Commit | Line | Data |
---|---|---|
f30664e2 SO |
1 | /* |
2 | * Block driver for s390 storage class memory. | |
3 | * | |
4 | * Copyright IBM Corp. 2012 | |
5 | * Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com> | |
6 | */ | |
7 | ||
8 | #define KMSG_COMPONENT "scm_block" | |
9 | #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt | |
10 | ||
11 | #include <linux/interrupt.h> | |
12 | #include <linux/spinlock.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/blkdev.h> | |
15 | #include <linux/genhd.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/list.h> | |
18 | #include <asm/eadm.h> | |
19 | #include "scm_blk.h" | |
20 | ||
21 | debug_info_t *scm_debug; | |
22 | static int scm_major; | |
23 | static DEFINE_SPINLOCK(list_lock); | |
24 | static LIST_HEAD(inactive_requests); | |
25 | static unsigned int nr_requests = 64; | |
26 | static atomic_t nr_devices = ATOMIC_INIT(0); | |
27 | module_param(nr_requests, uint, S_IRUGO); | |
28 | MODULE_PARM_DESC(nr_requests, "Number of parallel requests."); | |
29 | ||
30 | MODULE_DESCRIPTION("Block driver for s390 storage class memory."); | |
31 | MODULE_LICENSE("GPL"); | |
32 | MODULE_ALIAS("scm:scmdev*"); | |
33 | ||
34 | static void __scm_free_rq(struct scm_request *scmrq) | |
35 | { | |
36 | struct aob_rq_header *aobrq = to_aobrq(scmrq); | |
37 | ||
38 | free_page((unsigned long) scmrq->aob); | |
39 | free_page((unsigned long) scmrq->aidaw); | |
0d804b20 | 40 | __scm_free_rq_cluster(scmrq); |
f30664e2 SO |
41 | kfree(aobrq); |
42 | } | |
43 | ||
44 | static void scm_free_rqs(void) | |
45 | { | |
46 | struct list_head *iter, *safe; | |
47 | struct scm_request *scmrq; | |
48 | ||
49 | spin_lock_irq(&list_lock); | |
50 | list_for_each_safe(iter, safe, &inactive_requests) { | |
51 | scmrq = list_entry(iter, struct scm_request, list); | |
52 | list_del(&scmrq->list); | |
53 | __scm_free_rq(scmrq); | |
54 | } | |
55 | spin_unlock_irq(&list_lock); | |
56 | } | |
57 | ||
58 | static int __scm_alloc_rq(void) | |
59 | { | |
60 | struct aob_rq_header *aobrq; | |
61 | struct scm_request *scmrq; | |
62 | ||
63 | aobrq = kzalloc(sizeof(*aobrq) + sizeof(*scmrq), GFP_KERNEL); | |
64 | if (!aobrq) | |
65 | return -ENOMEM; | |
66 | ||
67 | scmrq = (void *) aobrq->data; | |
68 | scmrq->aidaw = (void *) get_zeroed_page(GFP_DMA); | |
69 | scmrq->aob = (void *) get_zeroed_page(GFP_DMA); | |
70 | if (!scmrq->aob || !scmrq->aidaw) { | |
71 | __scm_free_rq(scmrq); | |
72 | return -ENOMEM; | |
73 | } | |
0d804b20 SO |
74 | |
75 | if (__scm_alloc_rq_cluster(scmrq)) { | |
76 | __scm_free_rq(scmrq); | |
77 | return -ENOMEM; | |
78 | } | |
79 | ||
f30664e2 SO |
80 | INIT_LIST_HEAD(&scmrq->list); |
81 | spin_lock_irq(&list_lock); | |
82 | list_add(&scmrq->list, &inactive_requests); | |
83 | spin_unlock_irq(&list_lock); | |
84 | ||
85 | return 0; | |
86 | } | |
87 | ||
88 | static int scm_alloc_rqs(unsigned int nrqs) | |
89 | { | |
90 | int ret = 0; | |
91 | ||
92 | while (nrqs-- && !ret) | |
93 | ret = __scm_alloc_rq(); | |
94 | ||
95 | return ret; | |
96 | } | |
97 | ||
98 | static struct scm_request *scm_request_fetch(void) | |
99 | { | |
100 | struct scm_request *scmrq = NULL; | |
101 | ||
102 | spin_lock(&list_lock); | |
103 | if (list_empty(&inactive_requests)) | |
104 | goto out; | |
105 | scmrq = list_first_entry(&inactive_requests, struct scm_request, list); | |
106 | list_del(&scmrq->list); | |
107 | out: | |
108 | spin_unlock(&list_lock); | |
109 | return scmrq; | |
110 | } | |
111 | ||
112 | static void scm_request_done(struct scm_request *scmrq) | |
113 | { | |
114 | unsigned long flags; | |
115 | ||
116 | spin_lock_irqsave(&list_lock, flags); | |
117 | list_add(&scmrq->list, &inactive_requests); | |
118 | spin_unlock_irqrestore(&list_lock, flags); | |
119 | } | |
120 | ||
4fa3c019 SO |
121 | static bool scm_permit_request(struct scm_blk_dev *bdev, struct request *req) |
122 | { | |
123 | return rq_data_dir(req) != WRITE || bdev->state != SCM_WR_PROHIBIT; | |
124 | } | |
125 | ||
f30664e2 SO |
126 | static void scm_request_prepare(struct scm_request *scmrq) |
127 | { | |
128 | struct scm_blk_dev *bdev = scmrq->bdev; | |
129 | struct scm_device *scmdev = bdev->gendisk->private_data; | |
130 | struct aidaw *aidaw = scmrq->aidaw; | |
131 | struct msb *msb = &scmrq->aob->msb[0]; | |
132 | struct req_iterator iter; | |
7988613b | 133 | struct bio_vec bv; |
f30664e2 SO |
134 | |
135 | msb->bs = MSB_BS_4K; | |
136 | scmrq->aob->request.msb_count = 1; | |
137 | msb->scm_addr = scmdev->address + | |
138 | ((u64) blk_rq_pos(scmrq->request) << 9); | |
139 | msb->oc = (rq_data_dir(scmrq->request) == READ) ? | |
140 | MSB_OC_READ : MSB_OC_WRITE; | |
141 | msb->flags |= MSB_FLAG_IDA; | |
142 | msb->data_addr = (u64) aidaw; | |
143 | ||
144 | rq_for_each_segment(bv, scmrq->request, iter) { | |
7988613b KO |
145 | WARN_ON(bv.bv_offset); |
146 | msb->blk_count += bv.bv_len >> 12; | |
147 | aidaw->data_addr = (u64) page_address(bv.bv_page); | |
f30664e2 SO |
148 | aidaw++; |
149 | } | |
150 | } | |
151 | ||
152 | static inline void scm_request_init(struct scm_blk_dev *bdev, | |
153 | struct scm_request *scmrq, | |
154 | struct request *req) | |
155 | { | |
156 | struct aob_rq_header *aobrq = to_aobrq(scmrq); | |
157 | struct aob *aob = scmrq->aob; | |
158 | ||
159 | memset(aob, 0, sizeof(*aob)); | |
160 | memset(scmrq->aidaw, 0, PAGE_SIZE); | |
161 | aobrq->scmdev = bdev->scmdev; | |
162 | aob->request.cmd_code = ARQB_CMD_MOVE; | |
163 | aob->request.data = (u64) aobrq; | |
164 | scmrq->request = req; | |
165 | scmrq->bdev = bdev; | |
166 | scmrq->retries = 4; | |
167 | scmrq->error = 0; | |
0d804b20 | 168 | scm_request_cluster_init(scmrq); |
f30664e2 SO |
169 | } |
170 | ||
171 | static void scm_ensure_queue_restart(struct scm_blk_dev *bdev) | |
172 | { | |
173 | if (atomic_read(&bdev->queued_reqs)) { | |
174 | /* Queue restart is triggered by the next interrupt. */ | |
175 | return; | |
176 | } | |
177 | blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY); | |
178 | } | |
179 | ||
0d804b20 | 180 | void scm_request_requeue(struct scm_request *scmrq) |
f30664e2 SO |
181 | { |
182 | struct scm_blk_dev *bdev = scmrq->bdev; | |
183 | ||
0d804b20 | 184 | scm_release_cluster(scmrq); |
f30664e2 | 185 | blk_requeue_request(bdev->rq, scmrq->request); |
8360cb5f | 186 | atomic_dec(&bdev->queued_reqs); |
f30664e2 SO |
187 | scm_request_done(scmrq); |
188 | scm_ensure_queue_restart(bdev); | |
189 | } | |
190 | ||
0d804b20 | 191 | void scm_request_finish(struct scm_request *scmrq) |
f30664e2 | 192 | { |
8360cb5f SO |
193 | struct scm_blk_dev *bdev = scmrq->bdev; |
194 | ||
0d804b20 | 195 | scm_release_cluster(scmrq); |
f30664e2 | 196 | blk_end_request_all(scmrq->request, scmrq->error); |
8360cb5f | 197 | atomic_dec(&bdev->queued_reqs); |
f30664e2 SO |
198 | scm_request_done(scmrq); |
199 | } | |
200 | ||
201 | static void scm_blk_request(struct request_queue *rq) | |
202 | { | |
203 | struct scm_device *scmdev = rq->queuedata; | |
204 | struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev); | |
205 | struct scm_request *scmrq; | |
206 | struct request *req; | |
207 | int ret; | |
208 | ||
209 | while ((req = blk_peek_request(rq))) { | |
de9587a2 SM |
210 | if (req->cmd_type != REQ_TYPE_FS) { |
211 | blk_start_request(req); | |
212 | blk_dump_rq_flags(req, KMSG_COMPONENT " bad request"); | |
213 | blk_end_request_all(req, -EIO); | |
f30664e2 | 214 | continue; |
de9587a2 | 215 | } |
f30664e2 | 216 | |
4fa3c019 SO |
217 | if (!scm_permit_request(bdev, req)) { |
218 | scm_ensure_queue_restart(bdev); | |
219 | return; | |
220 | } | |
f30664e2 SO |
221 | scmrq = scm_request_fetch(); |
222 | if (!scmrq) { | |
223 | SCM_LOG(5, "no request"); | |
224 | scm_ensure_queue_restart(bdev); | |
225 | return; | |
226 | } | |
227 | scm_request_init(bdev, scmrq, req); | |
0d804b20 SO |
228 | if (!scm_reserve_cluster(scmrq)) { |
229 | SCM_LOG(5, "cluster busy"); | |
230 | scm_request_done(scmrq); | |
231 | return; | |
232 | } | |
233 | if (scm_need_cluster_request(scmrq)) { | |
8360cb5f | 234 | atomic_inc(&bdev->queued_reqs); |
0d804b20 SO |
235 | blk_start_request(req); |
236 | scm_initiate_cluster_request(scmrq); | |
237 | return; | |
238 | } | |
f30664e2 | 239 | scm_request_prepare(scmrq); |
8360cb5f | 240 | atomic_inc(&bdev->queued_reqs); |
f30664e2 SO |
241 | blk_start_request(req); |
242 | ||
605c3698 | 243 | ret = eadm_start_aob(scmrq->aob); |
f30664e2 SO |
244 | if (ret) { |
245 | SCM_LOG(5, "no subchannel"); | |
246 | scm_request_requeue(scmrq); | |
247 | return; | |
248 | } | |
f30664e2 SO |
249 | } |
250 | } | |
251 | ||
252 | static void __scmrq_log_error(struct scm_request *scmrq) | |
253 | { | |
254 | struct aob *aob = scmrq->aob; | |
255 | ||
256 | if (scmrq->error == -ETIMEDOUT) | |
257 | SCM_LOG(1, "Request timeout"); | |
258 | else { | |
259 | SCM_LOG(1, "Request error"); | |
260 | SCM_LOG_HEX(1, &aob->response, sizeof(aob->response)); | |
261 | } | |
262 | if (scmrq->retries) | |
263 | SCM_LOG(1, "Retry request"); | |
264 | else | |
265 | pr_err("An I/O operation to SCM failed with rc=%d\n", | |
266 | scmrq->error); | |
267 | } | |
268 | ||
269 | void scm_blk_irq(struct scm_device *scmdev, void *data, int error) | |
270 | { | |
271 | struct scm_request *scmrq = data; | |
272 | struct scm_blk_dev *bdev = scmrq->bdev; | |
273 | ||
274 | scmrq->error = error; | |
275 | if (error) | |
276 | __scmrq_log_error(scmrq); | |
277 | ||
278 | spin_lock(&bdev->lock); | |
279 | list_add_tail(&scmrq->list, &bdev->finished_requests); | |
280 | spin_unlock(&bdev->lock); | |
281 | tasklet_hi_schedule(&bdev->tasklet); | |
282 | } | |
283 | ||
4fa3c019 SO |
284 | static void scm_blk_handle_error(struct scm_request *scmrq) |
285 | { | |
286 | struct scm_blk_dev *bdev = scmrq->bdev; | |
287 | unsigned long flags; | |
288 | ||
289 | if (scmrq->error != -EIO) | |
290 | goto restart; | |
291 | ||
292 | /* For -EIO the response block is valid. */ | |
293 | switch (scmrq->aob->response.eqc) { | |
294 | case EQC_WR_PROHIBIT: | |
295 | spin_lock_irqsave(&bdev->lock, flags); | |
296 | if (bdev->state != SCM_WR_PROHIBIT) | |
3bff6038 | 297 | pr_info("%lx: Write access to the SCM increment is suspended\n", |
4fa3c019 SO |
298 | (unsigned long) bdev->scmdev->address); |
299 | bdev->state = SCM_WR_PROHIBIT; | |
300 | spin_unlock_irqrestore(&bdev->lock, flags); | |
301 | goto requeue; | |
302 | default: | |
303 | break; | |
304 | } | |
305 | ||
306 | restart: | |
605c3698 | 307 | if (!eadm_start_aob(scmrq->aob)) |
4fa3c019 SO |
308 | return; |
309 | ||
310 | requeue: | |
311 | spin_lock_irqsave(&bdev->rq_lock, flags); | |
312 | scm_request_requeue(scmrq); | |
313 | spin_unlock_irqrestore(&bdev->rq_lock, flags); | |
314 | } | |
315 | ||
f30664e2 SO |
316 | static void scm_blk_tasklet(struct scm_blk_dev *bdev) |
317 | { | |
318 | struct scm_request *scmrq; | |
319 | unsigned long flags; | |
320 | ||
321 | spin_lock_irqsave(&bdev->lock, flags); | |
322 | while (!list_empty(&bdev->finished_requests)) { | |
323 | scmrq = list_first_entry(&bdev->finished_requests, | |
324 | struct scm_request, list); | |
325 | list_del(&scmrq->list); | |
326 | spin_unlock_irqrestore(&bdev->lock, flags); | |
327 | ||
328 | if (scmrq->error && scmrq->retries-- > 0) { | |
4fa3c019 SO |
329 | scm_blk_handle_error(scmrq); |
330 | ||
f30664e2 SO |
331 | /* Request restarted or requeued, handle next. */ |
332 | spin_lock_irqsave(&bdev->lock, flags); | |
333 | continue; | |
334 | } | |
0d804b20 SO |
335 | |
336 | if (scm_test_cluster_request(scmrq)) { | |
337 | scm_cluster_request_irq(scmrq); | |
338 | spin_lock_irqsave(&bdev->lock, flags); | |
339 | continue; | |
340 | } | |
341 | ||
f30664e2 | 342 | scm_request_finish(scmrq); |
f30664e2 SO |
343 | spin_lock_irqsave(&bdev->lock, flags); |
344 | } | |
345 | spin_unlock_irqrestore(&bdev->lock, flags); | |
346 | /* Look out for more requests. */ | |
347 | blk_run_queue(bdev->rq); | |
348 | } | |
349 | ||
605c3698 SO |
350 | static const struct block_device_operations scm_blk_devops = { |
351 | .owner = THIS_MODULE, | |
352 | }; | |
353 | ||
f30664e2 SO |
354 | int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev) |
355 | { | |
356 | struct request_queue *rq; | |
357 | int len, ret = -ENOMEM; | |
358 | unsigned int devindex, nr_max_blk; | |
359 | ||
360 | devindex = atomic_inc_return(&nr_devices) - 1; | |
361 | /* scma..scmz + scmaa..scmzz */ | |
362 | if (devindex > 701) { | |
363 | ret = -ENODEV; | |
364 | goto out; | |
365 | } | |
366 | ||
367 | bdev->scmdev = scmdev; | |
4fa3c019 | 368 | bdev->state = SCM_OPER; |
f30664e2 SO |
369 | spin_lock_init(&bdev->rq_lock); |
370 | spin_lock_init(&bdev->lock); | |
371 | INIT_LIST_HEAD(&bdev->finished_requests); | |
372 | atomic_set(&bdev->queued_reqs, 0); | |
373 | tasklet_init(&bdev->tasklet, | |
374 | (void (*)(unsigned long)) scm_blk_tasklet, | |
375 | (unsigned long) bdev); | |
376 | ||
377 | rq = blk_init_queue(scm_blk_request, &bdev->rq_lock); | |
378 | if (!rq) | |
379 | goto out; | |
380 | ||
381 | bdev->rq = rq; | |
382 | nr_max_blk = min(scmdev->nr_max_block, | |
383 | (unsigned int) (PAGE_SIZE / sizeof(struct aidaw))); | |
384 | ||
385 | blk_queue_logical_block_size(rq, 1 << 12); | |
386 | blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */ | |
387 | blk_queue_max_segments(rq, nr_max_blk); | |
388 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq); | |
0d804b20 | 389 | scm_blk_dev_cluster_setup(bdev); |
f30664e2 SO |
390 | |
391 | bdev->gendisk = alloc_disk(SCM_NR_PARTS); | |
392 | if (!bdev->gendisk) | |
393 | goto out_queue; | |
394 | ||
395 | rq->queuedata = scmdev; | |
396 | bdev->gendisk->driverfs_dev = &scmdev->dev; | |
397 | bdev->gendisk->private_data = scmdev; | |
398 | bdev->gendisk->fops = &scm_blk_devops; | |
399 | bdev->gendisk->queue = rq; | |
400 | bdev->gendisk->major = scm_major; | |
401 | bdev->gendisk->first_minor = devindex * SCM_NR_PARTS; | |
402 | ||
403 | len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm"); | |
404 | if (devindex > 25) { | |
405 | len += snprintf(bdev->gendisk->disk_name + len, | |
406 | DISK_NAME_LEN - len, "%c", | |
407 | 'a' + (devindex / 26) - 1); | |
408 | devindex = devindex % 26; | |
409 | } | |
410 | snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c", | |
411 | 'a' + devindex); | |
412 | ||
413 | /* 512 byte sectors */ | |
414 | set_capacity(bdev->gendisk, scmdev->size >> 9); | |
415 | add_disk(bdev->gendisk); | |
416 | return 0; | |
417 | ||
418 | out_queue: | |
419 | blk_cleanup_queue(rq); | |
420 | out: | |
421 | atomic_dec(&nr_devices); | |
422 | return ret; | |
423 | } | |
424 | ||
425 | void scm_blk_dev_cleanup(struct scm_blk_dev *bdev) | |
426 | { | |
427 | tasklet_kill(&bdev->tasklet); | |
428 | del_gendisk(bdev->gendisk); | |
429 | blk_cleanup_queue(bdev->gendisk->queue); | |
430 | put_disk(bdev->gendisk); | |
431 | } | |
432 | ||
4fa3c019 SO |
433 | void scm_blk_set_available(struct scm_blk_dev *bdev) |
434 | { | |
435 | unsigned long flags; | |
436 | ||
437 | spin_lock_irqsave(&bdev->lock, flags); | |
438 | if (bdev->state == SCM_WR_PROHIBIT) | |
3bff6038 | 439 | pr_info("%lx: Write access to the SCM increment is restored\n", |
4fa3c019 SO |
440 | (unsigned long) bdev->scmdev->address); |
441 | bdev->state = SCM_OPER; | |
442 | spin_unlock_irqrestore(&bdev->lock, flags); | |
443 | } | |
444 | ||
f30664e2 SO |
445 | static int __init scm_blk_init(void) |
446 | { | |
0d804b20 SO |
447 | int ret = -EINVAL; |
448 | ||
449 | if (!scm_cluster_size_valid()) | |
450 | goto out; | |
f30664e2 SO |
451 | |
452 | ret = register_blkdev(0, "scm"); | |
453 | if (ret < 0) | |
454 | goto out; | |
455 | ||
456 | scm_major = ret; | |
94f9852d WY |
457 | ret = scm_alloc_rqs(nr_requests); |
458 | if (ret) | |
fff60fab | 459 | goto out_free; |
f30664e2 SO |
460 | |
461 | scm_debug = debug_register("scm_log", 16, 1, 16); | |
94f9852d WY |
462 | if (!scm_debug) { |
463 | ret = -ENOMEM; | |
f30664e2 | 464 | goto out_free; |
94f9852d | 465 | } |
f30664e2 SO |
466 | |
467 | debug_register_view(scm_debug, &debug_hex_ascii_view); | |
468 | debug_set_level(scm_debug, 2); | |
469 | ||
470 | ret = scm_drv_init(); | |
471 | if (ret) | |
472 | goto out_dbf; | |
473 | ||
474 | return ret; | |
475 | ||
476 | out_dbf: | |
477 | debug_unregister(scm_debug); | |
478 | out_free: | |
479 | scm_free_rqs(); | |
f30664e2 SO |
480 | unregister_blkdev(scm_major, "scm"); |
481 | out: | |
482 | return ret; | |
483 | } | |
484 | module_init(scm_blk_init); | |
485 | ||
486 | static void __exit scm_blk_cleanup(void) | |
487 | { | |
488 | scm_drv_cleanup(); | |
489 | debug_unregister(scm_debug); | |
490 | scm_free_rqs(); | |
491 | unregister_blkdev(scm_major, "scm"); | |
492 | } | |
493 | module_exit(scm_blk_cleanup); |