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