git.oblomov.eu Git - linux-2.6/blob - drivers/char/hvc_iucv.c

   1 /*
   2  * hvc_iucv.c - z/VM IUCV hypervisor console (HVC) device driver
   3  *
   4  * This HVC device driver provides terminal access using
   5  * z/VM IUCV communication paths.
   6  *
   7  * Copyright IBM Corp. 2008, 2009
   8  *
   9  * Author(s):   Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  10  */
  11 #define KMSG_COMPONENT          "hvc_iucv"
  12 #define pr_fmt(fmt)             KMSG_COMPONENT ": " fmt
  13
  14 #include <linux/types.h>
  15 #include <asm/ebcdic.h>
  16 #include <linux/ctype.h>
  17 #include <linux/delay.h>
  18 #include <linux/device.h>
  19 #include <linux/init.h>
  20 #include <linux/mempool.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/tty.h>
  23 #include <linux/wait.h>
  24 #include <net/iucv/iucv.h>
  25
  26 #include "hvc_console.h"
  27
  28
  29 /* General device driver settings */
  30 #define HVC_IUCV_MAGIC          0xc9e4c3e5
  31 #define MAX_HVC_IUCV_LINES      HVC_ALLOC_TTY_ADAPTERS
  32 #define MEMPOOL_MIN_NR          (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
  33
  34 /* IUCV TTY message  */
  35 #define MSG_VERSION             0x02    /* Message version */
  36 #define MSG_TYPE_ERROR          0x01    /* Error message */
  37 #define MSG_TYPE_TERMENV        0x02    /* Terminal environment variable */
  38 #define MSG_TYPE_TERMIOS        0x04    /* Terminal IO struct update */
  39 #define MSG_TYPE_WINSIZE        0x08    /* Terminal window size update */
  40 #define MSG_TYPE_DATA           0x10    /* Terminal data */
  41
  42 struct iucv_tty_msg {
  43         u8      version;                /* Message version */
  44         u8      type;                   /* Message type */
  45 #define MSG_MAX_DATALEN         ((u16)(~0))
  46         u16     datalen;                /* Payload length */
  47         u8      data[];                 /* Payload buffer */
  48 } __attribute__((packed));
  49 #define MSG_SIZE(s)             ((s) + offsetof(struct iucv_tty_msg, data))
  50
  51 enum iucv_state_t {
  52         IUCV_DISCONN    = 0,
  53         IUCV_CONNECTED  = 1,
  54         IUCV_SEVERED    = 2,
  55 };
  56
  57 enum tty_state_t {
  58         TTY_CLOSED      = 0,
  59         TTY_OPENED      = 1,
  60 };
  61
  62 struct hvc_iucv_private {
  63         struct hvc_struct       *hvc;           /* HVC struct reference */
  64         u8                      srv_name[8];    /* IUCV service name (ebcdic) */
  65         unsigned char           is_console;     /* Linux console usage flag */
  66         enum iucv_state_t       iucv_state;     /* IUCV connection status */
  67         enum tty_state_t        tty_state;      /* TTY status */
  68         struct iucv_path        *path;          /* IUCV path pointer */
  69         spinlock_t              lock;           /* hvc_iucv_private lock */
  70 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
  71         void                    *sndbuf;        /* send buffer            */
  72         size_t                  sndbuf_len;     /* length of send buffer  */
  73 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
  74         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
  75         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
  76         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
  77         struct list_head        tty_inqueue;    /* incoming IUCV messages */
  78         struct device           *dev;           /* device structure */
  79 };
  80
  81 struct iucv_tty_buffer {
  82         struct list_head        list;   /* list pointer */
  83         struct iucv_message     msg;    /* store an IUCV message */
  84         size_t                  offset; /* data buffer offset */
  85         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  86 };
  87
  88 /* IUCV callback handler */
  89 static  int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
  90 static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
  91 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  92 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  93
  94
  95 /* Kernel module parameter: use one terminal device as default */
  96 static unsigned long hvc_iucv_devices = 1;
  97
  98 /* Array of allocated hvc iucv tty lines... */
  99 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
 100 #define IUCV_HVC_CON_IDX        (0)
 101 /* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
 102 #define MAX_VMID_FILTER         (500)
 103 static size_t hvc_iucv_filter_size;
 104 static void *hvc_iucv_filter;
 105 static const char *hvc_iucv_filter_string;
 106 static DEFINE_RWLOCK(hvc_iucv_filter_lock);
 107
 108 /* Kmem cache and mempool for iucv_tty_buffer elements */
 109 static struct kmem_cache *hvc_iucv_buffer_cache;
 110 static mempool_t *hvc_iucv_mempool;
 111
 112 /* IUCV handler callback functions */
 113 static struct iucv_handler hvc_iucv_handler = {
 114         .path_pending  = hvc_iucv_path_pending,
 115         .path_severed  = hvc_iucv_path_severed,
 116         .message_complete = hvc_iucv_msg_complete,
 117         .message_pending  = hvc_iucv_msg_pending,
 118 };
 119
 120
 121 /**
 122  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 123  * @num:        The HVC virtual terminal number (vtermno)
 124  *
 125  * This function returns the struct hvc_iucv_private instance that corresponds
 126  * to the HVC virtual terminal number specified as parameter @num.
 127  */
 128 struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 129 {
 130         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
 131                 return NULL;
 132         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
 133 }
 134
 135 /**
 136  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
 137  * @size:       Size of the internal buffer used to store data.
 138  * @flags:      Memory allocation flags passed to mempool.
 139  *
 140  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 141  * allocates an internal data buffer with the specified size @size.
 142  * Note: The total message size arises from the internal buffer size and the
 143  *       members of the iucv_tty_msg structure.
 144  * The function returns NULL if memory allocation has failed.
 145  */
 146 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 147 {
 148         struct iucv_tty_buffer *bufp;
 149
 150         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 151         if (!bufp)
 152                 return NULL;
 153         memset(bufp, 0, sizeof(*bufp));
 154
 155         if (size > 0) {
 156                 bufp->msg.length = MSG_SIZE(size);
 157                 bufp->mbuf = kmalloc(bufp->msg.length, flags);
 158                 if (!bufp->mbuf) {
 159                         mempool_free(bufp, hvc_iucv_mempool);
 160                         return NULL;
 161                 }
 162                 bufp->mbuf->version = MSG_VERSION;
 163                 bufp->mbuf->type    = MSG_TYPE_DATA;
 164                 bufp->mbuf->datalen = (u16) size;
 165         }
 166         return bufp;
 167 }
 168
 169 /**
 170  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 171  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 172  */
 173 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 174 {
 175         kfree(bufp->mbuf);
 176         mempool_free(bufp, hvc_iucv_mempool);
 177 }
 178
 179 /**
 180  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 181  * @list:       List containing struct iucv_tty_buffer elements.
 182  */
 183 static void destroy_tty_buffer_list(struct list_head *list)
 184 {
 185         struct iucv_tty_buffer *ent, *next;
 186
 187         list_for_each_entry_safe(ent, next, list, list) {
 188                 list_del(&ent->list);
 189                 destroy_tty_buffer(ent);
 190         }
 191 }
 192
 193 /**
 194  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
 195  * @priv:               Pointer to struct hvc_iucv_private
 196  * @buf:                HVC buffer for writing received terminal data.
 197  * @count:              HVC buffer size.
 198  * @has_more_data:      Pointer to an int variable.
 199  *
 200  * The function picks up pending messages from the input queue and receives
 201  * the message data that is then written to the specified buffer @buf.
 202  * If the buffer size @count is less than the data message size, the
 203  * message is kept on the input queue and @has_more_data is set to 1.
 204  * If all message data has been written, the message is removed from
 205  * the input queue.
 206  *
 207  * The function returns the number of bytes written to the terminal, zero if
 208  * there are no pending data messages available or if there is no established
 209  * IUCV path.
 210  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 211  * hang up (that is issued by the HVC layer).
 212  */
 213 static int hvc_iucv_write(struct hvc_iucv_private *priv,
 214                           char *buf, int count, int *has_more_data)
 215 {
 216         struct iucv_tty_buffer *rb;
 217         int written;
 218         int rc;
 219
 220         /* immediately return if there is no IUCV connection */
 221         if (priv->iucv_state == IUCV_DISCONN)
 222                 return 0;
 223
 224         /* if the IUCV path has been severed, return -EPIPE to inform the
 225          * HVC layer to hang up the tty device. */
 226         if (priv->iucv_state == IUCV_SEVERED)
 227                 return -EPIPE;
 228
 229         /* check if there are pending messages */
 230         if (list_empty(&priv->tty_inqueue))
 231                 return 0;
 232
 233         /* receive an iucv message and flip data to the tty (ldisc) */
 234         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 235
 236         written = 0;
 237         if (!rb->mbuf) { /* message not yet received ... */
 238                 /* allocate mem to store msg data; if no memory is available
 239                  * then leave the buffer on the list and re-try later */
 240                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC);
 241                 if (!rb->mbuf)
 242                         return -ENOMEM;
 243
 244                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 245                                             rb->mbuf, rb->msg.length, NULL);
 246                 switch (rc) {
 247                 case 0: /* Successful       */
 248                         break;
 249                 case 2: /* No message found */
 250                 case 9: /* Message purged   */
 251                         break;
 252                 default:
 253                         written = -EIO;
 254                 }
 255                 /* remove buffer if an error has occured or received data
 256                  * is not correct */
 257                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 258                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 259                         goto out_remove_buffer;
 260         }
 261
 262         switch (rb->mbuf->type) {
 263         case MSG_TYPE_DATA:
 264                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 265                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 266                 if (written < (rb->mbuf->datalen - rb->offset)) {
 267                         rb->offset += written;
 268                         *has_more_data = 1;
 269                         goto out_written;
 270                 }
 271                 break;
 272
 273         case MSG_TYPE_WINSIZE:
 274                 if (rb->mbuf->datalen != sizeof(struct winsize))
 275                         break;
 276                 hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
 277                 break;
 278
 279         case MSG_TYPE_ERROR:    /* ignored ... */
 280         case MSG_TYPE_TERMENV:  /* ignored ... */
 281         case MSG_TYPE_TERMIOS:  /* ignored ... */
 282                 break;
 283         }
 284
 285 out_remove_buffer:
 286         list_del(&rb->list);
 287         destroy_tty_buffer(rb);
 288         *has_more_data = !list_empty(&priv->tty_inqueue);
 289
 290 out_written:
 291         return written;
 292 }
 293
 294 /**
 295  * hvc_iucv_get_chars() - HVC get_chars operation.
 296  * @vtermno:    HVC virtual terminal number.
 297  * @buf:        Pointer to a buffer to store data
 298  * @count:      Size of buffer available for writing
 299  *
 300  * The HVC thread calls this method to read characters from the back-end.
 301  * If an IUCV communication path has been established, pending IUCV messages
 302  * are received and data is copied into buffer @buf up to @count bytes.
 303  *
 304  * Locking:     The routine gets called under an irqsave() spinlock; and
 305  *              the routine locks the struct hvc_iucv_private->lock to call
 306  *              helper functions.
 307  */
 308 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
 309 {
 310         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 311         int written;
 312         int has_more_data;
 313
 314         if (count <= 0)
 315                 return 0;
 316
 317         if (!priv)
 318                 return -ENODEV;
 319
 320         spin_lock(&priv->lock);
 321         has_more_data = 0;
 322         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 323         spin_unlock(&priv->lock);
 324
 325         /* if there are still messages on the queue... schedule another run */
 326         if (has_more_data)
 327                 hvc_kick();
 328
 329         return written;
 330 }
 331
 332 /**
 333  * hvc_iucv_queue() - Buffer terminal data for sending.
 334  * @priv:       Pointer to struct hvc_iucv_private instance.
 335  * @buf:        Buffer containing data to send.
 336  * @count:      Size of buffer and amount of data to send.
 337  *
 338  * The function queues data for sending. To actually send the buffered data,
 339  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
 340  * The function returns the number of data bytes that has been buffered.
 341  *
 342  * If the device is not connected, data is ignored and the function returns
 343  * @count.
 344  * If the buffer is full, the function returns 0.
 345  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
 346  * (that can be passed to HVC layer to cause a tty hangup).
 347  */
 348 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
 349                           int count)
 350 {
 351         size_t len;
 352
 353         if (priv->iucv_state == IUCV_DISCONN)
 354                 return count;                   /* ignore data */
 355
 356         if (priv->iucv_state == IUCV_SEVERED)
 357                 return -EPIPE;
 358
 359         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 360         if (!len)
 361                 return 0;
 362
 363         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 364         priv->sndbuf_len += len;
 365
 366         if (priv->iucv_state == IUCV_CONNECTED)
 367                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 368
 369         return len;
 370 }
 371
 372 /**
 373  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 374  * @priv:       Pointer to struct hvc_iucv_private instance.
 375  *
 376  * If an IUCV communication path has been established, the buffered output data
 377  * is sent via an IUCV message and the number of bytes sent is returned.
 378  * Returns 0 if there is no established IUCV communication path or
 379  * -EPIPE if an existing IUCV communicaton path has been severed.
 380  */
 381 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 382 {
 383         struct iucv_tty_buffer *sb;
 384         int rc, len;
 385
 386         if (priv->iucv_state == IUCV_SEVERED)
 387                 return -EPIPE;
 388
 389         if (priv->iucv_state == IUCV_DISCONN)
 390                 return -EIO;
 391
 392         if (!priv->sndbuf_len)
 393                 return 0;
 394
 395         /* allocate internal buffer to store msg data and also compute total
 396          * message length */
 397         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 398         if (!sb)
 399                 return -ENOMEM;
 400
 401         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 402         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 403         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 404
 405         list_add_tail(&sb->list, &priv->tty_outqueue);
 406
 407         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 408                                  (void *) sb->mbuf, sb->msg.length);
 409         if (rc) {
 410                 /* drop the message here; however we might want to handle
 411                  * 0x03 (msg limit reached) by trying again... */
 412                 list_del(&sb->list);
 413                 destroy_tty_buffer(sb);
 414         }
 415         len = priv->sndbuf_len;
 416         priv->sndbuf_len = 0;
 417
 418         return len;
 419 }
 420
 421 /**
 422  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 423  * @work:       Work structure.
 424  *
 425  * This work queue function sends buffered output data over IUCV and,
 426  * if not all buffered data could be sent, reschedules itself.
 427  */
 428 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 429 {
 430         struct hvc_iucv_private *priv;
 431
 432         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 433         if (!priv)
 434                 return;
 435
 436         spin_lock_bh(&priv->lock);
 437         hvc_iucv_send(priv);
 438         spin_unlock_bh(&priv->lock);
 439 }
 440
 441 /**
 442  * hvc_iucv_put_chars() - HVC put_chars operation.
 443  * @vtermno:    HVC virtual terminal number.
 444  * @buf:        Pointer to an buffer to read data from
 445  * @count:      Size of buffer available for reading
 446  *
 447  * The HVC thread calls this method to write characters to the back-end.
 448  * The function calls hvc_iucv_queue() to queue terminal data for sending.
 449  *
 450  * Locking:     The method gets called under an irqsave() spinlock; and
 451  *              locks struct hvc_iucv_private->lock.
 452  */
 453 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 454 {
 455         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 456         int queued;
 457
 458         if (count <= 0)
 459                 return 0;
 460
 461         if (!priv)
 462                 return -ENODEV;
 463
 464         spin_lock(&priv->lock);
 465         queued = hvc_iucv_queue(priv, buf, count);
 466         spin_unlock(&priv->lock);
 467
 468         return queued;
 469 }
 470
 471 /**
 472  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 473  * @hp: Pointer to the HVC device (struct hvc_struct)
 474  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 475  *      hvc_iucv_private instance.
 476  *
 477  * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
 478  * instance that is derived from @id. Always returns 0.
 479  *
 480  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 481  */
 482 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 483 {
 484         struct hvc_iucv_private *priv;
 485
 486         priv = hvc_iucv_get_private(id);
 487         if (!priv)
 488                 return 0;
 489
 490         spin_lock_bh(&priv->lock);
 491         priv->tty_state = TTY_OPENED;
 492         spin_unlock_bh(&priv->lock);
 493
 494         return 0;
 495 }
 496
 497 /**
 498  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 499  * @priv:       Pointer to the struct hvc_iucv_private instance.
 500  */
 501 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 502 {
 503         destroy_tty_buffer_list(&priv->tty_outqueue);
 504         destroy_tty_buffer_list(&priv->tty_inqueue);
 505
 506         priv->tty_state = TTY_CLOSED;
 507         priv->iucv_state = IUCV_DISCONN;
 508
 509         priv->sndbuf_len = 0;
 510 }
 511
 512 /**
 513  * tty_outqueue_empty() - Test if the tty outq is empty
 514  * @priv:       Pointer to struct hvc_iucv_private instance.
 515  */
 516 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 517 {
 518         int rc;
 519
 520         spin_lock_bh(&priv->lock);
 521         rc = list_empty(&priv->tty_outqueue);
 522         spin_unlock_bh(&priv->lock);
 523
 524         return rc;
 525 }
 526
 527 /**
 528  * flush_sndbuf_sync() - Flush send buffer and wait for completion
 529  * @priv:       Pointer to struct hvc_iucv_private instance.
 530  *
 531  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 532  * to flush any buffered terminal output data and waits for completion.
 533  */
 534 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 535 {
 536         int sync_wait;
 537
 538         cancel_delayed_work_sync(&priv->sndbuf_work);
 539
 540         spin_lock_bh(&priv->lock);
 541         hvc_iucv_send(priv);            /* force sending buffered data */
 542         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 543         spin_unlock_bh(&priv->lock);
 544
 545         if (sync_wait)
 546                 wait_event_timeout(priv->sndbuf_waitq,
 547                                    tty_outqueue_empty(priv), HZ/10);
 548 }
 549
 550 /**
 551  * hvc_iucv_hangup() - Sever IUCV path and schedule hvc tty hang up
 552  * @priv:       Pointer to hvc_iucv_private structure
 553  *
 554  * This routine severs an existing IUCV communication path and hangs
 555  * up the underlying HVC terminal device.
 556  * The hang-up occurs only if an IUCV communication path is established;
 557  * otherwise there is no need to hang up the terminal device.
 558  *
 559  * The IUCV HVC hang-up is separated into two steps:
 560  * 1. After the IUCV path has been severed, the iucv_state is set to
 561  *    IUCV_SEVERED.
 562  * 2. Later, when the HVC thread calls hvc_iucv_get_chars(), the
 563  *    IUCV_SEVERED state causes the tty hang-up in the HVC layer.
 564  *
 565  * If the tty has not yet been opened, clean up the hvc_iucv_private
 566  * structure to allow re-connects.
 567  * If the tty has been opened, let get_chars() return -EPIPE to signal
 568  * the HVC layer to hang up the tty and, if so, wake up the HVC thread
 569  * to call get_chars()...
 570  *
 571  * Special notes on hanging up a HVC terminal instantiated as console:
 572  * Hang-up:     1. do_tty_hangup() replaces file ops (= hung_up_tty_fops)
 573  *              2. do_tty_hangup() calls tty->ops->close() for console_filp
 574  *                      => no hangup notifier is called by HVC (default)
 575  *              2. hvc_close() returns because of tty_hung_up_p(filp)
 576  *                      => no delete notifier is called!
 577  * Finally, the back-end is not being notified, thus, the tty session is
 578  * kept active (TTY_OPEN) to be ready for re-connects.
 579  *
 580  * Locking:     spin_lock(&priv->lock) w/o disabling bh
 581  */
 582 static void hvc_iucv_hangup(struct hvc_iucv_private *priv)
 583 {
 584         struct iucv_path *path;
 585
 586         path = NULL;
 587         spin_lock(&priv->lock);
 588         if (priv->iucv_state == IUCV_CONNECTED) {
 589                 path = priv->path;
 590                 priv->path = NULL;
 591                 priv->iucv_state = IUCV_SEVERED;
 592                 if (priv->tty_state == TTY_CLOSED)
 593                         hvc_iucv_cleanup(priv);
 594                 else
 595                         /* console is special (see above) */
 596                         if (priv->is_console) {
 597                                 hvc_iucv_cleanup(priv);
 598                                 priv->tty_state = TTY_OPENED;
 599                         } else
 600                                 hvc_kick();
 601         }
 602         spin_unlock(&priv->lock);
 603
 604         /* finally sever path (outside of priv->lock due to lock ordering) */
 605         if (path) {
 606                 iucv_path_sever(path, NULL);
 607                 iucv_path_free(path);
 608         }
 609 }
 610
 611 /**
 612  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 613  * @hp:         Pointer to the HVC device (struct hvc_struct)
 614  * @id:         Additional data (originally passed to hvc_alloc):
 615  *              the index of an struct hvc_iucv_private instance.
 616  *
 617  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 618  * virtual or otherwise) has occured.
 619  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 620  * to keep an existing IUCV communication path established.
 621  * (Background: vhangup() is called from user space (by getty or login) to
 622  *              disable writing to the tty by other applications).
 623  * If the tty has been opened and an established IUCV path has been severed
 624  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 625  *
 626  * Locking:     struct hvc_iucv_private->lock
 627  */
 628 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 629 {
 630         struct hvc_iucv_private *priv;
 631
 632         priv = hvc_iucv_get_private(id);
 633         if (!priv)
 634                 return;
 635
 636         flush_sndbuf_sync(priv);
 637
 638         spin_lock_bh(&priv->lock);
 639         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 640          *       path_servered callback [IUCV_SEVERED]), we have to clean up
 641          *       our structure and to set state to TTY_CLOSED.
 642          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 643          *       ignore this hangup and keep an established IUCV path open...
 644          *       (...the reason is that we are not able to connect back to the
 645          *       client if we disconnect on hang up) */
 646         priv->tty_state = TTY_CLOSED;
 647
 648         if (priv->iucv_state == IUCV_SEVERED)
 649                 hvc_iucv_cleanup(priv);
 650         spin_unlock_bh(&priv->lock);
 651 }
 652
 653 /**
 654  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 655  * @hp:         Pointer to the HVC device (struct hvc_struct)
 656  * @id:         Additional data (originally passed to hvc_alloc):
 657  *              the index of an struct hvc_iucv_private instance.
 658  *
 659  * This routine notifies the HVC back-end that the last tty device fd has been
 660  * closed.  The function calls hvc_iucv_cleanup() to clean up the struct
 661  * hvc_iucv_private instance.
 662  *
 663  * Locking:     struct hvc_iucv_private->lock
 664  */
 665 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 666 {
 667         struct hvc_iucv_private *priv;
 668         struct iucv_path        *path;
 669
 670         priv = hvc_iucv_get_private(id);
 671         if (!priv)
 672                 return;
 673
 674         flush_sndbuf_sync(priv);
 675
 676         spin_lock_bh(&priv->lock);
 677         path = priv->path;              /* save reference to IUCV path */
 678         priv->path = NULL;
 679         hvc_iucv_cleanup(priv);
 680         spin_unlock_bh(&priv->lock);
 681
 682         /* sever IUCV path outside of priv->lock due to lock ordering of:
 683          * priv->lock <--> iucv_table_lock */
 684         if (path) {
 685                 iucv_path_sever(path, NULL);
 686                 iucv_path_free(path);
 687         }
 688 }
 689
 690 /**
 691  * hvc_iucv_filter_connreq() - Filter connection request based on z/VM user ID
 692  * @ipvmid:     Originating z/VM user ID (right padded with blanks)
 693  *
 694  * Returns 0 if the z/VM user ID @ipvmid is allowed to connection, otherwise
 695  * non-zero.
 696  */
 697 static int hvc_iucv_filter_connreq(u8 ipvmid[8])
 698 {
 699         size_t i;
 700
 701         /* Note: default policy is ACCEPT if no filter is set */
 702         if (!hvc_iucv_filter_size)
 703                 return 0;
 704
 705         for (i = 0; i < hvc_iucv_filter_size; i++)
 706                 if (0 == memcmp(ipvmid, hvc_iucv_filter + (8 * i), 8))
 707                         return 0;
 708         return 1;
 709 }
 710
 711 /**
 712  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 713  * @path:       Pending path (struct iucv_path)
 714  * @ipvmid:     z/VM system identifier of originator
 715  * @ipuser:     User specified data for this path
 716  *              (AF_IUCV: port/service name and originator port)
 717  *
 718  * The function uses the @ipuser data to determine if the pending path belongs
 719  * to a terminal managed by this device driver.
 720  * If the path belongs to this driver, ensure that the terminal is not accessed
 721  * multiple times (only one connection to a terminal is allowed).
 722  * If the terminal is not yet connected, the pending path is accepted and is
 723  * associated to the appropriate struct hvc_iucv_private instance.
 724  *
 725  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 726  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 727  *
 728  * Locking:     struct hvc_iucv_private->lock
 729  */
 730 static  int hvc_iucv_path_pending(struct iucv_path *path,
 731                                   u8 ipvmid[8], u8 ipuser[16])
 732 {
 733         struct hvc_iucv_private *priv;
 734         u8 nuser_data[16];
 735         u8 vm_user_id[9];
 736         int i, rc;
 737
 738         priv = NULL;
 739         for (i = 0; i < hvc_iucv_devices; i++)
 740                 if (hvc_iucv_table[i] &&
 741                     (0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) {
 742                         priv = hvc_iucv_table[i];
 743                         break;
 744                 }
 745         if (!priv)
 746                 return -ENODEV;
 747
 748         /* Enforce that ipvmid is allowed to connect to us */
 749         read_lock(&hvc_iucv_filter_lock);
 750         rc = hvc_iucv_filter_connreq(ipvmid);
 751         read_unlock(&hvc_iucv_filter_lock);
 752         if (rc) {
 753                 iucv_path_sever(path, ipuser);
 754                 iucv_path_free(path);
 755                 memcpy(vm_user_id, ipvmid, 8);
 756                 vm_user_id[8] = 0;
 757                 pr_info("A connection request from z/VM user ID %s "
 758                         "was refused\n", vm_user_id);
 759                 return 0;
 760         }
 761
 762         spin_lock(&priv->lock);
 763
 764         /* If the terminal is already connected or being severed, then sever
 765          * this path to enforce that there is only ONE established communication
 766          * path per terminal. */
 767         if (priv->iucv_state != IUCV_DISCONN) {
 768                 iucv_path_sever(path, ipuser);
 769                 iucv_path_free(path);
 770                 goto out_path_handled;
 771         }
 772
 773         /* accept path */
 774         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 775         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 776         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 777         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 778         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 779         if (rc) {
 780                 iucv_path_sever(path, ipuser);
 781                 iucv_path_free(path);
 782                 goto out_path_handled;
 783         }
 784         priv->path = path;
 785         priv->iucv_state = IUCV_CONNECTED;
 786
 787         /* flush buffered output data... */
 788         schedule_delayed_work(&priv->sndbuf_work, 5);
 789
 790 out_path_handled:
 791         spin_unlock(&priv->lock);
 792         return 0;
 793 }
 794
 795 /**
 796  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 797  * @path:       Pending path (struct iucv_path)
 798  * @ipuser:     User specified data for this path
 799  *              (AF_IUCV: port/service name and originator port)
 800  *
 801  * This function calls the hvc_iucv_hangup() function for the
 802  * respective IUCV HVC terminal.
 803  *
 804  * Locking:     struct hvc_iucv_private->lock
 805  */
 806 static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 807 {
 808         struct hvc_iucv_private *priv = path->private;
 809
 810         hvc_iucv_hangup(priv);
 811 }
 812
 813 /**
 814  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 815  * @path:       Pending path (struct iucv_path)
 816  * @msg:        Pointer to the IUCV message
 817  *
 818  * The function puts an incoming message on the input queue for later
 819  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 820  * If the tty has not yet been opened, the message is rejected.
 821  *
 822  * Locking:     struct hvc_iucv_private->lock
 823  */
 824 static void hvc_iucv_msg_pending(struct iucv_path *path,
 825                                  struct iucv_message *msg)
 826 {
 827         struct hvc_iucv_private *priv = path->private;
 828         struct iucv_tty_buffer *rb;
 829
 830         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 831         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 832                 iucv_message_reject(path, msg);
 833                 return;
 834         }
 835
 836         spin_lock(&priv->lock);
 837
 838         /* reject messages if tty has not yet been opened */
 839         if (priv->tty_state == TTY_CLOSED) {
 840                 iucv_message_reject(path, msg);
 841                 goto unlock_return;
 842         }
 843
 844         /* allocate tty buffer to save iucv msg only */
 845         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 846         if (!rb) {
 847                 iucv_message_reject(path, msg);
 848                 goto unlock_return;     /* -ENOMEM */
 849         }
 850         rb->msg = *msg;
 851
 852         list_add_tail(&rb->list, &priv->tty_inqueue);
 853
 854         hvc_kick();     /* wake up hvc thread */
 855
 856 unlock_return:
 857         spin_unlock(&priv->lock);
 858 }
 859
 860 /**
 861  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 862  * @path:       Pending path (struct iucv_path)
 863  * @msg:        Pointer to the IUCV message
 864  *
 865  * The function is called upon completion of message delivery to remove the
 866  * message from the outqueue. Additional delivery information can be found
 867  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 868  *             purged messages   (0x010000 (IPADPGNR)).
 869  *
 870  * Locking:     struct hvc_iucv_private->lock
 871  */
 872 static void hvc_iucv_msg_complete(struct iucv_path *path,
 873                                   struct iucv_message *msg)
 874 {
 875         struct hvc_iucv_private *priv = path->private;
 876         struct iucv_tty_buffer  *ent, *next;
 877         LIST_HEAD(list_remove);
 878
 879         spin_lock(&priv->lock);
 880         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 881                 if (ent->msg.id == msg->id) {
 882                         list_move(&ent->list, &list_remove);
 883                         break;
 884                 }
 885         wake_up(&priv->sndbuf_waitq);
 886         spin_unlock(&priv->lock);
 887         destroy_tty_buffer_list(&list_remove);
 888 }
 889
 890 /**
 891  * hvc_iucv_pm_freeze() - Freeze PM callback
 892  * @dev:        IUVC HVC terminal device
 893  *
 894  * Sever an established IUCV communication path and
 895  * trigger a hang-up of the underlying HVC terminal.
 896  */
 897 static int hvc_iucv_pm_freeze(struct device *dev)
 898 {
 899         struct hvc_iucv_private *priv = dev_get_drvdata(dev);
 900
 901         local_bh_disable();
 902         hvc_iucv_hangup(priv);
 903         local_bh_enable();
 904
 905         return 0;
 906 }
 907
 908 /**
 909  * hvc_iucv_pm_restore_thaw() - Thaw and restore PM callback
 910  * @dev:        IUVC HVC terminal device
 911  *
 912  * Wake up the HVC thread to trigger hang-up and respective
 913  * HVC back-end notifier invocations.
 914  */
 915 static int hvc_iucv_pm_restore_thaw(struct device *dev)
 916 {
 917         hvc_kick();
 918         return 0;
 919 }
 920
 921
 922 /* HVC operations */
 923 static struct hv_ops hvc_iucv_ops = {
 924         .get_chars = hvc_iucv_get_chars,
 925         .put_chars = hvc_iucv_put_chars,
 926         .notifier_add = hvc_iucv_notifier_add,
 927         .notifier_del = hvc_iucv_notifier_del,
 928         .notifier_hangup = hvc_iucv_notifier_hangup,
 929 };
 930
 931 /* Suspend / resume device operations */
 932 static struct dev_pm_ops hvc_iucv_pm_ops = {
 933         .freeze   = hvc_iucv_pm_freeze,
 934         .thaw     = hvc_iucv_pm_restore_thaw,
 935         .restore  = hvc_iucv_pm_restore_thaw,
 936 };
 937
 938 /* IUCV HVC device driver */
 939 static struct device_driver hvc_iucv_driver = {
 940         .name = KMSG_COMPONENT,
 941         .bus  = &iucv_bus,
 942         .pm   = &hvc_iucv_pm_ops,
 943 };
 944
 945 /**
 946  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
 947  * @id:                 hvc_iucv_table index
 948  * @is_console:         Flag if the instance is used as Linux console
 949  *
 950  * This function allocates a new hvc_iucv_private structure and stores
 951  * the instance in hvc_iucv_table at index @id.
 952  * Returns 0 on success; otherwise non-zero.
 953  */
 954 static int __init hvc_iucv_alloc(int id, unsigned int is_console)
 955 {
 956         struct hvc_iucv_private *priv;
 957         char name[9];
 958         int rc;
 959
 960         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
 961         if (!priv)
 962                 return -ENOMEM;
 963
 964         spin_lock_init(&priv->lock);
 965         INIT_LIST_HEAD(&priv->tty_outqueue);
 966         INIT_LIST_HEAD(&priv->tty_inqueue);
 967         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
 968         init_waitqueue_head(&priv->sndbuf_waitq);
 969
 970         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
 971         if (!priv->sndbuf) {
 972                 kfree(priv);
 973                 return -ENOMEM;
 974         }
 975
 976         /* set console flag */
 977         priv->is_console = is_console;
 978
 979         /* allocate hvc device */
 980         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
 981                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
 982         if (IS_ERR(priv->hvc)) {
 983                 rc = PTR_ERR(priv->hvc);
 984                 goto out_error_hvc;
 985         }
 986
 987         /* notify HVC thread instead of using polling */
 988         priv->hvc->irq_requested = 1;
 989
 990         /* setup iucv related information */
 991         snprintf(name, 9, "lnxhvc%-2d", id);
 992         memcpy(priv->srv_name, name, 8);
 993         ASCEBC(priv->srv_name, 8);
 994
 995         /* create and setup device */
 996         priv->dev = kzalloc(sizeof(*priv->dev), GFP_KERNEL);
 997         if (!priv->dev) {
 998                 rc = -ENOMEM;
 999                 goto out_error_dev;
1000         }
1001         dev_set_name(priv->dev, "hvc_iucv%d", id);
1002         dev_set_drvdata(priv->dev, priv);
1003         priv->dev->bus = &iucv_bus;
1004         priv->dev->parent = iucv_root;
1005         priv->dev->driver = &hvc_iucv_driver;
1006         priv->dev->release = (void (*)(struct device *)) kfree;
1007         rc = device_register(priv->dev);
1008         if (rc) {
1009                 kfree(priv->dev);
1010                 goto out_error_dev;
1011         }
1012
1013         hvc_iucv_table[id] = priv;
1014         return 0;
1015
1016 out_error_dev:
1017         hvc_remove(priv->hvc);
1018 out_error_hvc:
1019         free_page((unsigned long) priv->sndbuf);
1020         kfree(priv);
1021
1022         return rc;
1023 }
1024
1025 /**
1026  * hvc_iucv_destroy() - Destroy and free hvc_iucv_private instances
1027  */
1028 static void __init hvc_iucv_destroy(struct hvc_iucv_private *priv)
1029 {
1030         hvc_remove(priv->hvc);
1031         device_unregister(priv->dev);
1032         free_page((unsigned long) priv->sndbuf);
1033         kfree(priv);
1034 }
1035
1036 /**
1037  * hvc_iucv_parse_filter() - Parse filter for a single z/VM user ID
1038  * @filter:     String containing a comma-separated list of z/VM user IDs
1039  */
1040 static const char *hvc_iucv_parse_filter(const char *filter, char *dest)
1041 {
1042         const char *nextdelim, *residual;
1043         size_t len;
1044
1045         nextdelim = strchr(filter, ',');
1046         if (nextdelim) {
1047                 len = nextdelim - filter;
1048                 residual = nextdelim + 1;
1049         } else {
1050                 len = strlen(filter);
1051                 residual = filter + len;
1052         }
1053
1054         if (len == 0)
1055                 return ERR_PTR(-EINVAL);
1056
1057         /* check for '\n' (if called from sysfs) */
1058         if (filter[len - 1] == '\n')
1059                 len--;
1060
1061         if (len > 8)
1062                 return ERR_PTR(-EINVAL);
1063
1064         /* pad with blanks and save upper case version of user ID */
1065         memset(dest, ' ', 8);
1066         while (len--)
1067                 dest[len] = toupper(filter[len]);
1068         return residual;
1069 }
1070
1071 /**
1072  * hvc_iucv_setup_filter() - Set up z/VM user ID filter
1073  * @filter:     String consisting of a comma-separated list of z/VM user IDs
1074  *
1075  * The function parses the @filter string and creates an array containing
1076  * the list of z/VM user ID filter entries.
1077  * Return code 0 means success, -EINVAL if the filter is syntactically
1078  * incorrect, -ENOMEM if there was not enough memory to allocate the
1079  * filter list array, or -ENOSPC if too many z/VM user IDs have been specified.
1080  */
1081 static int hvc_iucv_setup_filter(const char *val)
1082 {
1083         const char *residual;
1084         int err;
1085         size_t size, count;
1086         void *array, *old_filter;
1087
1088         count = strlen(val);
1089         if (count == 0 || (count == 1 && val[0] == '\n')) {
1090                 size  = 0;
1091                 array = NULL;
1092                 goto out_replace_filter;        /* clear filter */
1093         }
1094
1095         /* count user IDs in order to allocate sufficient memory */
1096         size = 1;
1097         residual = val;
1098         while ((residual = strchr(residual, ',')) != NULL) {
1099                 residual++;
1100                 size++;
1101         }
1102
1103         /* check if the specified list exceeds the filter limit */
1104         if (size > MAX_VMID_FILTER)
1105                 return -ENOSPC;
1106
1107         array = kzalloc(size * 8, GFP_KERNEL);
1108         if (!array)
1109                 return -ENOMEM;
1110
1111         count = size;
1112         residual = val;
1113         while (*residual && count) {
1114                 residual = hvc_iucv_parse_filter(residual,
1115                                                  array + ((size - count) * 8));
1116                 if (IS_ERR(residual)) {
1117                         err = PTR_ERR(residual);
1118                         kfree(array);
1119                         goto out_err;
1120                 }
1121                 count--;
1122         }
1123
1124 out_replace_filter:
1125         write_lock_bh(&hvc_iucv_filter_lock);
1126         old_filter = hvc_iucv_filter;
1127         hvc_iucv_filter_size = size;
1128         hvc_iucv_filter = array;
1129         write_unlock_bh(&hvc_iucv_filter_lock);
1130         kfree(old_filter);
1131
1132         err = 0;
1133 out_err:
1134         return err;
1135 }
1136
1137 /**
1138  * param_set_vmidfilter() - Set z/VM user ID filter parameter
1139  * @val:        String consisting of a comma-separated list of z/VM user IDs
1140  * @kp:         Kernel parameter pointing to hvc_iucv_filter array
1141  *
1142  * The function sets up the z/VM user ID filter specified as comma-separated
1143  * list of user IDs in @val.
1144  * Note: If it is called early in the boot process, @val is stored and
1145  *       parsed later in hvc_iucv_init().
1146  */
1147 static int param_set_vmidfilter(const char *val, struct kernel_param *kp)
1148 {
1149         int rc;
1150
1151         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1152                 return -ENODEV;
1153
1154         if (!val)
1155                 return -EINVAL;
1156
1157         rc = 0;
1158         if (slab_is_available())
1159                 rc = hvc_iucv_setup_filter(val);
1160         else
1161                 hvc_iucv_filter_string = val;   /* defer... */
1162         return rc;
1163 }
1164
1165 /**
1166  * param_get_vmidfilter() - Get z/VM user ID filter
1167  * @buffer:     Buffer to store z/VM user ID filter,
1168  *              (buffer size assumption PAGE_SIZE)
1169  * @kp:         Kernel parameter pointing to the hvc_iucv_filter array
1170  *
1171  * The function stores the filter as a comma-separated list of z/VM user IDs
1172  * in @buffer. Typically, sysfs routines call this function for attr show.
1173  */
1174 static int param_get_vmidfilter(char *buffer, struct kernel_param *kp)
1175 {
1176         int rc;
1177         size_t index, len;
1178         void *start, *end;
1179
1180         if (!MACHINE_IS_VM || !hvc_iucv_devices)
1181                 return -ENODEV;
1182
1183         rc = 0;
1184         read_lock_bh(&hvc_iucv_filter_lock);
1185         for (index = 0; index < hvc_iucv_filter_size; index++) {
1186                 start = hvc_iucv_filter + (8 * index);
1187                 end   = memchr(start, ' ', 8);
1188                 len   = (end) ? end - start : 8;
1189                 memcpy(buffer + rc, start, len);
1190                 rc += len;
1191                 buffer[rc++] = ',';
1192         }
1193         read_unlock_bh(&hvc_iucv_filter_lock);
1194         if (rc)
1195                 buffer[--rc] = '\0';    /* replace last comma and update rc */
1196         return rc;
1197 }
1198
1199 #define param_check_vmidfilter(name, p) __param_check(name, p, void)
1200
1201 /**
1202  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
1203  */
1204 static int __init hvc_iucv_init(void)
1205 {
1206         int rc;
1207         unsigned int i;
1208
1209         if (!hvc_iucv_devices)
1210                 return -ENODEV;
1211
1212         if (!MACHINE_IS_VM) {
1213                 pr_notice("The z/VM IUCV HVC device driver cannot "
1214                            "be used without z/VM\n");
1215                 rc = -ENODEV;
1216                 goto out_error;
1217         }
1218
1219         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) {
1220                 pr_err("%lu is not a valid value for the hvc_iucv= "
1221                         "kernel parameter\n", hvc_iucv_devices);
1222                 rc = -EINVAL;
1223                 goto out_error;
1224         }
1225
1226         /* register IUCV HVC device driver */
1227         rc = driver_register(&hvc_iucv_driver);
1228         if (rc)
1229                 goto out_error;
1230
1231         /* parse hvc_iucv_allow string and create z/VM user ID filter list */
1232         if (hvc_iucv_filter_string) {
1233                 rc = hvc_iucv_setup_filter(hvc_iucv_filter_string);
1234                 switch (rc) {
1235                 case 0:
1236                         break;
1237                 case -ENOMEM:
1238                         pr_err("Allocating memory failed with "
1239                                 "reason code=%d\n", 3);
1240                         goto out_error;
1241                 case -EINVAL:
1242                         pr_err("hvc_iucv_allow= does not specify a valid "
1243                                 "z/VM user ID list\n");
1244                         goto out_error;
1245                 case -ENOSPC:
1246                         pr_err("hvc_iucv_allow= specifies too many "
1247                                 "z/VM user IDs\n");
1248                         goto out_error;
1249                 default:
1250                         goto out_error;
1251                 }
1252         }
1253
1254         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
1255                                            sizeof(struct iucv_tty_buffer),
1256                                            0, 0, NULL);
1257         if (!hvc_iucv_buffer_cache) {
1258                 pr_err("Allocating memory failed with reason code=%d\n", 1);
1259                 rc = -ENOMEM;
1260                 goto out_error;
1261         }
1262
1263         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
1264                                                     hvc_iucv_buffer_cache);
1265         if (!hvc_iucv_mempool) {
1266                 pr_err("Allocating memory failed with reason code=%d\n", 2);
1267                 kmem_cache_destroy(hvc_iucv_buffer_cache);
1268                 rc = -ENOMEM;
1269                 goto out_error;
1270         }
1271
1272         /* register the first terminal device as console
1273          * (must be done before allocating hvc terminal devices) */
1274         rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
1275         if (rc) {
1276                 pr_err("Registering HVC terminal device as "
1277                        "Linux console failed\n");
1278                 goto out_error_memory;
1279         }
1280
1281         /* allocate hvc_iucv_private structs */
1282         for (i = 0; i < hvc_iucv_devices; i++) {
1283                 rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
1284                 if (rc) {
1285                         pr_err("Creating a new HVC terminal device "
1286                                 "failed with error code=%d\n", rc);
1287                         goto out_error_hvc;
1288                 }
1289         }
1290
1291         /* register IUCV callback handler */
1292         rc = iucv_register(&hvc_iucv_handler, 0);
1293         if (rc) {
1294                 pr_err("Registering IUCV handlers failed with error code=%d\n",
1295                         rc);
1296                 goto out_error_iucv;
1297         }
1298
1299         return 0;
1300
1301 out_error_iucv:
1302         iucv_unregister(&hvc_iucv_handler, 0);
1303 out_error_hvc:
1304         for (i = 0; i < hvc_iucv_devices; i++)
1305                 if (hvc_iucv_table[i])
1306                         hvc_iucv_destroy(hvc_iucv_table[i]);
1307 out_error_memory:
1308         mempool_destroy(hvc_iucv_mempool);
1309         kmem_cache_destroy(hvc_iucv_buffer_cache);
1310 out_error:
1311         if (hvc_iucv_filter)
1312                 kfree(hvc_iucv_filter);
1313         hvc_iucv_devices = 0; /* ensure that we do not provide any device */
1314         return rc;
1315 }
1316
1317 /**
1318  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
1319  * @val:        Parameter value (numeric)
1320  */
1321 static  int __init hvc_iucv_config(char *val)
1322 {
1323          return strict_strtoul(val, 10, &hvc_iucv_devices);
1324 }
1325
1326
1327 device_initcall(hvc_iucv_init);
1328 __setup("hvc_iucv=", hvc_iucv_config);
1329 core_param(hvc_iucv_allow, hvc_iucv_filter, vmidfilter, 0640);