drivers/block/viodasd.c

   1 /* -*- linux-c -*-
   2  * viodasd.c
   3  *  Authors: Dave Boutcher <boutcher@us.ibm.com>
   4  *           Ryan Arnold <ryanarn@us.ibm.com>
   5  *           Colin Devilbiss <devilbis@us.ibm.com>
   6  *           Stephen Rothwell <sfr@au1.ibm.com>
   7  *
   8  * (C) Copyright 2000-2004 IBM Corporation
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  *
  24  * This routine provides access to disk space (termed "DASD" in historical
  25  * IBM terms) owned and managed by an OS/400 partition running on the
  26  * same box as this Linux partition.
  27  *
  28  * All disk operations are performed by sending messages back and forth to
  29  * the OS/400 partition.
  30  */
  31 #include <linux/major.h>
  32 #include <linux/fs.h>
  33 #include <linux/module.h>
  34 #include <linux/kernel.h>
  35 #include <linux/blkdev.h>
  36 #include <linux/genhd.h>
  37 #include <linux/hdreg.h>
  38 #include <linux/errno.h>
  39 #include <linux/init.h>
  40 #include <linux/string.h>
  41 #include <linux/dma-mapping.h>
  42 #include <linux/completion.h>
  43
  44 #include <asm/uaccess.h>
  45 #include <asm/iSeries/HvTypes.h>
  46 #include <asm/iSeries/HvLpEvent.h>
  47 #include <asm/iSeries/HvLpConfig.h>
  48 #include <asm/iSeries/vio.h>
  49
  50 MODULE_DESCRIPTION("iSeries Virtual DASD");
  51 MODULE_AUTHOR("Dave Boutcher");
  52 MODULE_LICENSE("GPL");
  53
  54 /*
  55  * We only support 7 partitions per physical disk....so with minor
  56  * numbers 0-255 we get a maximum of 32 disks.
  57  */
  58 #define VIOD_GENHD_NAME         "iseries/vd"
  59 #define VIOD_GENHD_DEVFS_NAME   "iseries/disc"
  60
  61 #define VIOD_VERS               "1.64"
  62
  63 #define VIOD_KERN_WARNING       KERN_WARNING "viod: "
  64 #define VIOD_KERN_INFO          KERN_INFO "viod: "
  65
  66 enum {
  67         PARTITION_SHIFT = 3,
  68         MAX_DISKNO = 32,
  69         MAX_DISK_NAME = sizeof(((struct gendisk *)0)->disk_name)
  70 };
  71
  72 static spinlock_t       viodasd_spinlock = SPIN_LOCK_UNLOCKED;
  73
  74 #define VIOMAXREQ               16
  75 #define VIOMAXBLOCKDMA          12
  76
  77 #define DEVICE_NO(cell) ((struct viodasd_device *)(cell) - &viodasd_devices[0])
  78
  79 struct open_data {
  80         u64     disk_size;
  81         u16     max_disk;
  82         u16     cylinders;
  83         u16     tracks;
  84         u16     sectors;
  85         u16     bytes_per_sector;
  86 };
  87
  88 struct rw_data {
  89         u64     offset;
  90         struct {
  91                 u32     token;
  92                 u32     reserved;
  93                 u64     len;
  94         } dma_info[VIOMAXBLOCKDMA];
  95 };
  96
  97 struct vioblocklpevent {
  98         struct HvLpEvent        event;
  99         u32                     reserved;
 100         u16                     version;
 101         u16                     sub_result;
 102         u16                     disk;
 103         u16                     flags;
 104         union {
 105                 struct open_data        open_data;
 106                 struct rw_data          rw_data;
 107                 u64                     changed;
 108         } u;
 109 };
 110
 111 #define vioblockflags_ro   0x0001
 112
 113 enum vioblocksubtype {
 114         vioblockopen = 0x0001,
 115         vioblockclose = 0x0002,
 116         vioblockread = 0x0003,
 117         vioblockwrite = 0x0004,
 118         vioblockflush = 0x0005,
 119         vioblockcheck = 0x0007
 120 };
 121
 122 struct viodasd_waitevent {
 123         struct completion       com;
 124         int                     rc;
 125         u16                     sub_result;
 126         int                     max_disk;       /* open */
 127 };
 128
 129 static const struct vio_error_entry viodasd_err_table[] = {
 130         { 0x0201, EINVAL, "Invalid Range" },
 131         { 0x0202, EINVAL, "Invalid Token" },
 132         { 0x0203, EIO, "DMA Error" },
 133         { 0x0204, EIO, "Use Error" },
 134         { 0x0205, EIO, "Release Error" },
 135         { 0x0206, EINVAL, "Invalid Disk" },
 136         { 0x0207, EBUSY, "Cant Lock" },
 137         { 0x0208, EIO, "Already Locked" },
 138         { 0x0209, EIO, "Already Unlocked" },
 139         { 0x020A, EIO, "Invalid Arg" },
 140         { 0x020B, EIO, "Bad IFS File" },
 141         { 0x020C, EROFS, "Read Only Device" },
 142         { 0x02FF, EIO, "Internal Error" },
 143         { 0x0000, 0, NULL },
 144 };
 145
 146 /*
 147  * Figure out the biggest I/O request (in sectors) we can accept
 148  */
 149 #define VIODASD_MAXSECTORS (4096 / 512 * VIOMAXBLOCKDMA)
 150
 151 /*
 152  * Number of disk I/O requests we've sent to OS/400
 153  */
 154 static int num_req_outstanding;
 155
 156 /*
 157  * This is our internal structure for keeping track of disk devices
 158  */
 159 struct viodasd_device {
 160         u16             cylinders;
 161         u16             tracks;
 162         u16             sectors;
 163         u16             bytes_per_sector;
 164         u64             size;
 165         int             read_only;
 166         spinlock_t      q_lock;
 167         struct gendisk  *disk;
 168 } viodasd_devices[MAX_DISKNO];
 169
 170 /*
 171  * External open entry point.
 172  */
 173 static int viodasd_open(struct inode *ino, struct file *fil)
 174 {
 175         struct viodasd_device *d = ino->i_bdev->bd_disk->private_data;
 176         HvLpEvent_Rc hvrc;
 177         struct viodasd_waitevent we;
 178
 179         init_completion(&we.com);
 180
 181         /* Send the open event to OS/400 */
 182         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 183                         HvLpEvent_Type_VirtualIo,
 184                         viomajorsubtype_blockio | vioblockopen,
 185                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
 186                         viopath_sourceinst(viopath_hostLp),
 187                         viopath_targetinst(viopath_hostLp),
 188                         (u64)(unsigned long)&we, VIOVERSION << 16,
 189                         ((u64)DEVICE_NO(d) << 48) /* | ((u64)flags << 32) */,
 190                         0, 0, 0);
 191         if (hvrc != 0) {
 192                 printk(VIOD_KERN_WARNING "HV open failed %d\n", (int)hvrc);
 193                 return -EIO;
 194         }
 195
 196         wait_for_completion(&we.com);
 197
 198         /* Check the return code */
 199         if (we.rc != 0) {
 200                 const struct vio_error_entry *err =
 201                         vio_lookup_rc(viodasd_err_table, we.sub_result);
 202
 203                 printk(VIOD_KERN_WARNING
 204                                 "bad rc opening disk: %d:0x%04x (%s)\n",
 205                                 (int)we.rc, we.sub_result, err->msg);
 206                 return -EIO;
 207         }
 208
 209         return 0;
 210 }
 211
 212 /*
 213  * External release entry point.
 214  */
 215 static int viodasd_release(struct inode *ino, struct file *fil)
 216 {
 217         struct viodasd_device *d = ino->i_bdev->bd_disk->private_data;
 218         HvLpEvent_Rc hvrc;
 219
 220         /* Send the event to OS/400.  We DON'T expect a response */
 221         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 222                         HvLpEvent_Type_VirtualIo,
 223                         viomajorsubtype_blockio | vioblockclose,
 224                         HvLpEvent_AckInd_NoAck, HvLpEvent_AckType_ImmediateAck,
 225                         viopath_sourceinst(viopath_hostLp),
 226                         viopath_targetinst(viopath_hostLp),
 227                         0, VIOVERSION << 16,
 228                         ((u64)DEVICE_NO(d) << 48) /* | ((u64)flags << 32) */,
 229                         0, 0, 0);
 230         if (hvrc != 0)
 231                 printk(VIOD_KERN_WARNING "HV close call failed %d\n",
 232                                 (int)hvrc);
 233         return 0;
 234 }
 235
 236
 237 /* External ioctl entry point.
 238  */
 239 static int viodasd_ioctl(struct inode *ino, struct file *fil,
 240                          unsigned int cmd, unsigned long arg)
 241 {
 242         int err;
 243         unsigned char sectors;
 244         unsigned char heads;
 245         unsigned short cylinders;
 246         struct hd_geometry *geo;
 247         struct gendisk *gendisk;
 248         struct viodasd_device *d;
 249
 250         switch (cmd) {
 251         case HDIO_GETGEO:
 252                 geo = (struct hd_geometry *)arg;
 253                 if (geo == NULL)
 254                         return -EINVAL;
 255                 err = verify_area(VERIFY_WRITE, geo, sizeof(*geo));
 256                 if (err)
 257                         return err;
 258                 gendisk = ino->i_bdev->bd_disk;
 259                 d = gendisk->private_data;
 260                 sectors = d->sectors;
 261                 if (sectors == 0)
 262                         sectors = 32;
 263                 heads = d->tracks;
 264                 if (heads == 0)
 265                         heads = 64;
 266                 cylinders = d->cylinders;
 267                 if (cylinders == 0)
 268                         cylinders = get_capacity(gendisk) / (sectors * heads);
 269                 if (__put_user(sectors, &geo->sectors) ||
 270                     __put_user(heads, &geo->heads) ||
 271                     __put_user(cylinders, &geo->cylinders) ||
 272                     __put_user(get_start_sect(ino->i_bdev), &geo->start))
 273                         return -EFAULT;
 274                 return 0;
 275         }
 276
 277         return -EINVAL;
 278 }
 279
 280 /*
 281  * Our file operations table
 282  */
 283 static struct block_device_operations viodasd_fops = {
 284         .owner = THIS_MODULE,
 285         .open = viodasd_open,
 286         .release = viodasd_release,
 287         .ioctl = viodasd_ioctl,
 288 };
 289
 290 /*
 291  * End a request
 292  */
 293 static void viodasd_end_request(struct request *req, int uptodate,
 294                 int num_sectors)
 295 {
 296         if (end_that_request_first(req, uptodate, num_sectors))
 297                 return;
 298         add_disk_randomness(req->rq_disk);
 299         end_that_request_last(req);
 300 }
 301
 302 /*
 303  * Send an actual I/O request to OS/400
 304  */
 305 static int send_request(struct request *req)
 306 {
 307         u64 start;
 308         int direction;
 309         int nsg;
 310         u16 viocmd;
 311         HvLpEvent_Rc hvrc;
 312         struct vioblocklpevent *bevent;
 313         struct scatterlist sg[VIOMAXBLOCKDMA];
 314         int sgindex;
 315         int statindex;
 316         struct viodasd_device *d;
 317         unsigned long flags;
 318
 319         start = (u64)req->sector << 9;
 320
 321         if (rq_data_dir(req) == READ) {
 322                 direction = DMA_FROM_DEVICE;
 323                 viocmd = viomajorsubtype_blockio | vioblockread;
 324                 statindex = 0;
 325         } else {
 326                 direction = DMA_TO_DEVICE;
 327                 viocmd = viomajorsubtype_blockio | vioblockwrite;
 328                 statindex = 1;
 329         }
 330
 331         d = req->rq_disk->private_data;
 332
 333         /* Now build the scatter-gather list */
 334         nsg = blk_rq_map_sg(req->q, req, sg);
 335         nsg = dma_map_sg(iSeries_vio_dev, sg, nsg, direction);
 336
 337         spin_lock_irqsave(&viodasd_spinlock, flags);
 338         num_req_outstanding++;
 339
 340         /* This optimization handles a single DMA block */
 341         if (nsg == 1)
 342                 hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 343                                 HvLpEvent_Type_VirtualIo, viocmd,
 344                                 HvLpEvent_AckInd_DoAck,
 345                                 HvLpEvent_AckType_ImmediateAck,
 346                                 viopath_sourceinst(viopath_hostLp),
 347                                 viopath_targetinst(viopath_hostLp),
 348                                 (u64)(unsigned long)req, VIOVERSION << 16,
 349                                 ((u64)DEVICE_NO(d) << 48), start,
 350                                 ((u64)sg_dma_address(&sg[0])) << 32,
 351                                 sg_dma_len(&sg[0]));
 352         else {
 353                 bevent = (struct vioblocklpevent *)
 354                         vio_get_event_buffer(viomajorsubtype_blockio);
 355                 if (bevent == NULL) {
 356                         printk(VIOD_KERN_WARNING
 357                                "error allocating disk event buffer\n");
 358                         goto error_ret;
 359                 }
 360
 361                 /*
 362                  * Now build up the actual request.  Note that we store
 363                  * the pointer to the request in the correlation
 364                  * token so we can match the response up later
 365                  */
 366                 memset(bevent, 0, sizeof(struct vioblocklpevent));
 367                 bevent->event.xFlags.xValid = 1;
 368                 bevent->event.xFlags.xFunction = HvLpEvent_Function_Int;
 369                 bevent->event.xFlags.xAckInd = HvLpEvent_AckInd_DoAck;
 370                 bevent->event.xFlags.xAckType = HvLpEvent_AckType_ImmediateAck;
 371                 bevent->event.xType = HvLpEvent_Type_VirtualIo;
 372                 bevent->event.xSubtype = viocmd;
 373                 bevent->event.xSourceLp = HvLpConfig_getLpIndex();
 374                 bevent->event.xTargetLp = viopath_hostLp;
 375                 bevent->event.xSizeMinus1 =
 376                         offsetof(struct vioblocklpevent, u.rw_data.dma_info) +
 377                         (sizeof(bevent->u.rw_data.dma_info[0]) * nsg) - 1;
 378                 bevent->event.xSourceInstanceId =
 379                         viopath_sourceinst(viopath_hostLp);
 380                 bevent->event.xTargetInstanceId =
 381                         viopath_targetinst(viopath_hostLp);
 382                 bevent->event.xCorrelationToken = (u64)req;
 383                 bevent->version = VIOVERSION;
 384                 bevent->disk = DEVICE_NO(d);
 385                 bevent->u.rw_data.offset = start;
 386
 387                 /*
 388                  * Copy just the dma information from the sg list
 389                  * into the request
 390                  */
 391                 for (sgindex = 0; sgindex < nsg; sgindex++) {
 392                         bevent->u.rw_data.dma_info[sgindex].token =
 393                                 sg_dma_address(&sg[sgindex]);
 394                         bevent->u.rw_data.dma_info[sgindex].len =
 395                                 sg_dma_len(&sg[sgindex]);
 396                 }
 397
 398                 /* Send the request */
 399                 hvrc = HvCallEvent_signalLpEvent(&bevent->event);
 400                 vio_free_event_buffer(viomajorsubtype_blockio, bevent);
 401         }
 402
 403         if (hvrc != HvLpEvent_Rc_Good) {
 404                 printk(VIOD_KERN_WARNING
 405                        "error sending disk event to OS/400 (rc %d)\n",
 406                        (int)hvrc);
 407                 goto error_ret;
 408         }
 409         spin_unlock_irqrestore(&viodasd_spinlock, flags);
 410         return 0;
 411
 412 error_ret:
 413         num_req_outstanding--;
 414         spin_unlock_irqrestore(&viodasd_spinlock, flags);
 415         dma_unmap_sg(iSeries_vio_dev, sg, nsg, direction);
 416         return -1;
 417 }
 418
 419 /*
 420  * This is the external request processing routine
 421  */
 422 static void do_viodasd_request(request_queue_t *q)
 423 {
 424         struct request *req;
 425
 426         /*
 427          * If we already have the maximum number of requests
 428          * outstanding to OS/400 just bail out. We'll come
 429          * back later.
 430          */
 431         while (num_req_outstanding < VIOMAXREQ) {
 432                 req = elv_next_request(q);
 433                 if (req == NULL)
 434                         return;
 435                 /* dequeue the current request from the queue */
 436                 blkdev_dequeue_request(req);
 437                 /* check that request contains a valid command */
 438                 if (!blk_fs_request(req)) {
 439                         viodasd_end_request(req, 0, req->hard_nr_sectors);
 440                         continue;
 441                 }
 442                 /* Try sending the request */
 443                 if (send_request(req) != 0)
 444                         viodasd_end_request(req, 0, req->hard_nr_sectors);
 445         }
 446 }
 447
 448 /*
 449  * Probe a single disk and fill in the viodasd_device structure
 450  * for it.
 451  */
 452 static void probe_disk(struct viodasd_device *d)
 453 {
 454         HvLpEvent_Rc hvrc;
 455         struct viodasd_waitevent we;
 456         int dev_no = DEVICE_NO(d);
 457         struct gendisk *g;
 458         struct request_queue *q;
 459
 460         init_completion(&we.com);
 461
 462         /* Send the open event to OS/400 */
 463         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 464                         HvLpEvent_Type_VirtualIo,
 465                         viomajorsubtype_blockio | vioblockopen,
 466                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
 467                         viopath_sourceinst(viopath_hostLp),
 468                         viopath_targetinst(viopath_hostLp),
 469                         (u64)(unsigned long)&we, VIOVERSION << 16,
 470                         ((u64)dev_no << 48) | ((u64)vioblockflags_ro << 32),
 471                         0, 0, 0);
 472         if (hvrc != 0) {
 473                 printk(VIOD_KERN_WARNING "bad rc on HV open %d\n", (int)hvrc);
 474                 return;
 475         }
 476
 477         wait_for_completion(&we.com);
 478
 479         if (we.rc != 0)
 480                 return;
 481         if (we.max_disk > (MAX_DISKNO - 1)) {
 482                 static int warned;
 483
 484                 if (warned == 0) {
 485                         warned++;
 486                         printk(VIOD_KERN_INFO
 487                                 "Only examining the first %d "
 488                                 "of %d disks connected\n",
 489                                 MAX_DISKNO, we.max_disk + 1);
 490                 }
 491         }
 492
 493         /* Send the close event to OS/400.  We DON'T expect a response */
 494         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 495                         HvLpEvent_Type_VirtualIo,
 496                         viomajorsubtype_blockio | vioblockclose,
 497                         HvLpEvent_AckInd_NoAck, HvLpEvent_AckType_ImmediateAck,
 498                         viopath_sourceinst(viopath_hostLp),
 499                         viopath_targetinst(viopath_hostLp),
 500                         0, VIOVERSION << 16,
 501                         ((u64)dev_no << 48) | ((u64)vioblockflags_ro << 32),
 502                         0, 0, 0);
 503         if (hvrc != 0) {
 504                 printk(VIOD_KERN_WARNING
 505                        "bad rc sending event to OS/400 %d\n", (int)hvrc);
 506                 return;
 507         }
 508         printk(VIOD_KERN_INFO "disk %d: %lu sectors (%lu MB) "
 509                         "CHS=%d/%d/%d sector size %d\n",
 510                         dev_no, (unsigned long)(d->size >> 9),
 511                         (unsigned long)(d->size >> 20),
 512                         (int)d->cylinders, (int)d->tracks,
 513                         (int)d->sectors, (int)d->bytes_per_sector);
 514         /* create the request queue for the disk */
 515         spin_lock_init(&d->q_lock);
 516         q = blk_init_queue(do_viodasd_request, &d->q_lock);
 517         if (q == NULL) {
 518                 printk(VIOD_KERN_WARNING "cannot allocate queue for disk %d\n",
 519                                 dev_no);
 520                 return;
 521         }
 522         g = alloc_disk(1 << PARTITION_SHIFT);
 523         if (g == NULL) {
 524                 printk(VIOD_KERN_WARNING
 525                                 "cannot allocate disk structure for disk %d\n",
 526                                 dev_no);
 527                 blk_cleanup_queue(q);
 528                 return;
 529         }
 530
 531         d->disk = g;
 532         blk_queue_max_hw_segments(q, VIOMAXBLOCKDMA);
 533         blk_queue_max_phys_segments(q, VIOMAXBLOCKDMA);
 534         blk_queue_max_sectors(q, VIODASD_MAXSECTORS);
 535         g->major = VIODASD_MAJOR;
 536         g->first_minor = dev_no << PARTITION_SHIFT;
 537         if (dev_no >= 26)
 538                 snprintf(g->disk_name, sizeof(g->disk_name),
 539                                 VIOD_GENHD_NAME "%c%c",
 540                                 'a' + (dev_no / 26) - 1, 'a' + (dev_no % 26));
 541         else
 542                 snprintf(g->disk_name, sizeof(g->disk_name),
 543                                 VIOD_GENHD_NAME "%c", 'a' + (dev_no % 26));
 544         snprintf(g->devfs_name, sizeof(g->devfs_name),
 545                         "%s%d", VIOD_GENHD_DEVFS_NAME, dev_no);
 546         g->fops = &viodasd_fops;
 547         g->queue = q;
 548         g->private_data = d;
 549         set_capacity(g, d->size >> 9);
 550
 551         /* register us in the global list */
 552         add_disk(g);
 553 }
 554
 555 /* returns the total number of scatterlist elements converted */
 556 static int block_event_to_scatterlist(const struct vioblocklpevent *bevent,
 557                 struct scatterlist *sg, int *total_len)
 558 {
 559         int i, numsg;
 560         const struct rw_data *rw_data = &bevent->u.rw_data;
 561         static const int offset =
 562                 offsetof(struct vioblocklpevent, u.rw_data.dma_info);
 563         static const int element_size = sizeof(rw_data->dma_info[0]);
 564
 565         numsg = ((bevent->event.xSizeMinus1 + 1) - offset) / element_size;
 566         if (numsg > VIOMAXBLOCKDMA)
 567                 numsg = VIOMAXBLOCKDMA;
 568
 569         *total_len = 0;
 570         memset(sg, 0, sizeof(sg[0]) * VIOMAXBLOCKDMA);
 571
 572         for (i = 0; (i < numsg) && (rw_data->dma_info[i].len > 0); ++i) {
 573                 sg_dma_address(&sg[i]) = rw_data->dma_info[i].token;
 574                 sg_dma_len(&sg[i]) = rw_data->dma_info[i].len;
 575                 *total_len += rw_data->dma_info[i].len;
 576         }
 577         return i;
 578 }
 579
 580 /*
 581  * Restart all queues, starting with the one _after_ the disk given,
 582  * thus reducing the chance of starvation of higher numbered disks.
 583  */
 584 static void viodasd_restart_all_queues_starting_from(int first_index)
 585 {
 586         int i;
 587
 588         for (i = first_index + 1; i < MAX_DISKNO; ++i)
 589                 if (viodasd_devices[i].disk)
 590                         blk_run_queue(viodasd_devices[i].disk->queue);
 591         for (i = 0; i <= first_index; ++i)
 592                 if (viodasd_devices[i].disk)
 593                         blk_run_queue(viodasd_devices[i].disk->queue);
 594 }
 595
 596 /*
 597  * For read and write requests, decrement the number of outstanding requests,
 598  * Free the DMA buffers we allocated.
 599  */
 600 static int viodasd_handle_read_write(struct vioblocklpevent *bevent)
 601 {
 602         int num_sg, num_sect, pci_direction, total_len;
 603         struct request *req;
 604         struct scatterlist sg[VIOMAXBLOCKDMA];
 605         struct HvLpEvent *event = &bevent->event;
 606         unsigned long irq_flags;
 607         int device_no;
 608         int error;
 609         spinlock_t *qlock;
 610
 611         num_sg = block_event_to_scatterlist(bevent, sg, &total_len);
 612         num_sect = total_len >> 9;
 613         if (event->xSubtype == (viomajorsubtype_blockio | vioblockread))
 614                 pci_direction = DMA_FROM_DEVICE;
 615         else
 616                 pci_direction = DMA_TO_DEVICE;
 617         dma_unmap_sg(iSeries_vio_dev, sg, num_sg, pci_direction);
 618
 619         /*
 620          * Since this is running in interrupt mode, we need to make sure
 621          * we're not stepping on any global I/O operations
 622          */
 623         spin_lock_irqsave(&viodasd_spinlock, irq_flags);
 624         num_req_outstanding--;
 625         spin_unlock_irqrestore(&viodasd_spinlock, irq_flags);
 626
 627         req = (struct request *)bevent->event.xCorrelationToken;
 628         device_no = DEVICE_NO(req->rq_disk->private_data);
 629
 630         error = event->xRc != HvLpEvent_Rc_Good;
 631         if (error) {
 632                 const struct vio_error_entry *err;
 633                 err = vio_lookup_rc(viodasd_err_table, bevent->sub_result);
 634                 printk(VIOD_KERN_WARNING "read/write error %d:0x%04x (%s)\n",
 635                                 event->xRc, bevent->sub_result, err->msg);
 636                 num_sect = req->hard_nr_sectors;
 637         }
 638         qlock = req->q->queue_lock;
 639         spin_lock_irqsave(qlock, irq_flags);
 640         viodasd_end_request(req, !error, num_sect);
 641         spin_unlock_irqrestore(qlock, irq_flags);
 642
 643         /* Finally, try to get more requests off of this device's queue */
 644         viodasd_restart_all_queues_starting_from(device_no);
 645
 646         return 0;
 647 }
 648
 649 /* This routine handles incoming block LP events */
 650 static void handle_block_event(struct HvLpEvent *event)
 651 {
 652         struct vioblocklpevent *bevent = (struct vioblocklpevent *)event;
 653         struct viodasd_waitevent *pwe;
 654
 655         if (event == NULL)
 656                 /* Notification that a partition went away! */
 657                 return;
 658         /* First, we should NEVER get an int here...only acks */
 659         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 660                 printk(VIOD_KERN_WARNING
 661                        "Yikes! got an int in viodasd event handler!\n");
 662                 if (event->xFlags.xAckInd == HvLpEvent_AckInd_DoAck) {
 663                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 664                         HvCallEvent_ackLpEvent(event);
 665                 }
 666         }
 667
 668         switch (event->xSubtype & VIOMINOR_SUBTYPE_MASK) {
 669         case vioblockopen:
 670                 /*
 671                  * Handle a response to an open request.  We get all the
 672                  * disk information in the response, so update it.  The
 673                  * correlation token contains a pointer to a waitevent
 674                  * structure that has a completion in it.  update the
 675                  * return code in the waitevent structure and post the
 676                  * completion to wake up the guy who sent the request
 677                  */
 678                 pwe = (struct viodasd_waitevent *)event->xCorrelationToken;
 679                 pwe->rc = event->xRc;
 680                 pwe->sub_result = bevent->sub_result;
 681                 if (event->xRc == HvLpEvent_Rc_Good) {
 682                         const struct open_data *data = &bevent->u.open_data;
 683                         struct viodasd_device *device =
 684                                 &viodasd_devices[bevent->disk];
 685                         device->read_only =
 686                                 bevent->flags & vioblockflags_ro;
 687                         device->size = data->disk_size;
 688                         device->cylinders = data->cylinders;
 689                         device->tracks = data->tracks;
 690                         device->sectors = data->sectors;
 691                         device->bytes_per_sector = data->bytes_per_sector;
 692                         pwe->max_disk = data->max_disk;
 693                 }
 694                 complete(&pwe->com);
 695                 break;
 696         case vioblockclose:
 697                 break;
 698         case vioblockread:
 699         case vioblockwrite:
 700                 viodasd_handle_read_write(bevent);
 701                 break;
 702
 703         default:
 704                 printk(VIOD_KERN_WARNING "invalid subtype!");
 705                 if (event->xFlags.xAckInd == HvLpEvent_AckInd_DoAck) {
 706                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 707                         HvCallEvent_ackLpEvent(event);
 708                 }
 709         }
 710 }
 711
 712 /*
 713  * Initialize the whole device driver.  Handle module and non-module
 714  * versions
 715  */
 716 static int __init viodasd_init(void)
 717 {
 718         int i;
 719
 720         /* Try to open to our host lp */
 721         if (viopath_hostLp == HvLpIndexInvalid)
 722                 vio_set_hostlp();
 723
 724         if (viopath_hostLp == HvLpIndexInvalid) {
 725                 printk(VIOD_KERN_WARNING "invalid hosting partition\n");
 726                 return -EIO;
 727         }
 728
 729         printk(VIOD_KERN_INFO "vers " VIOD_VERS ", hosting partition %d\n",
 730                         viopath_hostLp);
 731
 732         /* register the block device */
 733         if (register_blkdev(VIODASD_MAJOR, VIOD_GENHD_NAME)) {
 734                 printk(VIOD_KERN_WARNING
 735                                 "Unable to get major number %d for %s\n",
 736                                 VIODASD_MAJOR, VIOD_GENHD_NAME);
 737                 return -EIO;
 738         }
 739         /* Actually open the path to the hosting partition */
 740         if (viopath_open(viopath_hostLp, viomajorsubtype_blockio,
 741                                 VIOMAXREQ + 2)) {
 742                 printk(VIOD_KERN_WARNING
 743                        "error opening path to host partition %d\n",
 744                        viopath_hostLp);
 745                 unregister_blkdev(VIODASD_MAJOR, VIOD_GENHD_NAME);
 746                 return -EIO;
 747         }
 748
 749         /* Initialize our request handler */
 750         vio_setHandler(viomajorsubtype_blockio, handle_block_event);
 751
 752         for (i = 0; i < MAX_DISKNO; i++)
 753                 probe_disk(&viodasd_devices[i]);
 754
 755         return 0;
 756 }
 757 module_init(viodasd_init);
 758
 759 void viodasd_exit(void)
 760 {
 761         int i;
 762         struct viodasd_device *d;
 763
 764         for (i = 0; i < MAX_DISKNO; i++) {
 765                 d = &viodasd_devices[i];
 766                 if (d->disk) {
 767                         del_gendisk(d->disk);
 768                         put_disk(d->disk);
 769                         blk_cleanup_queue(d->disk->queue);
 770                         d->disk = NULL;
 771                 }
 772         }
 773         vio_clearHandler(viomajorsubtype_blockio);
 774         unregister_blkdev(VIODASD_MAJOR, VIOD_GENHD_NAME);
 775         viopath_close(viopath_hostLp, viomajorsubtype_blockio, VIOMAXREQ + 2);
 776 }
 777
 778 module_exit(viodasd_exit);