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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * drivers/s390/char/tape_block.c | |
3 | * block device frontend for tape device driver | |
4 | * | |
5 | * S390 and zSeries version | |
6 | * Copyright (C) 2001,2003 IBM Deutschland Entwicklung GmbH, IBM Corporation | |
7 | * Author(s): Carsten Otte <cotte@de.ibm.com> | |
8 | * Tuan Ngo-Anh <ngoanh@de.ibm.com> | |
9 | * Martin Schwidefsky <schwidefsky@de.ibm.com> | |
10 | * Stefan Bader <shbader@de.ibm.com> | |
11 | */ | |
12 | ||
ab640db0 CO |
13 | #define KMSG_COMPONENT "tape" |
14 | ||
1da177e4 | 15 | #include <linux/fs.h> |
1da177e4 LT |
16 | #include <linux/module.h> |
17 | #include <linux/blkdev.h> | |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/buffer_head.h> | |
c1637532 | 20 | #include <linux/kernel.h> |
1da177e4 LT |
21 | |
22 | #include <asm/debug.h> | |
23 | ||
24 | #define TAPE_DBF_AREA tape_core_dbf | |
25 | ||
26 | #include "tape.h" | |
27 | ||
1da177e4 LT |
28 | #define TAPEBLOCK_MAX_SEC 100 |
29 | #define TAPEBLOCK_MIN_REQUEUE 3 | |
30 | ||
31 | /* | |
32 | * 2003/11/25 Stefan Bader <shbader@de.ibm.com> | |
33 | * | |
34 | * In 2.5/2.6 the block device request function is very likely to be called | |
35 | * with disabled interrupts (e.g. generic_unplug_device). So the driver can't | |
36 | * just call any function that tries to allocate CCW requests from that con- | |
37 | * text since it might sleep. There are two choices to work around this: | |
38 | * a) do not allocate with kmalloc but use its own memory pool | |
39 | * b) take requests from the queue outside that context, knowing that | |
40 | * allocation might sleep | |
41 | */ | |
42 | ||
43 | /* | |
44 | * file operation structure for tape block frontend | |
45 | */ | |
4e999af9 AV |
46 | static int tapeblock_open(struct block_device *, fmode_t); |
47 | static int tapeblock_release(struct gendisk *, fmode_t); | |
48 | static int tapeblock_ioctl(struct block_device *, fmode_t, unsigned int, | |
1da177e4 LT |
49 | unsigned long); |
50 | static int tapeblock_medium_changed(struct gendisk *); | |
51 | static int tapeblock_revalidate_disk(struct gendisk *); | |
52 | ||
53 | static struct block_device_operations tapeblock_fops = { | |
54 | .owner = THIS_MODULE, | |
4e999af9 AV |
55 | .open = tapeblock_open, |
56 | .release = tapeblock_release, | |
57 | .locked_ioctl = tapeblock_ioctl, | |
1da177e4 LT |
58 | .media_changed = tapeblock_medium_changed, |
59 | .revalidate_disk = tapeblock_revalidate_disk, | |
60 | }; | |
61 | ||
62 | static int tapeblock_major = 0; | |
63 | ||
64 | static void | |
65 | tapeblock_trigger_requeue(struct tape_device *device) | |
66 | { | |
67 | /* Protect against rescheduling. */ | |
973bd993 | 68 | if (atomic_cmpxchg(&device->blk_data.requeue_scheduled, 0, 1) != 0) |
1da177e4 LT |
69 | return; |
70 | schedule_work(&device->blk_data.requeue_task); | |
71 | } | |
72 | ||
73 | /* | |
74 | * Post finished request. | |
75 | */ | |
1da177e4 LT |
76 | static void |
77 | __tapeblock_end_request(struct tape_request *ccw_req, void *data) | |
78 | { | |
79 | struct tape_device *device; | |
80 | struct request *req; | |
81 | ||
82 | DBF_LH(6, "__tapeblock_end_request()\n"); | |
83 | ||
84 | device = ccw_req->device; | |
85 | req = (struct request *) data; | |
40cbbb78 | 86 | blk_end_request_all(req, (ccw_req->rc == 0) ? 0 : -EIO); |
1da177e4 LT |
87 | if (ccw_req->rc == 0) |
88 | /* Update position. */ | |
89 | device->blk_data.block_position = | |
83096ebf | 90 | (blk_rq_pos(req) + blk_rq_sectors(req)) >> TAPEBLOCK_HSEC_S2B; |
1da177e4 LT |
91 | else |
92 | /* We lost the position information due to an error. */ | |
93 | device->blk_data.block_position = -1; | |
94 | device->discipline->free_bread(ccw_req); | |
95 | if (!list_empty(&device->req_queue) || | |
96 | elv_next_request(device->blk_data.request_queue)) | |
97 | tapeblock_trigger_requeue(device); | |
98 | } | |
99 | ||
100 | /* | |
101 | * Feed the tape device CCW queue with requests supplied in a list. | |
102 | */ | |
4d284cac | 103 | static int |
1da177e4 LT |
104 | tapeblock_start_request(struct tape_device *device, struct request *req) |
105 | { | |
106 | struct tape_request * ccw_req; | |
107 | int rc; | |
108 | ||
109 | DBF_LH(6, "tapeblock_start_request(%p, %p)\n", device, req); | |
110 | ||
111 | ccw_req = device->discipline->bread(device, req); | |
112 | if (IS_ERR(ccw_req)) { | |
113 | DBF_EVENT(1, "TBLOCK: bread failed\n"); | |
40cbbb78 | 114 | blk_end_request_all(req, -EIO); |
1da177e4 LT |
115 | return PTR_ERR(ccw_req); |
116 | } | |
117 | ccw_req->callback = __tapeblock_end_request; | |
118 | ccw_req->callback_data = (void *) req; | |
119 | ccw_req->retries = TAPEBLOCK_RETRIES; | |
120 | ||
121 | rc = tape_do_io_async(device, ccw_req); | |
122 | if (rc) { | |
123 | /* | |
124 | * Start/enqueueing failed. No retries in | |
125 | * this case. | |
126 | */ | |
40cbbb78 | 127 | blk_end_request_all(req, -EIO); |
1da177e4 LT |
128 | device->discipline->free_bread(ccw_req); |
129 | } | |
130 | ||
131 | return rc; | |
132 | } | |
133 | ||
134 | /* | |
135 | * Move requests from the block device request queue to the tape device ccw | |
136 | * queue. | |
137 | */ | |
138 | static void | |
c1637532 MS |
139 | tapeblock_requeue(struct work_struct *work) { |
140 | struct tape_blk_data * blkdat; | |
1da177e4 | 141 | struct tape_device * device; |
165125e1 | 142 | struct request_queue * queue; |
1da177e4 LT |
143 | int nr_queued; |
144 | struct request * req; | |
145 | struct list_head * l; | |
146 | int rc; | |
147 | ||
c1637532 MS |
148 | blkdat = container_of(work, struct tape_blk_data, requeue_task); |
149 | device = blkdat->device; | |
1da177e4 LT |
150 | if (!device) |
151 | return; | |
152 | ||
153 | spin_lock_irq(get_ccwdev_lock(device->cdev)); | |
154 | queue = device->blk_data.request_queue; | |
155 | ||
156 | /* Count number of requests on ccw queue. */ | |
157 | nr_queued = 0; | |
158 | list_for_each(l, &device->req_queue) | |
159 | nr_queued++; | |
160 | spin_unlock(get_ccwdev_lock(device->cdev)); | |
161 | ||
7a4a1ccd | 162 | spin_lock_irq(&device->blk_data.request_queue_lock); |
1da177e4 LT |
163 | while ( |
164 | !blk_queue_plugged(queue) && | |
165 | elv_next_request(queue) && | |
166 | nr_queued < TAPEBLOCK_MIN_REQUEUE | |
167 | ) { | |
168 | req = elv_next_request(queue); | |
169 | if (rq_data_dir(req) == WRITE) { | |
170 | DBF_EVENT(1, "TBLOCK: Rejecting write request\n"); | |
171 | blkdev_dequeue_request(req); | |
7a4a1ccd | 172 | spin_unlock_irq(&device->blk_data.request_queue_lock); |
40cbbb78 | 173 | blk_end_request_all(req, -EIO); |
7a4a1ccd | 174 | spin_lock_irq(&device->blk_data.request_queue_lock); |
1da177e4 LT |
175 | continue; |
176 | } | |
f71ad62a MH |
177 | blkdev_dequeue_request(req); |
178 | nr_queued++; | |
1da177e4 LT |
179 | spin_unlock_irq(&device->blk_data.request_queue_lock); |
180 | rc = tapeblock_start_request(device, req); | |
181 | spin_lock_irq(&device->blk_data.request_queue_lock); | |
1da177e4 LT |
182 | } |
183 | spin_unlock_irq(&device->blk_data.request_queue_lock); | |
184 | atomic_set(&device->blk_data.requeue_scheduled, 0); | |
185 | } | |
186 | ||
187 | /* | |
188 | * Tape request queue function. Called from ll_rw_blk.c | |
189 | */ | |
190 | static void | |
165125e1 | 191 | tapeblock_request_fn(struct request_queue *queue) |
1da177e4 LT |
192 | { |
193 | struct tape_device *device; | |
194 | ||
195 | device = (struct tape_device *) queue->queuedata; | |
196 | DBF_LH(6, "tapeblock_request_fn(device=%p)\n", device); | |
3a8dc893 | 197 | BUG_ON(device == NULL); |
1da177e4 LT |
198 | tapeblock_trigger_requeue(device); |
199 | } | |
200 | ||
201 | /* | |
202 | * This function is called for every new tapedevice | |
203 | */ | |
204 | int | |
205 | tapeblock_setup_device(struct tape_device * device) | |
206 | { | |
207 | struct tape_blk_data * blkdat; | |
208 | struct gendisk * disk; | |
209 | int rc; | |
210 | ||
211 | blkdat = &device->blk_data; | |
c1637532 | 212 | blkdat->device = device; |
1da177e4 LT |
213 | spin_lock_init(&blkdat->request_queue_lock); |
214 | atomic_set(&blkdat->requeue_scheduled, 0); | |
215 | ||
216 | blkdat->request_queue = blk_init_queue( | |
217 | tapeblock_request_fn, | |
218 | &blkdat->request_queue_lock | |
219 | ); | |
220 | if (!blkdat->request_queue) | |
221 | return -ENOMEM; | |
222 | ||
223 | elevator_exit(blkdat->request_queue->elevator); | |
224 | rc = elevator_init(blkdat->request_queue, "noop"); | |
225 | if (rc) | |
226 | goto cleanup_queue; | |
227 | ||
228 | blk_queue_hardsect_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE); | |
229 | blk_queue_max_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC); | |
230 | blk_queue_max_phys_segments(blkdat->request_queue, -1L); | |
231 | blk_queue_max_hw_segments(blkdat->request_queue, -1L); | |
232 | blk_queue_max_segment_size(blkdat->request_queue, -1L); | |
233 | blk_queue_segment_boundary(blkdat->request_queue, -1L); | |
234 | ||
235 | disk = alloc_disk(1); | |
236 | if (!disk) { | |
237 | rc = -ENOMEM; | |
238 | goto cleanup_queue; | |
239 | } | |
240 | ||
241 | disk->major = tapeblock_major; | |
242 | disk->first_minor = device->first_minor; | |
243 | disk->fops = &tapeblock_fops; | |
244 | disk->private_data = tape_get_device_reference(device); | |
245 | disk->queue = blkdat->request_queue; | |
246 | set_capacity(disk, 0); | |
247 | sprintf(disk->disk_name, "btibm%d", | |
248 | device->first_minor / TAPE_MINORS_PER_DEV); | |
249 | ||
250 | blkdat->disk = disk; | |
251 | blkdat->medium_changed = 1; | |
252 | blkdat->request_queue->queuedata = tape_get_device_reference(device); | |
253 | ||
254 | add_disk(disk); | |
255 | ||
c1637532 MS |
256 | tape_get_device_reference(device); |
257 | INIT_WORK(&blkdat->requeue_task, tapeblock_requeue); | |
1da177e4 LT |
258 | |
259 | return 0; | |
260 | ||
261 | cleanup_queue: | |
262 | blk_cleanup_queue(blkdat->request_queue); | |
263 | blkdat->request_queue = NULL; | |
264 | ||
265 | return rc; | |
266 | } | |
267 | ||
268 | void | |
269 | tapeblock_cleanup_device(struct tape_device *device) | |
270 | { | |
271 | flush_scheduled_work(); | |
c1637532 | 272 | tape_put_device(device); |
1da177e4 LT |
273 | |
274 | if (!device->blk_data.disk) { | |
1da177e4 LT |
275 | goto cleanup_queue; |
276 | } | |
277 | ||
278 | del_gendisk(device->blk_data.disk); | |
279 | device->blk_data.disk->private_data = | |
280 | tape_put_device(device->blk_data.disk->private_data); | |
281 | put_disk(device->blk_data.disk); | |
282 | ||
283 | device->blk_data.disk = NULL; | |
284 | cleanup_queue: | |
285 | device->blk_data.request_queue->queuedata = tape_put_device(device); | |
286 | ||
287 | blk_cleanup_queue(device->blk_data.request_queue); | |
288 | device->blk_data.request_queue = NULL; | |
289 | } | |
290 | ||
291 | /* | |
292 | * Detect number of blocks of the tape. | |
293 | * FIXME: can we extent this to detect the blocks size as well ? | |
294 | */ | |
295 | static int | |
296 | tapeblock_revalidate_disk(struct gendisk *disk) | |
297 | { | |
298 | struct tape_device * device; | |
299 | unsigned int nr_of_blks; | |
300 | int rc; | |
301 | ||
302 | device = (struct tape_device *) disk->private_data; | |
3a8dc893 | 303 | BUG_ON(!device); |
1da177e4 LT |
304 | |
305 | if (!device->blk_data.medium_changed) | |
306 | return 0; | |
307 | ||
ab640db0 CO |
308 | dev_info(&device->cdev->dev, "Determining the size of the recorded " |
309 | "area...\n"); | |
1da177e4 LT |
310 | rc = tape_mtop(device, MTFSFM, 1); |
311 | if (rc) | |
312 | return rc; | |
313 | ||
314 | rc = tape_mtop(device, MTTELL, 1); | |
315 | if (rc < 0) | |
316 | return rc; | |
317 | ||
318 | DBF_LH(3, "Image file ends at %d\n", rc); | |
319 | nr_of_blks = rc; | |
320 | ||
321 | /* This will fail for the first file. Catch the error by checking the | |
322 | * position. */ | |
323 | tape_mtop(device, MTBSF, 1); | |
324 | ||
325 | rc = tape_mtop(device, MTTELL, 1); | |
326 | if (rc < 0) | |
327 | return rc; | |
328 | ||
329 | if (rc > nr_of_blks) | |
330 | return -EINVAL; | |
331 | ||
332 | DBF_LH(3, "Image file starts at %d\n", rc); | |
333 | device->bof = rc; | |
334 | nr_of_blks -= rc; | |
335 | ||
ab640db0 CO |
336 | dev_info(&device->cdev->dev, "The size of the recorded area is %i " |
337 | "blocks\n", nr_of_blks); | |
1da177e4 LT |
338 | set_capacity(device->blk_data.disk, |
339 | nr_of_blks*(TAPEBLOCK_HSEC_SIZE/512)); | |
340 | ||
341 | device->blk_data.block_position = 0; | |
342 | device->blk_data.medium_changed = 0; | |
343 | return 0; | |
344 | } | |
345 | ||
346 | static int | |
347 | tapeblock_medium_changed(struct gendisk *disk) | |
348 | { | |
349 | struct tape_device *device; | |
350 | ||
351 | device = (struct tape_device *) disk->private_data; | |
352 | DBF_LH(6, "tapeblock_medium_changed(%p) = %d\n", | |
353 | device, device->blk_data.medium_changed); | |
354 | ||
355 | return device->blk_data.medium_changed; | |
356 | } | |
357 | ||
358 | /* | |
359 | * Block frontend tape device open function. | |
360 | */ | |
361 | static int | |
4e999af9 | 362 | tapeblock_open(struct block_device *bdev, fmode_t mode) |
1da177e4 | 363 | { |
4e999af9 | 364 | struct gendisk * disk = bdev->bd_disk; |
1da177e4 LT |
365 | struct tape_device * device; |
366 | int rc; | |
367 | ||
1da177e4 LT |
368 | device = tape_get_device_reference(disk->private_data); |
369 | ||
370 | if (device->required_tapemarks) { | |
371 | DBF_EVENT(2, "TBLOCK: missing tapemarks\n"); | |
ab640db0 CO |
372 | dev_warn(&device->cdev->dev, "Opening the tape failed because" |
373 | " of missing end-of-file marks\n"); | |
1da177e4 LT |
374 | rc = -EPERM; |
375 | goto put_device; | |
376 | } | |
377 | ||
378 | rc = tape_open(device); | |
379 | if (rc) | |
380 | goto put_device; | |
381 | ||
382 | rc = tapeblock_revalidate_disk(disk); | |
383 | if (rc) | |
384 | goto release; | |
385 | ||
386 | /* | |
387 | * Note: The reference to <device> is hold until the release function | |
388 | * is called. | |
389 | */ | |
390 | tape_state_set(device, TS_BLKUSE); | |
391 | return 0; | |
392 | ||
393 | release: | |
394 | tape_release(device); | |
395 | put_device: | |
396 | tape_put_device(device); | |
397 | return rc; | |
398 | } | |
399 | ||
400 | /* | |
401 | * Block frontend tape device release function. | |
402 | * | |
403 | * Note: One reference to the tape device was made by the open function. So | |
404 | * we just get the pointer here and release the reference. | |
405 | */ | |
406 | static int | |
4e999af9 | 407 | tapeblock_release(struct gendisk *disk, fmode_t mode) |
1da177e4 | 408 | { |
1da177e4 LT |
409 | struct tape_device *device = disk->private_data; |
410 | ||
411 | tape_state_set(device, TS_IN_USE); | |
412 | tape_release(device); | |
413 | tape_put_device(device); | |
414 | ||
415 | return 0; | |
416 | } | |
417 | ||
418 | /* | |
419 | * Support of some generic block device IOCTLs. | |
420 | */ | |
421 | static int | |
422 | tapeblock_ioctl( | |
4e999af9 AV |
423 | struct block_device * bdev, |
424 | fmode_t mode, | |
1da177e4 LT |
425 | unsigned int command, |
426 | unsigned long arg | |
427 | ) { | |
428 | int rc; | |
429 | int minor; | |
4e999af9 | 430 | struct gendisk *disk = bdev->bd_disk; |
f976069a | 431 | struct tape_device *device; |
1da177e4 LT |
432 | |
433 | rc = 0; | |
3a8dc893 | 434 | BUG_ON(!disk); |
1da177e4 | 435 | device = disk->private_data; |
3a8dc893 | 436 | BUG_ON(!device); |
4e999af9 | 437 | minor = MINOR(bdev->bd_dev); |
1da177e4 LT |
438 | |
439 | DBF_LH(6, "tapeblock_ioctl(0x%0x)\n", command); | |
440 | DBF_LH(6, "device = %d:%d\n", tapeblock_major, minor); | |
441 | ||
442 | switch (command) { | |
443 | /* Refuse some IOCTL calls without complaining (mount). */ | |
444 | case 0x5310: /* CDROMMULTISESSION */ | |
445 | rc = -EINVAL; | |
446 | break; | |
447 | default: | |
1da177e4 LT |
448 | rc = -EINVAL; |
449 | } | |
450 | ||
451 | return rc; | |
452 | } | |
453 | ||
454 | /* | |
455 | * Initialize block device frontend. | |
456 | */ | |
457 | int | |
458 | tapeblock_init(void) | |
459 | { | |
460 | int rc; | |
461 | ||
462 | /* Register the tape major number to the kernel */ | |
463 | rc = register_blkdev(tapeblock_major, "tBLK"); | |
464 | if (rc < 0) | |
465 | return rc; | |
466 | ||
467 | if (tapeblock_major == 0) | |
468 | tapeblock_major = rc; | |
1da177e4 LT |
469 | return 0; |
470 | } | |
471 | ||
472 | /* | |
473 | * Deregister major for block device frontend | |
474 | */ | |
475 | void | |
476 | tapeblock_exit(void) | |
477 | { | |
478 | unregister_blkdev(tapeblock_major, "tBLK"); | |
479 | } |