1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Block driver for s390 storage class memory. 4 * 5 * Copyright IBM Corp. 2012 6 * Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com> 7 */ 8 9 #define KMSG_COMPONENT "scm_block" 10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 11 12 #include <linux/interrupt.h> 13 #include <linux/spinlock.h> 14 #include <linux/mempool.h> 15 #include <linux/module.h> 16 #include <linux/blkdev.h> 17 #include <linux/blk-mq.h> 18 #include <linux/slab.h> 19 #include <linux/list.h> 20 #include <asm/eadm.h> 21 #include "scm_blk.h" 22 23 debug_info_t *scm_debug; 24 static int scm_major; 25 static mempool_t *aidaw_pool; 26 static DEFINE_SPINLOCK(list_lock); 27 static LIST_HEAD(inactive_requests); 28 static unsigned int nr_requests = 64; 29 static unsigned int nr_requests_per_io = 8; 30 static atomic_t nr_devices = ATOMIC_INIT(0); 31 module_param(nr_requests, uint, S_IRUGO); 32 MODULE_PARM_DESC(nr_requests, "Number of parallel requests."); 33 34 module_param(nr_requests_per_io, uint, S_IRUGO); 35 MODULE_PARM_DESC(nr_requests_per_io, "Number of requests per IO."); 36 37 MODULE_DESCRIPTION("Block driver for s390 storage class memory."); 38 MODULE_LICENSE("GPL"); 39 MODULE_ALIAS("scm:scmdev*"); 40 41 static void __scm_free_rq(struct scm_request *scmrq) 42 { 43 struct aob_rq_header *aobrq = to_aobrq(scmrq); 44 45 free_page((unsigned long) scmrq->aob); 46 kfree(scmrq->request); 47 kfree(aobrq); 48 } 49 50 static 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 66 static 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 INIT_LIST_HEAD(&scmrq->list); 86 spin_lock_irq(&list_lock); 87 list_add(&scmrq->list, &inactive_requests); 88 spin_unlock_irq(&list_lock); 89 90 return 0; 91 free: 92 __scm_free_rq(scmrq); 93 return -ENOMEM; 94 } 95 96 static int scm_alloc_rqs(unsigned int nrqs) 97 { 98 int ret = 0; 99 100 aidaw_pool = mempool_create_page_pool(max(nrqs/8, 1U), 0); 101 if (!aidaw_pool) 102 return -ENOMEM; 103 104 while (nrqs-- && !ret) 105 ret = __scm_alloc_rq(); 106 107 return ret; 108 } 109 110 static struct scm_request *scm_request_fetch(void) 111 { 112 struct scm_request *scmrq = NULL; 113 114 spin_lock_irq(&list_lock); 115 if (list_empty(&inactive_requests)) 116 goto out; 117 scmrq = list_first_entry(&inactive_requests, struct scm_request, list); 118 list_del(&scmrq->list); 119 out: 120 spin_unlock_irq(&list_lock); 121 return scmrq; 122 } 123 124 static void scm_request_done(struct scm_request *scmrq) 125 { 126 unsigned long flags; 127 struct msb *msb; 128 u64 aidaw; 129 int i; 130 131 for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) { 132 msb = &scmrq->aob->msb[i]; 133 aidaw = msb->data_addr; 134 135 if ((msb->flags & MSB_FLAG_IDA) && aidaw && 136 IS_ALIGNED(aidaw, PAGE_SIZE)) 137 mempool_free(virt_to_page((void *)aidaw), aidaw_pool); 138 } 139 140 spin_lock_irqsave(&list_lock, flags); 141 list_add(&scmrq->list, &inactive_requests); 142 spin_unlock_irqrestore(&list_lock, flags); 143 } 144 145 static bool scm_permit_request(struct scm_blk_dev *bdev, struct request *req) 146 { 147 return rq_data_dir(req) != WRITE || bdev->state != SCM_WR_PROHIBIT; 148 } 149 150 static inline struct aidaw *scm_aidaw_alloc(void) 151 { 152 struct page *page = mempool_alloc(aidaw_pool, GFP_ATOMIC); 153 154 return page ? page_address(page) : NULL; 155 } 156 157 static inline unsigned long scm_aidaw_bytes(struct aidaw *aidaw) 158 { 159 unsigned long _aidaw = (unsigned long) aidaw; 160 unsigned long bytes = ALIGN(_aidaw, PAGE_SIZE) - _aidaw; 161 162 return (bytes / sizeof(*aidaw)) * PAGE_SIZE; 163 } 164 165 struct aidaw *scm_aidaw_fetch(struct scm_request *scmrq, unsigned int bytes) 166 { 167 struct aidaw *aidaw; 168 169 if (scm_aidaw_bytes(scmrq->next_aidaw) >= bytes) 170 return scmrq->next_aidaw; 171 172 aidaw = scm_aidaw_alloc(); 173 if (aidaw) 174 memset(aidaw, 0, PAGE_SIZE); 175 return aidaw; 176 } 177 178 static int scm_request_prepare(struct scm_request *scmrq) 179 { 180 struct scm_blk_dev *bdev = scmrq->bdev; 181 struct scm_device *scmdev = bdev->gendisk->private_data; 182 int pos = scmrq->aob->request.msb_count; 183 struct msb *msb = &scmrq->aob->msb[pos]; 184 struct request *req = scmrq->request[pos]; 185 struct req_iterator iter; 186 struct aidaw *aidaw; 187 struct bio_vec bv; 188 189 aidaw = scm_aidaw_fetch(scmrq, blk_rq_bytes(req)); 190 if (!aidaw) 191 return -ENOMEM; 192 193 msb->bs = MSB_BS_4K; 194 scmrq->aob->request.msb_count++; 195 msb->scm_addr = scmdev->address + ((u64) blk_rq_pos(req) << 9); 196 msb->oc = (rq_data_dir(req) == READ) ? MSB_OC_READ : MSB_OC_WRITE; 197 msb->flags |= MSB_FLAG_IDA; 198 msb->data_addr = (u64) aidaw; 199 200 rq_for_each_segment(bv, req, iter) { 201 WARN_ON(bv.bv_offset); 202 msb->blk_count += bv.bv_len >> 12; 203 aidaw->data_addr = (u64) page_address(bv.bv_page); 204 aidaw++; 205 } 206 207 scmrq->next_aidaw = aidaw; 208 return 0; 209 } 210 211 static inline void scm_request_set(struct scm_request *scmrq, 212 struct request *req) 213 { 214 scmrq->request[scmrq->aob->request.msb_count] = req; 215 } 216 217 static inline void scm_request_init(struct scm_blk_dev *bdev, 218 struct scm_request *scmrq) 219 { 220 struct aob_rq_header *aobrq = to_aobrq(scmrq); 221 struct aob *aob = scmrq->aob; 222 223 memset(scmrq->request, 0, 224 nr_requests_per_io * sizeof(scmrq->request[0])); 225 memset(aob, 0, sizeof(*aob)); 226 aobrq->scmdev = bdev->scmdev; 227 aob->request.cmd_code = ARQB_CMD_MOVE; 228 aob->request.data = (u64) aobrq; 229 scmrq->bdev = bdev; 230 scmrq->retries = 4; 231 scmrq->error = BLK_STS_OK; 232 /* We don't use all msbs - place aidaws at the end of the aob page. */ 233 scmrq->next_aidaw = (void *) &aob->msb[nr_requests_per_io]; 234 } 235 236 static void scm_request_requeue(struct scm_request *scmrq) 237 { 238 struct scm_blk_dev *bdev = scmrq->bdev; 239 int i; 240 241 for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) 242 blk_mq_requeue_request(scmrq->request[i], false); 243 244 atomic_dec(&bdev->queued_reqs); 245 scm_request_done(scmrq); 246 blk_mq_kick_requeue_list(bdev->rq); 247 } 248 249 static void scm_request_finish(struct scm_request *scmrq) 250 { 251 struct scm_blk_dev *bdev = scmrq->bdev; 252 blk_status_t *error; 253 int i; 254 255 for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) { 256 error = blk_mq_rq_to_pdu(scmrq->request[i]); 257 *error = scmrq->error; 258 if (likely(!blk_should_fake_timeout(scmrq->request[i]->q))) 259 blk_mq_complete_request(scmrq->request[i]); 260 } 261 262 atomic_dec(&bdev->queued_reqs); 263 scm_request_done(scmrq); 264 } 265 266 static void scm_request_start(struct scm_request *scmrq) 267 { 268 struct scm_blk_dev *bdev = scmrq->bdev; 269 270 atomic_inc(&bdev->queued_reqs); 271 if (eadm_start_aob(scmrq->aob)) { 272 SCM_LOG(5, "no subchannel"); 273 scm_request_requeue(scmrq); 274 } 275 } 276 277 struct scm_queue { 278 struct scm_request *scmrq; 279 spinlock_t lock; 280 }; 281 282 static blk_status_t scm_blk_request(struct blk_mq_hw_ctx *hctx, 283 const struct blk_mq_queue_data *qd) 284 { 285 struct scm_device *scmdev = hctx->queue->queuedata; 286 struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev); 287 struct scm_queue *sq = hctx->driver_data; 288 struct request *req = qd->rq; 289 struct scm_request *scmrq; 290 291 spin_lock(&sq->lock); 292 if (!scm_permit_request(bdev, req)) { 293 spin_unlock(&sq->lock); 294 return BLK_STS_RESOURCE; 295 } 296 297 scmrq = sq->scmrq; 298 if (!scmrq) { 299 scmrq = scm_request_fetch(); 300 if (!scmrq) { 301 SCM_LOG(5, "no request"); 302 spin_unlock(&sq->lock); 303 return BLK_STS_RESOURCE; 304 } 305 scm_request_init(bdev, scmrq); 306 sq->scmrq = scmrq; 307 } 308 scm_request_set(scmrq, req); 309 310 if (scm_request_prepare(scmrq)) { 311 SCM_LOG(5, "aidaw alloc failed"); 312 scm_request_set(scmrq, NULL); 313 314 if (scmrq->aob->request.msb_count) 315 scm_request_start(scmrq); 316 317 sq->scmrq = NULL; 318 spin_unlock(&sq->lock); 319 return BLK_STS_RESOURCE; 320 } 321 blk_mq_start_request(req); 322 323 if (qd->last || scmrq->aob->request.msb_count == nr_requests_per_io) { 324 scm_request_start(scmrq); 325 sq->scmrq = NULL; 326 } 327 spin_unlock(&sq->lock); 328 return BLK_STS_OK; 329 } 330 331 static int scm_blk_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, 332 unsigned int idx) 333 { 334 struct scm_queue *qd = kzalloc(sizeof(*qd), GFP_KERNEL); 335 336 if (!qd) 337 return -ENOMEM; 338 339 spin_lock_init(&qd->lock); 340 hctx->driver_data = qd; 341 342 return 0; 343 } 344 345 static void scm_blk_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int idx) 346 { 347 struct scm_queue *qd = hctx->driver_data; 348 349 WARN_ON(qd->scmrq); 350 kfree(hctx->driver_data); 351 hctx->driver_data = NULL; 352 } 353 354 static void __scmrq_log_error(struct scm_request *scmrq) 355 { 356 struct aob *aob = scmrq->aob; 357 358 if (scmrq->error == BLK_STS_TIMEOUT) 359 SCM_LOG(1, "Request timeout"); 360 else { 361 SCM_LOG(1, "Request error"); 362 SCM_LOG_HEX(1, &aob->response, sizeof(aob->response)); 363 } 364 if (scmrq->retries) 365 SCM_LOG(1, "Retry request"); 366 else 367 pr_err("An I/O operation to SCM failed with rc=%d\n", 368 scmrq->error); 369 } 370 371 static void scm_blk_handle_error(struct scm_request *scmrq) 372 { 373 struct scm_blk_dev *bdev = scmrq->bdev; 374 unsigned long flags; 375 376 if (scmrq->error != BLK_STS_IOERR) 377 goto restart; 378 379 /* For -EIO the response block is valid. */ 380 switch (scmrq->aob->response.eqc) { 381 case EQC_WR_PROHIBIT: 382 spin_lock_irqsave(&bdev->lock, flags); 383 if (bdev->state != SCM_WR_PROHIBIT) 384 pr_info("%lx: Write access to the SCM increment is suspended\n", 385 (unsigned long) bdev->scmdev->address); 386 bdev->state = SCM_WR_PROHIBIT; 387 spin_unlock_irqrestore(&bdev->lock, flags); 388 goto requeue; 389 default: 390 break; 391 } 392 393 restart: 394 if (!eadm_start_aob(scmrq->aob)) 395 return; 396 397 requeue: 398 scm_request_requeue(scmrq); 399 } 400 401 void scm_blk_irq(struct scm_device *scmdev, void *data, blk_status_t error) 402 { 403 struct scm_request *scmrq = data; 404 405 scmrq->error = error; 406 if (error) { 407 __scmrq_log_error(scmrq); 408 if (scmrq->retries-- > 0) { 409 scm_blk_handle_error(scmrq); 410 return; 411 } 412 } 413 414 scm_request_finish(scmrq); 415 } 416 417 static void scm_blk_request_done(struct request *req) 418 { 419 blk_status_t *error = blk_mq_rq_to_pdu(req); 420 421 blk_mq_end_request(req, *error); 422 } 423 424 static const struct block_device_operations scm_blk_devops = { 425 .owner = THIS_MODULE, 426 }; 427 428 static const struct blk_mq_ops scm_mq_ops = { 429 .queue_rq = scm_blk_request, 430 .complete = scm_blk_request_done, 431 .init_hctx = scm_blk_init_hctx, 432 .exit_hctx = scm_blk_exit_hctx, 433 }; 434 435 int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev) 436 { 437 unsigned int devindex, nr_max_blk; 438 struct request_queue *rq; 439 int len, ret; 440 441 devindex = atomic_inc_return(&nr_devices) - 1; 442 /* scma..scmz + scmaa..scmzz */ 443 if (devindex > 701) { 444 ret = -ENODEV; 445 goto out; 446 } 447 448 bdev->scmdev = scmdev; 449 bdev->state = SCM_OPER; 450 spin_lock_init(&bdev->lock); 451 atomic_set(&bdev->queued_reqs, 0); 452 453 bdev->tag_set.ops = &scm_mq_ops; 454 bdev->tag_set.cmd_size = sizeof(blk_status_t); 455 bdev->tag_set.nr_hw_queues = nr_requests; 456 bdev->tag_set.queue_depth = nr_requests_per_io * nr_requests; 457 bdev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 458 bdev->tag_set.numa_node = NUMA_NO_NODE; 459 460 ret = blk_mq_alloc_tag_set(&bdev->tag_set); 461 if (ret) 462 goto out; 463 464 bdev->gendisk = blk_mq_alloc_disk(&bdev->tag_set, scmdev); 465 if (IS_ERR(bdev->gendisk)) { 466 ret = PTR_ERR(bdev->gendisk); 467 goto out_tag; 468 } 469 rq = bdev->rq = bdev->gendisk->queue; 470 nr_max_blk = min(scmdev->nr_max_block, 471 (unsigned int) (PAGE_SIZE / sizeof(struct aidaw))); 472 473 blk_queue_logical_block_size(rq, 1 << 12); 474 blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */ 475 blk_queue_max_segments(rq, nr_max_blk); 476 blk_queue_flag_set(QUEUE_FLAG_NONROT, rq); 477 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, rq); 478 479 bdev->gendisk->private_data = scmdev; 480 bdev->gendisk->fops = &scm_blk_devops; 481 bdev->gendisk->major = scm_major; 482 bdev->gendisk->first_minor = devindex * SCM_NR_PARTS; 483 bdev->gendisk->minors = SCM_NR_PARTS; 484 485 len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm"); 486 if (devindex > 25) { 487 len += snprintf(bdev->gendisk->disk_name + len, 488 DISK_NAME_LEN - len, "%c", 489 'a' + (devindex / 26) - 1); 490 devindex = devindex % 26; 491 } 492 snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c", 493 'a' + devindex); 494 495 /* 512 byte sectors */ 496 set_capacity(bdev->gendisk, scmdev->size >> 9); 497 ret = device_add_disk(&scmdev->dev, bdev->gendisk, NULL); 498 if (ret) 499 goto out_cleanup_disk; 500 501 return 0; 502 503 out_cleanup_disk: 504 put_disk(bdev->gendisk); 505 out_tag: 506 blk_mq_free_tag_set(&bdev->tag_set); 507 out: 508 atomic_dec(&nr_devices); 509 return ret; 510 } 511 512 void scm_blk_dev_cleanup(struct scm_blk_dev *bdev) 513 { 514 del_gendisk(bdev->gendisk); 515 put_disk(bdev->gendisk); 516 blk_mq_free_tag_set(&bdev->tag_set); 517 } 518 519 void scm_blk_set_available(struct scm_blk_dev *bdev) 520 { 521 unsigned long flags; 522 523 spin_lock_irqsave(&bdev->lock, flags); 524 if (bdev->state == SCM_WR_PROHIBIT) 525 pr_info("%lx: Write access to the SCM increment is restored\n", 526 (unsigned long) bdev->scmdev->address); 527 bdev->state = SCM_OPER; 528 spin_unlock_irqrestore(&bdev->lock, flags); 529 } 530 531 static bool __init scm_blk_params_valid(void) 532 { 533 if (!nr_requests_per_io || nr_requests_per_io > 64) 534 return false; 535 536 return true; 537 } 538 539 static int __init scm_blk_init(void) 540 { 541 int ret = -EINVAL; 542 543 if (!scm_blk_params_valid()) 544 goto out; 545 546 ret = register_blkdev(0, "scm"); 547 if (ret < 0) 548 goto out; 549 550 scm_major = ret; 551 ret = scm_alloc_rqs(nr_requests); 552 if (ret) 553 goto out_free; 554 555 scm_debug = debug_register("scm_log", 16, 1, 16); 556 if (!scm_debug) { 557 ret = -ENOMEM; 558 goto out_free; 559 } 560 561 debug_register_view(scm_debug, &debug_hex_ascii_view); 562 debug_set_level(scm_debug, 2); 563 564 ret = scm_drv_init(); 565 if (ret) 566 goto out_dbf; 567 568 return ret; 569 570 out_dbf: 571 debug_unregister(scm_debug); 572 out_free: 573 scm_free_rqs(); 574 unregister_blkdev(scm_major, "scm"); 575 out: 576 return ret; 577 } 578 module_init(scm_blk_init); 579 580 static void __exit scm_blk_cleanup(void) 581 { 582 scm_drv_cleanup(); 583 debug_unregister(scm_debug); 584 scm_free_rqs(); 585 unregister_blkdev(scm_major, "scm"); 586 } 587 module_exit(scm_blk_cleanup); 588