drivers/misc/cxl/file.c

   1 /*
   2  * Copyright 2014 IBM Corp.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/spinlock.h>
  11 #include <linux/module.h>
  12 #include <linux/export.h>
  13 #include <linux/kernel.h>
  14 #include <linux/bitmap.h>
  15 #include <linux/sched/signal.h>
  16 #include <linux/poll.h>
  17 #include <linux/pid.h>
  18 #include <linux/fs.h>
  19 #include <linux/mm.h>
  20 #include <linux/slab.h>
  21 #include <asm/cputable.h>
  22 #include <asm/current.h>
  23 #include <asm/copro.h>
  24
  25 #include "cxl.h"
  26 #include "trace.h"
  27
  28 #define CXL_NUM_MINORS 256 /* Total to reserve */
  29
  30 #define CXL_AFU_MINOR_D(afu) (CXL_CARD_MINOR(afu->adapter) + 1 + (3 * afu->slice))
  31 #define CXL_AFU_MINOR_M(afu) (CXL_AFU_MINOR_D(afu) + 1)
  32 #define CXL_AFU_MINOR_S(afu) (CXL_AFU_MINOR_D(afu) + 2)
  33 #define CXL_AFU_MKDEV_D(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_D(afu))
  34 #define CXL_AFU_MKDEV_M(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_M(afu))
  35 #define CXL_AFU_MKDEV_S(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_S(afu))
  36
  37 #define CXL_DEVT_AFU(dev) ((MINOR(dev) % CXL_DEV_MINORS - 1) / 3)
  38
  39 #define CXL_DEVT_IS_CARD(dev) (MINOR(dev) % CXL_DEV_MINORS == 0)
  40
  41 static dev_t cxl_dev;
  42
  43 static struct class *cxl_class;
  44
  45 static int __afu_open(struct inode *inode, struct file *file, bool master)
  46 {
  47         struct cxl *adapter;
  48         struct cxl_afu *afu;
  49         struct cxl_context *ctx;
  50         int adapter_num = CXL_DEVT_ADAPTER(inode->i_rdev);
  51         int slice = CXL_DEVT_AFU(inode->i_rdev);
  52         int rc = -ENODEV;
  53
  54         pr_devel("afu_open afu%i.%i\n", slice, adapter_num);
  55
  56         if (!(adapter = get_cxl_adapter(adapter_num)))
  57                 return -ENODEV;
  58
  59         if (slice > adapter->slices)
  60                 goto err_put_adapter;
  61
  62         spin_lock(&adapter->afu_list_lock);
  63         if (!(afu = adapter->afu[slice])) {
  64                 spin_unlock(&adapter->afu_list_lock);
  65                 goto err_put_adapter;
  66         }
  67
  68         /*
  69          * taking a ref to the afu so that it doesn't go away
  70          * for rest of the function. This ref is released before
  71          * we return.
  72          */
  73         cxl_afu_get(afu);
  74         spin_unlock(&adapter->afu_list_lock);
  75
  76         if (!afu->current_mode)
  77                 goto err_put_afu;
  78
  79         if (!cxl_ops->link_ok(adapter, afu)) {
  80                 rc = -EIO;
  81                 goto err_put_afu;
  82         }
  83
  84         if (!(ctx = cxl_context_alloc())) {
  85                 rc = -ENOMEM;
  86                 goto err_put_afu;
  87         }
  88
  89         rc = cxl_context_init(ctx, afu, master);
  90         if (rc)
  91                 goto err_put_afu;
  92
  93         cxl_context_set_mapping(ctx, inode->i_mapping);
  94
  95         pr_devel("afu_open pe: %i\n", ctx->pe);
  96         file->private_data = ctx;
  97         cxl_ctx_get();
  98
  99         /* indicate success */
 100         rc = 0;
 101
 102 err_put_afu:
 103         /* release the ref taken earlier */
 104         cxl_afu_put(afu);
 105 err_put_adapter:
 106         put_device(&adapter->dev);
 107         return rc;
 108 }
 109
 110 int afu_open(struct inode *inode, struct file *file)
 111 {
 112         return __afu_open(inode, file, false);
 113 }
 114
 115 static int afu_master_open(struct inode *inode, struct file *file)
 116 {
 117         return __afu_open(inode, file, true);
 118 }
 119
 120 int afu_release(struct inode *inode, struct file *file)
 121 {
 122         struct cxl_context *ctx = file->private_data;
 123
 124         pr_devel("%s: closing cxl file descriptor. pe: %i\n",
 125                  __func__, ctx->pe);
 126         cxl_context_detach(ctx);
 127
 128
 129         /*
 130          * Delete the context's mapping pointer, unless it's created by the
 131          * kernel API, in which case leave it so it can be freed by reclaim_ctx()
 132          */
 133         if (!ctx->kernelapi) {
 134                 mutex_lock(&ctx->mapping_lock);
 135                 ctx->mapping = NULL;
 136                 mutex_unlock(&ctx->mapping_lock);
 137         }
 138
 139         /*
 140          * At this this point all bottom halfs have finished and we should be
 141          * getting no more IRQs from the hardware for this context.  Once it's
 142          * removed from the IDR (and RCU synchronised) it's safe to free the
 143          * sstp and context.
 144          */
 145         cxl_context_free(ctx);
 146
 147         return 0;
 148 }
 149
 150 static long afu_ioctl_start_work(struct cxl_context *ctx,
 151                                  struct cxl_ioctl_start_work __user *uwork)
 152 {
 153         struct cxl_ioctl_start_work work;
 154         u64 amr = 0;
 155         int rc;
 156
 157         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 158
 159         /* Do this outside the status_mutex to avoid a circular dependency with
 160          * the locking in cxl_mmap_fault() */
 161         if (copy_from_user(&work, uwork, sizeof(work)))
 162                 return -EFAULT;
 163
 164         mutex_lock(&ctx->status_mutex);
 165         if (ctx->status != OPENED) {
 166                 rc = -EIO;
 167                 goto out;
 168         }
 169
 170         /*
 171          * if any of the reserved fields are set or any of the unused
 172          * flags are set it's invalid
 173          */
 174         if (work.reserved1 || work.reserved2 || work.reserved3 ||
 175             work.reserved4 || work.reserved5 || work.reserved6 ||
 176             (work.flags & ~CXL_START_WORK_ALL)) {
 177                 rc = -EINVAL;
 178                 goto out;
 179         }
 180
 181         if (!(work.flags & CXL_START_WORK_NUM_IRQS))
 182                 work.num_interrupts = ctx->afu->pp_irqs;
 183         else if ((work.num_interrupts < ctx->afu->pp_irqs) ||
 184                  (work.num_interrupts > ctx->afu->irqs_max)) {
 185                 rc =  -EINVAL;
 186                 goto out;
 187         }
 188         if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
 189                 goto out;
 190
 191         if (work.flags & CXL_START_WORK_AMR)
 192                 amr = work.amr & mfspr(SPRN_UAMOR);
 193
 194         ctx->mmio_err_ff = !!(work.flags & CXL_START_WORK_ERR_FF);
 195
 196         /*
 197          * Increment the mapped context count for adapter. This also checks
 198          * if adapter_context_lock is taken.
 199          */
 200         rc = cxl_adapter_context_get(ctx->afu->adapter);
 201         if (rc) {
 202                 afu_release_irqs(ctx, ctx);
 203                 goto out;
 204         }
 205
 206         /*
 207          * We grab the PID here and not in the file open to allow for the case
 208          * where a process (master, some daemon, etc) has opened the chardev on
 209          * behalf of another process, so the AFU's mm gets bound to the process
 210          * that performs this ioctl and not the process that opened the file.
 211          * Also we grab the PID of the group leader so that if the task that
 212          * has performed the attach operation exits the mm context of the
 213          * process is still accessible.
 214          */
 215         ctx->pid = get_task_pid(current, PIDTYPE_PID);
 216         ctx->glpid = get_task_pid(current->group_leader, PIDTYPE_PID);
 217
 218
 219         trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
 220
 221         if ((rc = cxl_ops->attach_process(ctx, false, work.work_element_descriptor,
 222                                                         amr))) {
 223                 afu_release_irqs(ctx, ctx);
 224                 cxl_adapter_context_put(ctx->afu->adapter);
 225                 put_pid(ctx->glpid);
 226                 put_pid(ctx->pid);
 227                 ctx->glpid = ctx->pid = NULL;
 228                 goto out;
 229         }
 230
 231         ctx->status = STARTED;
 232         rc = 0;
 233 out:
 234         mutex_unlock(&ctx->status_mutex);
 235         return rc;
 236 }
 237
 238 static long afu_ioctl_process_element(struct cxl_context *ctx,
 239                                       int __user *upe)
 240 {
 241         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 242
 243         if (copy_to_user(upe, &ctx->external_pe, sizeof(__u32)))
 244                 return -EFAULT;
 245
 246         return 0;
 247 }
 248
 249 static long afu_ioctl_get_afu_id(struct cxl_context *ctx,
 250                                  struct cxl_afu_id __user *upafuid)
 251 {
 252         struct cxl_afu_id afuid = { 0 };
 253
 254         afuid.card_id = ctx->afu->adapter->adapter_num;
 255         afuid.afu_offset = ctx->afu->slice;
 256         afuid.afu_mode = ctx->afu->current_mode;
 257
 258         /* set the flag bit in case the afu is a slave */
 259         if (ctx->afu->current_mode == CXL_MODE_DIRECTED && !ctx->master)
 260                 afuid.flags |= CXL_AFUID_FLAG_SLAVE;
 261
 262         if (copy_to_user(upafuid, &afuid, sizeof(afuid)))
 263                 return -EFAULT;
 264
 265         return 0;
 266 }
 267
 268 long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 269 {
 270         struct cxl_context *ctx = file->private_data;
 271
 272         if (ctx->status == CLOSED)
 273                 return -EIO;
 274
 275         if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
 276                 return -EIO;
 277
 278         pr_devel("afu_ioctl\n");
 279         switch (cmd) {
 280         case CXL_IOCTL_START_WORK:
 281                 return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg);
 282         case CXL_IOCTL_GET_PROCESS_ELEMENT:
 283                 return afu_ioctl_process_element(ctx, (__u32 __user *)arg);
 284         case CXL_IOCTL_GET_AFU_ID:
 285                 return afu_ioctl_get_afu_id(ctx, (struct cxl_afu_id __user *)
 286                                             arg);
 287         }
 288         return -EINVAL;
 289 }
 290
 291 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
 292                              unsigned long arg)
 293 {
 294         return afu_ioctl(file, cmd, arg);
 295 }
 296
 297 int afu_mmap(struct file *file, struct vm_area_struct *vm)
 298 {
 299         struct cxl_context *ctx = file->private_data;
 300
 301         /* AFU must be started before we can MMIO */
 302         if (ctx->status != STARTED)
 303                 return -EIO;
 304
 305         if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
 306                 return -EIO;
 307
 308         return cxl_context_iomap(ctx, vm);
 309 }
 310
 311 static inline bool ctx_event_pending(struct cxl_context *ctx)
 312 {
 313         if (ctx->pending_irq || ctx->pending_fault || ctx->pending_afu_err)
 314                 return true;
 315
 316         if (ctx->afu_driver_ops && atomic_read(&ctx->afu_driver_events))
 317                 return true;
 318
 319         return false;
 320 }
 321
 322 unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
 323 {
 324         struct cxl_context *ctx = file->private_data;
 325         int mask = 0;
 326         unsigned long flags;
 327
 328
 329         poll_wait(file, &ctx->wq, poll);
 330
 331         pr_devel("afu_poll wait done pe: %i\n", ctx->pe);
 332
 333         spin_lock_irqsave(&ctx->lock, flags);
 334         if (ctx_event_pending(ctx))
 335                 mask |= POLLIN | POLLRDNORM;
 336         else if (ctx->status == CLOSED)
 337                 /* Only error on closed when there are no futher events pending
 338                  */
 339                 mask |= POLLERR;
 340         spin_unlock_irqrestore(&ctx->lock, flags);
 341
 342         pr_devel("afu_poll pe: %i returning %#x\n", ctx->pe, mask);
 343
 344         return mask;
 345 }
 346
 347 static ssize_t afu_driver_event_copy(struct cxl_context *ctx,
 348                                      char __user *buf,
 349                                      struct cxl_event *event,
 350                                      struct cxl_event_afu_driver_reserved *pl)
 351 {
 352         /* Check event */
 353         if (!pl) {
 354                 ctx->afu_driver_ops->event_delivered(ctx, pl, -EINVAL);
 355                 return -EFAULT;
 356         }
 357
 358         /* Check event size */
 359         event->header.size += pl->data_size;
 360         if (event->header.size > CXL_READ_MIN_SIZE) {
 361                 ctx->afu_driver_ops->event_delivered(ctx, pl, -EINVAL);
 362                 return -EFAULT;
 363         }
 364
 365         /* Copy event header */
 366         if (copy_to_user(buf, event, sizeof(struct cxl_event_header))) {
 367                 ctx->afu_driver_ops->event_delivered(ctx, pl, -EFAULT);
 368                 return -EFAULT;
 369         }
 370
 371         /* Copy event data */
 372         buf += sizeof(struct cxl_event_header);
 373         if (copy_to_user(buf, &pl->data, pl->data_size)) {
 374                 ctx->afu_driver_ops->event_delivered(ctx, pl, -EFAULT);
 375                 return -EFAULT;
 376         }
 377
 378         ctx->afu_driver_ops->event_delivered(ctx, pl, 0); /* Success */
 379         return event->header.size;
 380 }
 381
 382 ssize_t afu_read(struct file *file, char __user *buf, size_t count,
 383                         loff_t *off)
 384 {
 385         struct cxl_context *ctx = file->private_data;
 386         struct cxl_event_afu_driver_reserved *pl = NULL;
 387         struct cxl_event event;
 388         unsigned long flags;
 389         int rc;
 390         DEFINE_WAIT(wait);
 391
 392         if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
 393                 return -EIO;
 394
 395         if (count < CXL_READ_MIN_SIZE)
 396                 return -EINVAL;
 397
 398         spin_lock_irqsave(&ctx->lock, flags);
 399
 400         for (;;) {
 401                 prepare_to_wait(&ctx->wq, &wait, TASK_INTERRUPTIBLE);
 402                 if (ctx_event_pending(ctx) || (ctx->status == CLOSED))
 403                         break;
 404
 405                 if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)) {
 406                         rc = -EIO;
 407                         goto out;
 408                 }
 409
 410                 if (file->f_flags & O_NONBLOCK) {
 411                         rc = -EAGAIN;
 412                         goto out;
 413                 }
 414
 415                 if (signal_pending(current)) {
 416                         rc = -ERESTARTSYS;
 417                         goto out;
 418                 }
 419
 420                 spin_unlock_irqrestore(&ctx->lock, flags);
 421                 pr_devel("afu_read going to sleep...\n");
 422                 schedule();
 423                 pr_devel("afu_read woken up\n");
 424                 spin_lock_irqsave(&ctx->lock, flags);
 425         }
 426
 427         finish_wait(&ctx->wq, &wait);
 428
 429         memset(&event, 0, sizeof(event));
 430         event.header.process_element = ctx->pe;
 431         event.header.size = sizeof(struct cxl_event_header);
 432         if (ctx->afu_driver_ops && atomic_read(&ctx->afu_driver_events)) {
 433                 pr_devel("afu_read delivering AFU driver specific event\n");
 434                 pl = ctx->afu_driver_ops->fetch_event(ctx);
 435                 atomic_dec(&ctx->afu_driver_events);
 436                 event.header.type = CXL_EVENT_AFU_DRIVER;
 437         } else if (ctx->pending_irq) {
 438                 pr_devel("afu_read delivering AFU interrupt\n");
 439                 event.header.size += sizeof(struct cxl_event_afu_interrupt);
 440                 event.header.type = CXL_EVENT_AFU_INTERRUPT;
 441                 event.irq.irq = find_first_bit(ctx->irq_bitmap, ctx->irq_count) + 1;
 442                 clear_bit(event.irq.irq - 1, ctx->irq_bitmap);
 443                 if (bitmap_empty(ctx->irq_bitmap, ctx->irq_count))
 444                         ctx->pending_irq = false;
 445         } else if (ctx->pending_fault) {
 446                 pr_devel("afu_read delivering data storage fault\n");
 447                 event.header.size += sizeof(struct cxl_event_data_storage);
 448                 event.header.type = CXL_EVENT_DATA_STORAGE;
 449                 event.fault.addr = ctx->fault_addr;
 450                 event.fault.dsisr = ctx->fault_dsisr;
 451                 ctx->pending_fault = false;
 452         } else if (ctx->pending_afu_err) {
 453                 pr_devel("afu_read delivering afu error\n");
 454                 event.header.size += sizeof(struct cxl_event_afu_error);
 455                 event.header.type = CXL_EVENT_AFU_ERROR;
 456                 event.afu_error.error = ctx->afu_err;
 457                 ctx->pending_afu_err = false;
 458         } else if (ctx->status == CLOSED) {
 459                 pr_devel("afu_read fatal error\n");
 460                 spin_unlock_irqrestore(&ctx->lock, flags);
 461                 return -EIO;
 462         } else
 463                 WARN(1, "afu_read must be buggy\n");
 464
 465         spin_unlock_irqrestore(&ctx->lock, flags);
 466
 467         if (event.header.type == CXL_EVENT_AFU_DRIVER)
 468                 return afu_driver_event_copy(ctx, buf, &event, pl);
 469
 470         if (copy_to_user(buf, &event, event.header.size))
 471                 return -EFAULT;
 472         return event.header.size;
 473
 474 out:
 475         finish_wait(&ctx->wq, &wait);
 476         spin_unlock_irqrestore(&ctx->lock, flags);
 477         return rc;
 478 }
 479
 480 /*
 481  * Note: if this is updated, we need to update api.c to patch the new ones in
 482  * too
 483  */
 484 const struct file_operations afu_fops = {
 485         .owner          = THIS_MODULE,
 486         .open           = afu_open,
 487         .poll           = afu_poll,
 488         .read           = afu_read,
 489         .release        = afu_release,
 490         .unlocked_ioctl = afu_ioctl,
 491         .compat_ioctl   = afu_compat_ioctl,
 492         .mmap           = afu_mmap,
 493 };
 494
 495 static const struct file_operations afu_master_fops = {
 496         .owner          = THIS_MODULE,
 497         .open           = afu_master_open,
 498         .poll           = afu_poll,
 499         .read           = afu_read,
 500         .release        = afu_release,
 501         .unlocked_ioctl = afu_ioctl,
 502         .compat_ioctl   = afu_compat_ioctl,
 503         .mmap           = afu_mmap,
 504 };
 505
 506
 507 static char *cxl_devnode(struct device *dev, umode_t *mode)
 508 {
 509         if (cpu_has_feature(CPU_FTR_HVMODE) &&
 510             CXL_DEVT_IS_CARD(dev->devt)) {
 511                 /*
 512                  * These minor numbers will eventually be used to program the
 513                  * PSL and AFUs once we have dynamic reprogramming support
 514                  */
 515                 return NULL;
 516         }
 517         return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
 518 }
 519
 520 extern struct class *cxl_class;
 521
 522 static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 523                            struct device **chardev, char *postfix, char *desc,
 524                            const struct file_operations *fops)
 525 {
 526         struct device *dev;
 527         int rc;
 528
 529         cdev_init(cdev, fops);
 530         if ((rc = cdev_add(cdev, devt, 1))) {
 531                 dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc);
 532                 return rc;
 533         }
 534
 535         dev = device_create(cxl_class, &afu->dev, devt, afu,
 536                         "afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
 537         if (IS_ERR(dev)) {
 538                 dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
 539                 rc = PTR_ERR(dev);
 540                 goto err;
 541         }
 542
 543         *chardev = dev;
 544
 545         return 0;
 546 err:
 547         cdev_del(cdev);
 548         return rc;
 549 }
 550
 551 int cxl_chardev_d_afu_add(struct cxl_afu *afu)
 552 {
 553         return cxl_add_chardev(afu, CXL_AFU_MKDEV_D(afu), &afu->afu_cdev_d,
 554                                &afu->chardev_d, "d", "dedicated",
 555                                &afu_master_fops); /* Uses master fops */
 556 }
 557
 558 int cxl_chardev_m_afu_add(struct cxl_afu *afu)
 559 {
 560         return cxl_add_chardev(afu, CXL_AFU_MKDEV_M(afu), &afu->afu_cdev_m,
 561                                &afu->chardev_m, "m", "master",
 562                                &afu_master_fops);
 563 }
 564
 565 int cxl_chardev_s_afu_add(struct cxl_afu *afu)
 566 {
 567         return cxl_add_chardev(afu, CXL_AFU_MKDEV_S(afu), &afu->afu_cdev_s,
 568                                &afu->chardev_s, "s", "shared",
 569                                &afu_fops);
 570 }
 571
 572 void cxl_chardev_afu_remove(struct cxl_afu *afu)
 573 {
 574         if (afu->chardev_d) {
 575                 cdev_del(&afu->afu_cdev_d);
 576                 device_unregister(afu->chardev_d);
 577                 afu->chardev_d = NULL;
 578         }
 579         if (afu->chardev_m) {
 580                 cdev_del(&afu->afu_cdev_m);
 581                 device_unregister(afu->chardev_m);
 582                 afu->chardev_m = NULL;
 583         }
 584         if (afu->chardev_s) {
 585                 cdev_del(&afu->afu_cdev_s);
 586                 device_unregister(afu->chardev_s);
 587                 afu->chardev_s = NULL;
 588         }
 589 }
 590
 591 int cxl_register_afu(struct cxl_afu *afu)
 592 {
 593         afu->dev.class = cxl_class;
 594
 595         return device_register(&afu->dev);
 596 }
 597
 598 int cxl_register_adapter(struct cxl *adapter)
 599 {
 600         adapter->dev.class = cxl_class;
 601
 602         /*
 603          * Future: When we support dynamically reprogramming the PSL & AFU we
 604          * will expose the interface to do that via a chardev:
 605          * adapter->dev.devt = CXL_CARD_MKDEV(adapter);
 606          */
 607
 608         return device_register(&adapter->dev);
 609 }
 610
 611 dev_t cxl_get_dev(void)
 612 {
 613         return cxl_dev;
 614 }
 615
 616 int __init cxl_file_init(void)
 617 {
 618         int rc;
 619
 620         /*
 621          * If these change we really need to update API.  Either change some
 622          * flags or update API version number CXL_API_VERSION.
 623          */
 624         BUILD_BUG_ON(CXL_API_VERSION != 3);
 625         BUILD_BUG_ON(sizeof(struct cxl_ioctl_start_work) != 64);
 626         BUILD_BUG_ON(sizeof(struct cxl_event_header) != 8);
 627         BUILD_BUG_ON(sizeof(struct cxl_event_afu_interrupt) != 8);
 628         BUILD_BUG_ON(sizeof(struct cxl_event_data_storage) != 32);
 629         BUILD_BUG_ON(sizeof(struct cxl_event_afu_error) != 16);
 630
 631         if ((rc = alloc_chrdev_region(&cxl_dev, 0, CXL_NUM_MINORS, "cxl"))) {
 632                 pr_err("Unable to allocate CXL major number: %i\n", rc);
 633                 return rc;
 634         }
 635
 636         pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
 637
 638         cxl_class = class_create(THIS_MODULE, "cxl");
 639         if (IS_ERR(cxl_class)) {
 640                 pr_err("Unable to create CXL class\n");
 641                 rc = PTR_ERR(cxl_class);
 642                 goto err;
 643         }
 644         cxl_class->devnode = cxl_devnode;
 645
 646         return 0;
 647
 648 err:
 649         unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
 650         return rc;
 651 }
 652
 653 void cxl_file_exit(void)
 654 {
 655         unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
 656         class_destroy(cxl_class);
 657 }