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 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; 458 459 ret = blk_mq_alloc_tag_set(&bdev->tag_set); 460 if (ret) 461 goto out; 462 463 rq = blk_mq_init_queue(&bdev->tag_set); 464 if (IS_ERR(rq)) { 465 ret = PTR_ERR(rq); 466 goto out_tag; 467 } 468 bdev->rq = rq; 469 nr_max_blk = min(scmdev->nr_max_block, 470 (unsigned int) (PAGE_SIZE / sizeof(struct aidaw))); 471 472 blk_queue_logical_block_size(rq, 1 << 12); 473 blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */ 474 blk_queue_max_segments(rq, nr_max_blk); 475 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq); 476 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, rq); 477 478 bdev->gendisk = alloc_disk(SCM_NR_PARTS); 479 if (!bdev->gendisk) { 480 ret = -ENOMEM; 481 goto out_queue; 482 } 483 rq->queuedata = scmdev; 484 bdev->gendisk->private_data = scmdev; 485 bdev->gendisk->fops = &scm_blk_devops; 486 bdev->gendisk->queue = rq; 487 bdev->gendisk->major = scm_major; 488 bdev->gendisk->first_minor = devindex * SCM_NR_PARTS; 489 490 len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm"); 491 if (devindex > 25) { 492 len += snprintf(bdev->gendisk->disk_name + len, 493 DISK_NAME_LEN - len, "%c", 494 'a' + (devindex / 26) - 1); 495 devindex = devindex % 26; 496 } 497 snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c", 498 'a' + devindex); 499 500 /* 512 byte sectors */ 501 set_capacity(bdev->gendisk, scmdev->size >> 9); 502 device_add_disk(&scmdev->dev, bdev->gendisk); 503 return 0; 504 505 out_queue: 506 blk_cleanup_queue(rq); 507 out_tag: 508 blk_mq_free_tag_set(&bdev->tag_set); 509 out: 510 atomic_dec(&nr_devices); 511 return ret; 512 } 513 514 void scm_blk_dev_cleanup(struct scm_blk_dev *bdev) 515 { 516 del_gendisk(bdev->gendisk); 517 blk_cleanup_queue(bdev->gendisk->queue); 518 blk_mq_free_tag_set(&bdev->tag_set); 519 put_disk(bdev->gendisk); 520 } 521 522 void scm_blk_set_available(struct scm_blk_dev *bdev) 523 { 524 unsigned long flags; 525 526 spin_lock_irqsave(&bdev->lock, flags); 527 if (bdev->state == SCM_WR_PROHIBIT) 528 pr_info("%lx: Write access to the SCM increment is restored\n", 529 (unsigned long) bdev->scmdev->address); 530 bdev->state = SCM_OPER; 531 spin_unlock_irqrestore(&bdev->lock, flags); 532 } 533 534 static bool __init scm_blk_params_valid(void) 535 { 536 if (!nr_requests_per_io || nr_requests_per_io > 64) 537 return false; 538 539 return true; 540 } 541 542 static int __init scm_blk_init(void) 543 { 544 int ret = -EINVAL; 545 546 if (!scm_blk_params_valid()) 547 goto out; 548 549 ret = register_blkdev(0, "scm"); 550 if (ret < 0) 551 goto out; 552 553 scm_major = ret; 554 ret = scm_alloc_rqs(nr_requests); 555 if (ret) 556 goto out_free; 557 558 scm_debug = debug_register("scm_log", 16, 1, 16); 559 if (!scm_debug) { 560 ret = -ENOMEM; 561 goto out_free; 562 } 563 564 debug_register_view(scm_debug, &debug_hex_ascii_view); 565 debug_set_level(scm_debug, 2); 566 567 ret = scm_drv_init(); 568 if (ret) 569 goto out_dbf; 570 571 return ret; 572 573 out_dbf: 574 debug_unregister(scm_debug); 575 out_free: 576 scm_free_rqs(); 577 unregister_blkdev(scm_major, "scm"); 578 out: 579 return ret; 580 } 581 module_init(scm_blk_init); 582 583 static void __exit scm_blk_cleanup(void) 584 { 585 scm_drv_cleanup(); 586 debug_unregister(scm_debug); 587 scm_free_rqs(); 588 unregister_blkdev(scm_major, "scm"); 589 } 590 module_exit(scm_blk_cleanup); 591