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); 40 __scm_free_rq_cluster(scmrq); 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 } 74 75 if (__scm_alloc_rq_cluster(scmrq)) { 76 __scm_free_rq(scmrq); 77 return -ENOMEM; 78 } 79 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 } 120 121 static int scm_open(struct block_device *blkdev, fmode_t mode) 122 { 123 return scm_get_ref(); 124 } 125 126 static int scm_release(struct gendisk *gendisk, fmode_t mode) 127 { 128 scm_put_ref(); 129 return 0; 130 } 131 132 static const struct block_device_operations scm_blk_devops = { 133 .owner = THIS_MODULE, 134 .open = scm_open, 135 .release = scm_release, 136 }; 137 138 static void scm_request_prepare(struct scm_request *scmrq) 139 { 140 struct scm_blk_dev *bdev = scmrq->bdev; 141 struct scm_device *scmdev = bdev->gendisk->private_data; 142 struct aidaw *aidaw = scmrq->aidaw; 143 struct msb *msb = &scmrq->aob->msb[0]; 144 struct req_iterator iter; 145 struct bio_vec *bv; 146 147 msb->bs = MSB_BS_4K; 148 scmrq->aob->request.msb_count = 1; 149 msb->scm_addr = scmdev->address + 150 ((u64) blk_rq_pos(scmrq->request) << 9); 151 msb->oc = (rq_data_dir(scmrq->request) == READ) ? 152 MSB_OC_READ : MSB_OC_WRITE; 153 msb->flags |= MSB_FLAG_IDA; 154 msb->data_addr = (u64) aidaw; 155 156 rq_for_each_segment(bv, scmrq->request, iter) { 157 WARN_ON(bv->bv_offset); 158 msb->blk_count += bv->bv_len >> 12; 159 aidaw->data_addr = (u64) page_address(bv->bv_page); 160 aidaw++; 161 } 162 } 163 164 static inline void scm_request_init(struct scm_blk_dev *bdev, 165 struct scm_request *scmrq, 166 struct request *req) 167 { 168 struct aob_rq_header *aobrq = to_aobrq(scmrq); 169 struct aob *aob = scmrq->aob; 170 171 memset(aob, 0, sizeof(*aob)); 172 memset(scmrq->aidaw, 0, PAGE_SIZE); 173 aobrq->scmdev = bdev->scmdev; 174 aob->request.cmd_code = ARQB_CMD_MOVE; 175 aob->request.data = (u64) aobrq; 176 scmrq->request = req; 177 scmrq->bdev = bdev; 178 scmrq->retries = 4; 179 scmrq->error = 0; 180 scm_request_cluster_init(scmrq); 181 } 182 183 static void scm_ensure_queue_restart(struct scm_blk_dev *bdev) 184 { 185 if (atomic_read(&bdev->queued_reqs)) { 186 /* Queue restart is triggered by the next interrupt. */ 187 return; 188 } 189 blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY); 190 } 191 192 void scm_request_requeue(struct scm_request *scmrq) 193 { 194 struct scm_blk_dev *bdev = scmrq->bdev; 195 196 scm_release_cluster(scmrq); 197 blk_requeue_request(bdev->rq, scmrq->request); 198 scm_request_done(scmrq); 199 scm_ensure_queue_restart(bdev); 200 } 201 202 void scm_request_finish(struct scm_request *scmrq) 203 { 204 scm_release_cluster(scmrq); 205 blk_end_request_all(scmrq->request, scmrq->error); 206 scm_request_done(scmrq); 207 } 208 209 static void scm_blk_request(struct request_queue *rq) 210 { 211 struct scm_device *scmdev = rq->queuedata; 212 struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev); 213 struct scm_request *scmrq; 214 struct request *req; 215 int ret; 216 217 while ((req = blk_peek_request(rq))) { 218 if (req->cmd_type != REQ_TYPE_FS) 219 continue; 220 221 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); 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)) { 234 blk_start_request(req); 235 scm_initiate_cluster_request(scmrq); 236 return; 237 } 238 scm_request_prepare(scmrq); 239 blk_start_request(req); 240 241 ret = scm_start_aob(scmrq->aob); 242 if (ret) { 243 SCM_LOG(5, "no subchannel"); 244 scm_request_requeue(scmrq); 245 return; 246 } 247 atomic_inc(&bdev->queued_reqs); 248 } 249 } 250 251 static void __scmrq_log_error(struct scm_request *scmrq) 252 { 253 struct aob *aob = scmrq->aob; 254 255 if (scmrq->error == -ETIMEDOUT) 256 SCM_LOG(1, "Request timeout"); 257 else { 258 SCM_LOG(1, "Request error"); 259 SCM_LOG_HEX(1, &aob->response, sizeof(aob->response)); 260 } 261 if (scmrq->retries) 262 SCM_LOG(1, "Retry request"); 263 else 264 pr_err("An I/O operation to SCM failed with rc=%d\n", 265 scmrq->error); 266 } 267 268 void scm_blk_irq(struct scm_device *scmdev, void *data, int error) 269 { 270 struct scm_request *scmrq = data; 271 struct scm_blk_dev *bdev = scmrq->bdev; 272 273 scmrq->error = error; 274 if (error) 275 __scmrq_log_error(scmrq); 276 277 spin_lock(&bdev->lock); 278 list_add_tail(&scmrq->list, &bdev->finished_requests); 279 spin_unlock(&bdev->lock); 280 tasklet_hi_schedule(&bdev->tasklet); 281 } 282 283 static void scm_blk_tasklet(struct scm_blk_dev *bdev) 284 { 285 struct scm_request *scmrq; 286 unsigned long flags; 287 288 spin_lock_irqsave(&bdev->lock, flags); 289 while (!list_empty(&bdev->finished_requests)) { 290 scmrq = list_first_entry(&bdev->finished_requests, 291 struct scm_request, list); 292 list_del(&scmrq->list); 293 spin_unlock_irqrestore(&bdev->lock, flags); 294 295 if (scmrq->error && scmrq->retries-- > 0) { 296 if (scm_start_aob(scmrq->aob)) { 297 spin_lock_irqsave(&bdev->rq_lock, flags); 298 scm_request_requeue(scmrq); 299 spin_unlock_irqrestore(&bdev->rq_lock, flags); 300 } 301 /* Request restarted or requeued, handle next. */ 302 spin_lock_irqsave(&bdev->lock, flags); 303 continue; 304 } 305 306 if (scm_test_cluster_request(scmrq)) { 307 scm_cluster_request_irq(scmrq); 308 spin_lock_irqsave(&bdev->lock, flags); 309 continue; 310 } 311 312 scm_request_finish(scmrq); 313 atomic_dec(&bdev->queued_reqs); 314 spin_lock_irqsave(&bdev->lock, flags); 315 } 316 spin_unlock_irqrestore(&bdev->lock, flags); 317 /* Look out for more requests. */ 318 blk_run_queue(bdev->rq); 319 } 320 321 int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev) 322 { 323 struct request_queue *rq; 324 int len, ret = -ENOMEM; 325 unsigned int devindex, nr_max_blk; 326 327 devindex = atomic_inc_return(&nr_devices) - 1; 328 /* scma..scmz + scmaa..scmzz */ 329 if (devindex > 701) { 330 ret = -ENODEV; 331 goto out; 332 } 333 334 bdev->scmdev = scmdev; 335 spin_lock_init(&bdev->rq_lock); 336 spin_lock_init(&bdev->lock); 337 INIT_LIST_HEAD(&bdev->finished_requests); 338 atomic_set(&bdev->queued_reqs, 0); 339 tasklet_init(&bdev->tasklet, 340 (void (*)(unsigned long)) scm_blk_tasklet, 341 (unsigned long) bdev); 342 343 rq = blk_init_queue(scm_blk_request, &bdev->rq_lock); 344 if (!rq) 345 goto out; 346 347 bdev->rq = rq; 348 nr_max_blk = min(scmdev->nr_max_block, 349 (unsigned int) (PAGE_SIZE / sizeof(struct aidaw))); 350 351 blk_queue_logical_block_size(rq, 1 << 12); 352 blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */ 353 blk_queue_max_segments(rq, nr_max_blk); 354 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq); 355 scm_blk_dev_cluster_setup(bdev); 356 357 bdev->gendisk = alloc_disk(SCM_NR_PARTS); 358 if (!bdev->gendisk) 359 goto out_queue; 360 361 rq->queuedata = scmdev; 362 bdev->gendisk->driverfs_dev = &scmdev->dev; 363 bdev->gendisk->private_data = scmdev; 364 bdev->gendisk->fops = &scm_blk_devops; 365 bdev->gendisk->queue = rq; 366 bdev->gendisk->major = scm_major; 367 bdev->gendisk->first_minor = devindex * SCM_NR_PARTS; 368 369 len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm"); 370 if (devindex > 25) { 371 len += snprintf(bdev->gendisk->disk_name + len, 372 DISK_NAME_LEN - len, "%c", 373 'a' + (devindex / 26) - 1); 374 devindex = devindex % 26; 375 } 376 snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c", 377 'a' + devindex); 378 379 /* 512 byte sectors */ 380 set_capacity(bdev->gendisk, scmdev->size >> 9); 381 add_disk(bdev->gendisk); 382 return 0; 383 384 out_queue: 385 blk_cleanup_queue(rq); 386 out: 387 atomic_dec(&nr_devices); 388 return ret; 389 } 390 391 void scm_blk_dev_cleanup(struct scm_blk_dev *bdev) 392 { 393 tasklet_kill(&bdev->tasklet); 394 del_gendisk(bdev->gendisk); 395 blk_cleanup_queue(bdev->gendisk->queue); 396 put_disk(bdev->gendisk); 397 } 398 399 static int __init scm_blk_init(void) 400 { 401 int ret = -EINVAL; 402 403 if (!scm_cluster_size_valid()) 404 goto out; 405 406 ret = register_blkdev(0, "scm"); 407 if (ret < 0) 408 goto out; 409 410 scm_major = ret; 411 if (scm_alloc_rqs(nr_requests)) 412 goto out_unreg; 413 414 scm_debug = debug_register("scm_log", 16, 1, 16); 415 if (!scm_debug) 416 goto out_free; 417 418 debug_register_view(scm_debug, &debug_hex_ascii_view); 419 debug_set_level(scm_debug, 2); 420 421 ret = scm_drv_init(); 422 if (ret) 423 goto out_dbf; 424 425 return ret; 426 427 out_dbf: 428 debug_unregister(scm_debug); 429 out_free: 430 scm_free_rqs(); 431 out_unreg: 432 unregister_blkdev(scm_major, "scm"); 433 out: 434 return ret; 435 } 436 module_init(scm_blk_init); 437 438 static void __exit scm_blk_cleanup(void) 439 { 440 scm_drv_cleanup(); 441 debug_unregister(scm_debug); 442 scm_free_rqs(); 443 unregister_blkdev(scm_major, "scm"); 444 } 445 module_exit(scm_blk_cleanup); 446