdev_configure, | |
632 | .slave_destroy = scsifront_sdev_destroy, | |
633 | .cmd_per_lun = VSCSIIF_DEFAULT_CMD_PER_LUN, | |
634 | .can_queue = VSCSIIF_MAX_REQS, | |
635 | .this_id = -1, | |
636 | .cmd_size = sizeof(struct vscsifrnt_shadow), | |
637 | .sg_tablesize = VSCSIIF_SG_TABLESIZE, | |
638 | .use_clustering = DISABLE_CLUSTERING, | |
639 | .proc_name = "scsifront", | |
640 | }; | |
641 | ||
642 | static int scsifront_alloc_ring(struct vscsifrnt_info *info) | |
643 | { | |
644 | struct xenbus_device *dev = info->dev; | |
645 | struct vscsiif_sring *sring; | |
646 | int err = -ENOMEM; | |
647 | ||
648 | /***** Frontend to Backend ring start *****/ | |
649 | sring = (struct vscsiif_sring *)__get_free_page(GFP_KERNEL); | |
650 | if (!sring) { | |
651 | xenbus_dev_fatal(dev, err, | |
652 | "fail to allocate shared ring (Front to Back)"); | |
653 | return err; | |
654 | } | |
655 | SHARED_RING_INIT(sring); | |
656 | FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE); | |
657 | ||
658 | err = xenbus_grant_ring(dev, virt_to_mfn(sring)); | |
659 | if (err < 0) { | |
660 | free_page((unsigned long)sring); | |
661 | xenbus_dev_fatal(dev, err, | |
662 | "fail to grant shared ring (Front to Back)"); | |
663 | return err; | |
664 | } | |
665 | info->ring_ref = err; | |
666 | ||
667 | err = xenbus_alloc_evtchn(dev, &info->evtchn); | |
668 | if (err) { | |
669 | xenbus_dev_fatal(dev, err, "xenbus_alloc_evtchn"); | |
670 | goto free_gnttab; | |
671 | } | |
672 | ||
673 | err = bind_evtchn_to_irq(info->evtchn); | |
674 | if (err <= 0) { | |
675 | xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq"); | |
676 | goto free_gnttab; | |
677 | } | |
678 | ||
679 | info->irq = err; | |
680 | ||
681 | err = request_threaded_irq(info->irq, NULL, scsifront_irq_fn, | |
682 | IRQF_ONESHOT, "scsifront", info); | |
683 | if (err) { | |
684 | xenbus_dev_fatal(dev, err, "request_threaded_irq"); | |
685 | goto free_irq; | |
686 | } | |
687 | ||
688 | return 0; | |
689 | ||
690 | /* free resource */ | |
691 | free_irq: | |
692 | unbind_from_irqhandler(info->irq, info); | |
693 | free_gnttab: | |
694 | gnttab_end_foreign_access(info->ring_ref, 0, | |
695 | (unsigned long)info->ring.sring); | |
696 | ||
697 | return err; | |
698 | } | |
699 | ||
700 | static int scsifront_init_ring(struct vscsifrnt_info *info) | |
701 | { | |
702 | struct xenbus_device *dev = info->dev; | |
703 | struct xenbus_transaction xbt; | |
704 | int err; | |
705 | ||
706 | pr_debug("%s\n", __func__); | |
707 | ||
708 | err = scsifront_alloc_ring(info); | |
709 | if (err) | |
710 | return err; | |
711 | pr_debug("%s: %u %u\n", __func__, info->ring_ref, info->evtchn); | |
712 | ||
713 | again: | |
714 | err = xenbus_transaction_start(&xbt); | |
715 | if (err) | |
716 | xenbus_dev_fatal(dev, err, "starting transaction"); | |
717 | ||
718 | err = xenbus_printf(xbt, dev->nodename, "ring-ref", "%u", | |
719 | info->ring_ref); | |
720 | if (err) { | |
721 | xenbus_dev_fatal(dev, err, "%s", "writing ring-ref"); | |
722 | goto fail; | |
723 | } | |
724 | ||
725 | err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u", | |
726 | info->evtchn); | |
727 | ||
728 | if (err) { | |
729 | xenbus_dev_fatal(dev, err, "%s", "writing event-channel"); | |
730 | goto fail; | |
731 | } | |
732 | ||
733 | err = xenbus_transaction_end(xbt, 0); | |
734 | if (err) { | |
735 | if (err == -EAGAIN) | |
736 | goto again; | |
737 | xenbus_dev_fatal(dev, err, "completing transaction"); | |
738 | goto free_sring; | |
739 | } | |
740 | ||
741 | return 0; | |
742 | ||
743 | fail: | |
744 | xenbus_transaction_end(xbt, 1); | |
745 | free_sring: | |
746 | unbind_from_irqhandler(info->irq, info); | |
747 | gnttab_end_foreign_access(info->ring_ref, 0, | |
748 | (unsigned long)info->ring.sring); | |
749 | ||
750 | return err; | |
751 | } | |
752 | ||
753 | ||
754 | static int scsifront_probe(struct xenbus_device *dev, | |
755 | const struct xenbus_device_id *id) | |
756 | { | |
757 | struct vscsifrnt_info *info; | |
758 | struct Scsi_Host *host; | |
759 | int err = -ENOMEM; | |
760 | char name[TASK_COMM_LEN]; | |
761 | ||
762 | host = scsi_host_alloc(&scsifront_sht, sizeof(*info)); | |
763 | if (!host) { | |
764 | xenbus_dev_fatal(dev, err, "fail to allocate scsi host"); | |
765 | return err; | |
766 | } | |
767 | info = (struct vscsifrnt_info *)host->hostdata; | |
768 | ||
769 | dev_set_drvdata(&dev->dev, info); | |
770 | info->dev = dev; | |
771 | ||
772 | bitmap_fill(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); | |
773 | ||
774 | err = scsifront_init_ring(info); | |
775 | if (err) { | |
776 | scsi_host_put(host); | |
777 | return err; | |
778 | } | |
779 | ||
780 | init_waitqueue_head(&info->wq_sync); | |
781 | spin_lock_init(&info->shadow_lock); | |
782 | ||
783 | snprintf(name, TASK_COMM_LEN, "vscsiif.%d", host->host_no); | |
784 | ||
785 | host->max_id = VSCSIIF_MAX_TARGET; | |
786 | host->max_channel = 0; | |
787 | host->max_lun = VSCSIIF_MAX_LUN; | |
788 | host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512; | |
789 | host->max_cmd_len = VSCSIIF_MAX_COMMAND_SIZE; | |
790 | ||
791 | err = scsi_add_host(host, &dev->dev); | |
792 | if (err) { | |
793 | dev_err(&dev->dev, "fail to add scsi host %d\n", err); | |
794 | goto free_sring; | |
795 | } | |
796 | info->host = host; | |
797 | info->host_active = 1; | |
798 | ||
799 | xenbus_switch_state(dev, XenbusStateInitialised); | |
800 | ||
801 | return 0; | |
802 | ||
803 | free_sring: | |
804 | unbind_from_irqhandler(info->irq, info); | |
805 | gnttab_end_foreign_access(info->ring_ref, 0, | |
806 | (unsigned long)info->ring.sring); | |
807 | scsi_host_put(host); | |
808 | return err; | |
809 | } | |
810 | ||
811 | static int scsifront_remove(struct xenbus_device *dev) | |
812 | { | |
813 | struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); | |
814 | ||
815 | pr_debug("%s: %s removed\n", __func__, dev->nodename); | |
816 | ||
817 | mutex_lock(&scsifront_mutex); | |
818 | if (info->host_active) { | |
819 | /* Scsi_host not yet removed */ | |
820 | scsi_remove_host(info->host); | |
821 | info->host_active = 0; | |
822 | } | |
823 | mutex_unlock(&scsifront_mutex); | |
824 | ||
825 | gnttab_end_foreign_access(info->ring_ref, 0, | |
826 | (unsigned long)info->ring.sring); | |
827 | unbind_from_irqhandler(info->irq, info); | |
828 | ||
829 | scsi_host_put(info->host); | |
830 | ||
831 | return 0; | |
832 | } | |
833 | ||
834 | static void scsifront_disconnect(struct vscsifrnt_info *info) | |
835 | { | |
836 | struct xenbus_device *dev = info->dev; | |
837 | struct Scsi_Host *host = info->host; | |
838 | ||
839 | pr_debug("%s: %s disconnect\n", __func__, dev->nodename); | |
840 | ||
841 | /* | |
842 | * When this function is executed, all devices of | |
843 | * Frontend have been deleted. | |
844 | * Therefore, it need not block I/O before remove_host. | |
845 | */ | |
846 | ||
847 | mutex_lock(&scsifront_mutex); | |
848 | if (info->host_active) { | |
849 | scsi_remove_host(host); | |
850 | info->host_active = 0; | |
851 | } | |
852 | mutex_unlock(&scsifront_mutex); | |
853 | ||
854 | xenbus_frontend_closed(dev); | |
855 | } | |
856 | ||
857 | static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op) | |
858 | { | |
859 | struct xenbus_device *dev = info->dev; | |
860 | int i, err = 0; | |
861 | char str[64]; | |
862 | char **dir; | |
863 | unsigned int dir_n = 0; | |
864 | unsigned int device_state; | |
865 | unsigned int hst, chn, tgt, lun; | |
866 | struct scsi_device *sdev; | |
867 | ||
868 | dir = xenbus_directory(XBT_NIL, dev->otherend, "vscsi-devs", &dir_n); | |
869 | if (IS_ERR(dir)) | |
870 | return; | |
871 | ||
872 | /* mark current task as the one allowed to modify device states */ | |
873 | BUG_ON(info->curr); | |
874 | info->curr = current; | |
875 | ||
876 | for (i = 0; i < dir_n; i++) { | |
877 | /* read status */ | |
878 | snprintf(str, sizeof(str), "vscsi-devs/%s/state", dir[i]); | |
879 | err = xenbus_scanf(XBT_NIL, dev->otherend, str, "%u", | |
880 | &device_state); | |
881 | if (XENBUS_EXIST_ERR(err)) | |
882 | continue; | |
883 | ||
884 | /* virtual SCSI device */ | |
885 | snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", dir[i]); | |
886 | err = xenbus_scanf(XBT_NIL, dev->otherend, str, | |
887 | "%u:%u:%u:%u", &hst, &chn, &tgt, &lun); | |
888 | if (XENBUS_EXIST_ERR(err)) | |
889 | continue; | |
890 | ||
891 | /* | |
892 | * Front device state path, used in slave_configure called | |
893 | * on successfull scsi_add_device, and in slave_destroy called | |
894 | * on remove of a device. | |
895 | */ | |
896 | snprintf(info->dev_state_path, sizeof(info->dev_state_path), | |
897 | "vscsi-devs/%s/state", dir[i]); | |
898 | ||
899 | switch (op) { | |
900 | case VSCSIFRONT_OP_ADD_LUN: | |
901 | if (device_state != XenbusStateInitialised) | |
902 | break; | |
903 | ||
904 | if (scsi_add_device(info->host, chn, tgt, lun)) { | |
905 | dev_err(&dev->dev, "scsi_add_device\n"); | |
906 | xenbus_printf(XBT_NIL, dev->nodename, | |
907 | info->dev_state_path, | |
908 | "%d", XenbusStateClosed); | |
909 | } | |
910 | break; | |
911 | case VSCSIFRONT_OP_DEL_LUN: | |
912 | if (device_state != XenbusStateClosing) | |
913 | break; | |
914 | ||
915 | sdev = scsi_device_lookup(info->host, chn, tgt, lun); | |
916 | if (sdev) { | |
917 | scsi_remove_device(sdev); | |
918 | scsi_device_put(sdev); | |
919 | } | |
920 | break; | |
921 | default: | |
922 | break; | |
923 | } | |
924 | } | |
925 | ||
926 | info->curr = NULL; | |
927 | ||
928 | kfree(dir); | |
929 | } | |
930 | ||
931 | static void scsifront_read_backend_params(struct xenbus_device *dev, | |
932 | struct vscsifrnt_info *info) | |
933 | { | |
934 | unsigned int sg_grant; | |
935 | int ret; | |
936 | struct Scsi_Host *host = info->host; | |
937 | ||
938 | ret = xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg-grant", "%u", | |
939 | &sg_grant); | |
940 | if (ret == 1 && sg_grant) { | |
941 | sg_grant = min_t(unsigned int, sg_grant, SG_ALL); | |
942 | sg_grant = max_t(unsigned int, sg_grant, VSCSIIF_SG_TABLESIZE); | |
943 | host->sg_tablesize = min_t(unsigned int, sg_grant, | |
944 | VSCSIIF_SG_TABLESIZE * PAGE_SIZE / | |
945 | sizeof(struct scsiif_request_segment)); | |
946 | host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512; | |
947 | } | |
948 | dev_info(&dev->dev, "using up to %d SG entries\n", host->sg_tablesize); | |
949 | } | |
950 | ||
951 | static void scsifront_backend_changed(struct xenbus_device *dev, | |
952 | enum xenbus_state backend_state) | |
953 | { | |
954 | struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); | |
955 | ||
956 | pr_debug("%s: %p %u %u\n", __func__, dev, dev->state, backend_state); | |
957 | ||
958 | switch (backend_state) { | |
959 | case XenbusStateUnknown: | |
960 | case XenbusStateInitialising: | |
961 | case XenbusStateInitWait: | |
962 | case XenbusStateInitialised: | |
963 | break; | |
964 | ||
965 | case XenbusStateConnected: | |
966 | scsifront_read_backend_params(dev, info); | |
967 | if (xenbus_read_driver_state(dev->nodename) == | |
968 | XenbusStateInitialised) | |
969 | scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN); | |
970 | ||
971 | if (dev->state != XenbusStateConnected) | |
972 | xenbus_switch_state(dev, XenbusStateConnected); | |
973 | break; | |
974 | ||
975 | case XenbusStateClosed: | |
976 | if (dev->state == XenbusStateClosed) | |
977 | break; | |
978 | /* Missed the backend's Closing state -- fallthrough */ | |
979 | case XenbusStateClosing: | |
980 | scsifront_disconnect(info); | |
981 | break; | |
982 | ||
983 | case XenbusStateReconfiguring: | |
984 | scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_DEL_LUN); | |
985 | xenbus_switch_state(dev, XenbusStateReconfiguring); | |
986 | break; | |
987 | ||
988 | case XenbusStateReconfigured: | |
989 | scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN); | |
990 | xenbus_switch_state(dev, XenbusStateConnected); | |
991 | break; | |
992 | } | |
993 | } | |
994 | ||
995 | static const struct xenbus_device_id scsifront_ids[] = { | |
996 | { "vscsi" }, | |
997 | { "" } | |
998 | }; | |
999 | ||
1000 | static DEFINE_XENBUS_DRIVER(scsifront, , | |
1001 | .probe = scsifront_probe, | |
1002 | .remove = scsifront_remove, | |
1003 | .otherend_changed = scsifront_backend_changed, | |
1004 | ); | |
1005 | ||
1006 | static int __init scsifront_init(void) | |
1007 | { | |
1008 | if (!xen_domain()) | |
1009 | return -ENODEV; | |
1010 | ||
1011 | return xenbus_register_frontend(&scsifront_driver); | |
1012 | } | |
1013 | module_init(scsifront_init); | |
1014 | ||
1015 | static void __exit scsifront_exit(void) | |
1016 | { | |
1017 | xenbus_unregister_driver(&scsifront_driver); | |
1018 | } | |
1019 | module_exit(scsifront_exit); | |
1020 | ||
1021 | MODULE_DESCRIPTION("Xen SCSI frontend driver"); | |
1022 | MODULE_LICENSE("GPL"); | |
1023 | MODULE_ALIAS("xen:vscsi"); | |
1024 | MODULE_AUTHOR("Juergen Gross <jgross@suse.com>"); |