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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/mempool.h>
14#include <linux/module.h>
15#include <linux/blkdev.h>
16#include <linux/genhd.h>
17#include <linux/slab.h>
18#include <linux/list.h>
19#include <asm/eadm.h>
20#include "scm_blk.h"
21
22debug_info_t *scm_debug;
23static int scm_major;
24static mempool_t *aidaw_pool;
25static DEFINE_SPINLOCK(list_lock);
26static LIST_HEAD(inactive_requests);
27static unsigned int nr_requests = 64;
28static unsigned int nr_requests_per_io = 8;
29static atomic_t nr_devices = ATOMIC_INIT(0);
30module_param(nr_requests, uint, S_IRUGO);
31MODULE_PARM_DESC(nr_requests, "Number of parallel requests.");
32
33module_param(nr_requests_per_io, uint, S_IRUGO);
34MODULE_PARM_DESC(nr_requests_per_io, "Number of requests per IO.");
35
36MODULE_DESCRIPTION("Block driver for s390 storage class memory.");
37MODULE_LICENSE("GPL");
38MODULE_ALIAS("scm:scmdev*");
39
40static void __scm_free_rq(struct scm_request *scmrq)
41{
42 struct aob_rq_header *aobrq = to_aobrq(scmrq);
43
44 free_page((unsigned long) scmrq->aob);
45 __scm_free_rq_cluster(scmrq);
46 kfree(scmrq->request);
47 kfree(aobrq);
48}
49
50static void scm_free_rqs(void)
51{
52 struct list_head *iter, *safe;
53 struct scm_request *scmrq;
54
55 spin_lock_irq(&list_lock);
56 list_for_each_safe(iter, safe, &inactive_requests) {
57 scmrq = list_entry(iter, struct scm_request, list);
58 list_del(&scmrq->list);
59 __scm_free_rq(scmrq);
60 }
61 spin_unlock_irq(&list_lock);
62
63 mempool_destroy(aidaw_pool);
64}
65
66static int __scm_alloc_rq(void)
67{
68 struct aob_rq_header *aobrq;
69 struct scm_request *scmrq;
70
71 aobrq = kzalloc(sizeof(*aobrq) + sizeof(*scmrq), GFP_KERNEL);
72 if (!aobrq)
73 return -ENOMEM;
74
75 scmrq = (void *) aobrq->data;
76 scmrq->aob = (void *) get_zeroed_page(GFP_DMA);
77 if (!scmrq->aob)
78 goto free;
79
80 scmrq->request = kcalloc(nr_requests_per_io, sizeof(scmrq->request[0]),
81 GFP_KERNEL);
82 if (!scmrq->request)
83 goto free;
84
85 if (__scm_alloc_rq_cluster(scmrq))
86 goto free;
87
88 INIT_LIST_HEAD(&scmrq->list);
89 spin_lock_irq(&list_lock);
90 list_add(&scmrq->list, &inactive_requests);
91 spin_unlock_irq(&list_lock);
92
93 return 0;
94free:
95 __scm_free_rq(scmrq);
96 return -ENOMEM;
97}
98
99static int scm_alloc_rqs(unsigned int nrqs)
100{
101 int ret = 0;
102
103 aidaw_pool = mempool_create_page_pool(max(nrqs/8, 1U), 0);
104 if (!aidaw_pool)
105 return -ENOMEM;
106
107 while (nrqs-- && !ret)
108 ret = __scm_alloc_rq();
109
110 return ret;
111}
112
113static struct scm_request *scm_request_fetch(void)
114{
115 struct scm_request *scmrq = NULL;
116
117 spin_lock(&list_lock);
118 if (list_empty(&inactive_requests))
119 goto out;
120 scmrq = list_first_entry(&inactive_requests, struct scm_request, list);
121 list_del(&scmrq->list);
122out:
123 spin_unlock(&list_lock);
124 return scmrq;
125}
126
127static void scm_request_done(struct scm_request *scmrq)
128{
129 unsigned long flags;
130 struct msb *msb;
131 u64 aidaw;
132 int i;
133
134 for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) {
135 msb = &scmrq->aob->msb[i];
136 aidaw = msb->data_addr;
137
138 if ((msb->flags & MSB_FLAG_IDA) && aidaw &&
139 IS_ALIGNED(aidaw, PAGE_SIZE))
140 mempool_free(virt_to_page(aidaw), aidaw_pool);
141 }
142
143 spin_lock_irqsave(&list_lock, flags);
144 list_add(&scmrq->list, &inactive_requests);
145 spin_unlock_irqrestore(&list_lock, flags);
146}
147
148static bool scm_permit_request(struct scm_blk_dev *bdev, struct request *req)
149{
150 return rq_data_dir(req) != WRITE || bdev->state != SCM_WR_PROHIBIT;
151}
152
153static inline struct aidaw *scm_aidaw_alloc(void)
154{
155 struct page *page = mempool_alloc(aidaw_pool, GFP_ATOMIC);
156
157 return page ? page_address(page) : NULL;
158}
159
160static inline unsigned long scm_aidaw_bytes(struct aidaw *aidaw)
161{
162 unsigned long _aidaw = (unsigned long) aidaw;
163 unsigned long bytes = ALIGN(_aidaw, PAGE_SIZE) - _aidaw;
164
165 return (bytes / sizeof(*aidaw)) * PAGE_SIZE;
166}
167
168struct aidaw *scm_aidaw_fetch(struct scm_request *scmrq, unsigned int bytes)
169{
170 struct aidaw *aidaw;
171
172 if (scm_aidaw_bytes(scmrq->next_aidaw) >= bytes)
173 return scmrq->next_aidaw;
174
175 aidaw = scm_aidaw_alloc();
176 if (aidaw)
177 memset(aidaw, 0, PAGE_SIZE);
178 return aidaw;
179}
180
181static int scm_request_prepare(struct scm_request *scmrq)
182{
183 struct scm_blk_dev *bdev = scmrq->bdev;
184 struct scm_device *scmdev = bdev->gendisk->private_data;
185 int pos = scmrq->aob->request.msb_count;
186 struct msb *msb = &scmrq->aob->msb[pos];
187 struct request *req = scmrq->request[pos];
188 struct req_iterator iter;
189 struct aidaw *aidaw;
190 struct bio_vec bv;
191
192 aidaw = scm_aidaw_fetch(scmrq, blk_rq_bytes(req));
193 if (!aidaw)
194 return -ENOMEM;
195
196 msb->bs = MSB_BS_4K;
197 scmrq->aob->request.msb_count++;
198 msb->scm_addr = scmdev->address + ((u64) blk_rq_pos(req) << 9);
199 msb->oc = (rq_data_dir(req) == READ) ? MSB_OC_READ : MSB_OC_WRITE;
200 msb->flags |= MSB_FLAG_IDA;
201 msb->data_addr = (u64) aidaw;
202
203 rq_for_each_segment(bv, req, iter) {
204 WARN_ON(bv.bv_offset);
205 msb->blk_count += bv.bv_len >> 12;
206 aidaw->data_addr = (u64) page_address(bv.bv_page);
207 aidaw++;
208 }
209
210 scmrq->next_aidaw = aidaw;
211 return 0;
212}
213
214static inline void scm_request_set(struct scm_request *scmrq,
215 struct request *req)
216{
217 scmrq->request[scmrq->aob->request.msb_count] = req;
218}
219
220static inline void scm_request_init(struct scm_blk_dev *bdev,
221 struct scm_request *scmrq)
222{
223 struct aob_rq_header *aobrq = to_aobrq(scmrq);
224 struct aob *aob = scmrq->aob;
225
226 memset(scmrq->request, 0,
227 nr_requests_per_io * sizeof(scmrq->request[0]));
228 memset(aob, 0, sizeof(*aob));
229 aobrq->scmdev = bdev->scmdev;
230 aob->request.cmd_code = ARQB_CMD_MOVE;
231 aob->request.data = (u64) aobrq;
232 scmrq->bdev = bdev;
233 scmrq->retries = 4;
234 scmrq->error = 0;
235
236 scmrq->next_aidaw = (void *) &aob->msb[nr_requests_per_io];
237 scm_request_cluster_init(scmrq);
238}
239
240static void scm_ensure_queue_restart(struct scm_blk_dev *bdev)
241{
242 if (atomic_read(&bdev->queued_reqs)) {
243
244 return;
245 }
246 blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY);
247}
248
249void scm_request_requeue(struct scm_request *scmrq)
250{
251 struct scm_blk_dev *bdev = scmrq->bdev;
252 int i;
253
254 scm_release_cluster(scmrq);
255 for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++)
256 blk_requeue_request(bdev->rq, scmrq->request[i]);
257
258 atomic_dec(&bdev->queued_reqs);
259 scm_request_done(scmrq);
260 scm_ensure_queue_restart(bdev);
261}
262
263void scm_request_finish(struct scm_request *scmrq)
264{
265 struct scm_blk_dev *bdev = scmrq->bdev;
266 int i;
267
268 scm_release_cluster(scmrq);
269 for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++)
270 blk_end_request_all(scmrq->request[i], scmrq->error);
271
272 atomic_dec(&bdev->queued_reqs);
273 scm_request_done(scmrq);
274}
275
276static int scm_request_start(struct scm_request *scmrq)
277{
278 struct scm_blk_dev *bdev = scmrq->bdev;
279 int ret;
280
281 atomic_inc(&bdev->queued_reqs);
282 if (!scmrq->aob->request.msb_count) {
283 scm_request_requeue(scmrq);
284 return -EINVAL;
285 }
286
287 ret = eadm_start_aob(scmrq->aob);
288 if (ret) {
289 SCM_LOG(5, "no subchannel");
290 scm_request_requeue(scmrq);
291 }
292 return ret;
293}
294
295static void scm_blk_request(struct request_queue *rq)
296{
297 struct scm_device *scmdev = rq->queuedata;
298 struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev);
299 struct scm_request *scmrq = NULL;
300 struct request *req;
301
302 while ((req = blk_peek_request(rq))) {
303 if (req->cmd_type != REQ_TYPE_FS) {
304 blk_start_request(req);
305 blk_dump_rq_flags(req, KMSG_COMPONENT " bad request");
306 __blk_end_request_all(req, -EIO);
307 continue;
308 }
309
310 if (!scm_permit_request(bdev, req))
311 goto out;
312
313 if (!scmrq) {
314 scmrq = scm_request_fetch();
315 if (!scmrq) {
316 SCM_LOG(5, "no request");
317 goto out;
318 }
319 scm_request_init(bdev, scmrq);
320 }
321 scm_request_set(scmrq, req);
322
323 if (!scm_reserve_cluster(scmrq)) {
324 SCM_LOG(5, "cluster busy");
325 scm_request_set(scmrq, NULL);
326 if (scmrq->aob->request.msb_count)
327 goto out;
328
329 scm_request_done(scmrq);
330 return;
331 }
332
333 if (scm_need_cluster_request(scmrq)) {
334 if (scmrq->aob->request.msb_count) {
335
336 scm_request_set(scmrq, NULL);
337 if (scm_request_start(scmrq))
338 return;
339 } else {
340 atomic_inc(&bdev->queued_reqs);
341 blk_start_request(req);
342 scm_initiate_cluster_request(scmrq);
343 }
344 scmrq = NULL;
345 continue;
346 }
347
348 if (scm_request_prepare(scmrq)) {
349 SCM_LOG(5, "aidaw alloc failed");
350 scm_request_set(scmrq, NULL);
351 goto out;
352 }
353 blk_start_request(req);
354
355 if (scmrq->aob->request.msb_count < nr_requests_per_io)
356 continue;
357
358 if (scm_request_start(scmrq))
359 return;
360
361 scmrq = NULL;
362 }
363out:
364 if (scmrq)
365 scm_request_start(scmrq);
366 else
367 scm_ensure_queue_restart(bdev);
368}
369
370static void __scmrq_log_error(struct scm_request *scmrq)
371{
372 struct aob *aob = scmrq->aob;
373
374 if (scmrq->error == -ETIMEDOUT)
375 SCM_LOG(1, "Request timeout");
376 else {
377 SCM_LOG(1, "Request error");
378 SCM_LOG_HEX(1, &aob->response, sizeof(aob->response));
379 }
380 if (scmrq->retries)
381 SCM_LOG(1, "Retry request");
382 else
383 pr_err("An I/O operation to SCM failed with rc=%d\n",
384 scmrq->error);
385}
386
387void scm_blk_irq(struct scm_device *scmdev, void *data, int error)
388{
389 struct scm_request *scmrq = data;
390 struct scm_blk_dev *bdev = scmrq->bdev;
391
392 scmrq->error = error;
393 if (error)
394 __scmrq_log_error(scmrq);
395
396 spin_lock(&bdev->lock);
397 list_add_tail(&scmrq->list, &bdev->finished_requests);
398 spin_unlock(&bdev->lock);
399 tasklet_hi_schedule(&bdev->tasklet);
400}
401
402static void scm_blk_handle_error(struct scm_request *scmrq)
403{
404 struct scm_blk_dev *bdev = scmrq->bdev;
405 unsigned long flags;
406
407 if (scmrq->error != -EIO)
408 goto restart;
409
410
411 switch (scmrq->aob->response.eqc) {
412 case EQC_WR_PROHIBIT:
413 spin_lock_irqsave(&bdev->lock, flags);
414 if (bdev->state != SCM_WR_PROHIBIT)
415 pr_info("%lx: Write access to the SCM increment is suspended\n",
416 (unsigned long) bdev->scmdev->address);
417 bdev->state = SCM_WR_PROHIBIT;
418 spin_unlock_irqrestore(&bdev->lock, flags);
419 goto requeue;
420 default:
421 break;
422 }
423
424restart:
425 if (!eadm_start_aob(scmrq->aob))
426 return;
427
428requeue:
429 spin_lock_irqsave(&bdev->rq_lock, flags);
430 scm_request_requeue(scmrq);
431 spin_unlock_irqrestore(&bdev->rq_lock, flags);
432}
433
434static void scm_blk_tasklet(struct scm_blk_dev *bdev)
435{
436 struct scm_request *scmrq;
437 unsigned long flags;
438
439 spin_lock_irqsave(&bdev->lock, flags);
440 while (!list_empty(&bdev->finished_requests)) {
441 scmrq = list_first_entry(&bdev->finished_requests,
442 struct scm_request, list);
443 list_del(&scmrq->list);
444 spin_unlock_irqrestore(&bdev->lock, flags);
445
446 if (scmrq->error && scmrq->retries-- > 0) {
447 scm_blk_handle_error(scmrq);
448
449
450 spin_lock_irqsave(&bdev->lock, flags);
451 continue;
452 }
453
454 if (scm_test_cluster_request(scmrq)) {
455 scm_cluster_request_irq(scmrq);
456 spin_lock_irqsave(&bdev->lock, flags);
457 continue;
458 }
459
460 scm_request_finish(scmrq);
461 spin_lock_irqsave(&bdev->lock, flags);
462 }
463 spin_unlock_irqrestore(&bdev->lock, flags);
464
465 blk_run_queue(bdev->rq);
466}
467
468static const struct block_device_operations scm_blk_devops = {
469 .owner = THIS_MODULE,
470};
471
472int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
473{
474 struct request_queue *rq;
475 int len, ret = -ENOMEM;
476 unsigned int devindex, nr_max_blk;
477
478 devindex = atomic_inc_return(&nr_devices) - 1;
479
480 if (devindex > 701) {
481 ret = -ENODEV;
482 goto out;
483 }
484
485 bdev->scmdev = scmdev;
486 bdev->state = SCM_OPER;
487 spin_lock_init(&bdev->rq_lock);
488 spin_lock_init(&bdev->lock);
489 INIT_LIST_HEAD(&bdev->finished_requests);
490 atomic_set(&bdev->queued_reqs, 0);
491 tasklet_init(&bdev->tasklet,
492 (void (*)(unsigned long)) scm_blk_tasklet,
493 (unsigned long) bdev);
494
495 rq = blk_init_queue(scm_blk_request, &bdev->rq_lock);
496 if (!rq)
497 goto out;
498
499 bdev->rq = rq;
500 nr_max_blk = min(scmdev->nr_max_block,
501 (unsigned int) (PAGE_SIZE / sizeof(struct aidaw)));
502
503 blk_queue_logical_block_size(rq, 1 << 12);
504 blk_queue_max_hw_sectors(rq, nr_max_blk << 3);
505 blk_queue_max_segments(rq, nr_max_blk);
506 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq);
507 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, rq);
508 scm_blk_dev_cluster_setup(bdev);
509
510 bdev->gendisk = alloc_disk(SCM_NR_PARTS);
511 if (!bdev->gendisk)
512 goto out_queue;
513
514 rq->queuedata = scmdev;
515 bdev->gendisk->driverfs_dev = &scmdev->dev;
516 bdev->gendisk->private_data = scmdev;
517 bdev->gendisk->fops = &scm_blk_devops;
518 bdev->gendisk->queue = rq;
519 bdev->gendisk->major = scm_major;
520 bdev->gendisk->first_minor = devindex * SCM_NR_PARTS;
521
522 len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm");
523 if (devindex > 25) {
524 len += snprintf(bdev->gendisk->disk_name + len,
525 DISK_NAME_LEN - len, "%c",
526 'a' + (devindex / 26) - 1);
527 devindex = devindex % 26;
528 }
529 snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c",
530 'a' + devindex);
531
532
533 set_capacity(bdev->gendisk, scmdev->size >> 9);
534 add_disk(bdev->gendisk);
535 return 0;
536
537out_queue:
538 blk_cleanup_queue(rq);
539out:
540 atomic_dec(&nr_devices);
541 return ret;
542}
543
544void scm_blk_dev_cleanup(struct scm_blk_dev *bdev)
545{
546 tasklet_kill(&bdev->tasklet);
547 del_gendisk(bdev->gendisk);
548 blk_cleanup_queue(bdev->gendisk->queue);
549 put_disk(bdev->gendisk);
550}
551
552void scm_blk_set_available(struct scm_blk_dev *bdev)
553{
554 unsigned long flags;
555
556 spin_lock_irqsave(&bdev->lock, flags);
557 if (bdev->state == SCM_WR_PROHIBIT)
558 pr_info("%lx: Write access to the SCM increment is restored\n",
559 (unsigned long) bdev->scmdev->address);
560 bdev->state = SCM_OPER;
561 spin_unlock_irqrestore(&bdev->lock, flags);
562}
563
564static bool __init scm_blk_params_valid(void)
565{
566 if (!nr_requests_per_io || nr_requests_per_io > 64)
567 return false;
568
569 return scm_cluster_size_valid();
570}
571
572static int __init scm_blk_init(void)
573{
574 int ret = -EINVAL;
575
576 if (!scm_blk_params_valid())
577 goto out;
578
579 ret = register_blkdev(0, "scm");
580 if (ret < 0)
581 goto out;
582
583 scm_major = ret;
584 ret = scm_alloc_rqs(nr_requests);
585 if (ret)
586 goto out_free;
587
588 scm_debug = debug_register("scm_log", 16, 1, 16);
589 if (!scm_debug) {
590 ret = -ENOMEM;
591 goto out_free;
592 }
593
594 debug_register_view(scm_debug, &debug_hex_ascii_view);
595 debug_set_level(scm_debug, 2);
596
597 ret = scm_drv_init();
598 if (ret)
599 goto out_dbf;
600
601 return ret;
602
603out_dbf:
604 debug_unregister(scm_debug);
605out_free:
606 scm_free_rqs();
607 unregister_blkdev(scm_major, "scm");
608out:
609 return ret;
610}
611module_init(scm_blk_init);
612
613static void __exit scm_blk_cleanup(void)
614{
615 scm_drv_cleanup();
616 debug_unregister(scm_debug);
617 scm_free_rqs();
618 unregister_blkdev(scm_major, "scm");
619}
620module_exit(scm_blk_cleanup);
621
