linux/drivers/s390/char/vmur.c
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   1/*
   2 * Linux driver for System z and s390 unit record devices
   3 * (z/VM virtual punch, reader, printer)
   4 *
   5 * Copyright IBM Corp. 2001, 2009
   6 * Authors: Malcolm Beattie <beattiem@uk.ibm.com>
   7 *          Michael Holzheu <holzheu@de.ibm.com>
   8 *          Frank Munzert <munzert@de.ibm.com>
   9 */
  10
  11#define KMSG_COMPONENT "vmur"
  12#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  13
  14#include <linux/cdev.h>
  15#include <linux/slab.h>
  16#include <linux/module.h>
  17
  18#include <asm/uaccess.h>
  19#include <asm/cio.h>
  20#include <asm/ccwdev.h>
  21#include <asm/debug.h>
  22#include <asm/diag.h>
  23
  24#include "vmur.h"
  25
  26/*
  27 * Driver overview
  28 *
  29 * Unit record device support is implemented as a character device driver.
  30 * We can fit at least 16 bits into a device minor number and use the
  31 * simple method of mapping a character device number with minor abcd
  32 * to the unit record device with devno abcd.
  33 * I/O to virtual unit record devices is handled as follows:
  34 * Reads: Diagnose code 0x14 (input spool file manipulation)
  35 * is used to read spool data page-wise.
  36 * Writes: The CCW used is WRITE_CCW_CMD (0x01). The device's record length
  37 * is available by reading sysfs attr reclen. Each write() to the device
  38 * must specify an integral multiple (maximal 511) of reclen.
  39 */
  40
  41static char ur_banner[] = "z/VM virtual unit record device driver";
  42
  43MODULE_AUTHOR("IBM Corporation");
  44MODULE_DESCRIPTION("s390 z/VM virtual unit record device driver");
  45MODULE_LICENSE("GPL");
  46
  47static dev_t ur_first_dev_maj_min;
  48static struct class *vmur_class;
  49static struct debug_info *vmur_dbf;
  50
  51/* We put the device's record length (for writes) in the driver_info field */
  52static struct ccw_device_id ur_ids[] = {
  53        { CCWDEV_CU_DI(READER_PUNCH_DEVTYPE, 80) },
  54        { CCWDEV_CU_DI(PRINTER_DEVTYPE, 132) },
  55        { /* end of list */ }
  56};
  57
  58MODULE_DEVICE_TABLE(ccw, ur_ids);
  59
  60static int ur_probe(struct ccw_device *cdev);
  61static void ur_remove(struct ccw_device *cdev);
  62static int ur_set_online(struct ccw_device *cdev);
  63static int ur_set_offline(struct ccw_device *cdev);
  64static int ur_pm_suspend(struct ccw_device *cdev);
  65
  66static struct ccw_driver ur_driver = {
  67        .driver = {
  68                .name   = "vmur",
  69                .owner  = THIS_MODULE,
  70        },
  71        .ids            = ur_ids,
  72        .probe          = ur_probe,
  73        .remove         = ur_remove,
  74        .set_online     = ur_set_online,
  75        .set_offline    = ur_set_offline,
  76        .freeze         = ur_pm_suspend,
  77        .int_class      = IOINT_VMR,
  78};
  79
  80static DEFINE_MUTEX(vmur_mutex);
  81
  82/*
  83 * Allocation, freeing, getting and putting of urdev structures
  84 *
  85 * Each ur device (urd) contains a reference to its corresponding ccw device
  86 * (cdev) using the urd->cdev pointer. Each ccw device has a reference to the
  87 * ur device using dev_get_drvdata(&cdev->dev) pointer.
  88 *
  89 * urd references:
  90 * - ur_probe gets a urd reference, ur_remove drops the reference
  91 *   dev_get_drvdata(&cdev->dev)
  92 * - ur_open gets a urd reference, ur_relase drops the reference
  93 *   (urf->urd)
  94 *
  95 * cdev references:
  96 * - urdev_alloc get a cdev reference (urd->cdev)
  97 * - urdev_free drops the cdev reference (urd->cdev)
  98 *
  99 * Setting and clearing of dev_get_drvdata(&cdev->dev) is protected by the ccwdev lock
 100 */
 101static struct urdev *urdev_alloc(struct ccw_device *cdev)
 102{
 103        struct urdev *urd;
 104
 105        urd = kzalloc(sizeof(struct urdev), GFP_KERNEL);
 106        if (!urd)
 107                return NULL;
 108        urd->reclen = cdev->id.driver_info;
 109        ccw_device_get_id(cdev, &urd->dev_id);
 110        mutex_init(&urd->io_mutex);
 111        init_waitqueue_head(&urd->wait);
 112        spin_lock_init(&urd->open_lock);
 113        atomic_set(&urd->ref_count,  1);
 114        urd->cdev = cdev;
 115        get_device(&cdev->dev);
 116        return urd;
 117}
 118
 119static void urdev_free(struct urdev *urd)
 120{
 121        TRACE("urdev_free: %p\n", urd);
 122        if (urd->cdev)
 123                put_device(&urd->cdev->dev);
 124        kfree(urd);
 125}
 126
 127static void urdev_get(struct urdev *urd)
 128{
 129        atomic_inc(&urd->ref_count);
 130}
 131
 132static struct urdev *urdev_get_from_cdev(struct ccw_device *cdev)
 133{
 134        struct urdev *urd;
 135        unsigned long flags;
 136
 137        spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
 138        urd = dev_get_drvdata(&cdev->dev);
 139        if (urd)
 140                urdev_get(urd);
 141        spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
 142        return urd;
 143}
 144
 145static struct urdev *urdev_get_from_devno(u16 devno)
 146{
 147        char bus_id[16];
 148        struct ccw_device *cdev;
 149        struct urdev *urd;
 150
 151        sprintf(bus_id, "0.0.%04x", devno);
 152        cdev = get_ccwdev_by_busid(&ur_driver, bus_id);
 153        if (!cdev)
 154                return NULL;
 155        urd = urdev_get_from_cdev(cdev);
 156        put_device(&cdev->dev);
 157        return urd;
 158}
 159
 160static void urdev_put(struct urdev *urd)
 161{
 162        if (atomic_dec_and_test(&urd->ref_count))
 163                urdev_free(urd);
 164}
 165
 166/*
 167 * State and contents of ur devices can be changed by class D users issuing
 168 * CP commands such as PURGE or TRANSFER, while the Linux guest is suspended.
 169 * Also the Linux guest might be logged off, which causes all active spool
 170 * files to be closed.
 171 * So we cannot guarantee that spool files are still the same when the Linux
 172 * guest is resumed. In order to avoid unpredictable results at resume time
 173 * we simply refuse to suspend if a ur device node is open.
 174 */
 175static int ur_pm_suspend(struct ccw_device *cdev)
 176{
 177        struct urdev *urd = dev_get_drvdata(&cdev->dev);
 178
 179        TRACE("ur_pm_suspend: cdev=%p\n", cdev);
 180        if (urd->open_flag) {
 181                pr_err("Unit record device %s is busy, %s refusing to "
 182                       "suspend.\n", dev_name(&cdev->dev), ur_banner);
 183                return -EBUSY;
 184        }
 185        return 0;
 186}
 187
 188/*
 189 * Low-level functions to do I/O to a ur device.
 190 *     alloc_chan_prog
 191 *     free_chan_prog
 192 *     do_ur_io
 193 *     ur_int_handler
 194 *
 195 * alloc_chan_prog allocates and builds the channel program
 196 * free_chan_prog frees memory of the channel program
 197 *
 198 * do_ur_io issues the channel program to the device and blocks waiting
 199 * on a completion event it publishes at urd->io_done. The function
 200 * serialises itself on the device's mutex so that only one I/O
 201 * is issued at a time (and that I/O is synchronous).
 202 *
 203 * ur_int_handler catches the "I/O done" interrupt, writes the
 204 * subchannel status word into the scsw member of the urdev structure
 205 * and complete()s the io_done to wake the waiting do_ur_io.
 206 *
 207 * The caller of do_ur_io is responsible for kfree()ing the channel program
 208 * address pointer that alloc_chan_prog returned.
 209 */
 210
 211static void free_chan_prog(struct ccw1 *cpa)
 212{
 213        struct ccw1 *ptr = cpa;
 214
 215        while (ptr->cda) {
 216                kfree((void *)(addr_t) ptr->cda);
 217                ptr++;
 218        }
 219        kfree(cpa);
 220}
 221
 222/*
 223 * alloc_chan_prog
 224 * The channel program we use is write commands chained together
 225 * with a final NOP CCW command-chained on (which ensures that CE and DE
 226 * are presented together in a single interrupt instead of as separate
 227 * interrupts unless an incorrect length indication kicks in first). The
 228 * data length in each CCW is reclen.
 229 */
 230static struct ccw1 *alloc_chan_prog(const char __user *ubuf, int rec_count,
 231                                    int reclen)
 232{
 233        struct ccw1 *cpa;
 234        void *kbuf;
 235        int i;
 236
 237        TRACE("alloc_chan_prog(%p, %i, %i)\n", ubuf, rec_count, reclen);
 238
 239        /*
 240         * We chain a NOP onto the writes to force CE+DE together.
 241         * That means we allocate room for CCWs to cover count/reclen
 242         * records plus a NOP.
 243         */
 244        cpa = kzalloc((rec_count + 1) * sizeof(struct ccw1),
 245                      GFP_KERNEL | GFP_DMA);
 246        if (!cpa)
 247                return ERR_PTR(-ENOMEM);
 248
 249        for (i = 0; i < rec_count; i++) {
 250                cpa[i].cmd_code = WRITE_CCW_CMD;
 251                cpa[i].flags = CCW_FLAG_CC | CCW_FLAG_SLI;
 252                cpa[i].count = reclen;
 253                kbuf = kmalloc(reclen, GFP_KERNEL | GFP_DMA);
 254                if (!kbuf) {
 255                        free_chan_prog(cpa);
 256                        return ERR_PTR(-ENOMEM);
 257                }
 258                cpa[i].cda = (u32)(addr_t) kbuf;
 259                if (copy_from_user(kbuf, ubuf, reclen)) {
 260                        free_chan_prog(cpa);
 261                        return ERR_PTR(-EFAULT);
 262                }
 263                ubuf += reclen;
 264        }
 265        /* The following NOP CCW forces CE+DE to be presented together */
 266        cpa[i].cmd_code = CCW_CMD_NOOP;
 267        return cpa;
 268}
 269
 270static int do_ur_io(struct urdev *urd, struct ccw1 *cpa)
 271{
 272        int rc;
 273        struct ccw_device *cdev = urd->cdev;
 274        DECLARE_COMPLETION_ONSTACK(event);
 275
 276        TRACE("do_ur_io: cpa=%p\n", cpa);
 277
 278        rc = mutex_lock_interruptible(&urd->io_mutex);
 279        if (rc)
 280                return rc;
 281
 282        urd->io_done = &event;
 283
 284        spin_lock_irq(get_ccwdev_lock(cdev));
 285        rc = ccw_device_start(cdev, cpa, 1, 0, 0);
 286        spin_unlock_irq(get_ccwdev_lock(cdev));
 287
 288        TRACE("do_ur_io: ccw_device_start returned %d\n", rc);
 289        if (rc)
 290                goto out;
 291
 292        wait_for_completion(&event);
 293        TRACE("do_ur_io: I/O complete\n");
 294        rc = 0;
 295
 296out:
 297        mutex_unlock(&urd->io_mutex);
 298        return rc;
 299}
 300
 301/*
 302 * ur interrupt handler, called from the ccw_device layer
 303 */
 304static void ur_int_handler(struct ccw_device *cdev, unsigned long intparm,
 305                           struct irb *irb)
 306{
 307        struct urdev *urd;
 308
 309        TRACE("ur_int_handler: intparm=0x%lx cstat=%02x dstat=%02x res=%u\n",
 310              intparm, irb->scsw.cmd.cstat, irb->scsw.cmd.dstat,
 311              irb->scsw.cmd.count);
 312
 313        if (!intparm) {
 314                TRACE("ur_int_handler: unsolicited interrupt\n");
 315                return;
 316        }
 317        urd = dev_get_drvdata(&cdev->dev);
 318        BUG_ON(!urd);
 319        /* On special conditions irb is an error pointer */
 320        if (IS_ERR(irb))
 321                urd->io_request_rc = PTR_ERR(irb);
 322        else if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END))
 323                urd->io_request_rc = 0;
 324        else
 325                urd->io_request_rc = -EIO;
 326
 327        complete(urd->io_done);
 328}
 329
 330/*
 331 * reclen sysfs attribute - The record length to be used for write CCWs
 332 */
 333static ssize_t ur_attr_reclen_show(struct device *dev,
 334                                   struct device_attribute *attr, char *buf)
 335{
 336        struct urdev *urd;
 337        int rc;
 338
 339        urd = urdev_get_from_cdev(to_ccwdev(dev));
 340        if (!urd)
 341                return -ENODEV;
 342        rc = sprintf(buf, "%zu\n", urd->reclen);
 343        urdev_put(urd);
 344        return rc;
 345}
 346
 347static DEVICE_ATTR(reclen, 0444, ur_attr_reclen_show, NULL);
 348
 349static int ur_create_attributes(struct device *dev)
 350{
 351        return device_create_file(dev, &dev_attr_reclen);
 352}
 353
 354static void ur_remove_attributes(struct device *dev)
 355{
 356        device_remove_file(dev, &dev_attr_reclen);
 357}
 358
 359/*
 360 * diagnose code 0x210 - retrieve device information
 361 * cc=0  normal completion, we have a real device
 362 * cc=1  CP paging error
 363 * cc=2  The virtual device exists, but is not associated with a real device
 364 * cc=3  Invalid device address, or the virtual device does not exist
 365 */
 366static int get_urd_class(struct urdev *urd)
 367{
 368        static struct diag210 ur_diag210;
 369        int cc;
 370
 371        ur_diag210.vrdcdvno = urd->dev_id.devno;
 372        ur_diag210.vrdclen = sizeof(struct diag210);
 373
 374        cc = diag210(&ur_diag210);
 375        switch (cc) {
 376        case 0:
 377                return -EOPNOTSUPP;
 378        case 2:
 379                return ur_diag210.vrdcvcla; /* virtual device class */
 380        case 3:
 381                return -ENODEV;
 382        default:
 383                return -EIO;
 384        }
 385}
 386
 387/*
 388 * Allocation and freeing of urfile structures
 389 */
 390static struct urfile *urfile_alloc(struct urdev *urd)
 391{
 392        struct urfile *urf;
 393
 394        urf = kzalloc(sizeof(struct urfile), GFP_KERNEL);
 395        if (!urf)
 396                return NULL;
 397        urf->urd = urd;
 398
 399        TRACE("urfile_alloc: urd=%p urf=%p rl=%zu\n", urd, urf,
 400              urf->dev_reclen);
 401
 402        return urf;
 403}
 404
 405static void urfile_free(struct urfile *urf)
 406{
 407        TRACE("urfile_free: urf=%p urd=%p\n", urf, urf->urd);
 408        kfree(urf);
 409}
 410
 411/*
 412 * The fops implementation of the character device driver
 413 */
 414static ssize_t do_write(struct urdev *urd, const char __user *udata,
 415                        size_t count, size_t reclen, loff_t *ppos)
 416{
 417        struct ccw1 *cpa;
 418        int rc;
 419
 420        cpa = alloc_chan_prog(udata, count / reclen, reclen);
 421        if (IS_ERR(cpa))
 422                return PTR_ERR(cpa);
 423
 424        rc = do_ur_io(urd, cpa);
 425        if (rc)
 426                goto fail_kfree_cpa;
 427
 428        if (urd->io_request_rc) {
 429                rc = urd->io_request_rc;
 430                goto fail_kfree_cpa;
 431        }
 432        *ppos += count;
 433        rc = count;
 434
 435fail_kfree_cpa:
 436        free_chan_prog(cpa);
 437        return rc;
 438}
 439
 440static ssize_t ur_write(struct file *file, const char __user *udata,
 441                        size_t count, loff_t *ppos)
 442{
 443        struct urfile *urf = file->private_data;
 444
 445        TRACE("ur_write: count=%zu\n", count);
 446
 447        if (count == 0)
 448                return 0;
 449
 450        if (count % urf->dev_reclen)
 451                return -EINVAL; /* count must be a multiple of reclen */
 452
 453        if (count > urf->dev_reclen * MAX_RECS_PER_IO)
 454                count = urf->dev_reclen * MAX_RECS_PER_IO;
 455
 456        return do_write(urf->urd, udata, count, urf->dev_reclen, ppos);
 457}
 458
 459/*
 460 * diagnose code 0x14 subcode 0x0028 - position spool file to designated
 461 *                                     record
 462 * cc=0  normal completion
 463 * cc=2  no file active on the virtual reader or device not ready
 464 * cc=3  record specified is beyond EOF
 465 */
 466static int diag_position_to_record(int devno, int record)
 467{
 468        int cc;
 469
 470        cc = diag14(record, devno, 0x28);
 471        switch (cc) {
 472        case 0:
 473                return 0;
 474        case 2:
 475                return -ENOMEDIUM;
 476        case 3:
 477                return -ENODATA; /* position beyond end of file */
 478        default:
 479                return -EIO;
 480        }
 481}
 482
 483/*
 484 * diagnose code 0x14 subcode 0x0000 - read next spool file buffer
 485 * cc=0  normal completion
 486 * cc=1  EOF reached
 487 * cc=2  no file active on the virtual reader, and no file eligible
 488 * cc=3  file already active on the virtual reader or specified virtual
 489 *       reader does not exist or is not a reader
 490 */
 491static int diag_read_file(int devno, char *buf)
 492{
 493        int cc;
 494
 495        cc = diag14((unsigned long) buf, devno, 0x00);
 496        switch (cc) {
 497        case 0:
 498                return 0;
 499        case 1:
 500                return -ENODATA;
 501        case 2:
 502                return -ENOMEDIUM;
 503        default:
 504                return -EIO;
 505        }
 506}
 507
 508static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
 509                           loff_t *offs)
 510{
 511        size_t len, copied, res;
 512        char *buf;
 513        int rc;
 514        u16 reclen;
 515        struct urdev *urd;
 516
 517        urd = ((struct urfile *) file->private_data)->urd;
 518        reclen = ((struct urfile *) file->private_data)->file_reclen;
 519
 520        rc = diag_position_to_record(urd->dev_id.devno, *offs / PAGE_SIZE + 1);
 521        if (rc == -ENODATA)
 522                return 0;
 523        if (rc)
 524                return rc;
 525
 526        len = min((size_t) PAGE_SIZE, count);
 527        buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
 528        if (!buf)
 529                return -ENOMEM;
 530
 531        copied = 0;
 532        res = (size_t) (*offs % PAGE_SIZE);
 533        do {
 534                rc = diag_read_file(urd->dev_id.devno, buf);
 535                if (rc == -ENODATA) {
 536                        break;
 537                }
 538                if (rc)
 539                        goto fail;
 540                if (reclen && (copied == 0) && (*offs < PAGE_SIZE))
 541                        *((u16 *) &buf[FILE_RECLEN_OFFSET]) = reclen;
 542                len = min(count - copied, PAGE_SIZE - res);
 543                if (copy_to_user(ubuf + copied, buf + res, len)) {
 544                        rc = -EFAULT;
 545                        goto fail;
 546                }
 547                res = 0;
 548                copied += len;
 549        } while (copied != count);
 550
 551        *offs += copied;
 552        rc = copied;
 553fail:
 554        free_page((unsigned long) buf);
 555        return rc;
 556}
 557
 558static ssize_t ur_read(struct file *file, char __user *ubuf, size_t count,
 559                       loff_t *offs)
 560{
 561        struct urdev *urd;
 562        int rc;
 563
 564        TRACE("ur_read: count=%zu ppos=%li\n", count, (unsigned long) *offs);
 565
 566        if (count == 0)
 567                return 0;
 568
 569        urd = ((struct urfile *) file->private_data)->urd;
 570        rc = mutex_lock_interruptible(&urd->io_mutex);
 571        if (rc)
 572                return rc;
 573        rc = diag14_read(file, ubuf, count, offs);
 574        mutex_unlock(&urd->io_mutex);
 575        return rc;
 576}
 577
 578/*
 579 * diagnose code 0x14 subcode 0x0fff - retrieve next file descriptor
 580 * cc=0  normal completion
 581 * cc=1  no files on reader queue or no subsequent file
 582 * cc=2  spid specified is invalid
 583 */
 584static int diag_read_next_file_info(struct file_control_block *buf, int spid)
 585{
 586        int cc;
 587
 588        cc = diag14((unsigned long) buf, spid, 0xfff);
 589        switch (cc) {
 590        case 0:
 591                return 0;
 592        default:
 593                return -ENODATA;
 594        }
 595}
 596
 597static int verify_uri_device(struct urdev *urd)
 598{
 599        struct file_control_block *fcb;
 600        char *buf;
 601        int rc;
 602
 603        fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
 604        if (!fcb)
 605                return -ENOMEM;
 606
 607        /* check for empty reader device (beginning of chain) */
 608        rc = diag_read_next_file_info(fcb, 0);
 609        if (rc)
 610                goto fail_free_fcb;
 611
 612        /* if file is in hold status, we do not read it */
 613        if (fcb->file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD)) {
 614                rc = -EPERM;
 615                goto fail_free_fcb;
 616        }
 617
 618        /* open file on virtual reader  */
 619        buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
 620        if (!buf) {
 621                rc = -ENOMEM;
 622                goto fail_free_fcb;
 623        }
 624        rc = diag_read_file(urd->dev_id.devno, buf);
 625        if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
 626                goto fail_free_buf;
 627
 628        /* check if the file on top of the queue is open now */
 629        rc = diag_read_next_file_info(fcb, 0);
 630        if (rc)
 631                goto fail_free_buf;
 632        if (!(fcb->file_stat & FLG_IN_USE)) {
 633                rc = -EMFILE;
 634                goto fail_free_buf;
 635        }
 636        rc = 0;
 637
 638fail_free_buf:
 639        free_page((unsigned long) buf);
 640fail_free_fcb:
 641        kfree(fcb);
 642        return rc;
 643}
 644
 645static int verify_device(struct urdev *urd)
 646{
 647        switch (urd->class) {
 648        case DEV_CLASS_UR_O:
 649                return 0; /* no check needed here */
 650        case DEV_CLASS_UR_I:
 651                return verify_uri_device(urd);
 652        default:
 653                return -EOPNOTSUPP;
 654        }
 655}
 656
 657static int get_uri_file_reclen(struct urdev *urd)
 658{
 659        struct file_control_block *fcb;
 660        int rc;
 661
 662        fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
 663        if (!fcb)
 664                return -ENOMEM;
 665        rc = diag_read_next_file_info(fcb, 0);
 666        if (rc)
 667                goto fail_free;
 668        if (fcb->file_stat & FLG_CP_DUMP)
 669                rc = 0;
 670        else
 671                rc = fcb->rec_len;
 672
 673fail_free:
 674        kfree(fcb);
 675        return rc;
 676}
 677
 678static int get_file_reclen(struct urdev *urd)
 679{
 680        switch (urd->class) {
 681        case DEV_CLASS_UR_O:
 682                return 0;
 683        case DEV_CLASS_UR_I:
 684                return get_uri_file_reclen(urd);
 685        default:
 686                return -EOPNOTSUPP;
 687        }
 688}
 689
 690static int ur_open(struct inode *inode, struct file *file)
 691{
 692        u16 devno;
 693        struct urdev *urd;
 694        struct urfile *urf;
 695        unsigned short accmode;
 696        int rc;
 697
 698        accmode = file->f_flags & O_ACCMODE;
 699
 700        if (accmode == O_RDWR)
 701                return -EACCES;
 702        /*
 703         * We treat the minor number as the devno of the ur device
 704         * to find in the driver tree.
 705         */
 706        devno = MINOR(file->f_dentry->d_inode->i_rdev);
 707
 708        urd = urdev_get_from_devno(devno);
 709        if (!urd) {
 710                rc = -ENXIO;
 711                goto out;
 712        }
 713
 714        spin_lock(&urd->open_lock);
 715        while (urd->open_flag) {
 716                spin_unlock(&urd->open_lock);
 717                if (file->f_flags & O_NONBLOCK) {
 718                        rc = -EBUSY;
 719                        goto fail_put;
 720                }
 721                if (wait_event_interruptible(urd->wait, urd->open_flag == 0)) {
 722                        rc = -ERESTARTSYS;
 723                        goto fail_put;
 724                }
 725                spin_lock(&urd->open_lock);
 726        }
 727        urd->open_flag++;
 728        spin_unlock(&urd->open_lock);
 729
 730        TRACE("ur_open\n");
 731
 732        if (((accmode == O_RDONLY) && (urd->class != DEV_CLASS_UR_I)) ||
 733            ((accmode == O_WRONLY) && (urd->class != DEV_CLASS_UR_O))) {
 734                TRACE("ur_open: unsupported dev class (%d)\n", urd->class);
 735                rc = -EACCES;
 736                goto fail_unlock;
 737        }
 738
 739        rc = verify_device(urd);
 740        if (rc)
 741                goto fail_unlock;
 742
 743        urf = urfile_alloc(urd);
 744        if (!urf) {
 745                rc = -ENOMEM;
 746                goto fail_unlock;
 747        }
 748
 749        urf->dev_reclen = urd->reclen;
 750        rc = get_file_reclen(urd);
 751        if (rc < 0)
 752                goto fail_urfile_free;
 753        urf->file_reclen = rc;
 754        file->private_data = urf;
 755        return 0;
 756
 757fail_urfile_free:
 758        urfile_free(urf);
 759fail_unlock:
 760        spin_lock(&urd->open_lock);
 761        urd->open_flag--;
 762        spin_unlock(&urd->open_lock);
 763fail_put:
 764        urdev_put(urd);
 765out:
 766        return rc;
 767}
 768
 769static int ur_release(struct inode *inode, struct file *file)
 770{
 771        struct urfile *urf = file->private_data;
 772
 773        TRACE("ur_release\n");
 774        spin_lock(&urf->urd->open_lock);
 775        urf->urd->open_flag--;
 776        spin_unlock(&urf->urd->open_lock);
 777        wake_up_interruptible(&urf->urd->wait);
 778        urdev_put(urf->urd);
 779        urfile_free(urf);
 780        return 0;
 781}
 782
 783static loff_t ur_llseek(struct file *file, loff_t offset, int whence)
 784{
 785        loff_t newpos;
 786
 787        if ((file->f_flags & O_ACCMODE) != O_RDONLY)
 788                return -ESPIPE; /* seek allowed only for reader */
 789        if (offset % PAGE_SIZE)
 790                return -ESPIPE; /* only multiples of 4K allowed */
 791        switch (whence) {
 792        case 0: /* SEEK_SET */
 793                newpos = offset;
 794                break;
 795        case 1: /* SEEK_CUR */
 796                newpos = file->f_pos + offset;
 797                break;
 798        default:
 799                return -EINVAL;
 800        }
 801        file->f_pos = newpos;
 802        return newpos;
 803}
 804
 805static const struct file_operations ur_fops = {
 806        .owner   = THIS_MODULE,
 807        .open    = ur_open,
 808        .release = ur_release,
 809        .read    = ur_read,
 810        .write   = ur_write,
 811        .llseek  = ur_llseek,
 812};
 813
 814/*
 815 * ccw_device infrastructure:
 816 *     ur_probe creates the struct urdev (with refcount = 1), the device
 817 *     attributes, sets up the interrupt handler and validates the virtual
 818 *     unit record device.
 819 *     ur_remove removes the device attributes and drops the reference to
 820 *     struct urdev.
 821 *
 822 *     ur_probe, ur_remove, ur_set_online and ur_set_offline are serialized
 823 *     by the vmur_mutex lock.
 824 *
 825 *     urd->char_device is used as indication that the online function has
 826 *     been completed successfully.
 827 */
 828static int ur_probe(struct ccw_device *cdev)
 829{
 830        struct urdev *urd;
 831        int rc;
 832
 833        TRACE("ur_probe: cdev=%p\n", cdev);
 834
 835        mutex_lock(&vmur_mutex);
 836        urd = urdev_alloc(cdev);
 837        if (!urd) {
 838                rc = -ENOMEM;
 839                goto fail_unlock;
 840        }
 841
 842        rc = ur_create_attributes(&cdev->dev);
 843        if (rc) {
 844                rc = -ENOMEM;
 845                goto fail_urdev_put;
 846        }
 847        cdev->handler = ur_int_handler;
 848
 849        /* validate virtual unit record device */
 850        urd->class = get_urd_class(urd);
 851        if (urd->class < 0) {
 852                rc = urd->class;
 853                goto fail_remove_attr;
 854        }
 855        if ((urd->class != DEV_CLASS_UR_I) && (urd->class != DEV_CLASS_UR_O)) {
 856                rc = -EOPNOTSUPP;
 857                goto fail_remove_attr;
 858        }
 859        spin_lock_irq(get_ccwdev_lock(cdev));
 860        dev_set_drvdata(&cdev->dev, urd);
 861        spin_unlock_irq(get_ccwdev_lock(cdev));
 862
 863        mutex_unlock(&vmur_mutex);
 864        return 0;
 865
 866fail_remove_attr:
 867        ur_remove_attributes(&cdev->dev);
 868fail_urdev_put:
 869        urdev_put(urd);
 870fail_unlock:
 871        mutex_unlock(&vmur_mutex);
 872        return rc;
 873}
 874
 875static int ur_set_online(struct ccw_device *cdev)
 876{
 877        struct urdev *urd;
 878        int minor, major, rc;
 879        char node_id[16];
 880
 881        TRACE("ur_set_online: cdev=%p\n", cdev);
 882
 883        mutex_lock(&vmur_mutex);
 884        urd = urdev_get_from_cdev(cdev);
 885        if (!urd) {
 886                /* ur_remove already deleted our urd */
 887                rc = -ENODEV;
 888                goto fail_unlock;
 889        }
 890
 891        if (urd->char_device) {
 892                /* Another ur_set_online was faster */
 893                rc = -EBUSY;
 894                goto fail_urdev_put;
 895        }
 896
 897        minor = urd->dev_id.devno;
 898        major = MAJOR(ur_first_dev_maj_min);
 899
 900        urd->char_device = cdev_alloc();
 901        if (!urd->char_device) {
 902                rc = -ENOMEM;
 903                goto fail_urdev_put;
 904        }
 905
 906        cdev_init(urd->char_device, &ur_fops);
 907        urd->char_device->dev = MKDEV(major, minor);
 908        urd->char_device->owner = ur_fops.owner;
 909
 910        rc = cdev_add(urd->char_device, urd->char_device->dev, 1);
 911        if (rc)
 912                goto fail_free_cdev;
 913        if (urd->cdev->id.cu_type == READER_PUNCH_DEVTYPE) {
 914                if (urd->class == DEV_CLASS_UR_I)
 915                        sprintf(node_id, "vmrdr-%s", dev_name(&cdev->dev));
 916                if (urd->class == DEV_CLASS_UR_O)
 917                        sprintf(node_id, "vmpun-%s", dev_name(&cdev->dev));
 918        } else if (urd->cdev->id.cu_type == PRINTER_DEVTYPE) {
 919                sprintf(node_id, "vmprt-%s", dev_name(&cdev->dev));
 920        } else {
 921                rc = -EOPNOTSUPP;
 922                goto fail_free_cdev;
 923        }
 924
 925        urd->device = device_create(vmur_class, NULL, urd->char_device->dev,
 926                                    NULL, "%s", node_id);
 927        if (IS_ERR(urd->device)) {
 928                rc = PTR_ERR(urd->device);
 929                TRACE("ur_set_online: device_create rc=%d\n", rc);
 930                goto fail_free_cdev;
 931        }
 932        urdev_put(urd);
 933        mutex_unlock(&vmur_mutex);
 934        return 0;
 935
 936fail_free_cdev:
 937        cdev_del(urd->char_device);
 938        urd->char_device = NULL;
 939fail_urdev_put:
 940        urdev_put(urd);
 941fail_unlock:
 942        mutex_unlock(&vmur_mutex);
 943        return rc;
 944}
 945
 946static int ur_set_offline_force(struct ccw_device *cdev, int force)
 947{
 948        struct urdev *urd;
 949        int rc;
 950
 951        TRACE("ur_set_offline: cdev=%p\n", cdev);
 952        urd = urdev_get_from_cdev(cdev);
 953        if (!urd)
 954                /* ur_remove already deleted our urd */
 955                return -ENODEV;
 956        if (!urd->char_device) {
 957                /* Another ur_set_offline was faster */
 958                rc = -EBUSY;
 959                goto fail_urdev_put;
 960        }
 961        if (!force && (atomic_read(&urd->ref_count) > 2)) {
 962                /* There is still a user of urd (e.g. ur_open) */
 963                TRACE("ur_set_offline: BUSY\n");
 964                rc = -EBUSY;
 965                goto fail_urdev_put;
 966        }
 967        device_destroy(vmur_class, urd->char_device->dev);
 968        cdev_del(urd->char_device);
 969        urd->char_device = NULL;
 970        rc = 0;
 971
 972fail_urdev_put:
 973        urdev_put(urd);
 974        return rc;
 975}
 976
 977static int ur_set_offline(struct ccw_device *cdev)
 978{
 979        int rc;
 980
 981        mutex_lock(&vmur_mutex);
 982        rc = ur_set_offline_force(cdev, 0);
 983        mutex_unlock(&vmur_mutex);
 984        return rc;
 985}
 986
 987static void ur_remove(struct ccw_device *cdev)
 988{
 989        unsigned long flags;
 990
 991        TRACE("ur_remove\n");
 992
 993        mutex_lock(&vmur_mutex);
 994
 995        if (cdev->online)
 996                ur_set_offline_force(cdev, 1);
 997        ur_remove_attributes(&cdev->dev);
 998
 999        spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
1000        urdev_put(dev_get_drvdata(&cdev->dev));
1001        dev_set_drvdata(&cdev->dev, NULL);
1002        spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
1003
1004        mutex_unlock(&vmur_mutex);
1005}
1006
1007/*
1008 * Module initialisation and cleanup
1009 */
1010static int __init ur_init(void)
1011{
1012        int rc;
1013        dev_t dev;
1014
1015        if (!MACHINE_IS_VM) {
1016                pr_err("The %s cannot be loaded without z/VM\n",
1017                       ur_banner);
1018                return -ENODEV;
1019        }
1020
1021        vmur_dbf = debug_register("vmur", 4, 1, 4 * sizeof(long));
1022        if (!vmur_dbf)
1023                return -ENOMEM;
1024        rc = debug_register_view(vmur_dbf, &debug_sprintf_view);
1025        if (rc)
1026                goto fail_free_dbf;
1027
1028        debug_set_level(vmur_dbf, 6);
1029
1030        vmur_class = class_create(THIS_MODULE, "vmur");
1031        if (IS_ERR(vmur_class)) {
1032                rc = PTR_ERR(vmur_class);
1033                goto fail_free_dbf;
1034        }
1035
1036        rc = ccw_driver_register(&ur_driver);
1037        if (rc)
1038                goto fail_class_destroy;
1039
1040        rc = alloc_chrdev_region(&dev, 0, NUM_MINORS, "vmur");
1041        if (rc) {
1042                pr_err("Kernel function alloc_chrdev_region failed with "
1043                       "error code %d\n", rc);
1044                goto fail_unregister_driver;
1045        }
1046        ur_first_dev_maj_min = MKDEV(MAJOR(dev), 0);
1047
1048        pr_info("%s loaded.\n", ur_banner);
1049        return 0;
1050
1051fail_unregister_driver:
1052        ccw_driver_unregister(&ur_driver);
1053fail_class_destroy:
1054        class_destroy(vmur_class);
1055fail_free_dbf:
1056        debug_unregister(vmur_dbf);
1057        return rc;
1058}
1059
1060static void __exit ur_exit(void)
1061{
1062        unregister_chrdev_region(ur_first_dev_maj_min, NUM_MINORS);
1063        ccw_driver_unregister(&ur_driver);
1064        class_destroy(vmur_class);
1065        debug_unregister(vmur_dbf);
1066        pr_info("%s unloaded.\n", ur_banner);
1067}
1068
1069module_init(ur_init);
1070module_exit(ur_exit);
1071