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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 | #define VSCSIFRONT_OP_READD_LUN 3 | |
67 | ||
68 | /* Tuning point. */ | |
69 | #define VSCSIIF_DEFAULT_CMD_PER_LUN 10 | |
70 | #define VSCSIIF_MAX_TARGET 64 | |
71 | #define VSCSIIF_MAX_LUN 255 | |
72 | ||
73 | #define VSCSIIF_RING_SIZE __CONST_RING_SIZE(vscsiif, PAGE_SIZE) | |
74 | #define VSCSIIF_MAX_REQS VSCSIIF_RING_SIZE | |
75 | ||
76 | #define vscsiif_grants_sg(_sg) (PFN_UP((_sg) * \ | |
77 | sizeof(struct scsiif_request_segment))) | |
78 | ||
79 | struct vscsifrnt_shadow { | |
80 | /* command between backend and frontend */ | |
81 | unsigned char act; | |
82 | uint8_t nr_segments; | |
83 | uint16_t rqid; | |
84 | uint16_t ref_rqid; | |
85 | ||
86 | unsigned int nr_grants; /* number of grants in gref[] */ | |
87 | struct scsiif_request_segment *sg; /* scatter/gather elements */ | |
88 | struct scsiif_request_segment seg[VSCSIIF_SG_TABLESIZE]; | |
89 | ||
90 | /* Do reset or abort function. */ | |
91 | wait_queue_head_t wq_reset; /* reset work queue */ | |
92 | int wait_reset; /* reset work queue condition */ | |
93 | int32_t rslt_reset; /* reset response status: */ | |
94 | /* SUCCESS or FAILED or: */ | |
95 | #define RSLT_RESET_WAITING 0 | |
96 | #define RSLT_RESET_ERR -1 | |
97 | ||
98 | /* Requested struct scsi_cmnd is stored from kernel. */ | |
99 | struct scsi_cmnd *sc; | |
100 | int gref[vscsiif_grants_sg(SG_ALL) + SG_ALL]; | |
101 | }; | |
102 | ||
103 | struct vscsifrnt_info { | |
104 | struct xenbus_device *dev; | |
105 | ||
106 | struct Scsi_Host *host; | |
107 | int host_active; | |
108 | ||
109 | unsigned int evtchn; | |
110 | unsigned int irq; | |
111 | ||
112 | grant_ref_t ring_ref; | |
113 | struct vscsiif_front_ring ring; | |
114 | struct vscsiif_response ring_rsp; | |
115 | ||
116 | spinlock_t shadow_lock; | |
117 | DECLARE_BITMAP(shadow_free_bitmap, VSCSIIF_MAX_REQS); | |
118 | struct vscsifrnt_shadow *shadow[VSCSIIF_MAX_REQS]; | |
119 | ||
120 | /* Following items are protected by the host lock. */ | |
121 | wait_queue_head_t wq_sync; | |
122 | wait_queue_head_t wq_pause; | |
123 | unsigned int wait_ring_available:1; | |
124 | unsigned int waiting_pause:1; | |
125 | unsigned int pause:1; | |
126 | unsigned callers; | |
127 | ||
128 | char dev_state_path[64]; | |
129 | struct task_struct *curr; | |
130 | }; | |
131 | ||
132 | static DEFINE_MUTEX(scsifront_mutex); | |
133 | ||
134 | static void scsifront_wake_up(struct vscsifrnt_info *info) | |
135 | { | |
136 | info->wait_ring_available = 0; | |
137 | wake_up(&info->wq_sync); | |
138 | } | |
139 | ||
140 | static int scsifront_get_rqid(struct vscsifrnt_info *info) | |
141 | { | |
142 | unsigned long flags; | |
143 | int free; | |
144 | ||
145 | spin_lock_irqsave(&info->shadow_lock, flags); | |
146 | ||
147 | free = find_first_bit(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); | |
148 | __clear_bit(free, info->shadow_free_bitmap); | |
149 | ||
150 | spin_unlock_irqrestore(&info->shadow_lock, flags); | |
151 | ||
152 | return free; | |
153 | } | |
154 | ||
155 | static int _scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id) | |
156 | { | |
157 | int empty = bitmap_empty(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); | |
158 | ||
159 | __set_bit(id, info->shadow_free_bitmap); | |
160 | info->shadow[id] = NULL; | |
161 | ||
162 | return empty || info->wait_ring_available; | |
163 | } | |
164 | ||
165 | static void scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id) | |
166 | { | |
167 | unsigned long flags; | |
168 | int kick; | |
169 | ||
170 | spin_lock_irqsave(&info->shadow_lock, flags); | |
171 | kick = _scsifront_put_rqid(info, id); | |
172 | spin_unlock_irqrestore(&info->shadow_lock, flags); | |
173 | ||
174 | if (kick) | |
175 | scsifront_wake_up(info); | |
176 | } | |
177 | ||
178 | static int scsifront_do_request(struct vscsifrnt_info *info, | |
179 | struct vscsifrnt_shadow *shadow) | |
180 | { | |
181 | struct vscsiif_front_ring *ring = &(info->ring); | |
182 | struct vscsiif_request *ring_req; | |
183 | struct scsi_cmnd *sc = shadow->sc; | |
184 | uint32_t id; | |
185 | int i, notify; | |
186 | ||
187 | if (RING_FULL(&info->ring)) | |
188 | return -EBUSY; | |
189 | ||
190 | id = scsifront_get_rqid(info); /* use id in response */ | |
191 | if (id >= VSCSIIF_MAX_REQS) | |
192 | return -EBUSY; | |
193 | ||
194 | info->shadow[id] = shadow; | |
195 | shadow->rqid = id; | |
196 | ||
197 | ring_req = RING_GET_REQUEST(&(info->ring), ring->req_prod_pvt); | |
198 | ring->req_prod_pvt++; | |
199 | ||
200 | ring_req->rqid = id; | |
201 | ring_req->act = shadow->act; | |
202 | ring_req->ref_rqid = shadow->ref_rqid; | |
203 | ring_req->nr_segments = shadow->nr_segments; | |
204 | ||
205 | ring_req->id = sc->device->id; | |
206 | ring_req->lun = sc->device->lun; | |
207 | ring_req->channel = sc->device->channel; | |
208 | ring_req->cmd_len = sc->cmd_len; | |
209 | ||
210 | BUG_ON(sc->cmd_len > VSCSIIF_MAX_COMMAND_SIZE); | |
211 | ||
212 | memcpy(ring_req->cmnd, sc->cmnd, sc->cmd_len); | |
213 | ||
214 | ring_req->sc_data_direction = (uint8_t)sc->sc_data_direction; | |
215 | ring_req->timeout_per_command = sc->request->timeout / HZ; | |
216 | ||
217 | for (i = 0; i < (shadow->nr_segments & ~VSCSIIF_SG_GRANT); i++) | |
218 | ring_req->seg[i] = shadow->seg[i]; | |
219 | ||
220 | RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(ring, notify); | |
221 | if (notify) | |
222 | notify_remote_via_irq(info->irq); | |
223 | ||
224 | return 0; | |
225 | } | |
226 | ||
227 | static void scsifront_gnttab_done(struct vscsifrnt_info *info, | |
228 | struct vscsifrnt_shadow *shadow) | |
229 | { | |
230 | int i; | |
231 | ||
232 | if (shadow->sc->sc_data_direction == DMA_NONE) | |
233 | return; | |
234 | ||
235 | for (i = 0; i < shadow->nr_grants; i++) { | |
236 | if (unlikely(gnttab_query_foreign_access(shadow->gref[i]))) { | |
237 | shost_printk(KERN_ALERT, info->host, KBUILD_MODNAME | |
238 | "grant still in use by backend\n"); | |
239 | BUG(); | |
240 | } | |
241 | gnttab_end_foreign_access(shadow->gref[i], 0, 0UL); | |
242 | } | |
243 | ||
244 | kfree(shadow->sg); | |
245 | } | |
246 | ||
247 | static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info, | |
248 | struct vscsiif_response *ring_rsp) | |
249 | { | |
250 | struct vscsifrnt_shadow *shadow; | |
251 | struct scsi_cmnd *sc; | |
252 | uint32_t id; | |
253 | uint8_t sense_len; | |
254 | ||
255 | id = ring_rsp->rqid; | |
256 | shadow = info->shadow[id]; | |
257 | sc = shadow->sc; | |
258 | ||
259 | BUG_ON(sc == NULL); | |
260 | ||
261 | scsifront_gnttab_done(info, shadow); | |
262 | scsifront_put_rqid(info, id); | |
263 | ||
264 | sc->result = ring_rsp->rslt; | |
265 | scsi_set_resid(sc, ring_rsp->residual_len); | |
266 | ||
267 | sense_len = min_t(uint8_t, VSCSIIF_SENSE_BUFFERSIZE, | |
268 | ring_rsp->sense_len); | |
269 | ||
270 | if (sense_len) | |
271 | memcpy(sc->sense_buffer, ring_rsp->sense_buffer, sense_len); | |
272 | ||
273 | sc->scsi_done(sc); | |
274 | } | |
275 | ||
276 | static void scsifront_sync_cmd_done(struct vscsifrnt_info *info, | |
277 | struct vscsiif_response *ring_rsp) | |
278 | { | |
279 | uint16_t id = ring_rsp->rqid; | |
280 | unsigned long flags; | |
281 | struct vscsifrnt_shadow *shadow = info->shadow[id]; | |
282 | int kick; | |
283 | ||
284 | spin_lock_irqsave(&info->shadow_lock, flags); | |
285 | shadow->wait_reset = 1; | |
286 | switch (shadow->rslt_reset) { | |
287 | case RSLT_RESET_WAITING: | |
288 | shadow->rslt_reset = ring_rsp->rslt; | |
289 | break; | |
290 | case RSLT_RESET_ERR: | |
291 | kick = _scsifront_put_rqid(info, id); | |
292 | spin_unlock_irqrestore(&info->shadow_lock, flags); | |
293 | kfree(shadow); | |
294 | if (kick) | |
295 | scsifront_wake_up(info); | |
296 | return; | |
297 | default: | |
298 | shost_printk(KERN_ERR, info->host, KBUILD_MODNAME | |
299 | "bad reset state %d, possibly leaking %u\n", | |
300 | shadow->rslt_reset, id); | |
301 | break; | |
302 | } | |
303 | spin_unlock_irqrestore(&info->shadow_lock, flags); | |
304 | ||
305 | wake_up(&shadow->wq_reset); | |
306 | } | |
307 | ||
308 | static void scsifront_do_response(struct vscsifrnt_info *info, | |
309 | struct vscsiif_response *ring_rsp) | |
310 | { | |
311 | if (WARN(ring_rsp->rqid >= VSCSIIF_MAX_REQS || | |
312 | test_bit(ring_rsp->rqid, info->shadow_free_bitmap), | |
313 | "illegal rqid %u returned by backend!\n", ring_rsp->rqid)) | |
314 | return; | |
315 | ||
316 | if (info->shadow[ring_rsp->rqid]->act == VSCSIIF_ACT_SCSI_CDB) | |
317 | scsifront_cdb_cmd_done(info, ring_rsp); | |
318 | else | |
319 | scsifront_sync_cmd_done(info, ring_rsp); | |
320 | } | |
321 | ||
322 | static int scsifront_ring_drain(struct vscsifrnt_info *info) | |
323 | { | |
324 | struct vscsiif_response *ring_rsp; | |
325 | RING_IDX i, rp; | |
326 | int more_to_do = 0; | |
327 | ||
328 | rp = info->ring.sring->rsp_prod; | |
329 | rmb(); /* ordering required respective to dom0 */ | |
330 | for (i = info->ring.rsp_cons; i != rp; i++) { | |
331 | ring_rsp = RING_GET_RESPONSE(&info->ring, i); | |
332 | scsifront_do_response(info, ring_rsp); | |
333 | } | |
334 | ||
335 | info->ring.rsp_cons = i; | |
336 | ||
337 | if (i != info->ring.req_prod_pvt) | |
338 | RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do); | |
339 | else | |
340 | info->ring.sring->rsp_event = i + 1; | |
341 | ||
342 | return more_to_do; | |
343 | } | |
344 | ||
345 | static int scsifront_cmd_done(struct vscsifrnt_info *info) | |
346 | { | |
347 | int more_to_do; | |
348 | unsigned long flags; | |
349 | ||
350 | spin_lock_irqsave(info->host->host_lock, flags); | |
351 | ||
352 | more_to_do = scsifront_ring_drain(info); | |
353 | ||
354 | info->wait_ring_available = 0; | |
355 | ||
356 | spin_unlock_irqrestore(info->host->host_lock, flags); | |
357 | ||
358 | wake_up(&info->wq_sync); | |
359 | ||
360 | return more_to_do; | |
361 | } | |
362 | ||
363 | static irqreturn_t scsifront_irq_fn(int irq, void *dev_id) | |
364 | { | |
365 | struct vscsifrnt_info *info = dev_id; | |
366 | ||
367 | while (scsifront_cmd_done(info)) | |
368 | /* Yield point for this unbounded loop. */ | |
369 | cond_resched(); | |
370 | ||
371 | return IRQ_HANDLED; | |
372 | } | |
373 | ||
374 | static void scsifront_finish_all(struct vscsifrnt_info *info) | |
375 | { | |
376 | unsigned i; | |
377 | struct vscsiif_response resp; | |
378 | ||
379 | scsifront_ring_drain(info); | |
380 | ||
381 | for (i = 0; i < VSCSIIF_MAX_REQS; i++) { | |
382 | if (test_bit(i, info->shadow_free_bitmap)) | |
383 | continue; | |
384 | resp.rqid = i; | |
385 | resp.sense_len = 0; | |
386 | resp.rslt = DID_RESET << 16; | |
387 | resp.residual_len = 0; | |
388 | scsifront_do_response(info, &resp); | |
389 | } | |
390 | } | |
391 | ||
392 | static int map_data_for_request(struct vscsifrnt_info *info, | |
393 | struct scsi_cmnd *sc, | |
394 | struct vscsifrnt_shadow *shadow) | |
395 | { | |
396 | grant_ref_t gref_head; | |
397 | struct page *page; | |
398 | int err, ref, ref_cnt = 0; | |
399 | int grant_ro = (sc->sc_data_direction == DMA_TO_DEVICE); | |
400 | unsigned int i, off, len, bytes; | |
401 | unsigned int data_len = scsi_bufflen(sc); | |
402 | unsigned int data_grants = 0, seg_grants = 0; | |
403 | struct scatterlist *sg; | |
404 | struct scsiif_request_segment *seg; | |
405 | ||
406 | if (sc->sc_data_direction == DMA_NONE || !data_len) | |
407 | return 0; | |
408 | ||
409 | scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) | |
410 | data_grants += PFN_UP(sg->offset + sg->length); | |
411 | ||
412 | if (data_grants > VSCSIIF_SG_TABLESIZE) { | |
413 | if (data_grants > info->host->sg_tablesize) { | |
414 | shost_printk(KERN_ERR, info->host, KBUILD_MODNAME | |
415 | "Unable to map request_buffer for command!\n"); | |
416 | return -E2BIG; | |
417 | } | |
418 | seg_grants = vscsiif_grants_sg(data_grants); | |
419 | shadow->sg = kcalloc(data_grants, | |
420 | sizeof(struct scsiif_request_segment), GFP_ATOMIC); | |
421 | if (!shadow->sg) | |
422 | return -ENOMEM; | |
423 | } | |
424 | seg = shadow->sg ? : shadow->seg; | |
425 | ||
426 | err = gnttab_alloc_grant_references(seg_grants + data_grants, | |
427 | &gref_head); | |
428 | if (err) { | |
429 | kfree(shadow->sg); | |
430 | shost_printk(KERN_ERR, info->host, KBUILD_MODNAME | |
431 | "gnttab_alloc_grant_references() error\n"); | |
432 | return -ENOMEM; | |
433 | } | |
434 | ||
435 | if (seg_grants) { | |
436 | page = virt_to_page(seg); | |
437 | off = offset_in_page(seg); | |
438 | len = sizeof(struct scsiif_request_segment) * data_grants; | |
439 | while (len > 0) { | |
440 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); | |
441 | ||
442 | ref = gnttab_claim_grant_reference(&gref_head); | |
443 | BUG_ON(ref == -ENOSPC); | |
444 | ||
445 | gnttab_grant_foreign_access_ref(ref, | |
446 | info->dev->otherend_id, | |
447 | xen_page_to_gfn(page), 1); | |
448 | shadow->gref[ref_cnt] = ref; | |
449 | shadow->seg[ref_cnt].gref = ref; | |
450 | shadow->seg[ref_cnt].offset = (uint16_t)off; | |
451 | shadow->seg[ref_cnt].length = (uint16_t)bytes; | |
452 | ||
453 | page++; | |
454 | len -= bytes; | |
455 | off = 0; | |
456 | ref_cnt++; | |
457 | } | |
458 | BUG_ON(seg_grants < ref_cnt); | |
459 | seg_grants = ref_cnt; | |
460 | } | |
461 | ||
462 | scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) { | |
463 | page = sg_page(sg); | |
464 | off = sg->offset; | |
465 | len = sg->length; | |
466 | ||
467 | while (len > 0 && data_len > 0) { | |
468 | /* | |
469 | * sg sends a scatterlist that is larger than | |
470 | * the data_len it wants transferred for certain | |
471 | * IO sizes. | |
472 | */ | |
473 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); | |
474 | bytes = min(bytes, data_len); | |
475 | ||
476 | ref = gnttab_claim_grant_reference(&gref_head); | |
477 | BUG_ON(ref == -ENOSPC); | |
478 | ||
479 | gnttab_grant_foreign_access_ref(ref, | |
480 | info->dev->otherend_id, | |
481 | xen_page_to_gfn(page), | |
482 | grant_ro); | |
483 | ||
484 | shadow->gref[ref_cnt] = ref; | |
485 | seg->gref = ref; | |
486 | seg->offset = (uint16_t)off; | |
487 | seg->length = (uint16_t)bytes; | |
488 | ||
489 | page++; | |
490 | seg++; | |
491 | len -= bytes; | |
492 | data_len -= bytes; | |
493 | off = 0; | |
494 | ref_cnt++; | |
495 | } | |
496 | } | |
497 | ||
498 | if (seg_grants) | |
499 | shadow->nr_segments = VSCSIIF_SG_GRANT | seg_grants; | |
500 | else | |
501 | shadow->nr_segments = (uint8_t)ref_cnt; | |
502 | shadow->nr_grants = ref_cnt; | |
503 | ||
504 | return 0; | |
505 | } | |
506 | ||
507 | static int scsifront_enter(struct vscsifrnt_info *info) | |
508 | { | |
509 | if (info->pause) | |
510 | return 1; | |
511 | info->callers++; | |
512 | return 0; | |
513 | } | |
514 | ||
515 | static void scsifront_return(struct vscsifrnt_info *info) | |
516 | { | |
517 | info->callers--; | |
518 | if (info->callers) | |
519 | return; | |
520 | ||
521 | if (!info->waiting_pause) | |
522 | return; | |
523 | ||
524 | info->waiting_pause = 0; | |
525 | wake_up(&info->wq_pause); | |
526 | } | |
527 | ||
528 | static int scsifront_queuecommand(struct Scsi_Host *shost, | |
529 | struct scsi_cmnd *sc) | |
530 | { | |
531 | struct vscsifrnt_info *info = shost_priv(shost); | |
532 | struct vscsifrnt_shadow *shadow = scsi_cmd_priv(sc); | |
533 | unsigned long flags; | |
534 | int err; | |
535 | ||
536 | sc->result = 0; | |
537 | ||
538 | shadow->sc = sc; | |
539 | shadow->act = VSCSIIF_ACT_SCSI_CDB; | |
540 | ||
541 | spin_lock_irqsave(shost->host_lock, flags); | |
542 | if (scsifront_enter(info)) { | |
543 | spin_unlock_irqrestore(shost->host_lock, flags); | |
544 | return SCSI_MLQUEUE_HOST_BUSY; | |
545 | } | |
546 | ||
547 | err = map_data_for_request(info, sc, shadow); | |
548 | if (err < 0) { | |
549 | pr_debug("%s: err %d\n", __func__, err); | |
550 | scsifront_return(info); | |
551 | spin_unlock_irqrestore(shost->host_lock, flags); | |
552 | if (err == -ENOMEM) | |
553 | return SCSI_MLQUEUE_HOST_BUSY; | |
554 | sc->result = DID_ERROR << 16; | |
555 | sc->scsi_done(sc); | |
556 | return 0; | |
557 | } | |
558 | ||
559 | if (scsifront_do_request(info, shadow)) { | |
560 | scsifront_gnttab_done(info, shadow); | |
561 | goto busy; | |
562 | } | |
563 | ||
564 | scsifront_return(info); | |
565 | spin_unlock_irqrestore(shost->host_lock, flags); | |
566 | ||
567 | return 0; | |
568 | ||
569 | busy: | |
570 | scsifront_return(info); | |
571 | spin_unlock_irqrestore(shost->host_lock, flags); | |
572 | pr_debug("%s: busy\n", __func__); | |
573 | return SCSI_MLQUEUE_HOST_BUSY; | |
574 | } | |
575 | ||
576 | /* | |
577 | * Any exception handling (reset or abort) must be forwarded to the backend. | |
578 | * We have to wait until an answer is returned. This answer contains the | |
579 | * result to be returned to the requestor. | |
580 | */ | |
581 | static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act) | |
582 | { | |
583 | struct Scsi_Host *host = sc->device->host; | |
584 | struct vscsifrnt_info *info = shost_priv(host); | |
585 | struct vscsifrnt_shadow *shadow, *s = scsi_cmd_priv(sc); | |
586 | int err = 0; | |
587 | ||
588 | shadow = kzalloc(sizeof(*shadow), GFP_NOIO); | |
589 | if (!shadow) | |
590 | return FAILED; | |
591 | ||
592 | shadow->act = act; | |
593 | shadow->rslt_reset = RSLT_RESET_WAITING; | |
594 | shadow->sc = sc; | |
595 | shadow->ref_rqid = s->rqid; | |
596 | init_waitqueue_head(&shadow->wq_reset); | |
597 | ||
598 | spin_lock_irq(host->host_lock); | |
599 | ||
600 | for (;;) { | |
601 | if (scsifront_enter(info)) | |
602 | goto fail; | |
603 | ||
604 | if (!scsifront_do_request(info, shadow)) | |
605 | break; | |
606 | ||
607 | scsifront_return(info); | |
608 | if (err) | |
609 | goto fail; | |
610 | info->wait_ring_available = 1; | |
611 | spin_unlock_irq(host->host_lock); | |
612 | err = wait_event_interruptible(info->wq_sync, | |
613 | !info->wait_ring_available); | |
614 | spin_lock_irq(host->host_lock); | |
615 | } | |
616 | ||
617 | spin_unlock_irq(host->host_lock); | |
618 | err = wait_event_interruptible(shadow->wq_reset, shadow->wait_reset); | |
619 | spin_lock_irq(host->host_lock); | |
620 | ||
621 | if (!err) { | |
622 | err = shadow->rslt_reset; | |
623 | scsifront_put_rqid(info, shadow->rqid); | |
624 | kfree(shadow); | |
625 | } else { | |
626 | spin_lock(&info->shadow_lock); | |
627 | shadow->rslt_reset = RSLT_RESET_ERR; | |
628 | spin_unlock(&info->shadow_lock); | |
629 | err = FAILED; | |
630 | } | |
631 | ||
632 | scsifront_return(info); | |
633 | spin_unlock_irq(host->host_lock); | |
634 | return err; | |
635 | ||
636 | fail: | |
637 | spin_unlock_irq(host->host_lock); | |
638 | kfree(shadow); | |
639 | return FAILED; | |
640 | } | |
641 | ||
642 | static int scsifront_eh_abort_handler(struct scsi_cmnd *sc) | |
643 | { | |
644 | pr_debug("%s\n", __func__); | |
645 | return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_ABORT); | |
646 | } | |
647 | ||
648 | static int scsifront_dev_reset_handler(struct scsi_cmnd *sc) | |
649 | { | |
650 | pr_debug("%s\n", __func__); | |
651 | return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_RESET); | |
652 | } | |
653 | ||
654 | static int scsifront_sdev_configure(struct scsi_device *sdev) | |
655 | { | |
656 | struct vscsifrnt_info *info = shost_priv(sdev->host); | |
657 | int err; | |
658 | ||
659 | if (info && current == info->curr) { | |
660 | err = xenbus_printf(XBT_NIL, info->dev->nodename, | |
661 | info->dev_state_path, "%d", XenbusStateConnected); | |
662 | if (err) { | |
663 | xenbus_dev_error(info->dev, err, | |
664 | "%s: writing dev_state_path", __func__); | |
665 | return err; | |
666 | } | |
667 | } | |
668 | ||
669 | return 0; | |
670 | } | |
671 | ||
672 | static void scsifront_sdev_destroy(struct scsi_device *sdev) | |
673 | { | |
674 | struct vscsifrnt_info *info = shost_priv(sdev->host); | |
675 | int err; | |
676 | ||
677 | if (info && current == info->curr) { | |
678 | err = xenbus_printf(XBT_NIL, info->dev->nodename, | |
679 | info->dev_state_path, "%d", XenbusStateClosed); | |
680 | if (err) | |
681 | xenbus_dev_error(info->dev, err, | |
682 | "%s: writing dev_state_path", __func__); | |
683 | } | |
684 | } | |
685 | ||
686 | static struct scsi_host_template scsifront_sht = { | |
687 | .module = THIS_MODULE, | |
688 | .name = "Xen SCSI frontend driver", | |
689 | .queuecommand = scsifront_queuecommand, | |
690 | .eh_abort_handler = scsifront_eh_abort_handler, | |
691 | .eh_device_reset_handler = scsifront_dev_reset_handler, | |
692 | .slave_configure = scsifront_sdev_configure, | |
693 | .slave_destroy = scsifront_sdev_destroy, | |
694 | .cmd_per_lun = VSCSIIF_DEFAULT_CMD_PER_LUN, | |
695 | .can_queue = VSCSIIF_MAX_REQS, | |
696 | .this_id = -1, | |
697 | .cmd_size = sizeof(struct vscsifrnt_shadow), | |
698 | .sg_tablesize = VSCSIIF_SG_TABLESIZE, | |
699 | .proc_name = "scsifront", | |
700 | }; | |
701 | ||
702 | static int scsifront_alloc_ring(struct vscsifrnt_info *info) | |
703 | { | |
704 | struct xenbus_device *dev = info->dev; | |
705 | struct vscsiif_sring *sring; | |
706 | grant_ref_t gref; | |
707 | int err = -ENOMEM; | |
708 | ||
709 | /***** Frontend to Backend ring start *****/ | |
710 | sring = (struct vscsiif_sring *)__get_free_page(GFP_KERNEL); | |
711 | if (!sring) { | |
712 | xenbus_dev_fatal(dev, err, | |
713 | "fail to allocate shared ring (Front to Back)"); | |
714 | return err; | |
715 | } | |
716 | SHARED_RING_INIT(sring); | |
717 | FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE); | |
718 | ||
719 | err = xenbus_grant_ring(dev, sring, 1, &gref); | |
720 | if (err < 0) { | |
721 | free_page((unsigned long)sring); | |
722 | xenbus_dev_fatal(dev, err, | |
723 | "fail to grant shared ring (Front to Back)"); | |
724 | return err; | |
725 | } | |
726 | info->ring_ref = gref; | |
727 | ||
728 | err = xenbus_alloc_evtchn(dev, &info->evtchn); | |
729 | if (err) { | |
730 | xenbus_dev_fatal(dev, err, "xenbus_alloc_evtchn"); | |
731 | goto free_gnttab; | |
732 | } | |
733 | ||
734 | err = bind_evtchn_to_irq(info->evtchn); | |
735 | if (err <= 0) { | |
736 | xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq"); | |
737 | goto free_gnttab; | |
738 | } | |
739 | ||
740 | info->irq = err; | |
741 | ||
742 | err = request_threaded_irq(info->irq, NULL, scsifront_irq_fn, | |
743 | IRQF_ONESHOT, "scsifront", info); | |
744 | if (err) { | |
745 | xenbus_dev_fatal(dev, err, "request_threaded_irq"); | |
746 | goto free_irq; | |
747 | } | |
748 | ||
749 | return 0; | |
750 | ||
751 | /* free resource */ | |
752 | free_irq: | |
753 | unbind_from_irqhandler(info->irq, info); | |
754 | free_gnttab: | |
755 | gnttab_end_foreign_access(info->ring_ref, 0, | |
756 | (unsigned long)info->ring.sring); | |
757 | ||
758 | return err; | |
759 | } | |
760 | ||
761 | static void scsifront_free_ring(struct vscsifrnt_info *info) | |
762 | { | |
763 | unbind_from_irqhandler(info->irq, info); | |
764 | gnttab_end_foreign_access(info->ring_ref, 0, | |
765 | (unsigned long)info->ring.sring); | |
766 | } | |
767 | ||
768 | static int scsifront_init_ring(struct vscsifrnt_info *info) | |
769 | { | |
770 | struct xenbus_device *dev = info->dev; | |
771 | struct xenbus_transaction xbt; | |
772 | int err; | |
773 | ||
774 | pr_debug("%s\n", __func__); | |
775 | ||
776 | err = scsifront_alloc_ring(info); | |
777 | if (err) | |
778 | return err; | |
779 | pr_debug("%s: %u %u\n", __func__, info->ring_ref, info->evtchn); | |
780 | ||
781 | again: | |
782 | err = xenbus_transaction_start(&xbt); | |
783 | if (err) | |
784 | xenbus_dev_fatal(dev, err, "starting transaction"); | |
785 | ||
786 | err = xenbus_printf(xbt, dev->nodename, "ring-ref", "%u", | |
787 | info->ring_ref); | |
788 | if (err) { | |
789 | xenbus_dev_fatal(dev, err, "%s", "writing ring-ref"); | |
790 | goto fail; | |
791 | } | |
792 | ||
793 | err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u", | |
794 | info->evtchn); | |
795 | ||
796 | if (err) { | |
797 | xenbus_dev_fatal(dev, err, "%s", "writing event-channel"); | |
798 | goto fail; | |
799 | } | |
800 | ||
801 | err = xenbus_transaction_end(xbt, 0); | |
802 | if (err) { | |
803 | if (err == -EAGAIN) | |
804 | goto again; | |
805 | xenbus_dev_fatal(dev, err, "completing transaction"); | |
806 | goto free_sring; | |
807 | } | |
808 | ||
809 | return 0; | |
810 | ||
811 | fail: | |
812 | xenbus_transaction_end(xbt, 1); | |
813 | free_sring: | |
814 | scsifront_free_ring(info); | |
815 | ||
816 | return err; | |
817 | } | |
818 | ||
819 | ||
820 | static int scsifront_probe(struct xenbus_device *dev, | |
821 | const struct xenbus_device_id *id) | |
822 | { | |
823 | struct vscsifrnt_info *info; | |
824 | struct Scsi_Host *host; | |
825 | int err = -ENOMEM; | |
826 | char name[TASK_COMM_LEN]; | |
827 | ||
828 | host = scsi_host_alloc(&scsifront_sht, sizeof(*info)); | |
829 | if (!host) { | |
830 | xenbus_dev_fatal(dev, err, "fail to allocate scsi host"); | |
831 | return err; | |
832 | } | |
833 | info = (struct vscsifrnt_info *)host->hostdata; | |
834 | ||
835 | dev_set_drvdata(&dev->dev, info); | |
836 | info->dev = dev; | |
837 | ||
838 | bitmap_fill(info->shadow_free_bitmap, VSCSIIF_MAX_REQS); | |
839 | ||
840 | err = scsifront_init_ring(info); | |
841 | if (err) { | |
842 | scsi_host_put(host); | |
843 | return err; | |
844 | } | |
845 | ||
846 | init_waitqueue_head(&info->wq_sync); | |
847 | init_waitqueue_head(&info->wq_pause); | |
848 | spin_lock_init(&info->shadow_lock); | |
849 | ||
850 | snprintf(name, TASK_COMM_LEN, "vscsiif.%d", host->host_no); | |
851 | ||
852 | host->max_id = VSCSIIF_MAX_TARGET; | |
853 | host->max_channel = 0; | |
854 | host->max_lun = VSCSIIF_MAX_LUN; | |
855 | host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512; | |
856 | host->max_cmd_len = VSCSIIF_MAX_COMMAND_SIZE; | |
857 | ||
858 | err = scsi_add_host(host, &dev->dev); | |
859 | if (err) { | |
860 | dev_err(&dev->dev, "fail to add scsi host %d\n", err); | |
861 | goto free_sring; | |
862 | } | |
863 | info->host = host; | |
864 | info->host_active = 1; | |
865 | ||
866 | xenbus_switch_state(dev, XenbusStateInitialised); | |
867 | ||
868 | return 0; | |
869 | ||
870 | free_sring: | |
871 | scsifront_free_ring(info); | |
872 | scsi_host_put(host); | |
873 | return err; | |
874 | } | |
875 | ||
876 | static int scsifront_resume(struct xenbus_device *dev) | |
877 | { | |
878 | struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); | |
879 | struct Scsi_Host *host = info->host; | |
880 | int err; | |
881 | ||
882 | spin_lock_irq(host->host_lock); | |
883 | ||
884 | /* Finish all still pending commands. */ | |
885 | scsifront_finish_all(info); | |
886 | ||
887 | spin_unlock_irq(host->host_lock); | |
888 | ||
889 | /* Reconnect to dom0. */ | |
890 | scsifront_free_ring(info); | |
891 | err = scsifront_init_ring(info); | |
892 | if (err) { | |
893 | dev_err(&dev->dev, "fail to resume %d\n", err); | |
894 | scsi_host_put(host); | |
895 | return err; | |
896 | } | |
897 | ||
898 | xenbus_switch_state(dev, XenbusStateInitialised); | |
899 | ||
900 | return 0; | |
901 | } | |
902 | ||
903 | static int scsifront_suspend(struct xenbus_device *dev) | |
904 | { | |
905 | struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); | |
906 | struct Scsi_Host *host = info->host; | |
907 | int err = 0; | |
908 | ||
909 | /* No new commands for the backend. */ | |
910 | spin_lock_irq(host->host_lock); | |
911 | info->pause = 1; | |
912 | while (info->callers && !err) { | |
913 | info->waiting_pause = 1; | |
914 | info->wait_ring_available = 0; | |
915 | spin_unlock_irq(host->host_lock); | |
916 | wake_up(&info->wq_sync); | |
917 | err = wait_event_interruptible(info->wq_pause, | |
918 | !info->waiting_pause); | |
919 | spin_lock_irq(host->host_lock); | |
920 | } | |
921 | spin_unlock_irq(host->host_lock); | |
922 | return err; | |
923 | } | |
924 | ||
925 | static int scsifront_remove(struct xenbus_device *dev) | |
926 | { | |
927 | struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); | |
928 | ||
929 | pr_debug("%s: %s removed\n", __func__, dev->nodename); | |
930 | ||
931 | mutex_lock(&scsifront_mutex); | |
932 | if (info->host_active) { | |
933 | /* Scsi_host not yet removed */ | |
934 | scsi_remove_host(info->host); | |
935 | info->host_active = 0; | |
936 | } | |
937 | mutex_unlock(&scsifront_mutex); | |
938 | ||
939 | scsifront_free_ring(info); | |
940 | scsi_host_put(info->host); | |
941 | ||
942 | return 0; | |
943 | } | |
944 | ||
945 | static void scsifront_disconnect(struct vscsifrnt_info *info) | |
946 | { | |
947 | struct xenbus_device *dev = info->dev; | |
948 | struct Scsi_Host *host = info->host; | |
949 | ||
950 | pr_debug("%s: %s disconnect\n", __func__, dev->nodename); | |
951 | ||
952 | /* | |
953 | * When this function is executed, all devices of | |
954 | * Frontend have been deleted. | |
955 | * Therefore, it need not block I/O before remove_host. | |
956 | */ | |
957 | ||
958 | mutex_lock(&scsifront_mutex); | |
959 | if (info->host_active) { | |
960 | scsi_remove_host(host); | |
961 | info->host_active = 0; | |
962 | } | |
963 | mutex_unlock(&scsifront_mutex); | |
964 | ||
965 | xenbus_frontend_closed(dev); | |
966 | } | |
967 | ||
968 | static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op) | |
969 | { | |
970 | struct xenbus_device *dev = info->dev; | |
971 | int i, err = 0; | |
972 | char str[64]; | |
973 | char **dir; | |
974 | unsigned int dir_n = 0; | |
975 | unsigned int device_state; | |
976 | unsigned int hst, chn, tgt, lun; | |
977 | struct scsi_device *sdev; | |
978 | ||
979 | dir = xenbus_directory(XBT_NIL, dev->otherend, "vscsi-devs", &dir_n); | |
980 | if (IS_ERR(dir)) | |
981 | return; | |
982 | ||
983 | /* mark current task as the one allowed to modify device states */ | |
984 | BUG_ON(info->curr); | |
985 | info->curr = current; | |
986 | ||
987 | for (i = 0; i < dir_n; i++) { | |
988 | /* read status */ | |
989 | snprintf(str, sizeof(str), "vscsi-devs/%s/state", dir[i]); | |
990 | err = xenbus_scanf(XBT_NIL, dev->otherend, str, "%u", | |
991 | &device_state); | |
992 | if (XENBUS_EXIST_ERR(err)) | |
993 | continue; | |
994 | ||
995 | /* virtual SCSI device */ | |
996 | snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", dir[i]); | |
997 | err = xenbus_scanf(XBT_NIL, dev->otherend, str, | |
998 | "%u:%u:%u:%u", &hst, &chn, &tgt, &lun); | |
999 | if (XENBUS_EXIST_ERR(err)) | |
1000 | continue; | |
1001 | ||
1002 | /* | |
1003 | * Front device state path, used in slave_configure called | |
1004 | * on successfull scsi_add_device, and in slave_destroy called | |
1005 | * on remove of a device. | |
1006 | */ | |
1007 | snprintf(info->dev_state_path, sizeof(info->dev_state_path), | |
1008 | "vscsi-devs/%s/state", dir[i]); | |
1009 | ||
1010 | switch (op) { | |
1011 | case VSCSIFRONT_OP_ADD_LUN: | |
1012 | if (device_state != XenbusStateInitialised) | |
1013 | break; | |
1014 | ||
1015 | if (scsi_add_device(info->host, chn, tgt, lun)) { | |
1016 | dev_err(&dev->dev, "scsi_add_device\n"); | |
1017 | err = xenbus_printf(XBT_NIL, dev->nodename, | |
1018 | info->dev_state_path, | |
1019 | "%d", XenbusStateClosed); | |
1020 | if (err) | |
1021 | xenbus_dev_error(dev, err, | |
1022 | "%s: writing dev_state_path", __func__); | |
1023 | } | |
1024 | break; | |
1025 | case VSCSIFRONT_OP_DEL_LUN: | |
1026 | if (device_state != XenbusStateClosing) | |
1027 | break; | |
1028 | ||
1029 | sdev = scsi_device_lookup(info->host, chn, tgt, lun); | |
1030 | if (sdev) { | |
1031 | scsi_remove_device(sdev); | |
1032 | scsi_device_put(sdev); | |
1033 | } | |
1034 | break; | |
1035 | case VSCSIFRONT_OP_READD_LUN: | |
1036 | if (device_state == XenbusStateConnected) { | |
1037 | err = xenbus_printf(XBT_NIL, dev->nodename, | |
1038 | info->dev_state_path, | |
1039 | "%d", XenbusStateConnected); | |
1040 | if (err) | |
1041 | xenbus_dev_error(dev, err, | |
1042 | "%s: writing dev_state_path", __func__); | |
1043 | } | |
1044 | break; | |
1045 | default: | |
1046 | break; | |
1047 | } | |
1048 | } | |
1049 | ||
1050 | info->curr = NULL; | |
1051 | ||
1052 | kfree(dir); | |
1053 | } | |
1054 | ||
1055 | static void scsifront_read_backend_params(struct xenbus_device *dev, | |
1056 | struct vscsifrnt_info *info) | |
1057 | { | |
1058 | unsigned int sg_grant, nr_segs; | |
1059 | struct Scsi_Host *host = info->host; | |
1060 | ||
1061 | sg_grant = xenbus_read_unsigned(dev->otherend, "feature-sg-grant", 0); | |
1062 | nr_segs = min_t(unsigned int, sg_grant, SG_ALL); | |
1063 | nr_segs = max_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE); | |
1064 | nr_segs = min_t(unsigned int, nr_segs, | |
1065 | VSCSIIF_SG_TABLESIZE * PAGE_SIZE / | |
1066 | sizeof(struct scsiif_request_segment)); | |
1067 | ||
1068 | if (!info->pause && sg_grant) | |
1069 | dev_info(&dev->dev, "using up to %d SG entries\n", nr_segs); | |
1070 | else if (info->pause && nr_segs < host->sg_tablesize) | |
1071 | dev_warn(&dev->dev, | |
1072 | "SG entries decreased from %d to %u - device may not work properly anymore\n", | |
1073 | host->sg_tablesize, nr_segs); | |
1074 | ||
1075 | host->sg_tablesize = nr_segs; | |
1076 | host->max_sectors = (nr_segs - 1) * PAGE_SIZE / 512; | |
1077 | } | |
1078 | ||
1079 | static void scsifront_backend_changed(struct xenbus_device *dev, | |
1080 | enum xenbus_state backend_state) | |
1081 | { | |
1082 | struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev); | |
1083 | ||
1084 | pr_debug("%s: %p %u %u\n", __func__, dev, dev->state, backend_state); | |
1085 | ||
1086 | switch (backend_state) { | |
1087 | case XenbusStateUnknown: | |
1088 | case XenbusStateInitialising: | |
1089 | case XenbusStateInitWait: | |
1090 | case XenbusStateInitialised: | |
1091 | break; | |
1092 | ||
1093 | case XenbusStateConnected: | |
1094 | scsifront_read_backend_params(dev, info); | |
1095 | ||
1096 | if (info->pause) { | |
1097 | scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_READD_LUN); | |
1098 | xenbus_switch_state(dev, XenbusStateConnected); | |
1099 | info->pause = 0; | |
1100 | return; | |
1101 | } | |
1102 | ||
1103 | if (xenbus_read_driver_state(dev->nodename) == | |
1104 | XenbusStateInitialised) | |
1105 | scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN); | |
1106 | ||
1107 | if (dev->state != XenbusStateConnected) | |
1108 | xenbus_switch_state(dev, XenbusStateConnected); | |
1109 | break; | |
1110 | ||
1111 | case XenbusStateClosed: | |
1112 | if (dev->state == XenbusStateClosed) | |
1113 | break; | |
1114 | /* fall through - Missed the backend's Closing state */ | |
1115 | case XenbusStateClosing: | |
1116 | scsifront_disconnect(info); | |
1117 | break; | |
1118 | ||
1119 | case XenbusStateReconfiguring: | |
1120 | scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_DEL_LUN); | |
1121 | xenbus_switch_state(dev, XenbusStateReconfiguring); | |
1122 | break; | |
1123 | ||
1124 | case XenbusStateReconfigured: | |
1125 | scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN); | |
1126 | xenbus_switch_state(dev, XenbusStateConnected); | |
1127 | break; | |
1128 | } | |
1129 | } | |
1130 | ||
1131 | static const struct xenbus_device_id scsifront_ids[] = { | |
1132 | { "vscsi" }, | |
1133 | { "" } | |
1134 | }; | |
1135 | ||
1136 | static struct xenbus_driver scsifront_driver = { | |
1137 | .ids = scsifront_ids, | |
1138 | .probe = scsifront_probe, | |
1139 | .remove = scsifront_remove, | |
1140 | .resume = scsifront_resume, | |
1141 | .suspend = scsifront_suspend, | |
1142 | .otherend_changed = scsifront_backend_changed, | |
1143 | }; | |
1144 | ||
1145 | static int __init scsifront_init(void) | |
1146 | { | |
1147 | if (!xen_domain()) | |
1148 | return -ENODEV; | |
1149 | ||
1150 | return xenbus_register_frontend(&scsifront_driver); | |
1151 | } | |
1152 | module_init(scsifront_init); | |
1153 | ||
1154 | static void __exit scsifront_exit(void) | |
1155 | { | |
1156 | xenbus_unregister_driver(&scsifront_driver); | |
1157 | } | |
1158 | module_exit(scsifront_exit); | |
1159 | ||
1160 | MODULE_DESCRIPTION("Xen SCSI frontend driver"); | |
1161 | MODULE_LICENSE("GPL"); | |
1162 | MODULE_ALIAS("xen:vscsi"); | |
1163 | MODULE_AUTHOR("Juergen Gross <jgross@suse.com>"); |