drivers/s390/char/tape_char.c

   1 /*
   2  *  drivers/s390/char/tape_char.c
   3  *    character device frontend for tape device driver
   4  *
   5  *  S390 and zSeries version
   6  *    Copyright IBM Corp. 2001,2006
   7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
   8  *               Michael Holzheu <holzheu@de.ibm.com>
   9  *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
  10  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
  11  */
  12
  13 #define KMSG_COMPONENT "tape"
  14 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  15
  16 #include <linux/module.h>
  17 #include <linux/types.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/mtio.h>
  20 #include <linux/compat.h>
  21
  22 #include <asm/uaccess.h>
  23
  24 #define TAPE_DBF_AREA   tape_core_dbf
  25
  26 #include "tape.h"
  27 #include "tape_std.h"
  28 #include "tape_class.h"
  29
  30 #define TAPECHAR_MAJOR          0       /* get dynamic major */
  31
  32 /*
  33  * file operation structure for tape character frontend
  34  */
  35 static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
  36 static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
  37 static int tapechar_open(struct inode *,struct file *);
  38 static int tapechar_release(struct inode *,struct file *);
  39 static long tapechar_ioctl(struct file *, unsigned int, unsigned long);
  40 #ifdef CONFIG_COMPAT
  41 static long tapechar_compat_ioctl(struct file *, unsigned int, unsigned long);
  42 #endif
  43
  44 static const struct file_operations tape_fops =
  45 {
  46         .owner = THIS_MODULE,
  47         .read = tapechar_read,
  48         .write = tapechar_write,
  49         .unlocked_ioctl = tapechar_ioctl,
  50 #ifdef CONFIG_COMPAT
  51         .compat_ioctl = tapechar_compat_ioctl,
  52 #endif
  53         .open = tapechar_open,
  54         .release = tapechar_release,
  55         .llseek = no_llseek,
  56 };
  57
  58 static int tapechar_major = TAPECHAR_MAJOR;
  59
  60 /*
  61  * This function is called for every new tapedevice
  62  */
  63 int
  64 tapechar_setup_device(struct tape_device * device)
  65 {
  66         char    device_name[20];
  67
  68         sprintf(device_name, "ntibm%i", device->first_minor / 2);
  69         device->nt = register_tape_dev(
  70                 &device->cdev->dev,
  71                 MKDEV(tapechar_major, device->first_minor),
  72                 &tape_fops,
  73                 device_name,
  74                 "non-rewinding"
  75         );
  76         device_name[0] = 'r';
  77         device->rt = register_tape_dev(
  78                 &device->cdev->dev,
  79                 MKDEV(tapechar_major, device->first_minor + 1),
  80                 &tape_fops,
  81                 device_name,
  82                 "rewinding"
  83         );
  84
  85         return 0;
  86 }
  87
  88 void
  89 tapechar_cleanup_device(struct tape_device *device)
  90 {
  91         unregister_tape_dev(&device->cdev->dev, device->rt);
  92         device->rt = NULL;
  93         unregister_tape_dev(&device->cdev->dev, device->nt);
  94         device->nt = NULL;
  95 }
  96
  97 static int
  98 tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
  99 {
 100         struct idal_buffer *new;
 101
 102         if (device->char_data.idal_buf != NULL &&
 103             device->char_data.idal_buf->size == block_size)
 104                 return 0;
 105
 106         if (block_size > MAX_BLOCKSIZE) {
 107                 DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
 108                         block_size, MAX_BLOCKSIZE);
 109                 return -EINVAL;
 110         }
 111
 112         /* The current idal buffer is not correct. Allocate a new one. */
 113         new = idal_buffer_alloc(block_size, 0);
 114         if (IS_ERR(new))
 115                 return -ENOMEM;
 116
 117         if (device->char_data.idal_buf != NULL)
 118                 idal_buffer_free(device->char_data.idal_buf);
 119
 120         device->char_data.idal_buf = new;
 121
 122         return 0;
 123 }
 124
 125 /*
 126  * Tape device read function
 127  */
 128 static ssize_t
 129 tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
 130 {
 131         struct tape_device *device;
 132         struct tape_request *request;
 133         size_t block_size;
 134         int rc;
 135
 136         DBF_EVENT(6, "TCHAR:read\n");
 137         device = (struct tape_device *) filp->private_data;
 138
 139         /*
 140          * If the tape isn't terminated yet, do it now. And since we then
 141          * are at the end of the tape there wouldn't be anything to read
 142          * anyways. So we return immediatly.
 143          */
 144         if(device->required_tapemarks) {
 145                 return tape_std_terminate_write(device);
 146         }
 147
 148         /* Find out block size to use */
 149         if (device->char_data.block_size != 0) {
 150                 if (count < device->char_data.block_size) {
 151                         DBF_EVENT(3, "TCHAR:read smaller than block "
 152                                   "size was requested\n");
 153                         return -EINVAL;
 154                 }
 155                 block_size = device->char_data.block_size;
 156         } else {
 157                 block_size = count;
 158         }
 159
 160         rc = tapechar_check_idalbuffer(device, block_size);
 161         if (rc)
 162                 return rc;
 163
 164 #ifdef CONFIG_S390_TAPE_BLOCK
 165         /* Changes position. */
 166         device->blk_data.medium_changed = 1;
 167 #endif
 168
 169         DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
 170         /* Let the discipline build the ccw chain. */
 171         request = device->discipline->read_block(device, block_size);
 172         if (IS_ERR(request))
 173                 return PTR_ERR(request);
 174         /* Execute it. */
 175         rc = tape_do_io(device, request);
 176         if (rc == 0) {
 177                 rc = block_size - request->rescnt;
 178                 DBF_EVENT(6, "TCHAR:rbytes:  %x\n", rc);
 179                 /* Copy data from idal buffer to user space. */
 180                 if (idal_buffer_to_user(device->char_data.idal_buf,
 181                                         data, rc) != 0)
 182                         rc = -EFAULT;
 183         }
 184         tape_free_request(request);
 185         return rc;
 186 }
 187
 188 /*
 189  * Tape device write function
 190  */
 191 static ssize_t
 192 tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
 193 {
 194         struct tape_device *device;
 195         struct tape_request *request;
 196         size_t block_size;
 197         size_t written;
 198         int nblocks;
 199         int i, rc;
 200
 201         DBF_EVENT(6, "TCHAR:write\n");
 202         device = (struct tape_device *) filp->private_data;
 203         /* Find out block size and number of blocks */
 204         if (device->char_data.block_size != 0) {
 205                 if (count < device->char_data.block_size) {
 206                         DBF_EVENT(3, "TCHAR:write smaller than block "
 207                                   "size was requested\n");
 208                         return -EINVAL;
 209                 }
 210                 block_size = device->char_data.block_size;
 211                 nblocks = count / block_size;
 212         } else {
 213                 block_size = count;
 214                 nblocks = 1;
 215         }
 216
 217         rc = tapechar_check_idalbuffer(device, block_size);
 218         if (rc)
 219                 return rc;
 220
 221 #ifdef CONFIG_S390_TAPE_BLOCK
 222         /* Changes position. */
 223         device->blk_data.medium_changed = 1;
 224 #endif
 225
 226         DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
 227         DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
 228         /* Let the discipline build the ccw chain. */
 229         request = device->discipline->write_block(device, block_size);
 230         if (IS_ERR(request))
 231                 return PTR_ERR(request);
 232         rc = 0;
 233         written = 0;
 234         for (i = 0; i < nblocks; i++) {
 235                 /* Copy data from user space to idal buffer. */
 236                 if (idal_buffer_from_user(device->char_data.idal_buf,
 237                                           data, block_size)) {
 238                         rc = -EFAULT;
 239                         break;
 240                 }
 241                 rc = tape_do_io(device, request);
 242                 if (rc)
 243                         break;
 244                 DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
 245                           block_size - request->rescnt);
 246                 written += block_size - request->rescnt;
 247                 if (request->rescnt != 0)
 248                         break;
 249                 data += block_size;
 250         }
 251         tape_free_request(request);
 252         if (rc == -ENOSPC) {
 253                 /*
 254                  * Ok, the device has no more space. It has NOT written
 255                  * the block.
 256                  */
 257                 if (device->discipline->process_eov)
 258                         device->discipline->process_eov(device);
 259                 if (written > 0)
 260                         rc = 0;
 261
 262         }
 263
 264         /*
 265          * After doing a write we always need two tapemarks to correctly
 266          * terminate the tape (one to terminate the file, the second to
 267          * flag the end of recorded data.
 268          * Since process_eov positions the tape in front of the written
 269          * tapemark it doesn't hurt to write two marks again.
 270          */
 271         if (!rc)
 272                 device->required_tapemarks = 2;
 273
 274         return rc ? rc : written;
 275 }
 276
 277 /*
 278  * Character frontend tape device open function.
 279  */
 280 static int
 281 tapechar_open (struct inode *inode, struct file *filp)
 282 {
 283         struct tape_device *device;
 284         int minor, rc;
 285
 286         DBF_EVENT(6, "TCHAR:open: %i:%i\n",
 287                 imajor(filp->f_path.dentry->d_inode),
 288                 iminor(filp->f_path.dentry->d_inode));
 289
 290         if (imajor(filp->f_path.dentry->d_inode) != tapechar_major)
 291                 return -ENODEV;
 292
 293         minor = iminor(filp->f_path.dentry->d_inode);
 294         device = tape_find_device(minor / TAPE_MINORS_PER_DEV);
 295         if (IS_ERR(device)) {
 296                 DBF_EVENT(3, "TCHAR:open: tape_find_device() failed\n");
 297                 return PTR_ERR(device);
 298         }
 299
 300         rc = tape_open(device);
 301         if (rc == 0) {
 302                 filp->private_data = device;
 303                 nonseekable_open(inode, filp);
 304         } else
 305                 tape_put_device(device);
 306
 307         return rc;
 308 }
 309
 310 /*
 311  * Character frontend tape device release function.
 312  */
 313
 314 static int
 315 tapechar_release(struct inode *inode, struct file *filp)
 316 {
 317         struct tape_device *device;
 318
 319         DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
 320         device = (struct tape_device *) filp->private_data;
 321
 322         /*
 323          * If this is the rewinding tape minor then rewind. In that case we
 324          * write all required tapemarks. Otherwise only one to terminate the
 325          * file.
 326          */
 327         if ((iminor(inode) & 1) != 0) {
 328                 if (device->required_tapemarks)
 329                         tape_std_terminate_write(device);
 330                 tape_mtop(device, MTREW, 1);
 331         } else {
 332                 if (device->required_tapemarks > 1) {
 333                         if (tape_mtop(device, MTWEOF, 1) == 0)
 334                                 device->required_tapemarks--;
 335                 }
 336         }
 337
 338         if (device->char_data.idal_buf != NULL) {
 339                 idal_buffer_free(device->char_data.idal_buf);
 340                 device->char_data.idal_buf = NULL;
 341         }
 342         tape_release(device);
 343         filp->private_data = NULL;
 344         tape_put_device(device);
 345
 346         return 0;
 347 }
 348
 349 /*
 350  * Tape device io controls.
 351  */
 352 static int
 353 __tapechar_ioctl(struct tape_device *device,
 354                  unsigned int no, unsigned long data)
 355 {
 356         int rc;
 357
 358         if (no == MTIOCTOP) {
 359                 struct mtop op;
 360
 361                 if (copy_from_user(&op, (char __user *) data, sizeof(op)) != 0)
 362                         return -EFAULT;
 363                 if (op.mt_count < 0)
 364                         return -EINVAL;
 365
 366                 /*
 367                  * Operations that change tape position should write final
 368                  * tapemarks.
 369                  */
 370                 switch (op.mt_op) {
 371                         case MTFSF:
 372                         case MTBSF:
 373                         case MTFSR:
 374                         case MTBSR:
 375                         case MTREW:
 376                         case MTOFFL:
 377                         case MTEOM:
 378                         case MTRETEN:
 379                         case MTBSFM:
 380                         case MTFSFM:
 381                         case MTSEEK:
 382 #ifdef CONFIG_S390_TAPE_BLOCK
 383                                 device->blk_data.medium_changed = 1;
 384 #endif
 385                                 if (device->required_tapemarks)
 386                                         tape_std_terminate_write(device);
 387                         default:
 388                                 ;
 389                 }
 390                 rc = tape_mtop(device, op.mt_op, op.mt_count);
 391
 392                 if (op.mt_op == MTWEOF && rc == 0) {
 393                         if (op.mt_count > device->required_tapemarks)
 394                                 device->required_tapemarks = 0;
 395                         else
 396                                 device->required_tapemarks -= op.mt_count;
 397                 }
 398                 return rc;
 399         }
 400         if (no == MTIOCPOS) {
 401                 /* MTIOCPOS: query the tape position. */
 402                 struct mtpos pos;
 403
 404                 rc = tape_mtop(device, MTTELL, 1);
 405                 if (rc < 0)
 406                         return rc;
 407                 pos.mt_blkno = rc;
 408                 if (copy_to_user((char __user *) data, &pos, sizeof(pos)) != 0)
 409                         return -EFAULT;
 410                 return 0;
 411         }
 412         if (no == MTIOCGET) {
 413                 /* MTIOCGET: query the tape drive status. */
 414                 struct mtget get;
 415
 416                 memset(&get, 0, sizeof(get));
 417                 get.mt_type = MT_ISUNKNOWN;
 418                 get.mt_resid = 0 /* device->devstat.rescnt */;
 419                 get.mt_dsreg = device->tape_state;
 420                 /* FIXME: mt_gstat, mt_erreg, mt_fileno */
 421                 get.mt_gstat = 0;
 422                 get.mt_erreg = 0;
 423                 get.mt_fileno = 0;
 424                 get.mt_gstat  = device->tape_generic_status;
 425
 426                 if (device->medium_state == MS_LOADED) {
 427                         rc = tape_mtop(device, MTTELL, 1);
 428
 429                         if (rc < 0)
 430                                 return rc;
 431
 432                         if (rc == 0)
 433                                 get.mt_gstat |= GMT_BOT(~0);
 434
 435                         get.mt_blkno = rc;
 436                 }
 437
 438                 if (copy_to_user((char __user *) data, &get, sizeof(get)) != 0)
 439                         return -EFAULT;
 440
 441                 return 0;
 442         }
 443         /* Try the discipline ioctl function. */
 444         if (device->discipline->ioctl_fn == NULL)
 445                 return -EINVAL;
 446         return device->discipline->ioctl_fn(device, no, data);
 447 }
 448
 449 static long
 450 tapechar_ioctl(struct file *filp, unsigned int no, unsigned long data)
 451 {
 452         struct tape_device *device;
 453         long rc;
 454
 455         DBF_EVENT(6, "TCHAR:ioct\n");
 456
 457         device = (struct tape_device *) filp->private_data;
 458         mutex_lock(&device->mutex);
 459         rc = __tapechar_ioctl(device, no, data);
 460         mutex_unlock(&device->mutex);
 461         return rc;
 462 }
 463
 464 #ifdef CONFIG_COMPAT
 465 static long
 466 tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
 467 {
 468         struct tape_device *device = filp->private_data;
 469         int rval = -ENOIOCTLCMD;
 470         unsigned long argp;
 471
 472         /* The 'arg' argument of any ioctl function may only be used for
 473          * pointers because of the compat pointer conversion.
 474          * Consider this when adding new ioctls.
 475          */
 476         argp = (unsigned long) compat_ptr(data);
 477         if (device->discipline->ioctl_fn) {
 478                 mutex_lock(&device->mutex);
 479                 rval = device->discipline->ioctl_fn(device, no, argp);
 480                 mutex_unlock(&device->mutex);
 481                 if (rval == -EINVAL)
 482                         rval = -ENOIOCTLCMD;
 483         }
 484
 485         return rval;
 486 }
 487 #endif /* CONFIG_COMPAT */
 488
 489 /*
 490  * Initialize character device frontend.
 491  */
 492 int
 493 tapechar_init (void)
 494 {
 495         dev_t   dev;
 496
 497         if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
 498                 return -1;
 499
 500         tapechar_major = MAJOR(dev);
 501
 502         return 0;
 503 }
 504
 505 /*
 506  * cleanup
 507  */
 508 void
 509 tapechar_exit(void)
 510 {
 511         unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
 512 }