git.oblomov.eu Git - linux-2.6/blob - 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 #include <linux/device.h>
  44 #include <linux/kernel.h>
  45
  46 #include <asm/uaccess.h>
  47 #include <asm/vio.h>
  48 #include <asm/iseries/hv_types.h>
  49 #include <asm/iseries/hv_lp_event.h>
  50 #include <asm/iseries/hv_lp_config.h>
  51 #include <asm/iseries/vio.h>
  52 #include <asm/firmware.h>
  53
  54 MODULE_DESCRIPTION("iSeries Virtual DASD");
  55 MODULE_AUTHOR("Dave Boutcher");
  56 MODULE_LICENSE("GPL");
  57
  58 /*
  59  * We only support 7 partitions per physical disk....so with minor
  60  * numbers 0-255 we get a maximum of 32 disks.
  61  */
  62 #define VIOD_GENHD_NAME         "iseries/vd"
  63
  64 #define VIOD_VERS               "1.64"
  65
  66 #define VIOD_KERN_WARNING       KERN_WARNING "viod: "
  67 #define VIOD_KERN_INFO          KERN_INFO "viod: "
  68
  69 enum {
  70         PARTITION_SHIFT = 3,
  71         MAX_DISKNO = HVMAXARCHITECTEDVIRTUALDISKS,
  72         MAX_DISK_NAME = sizeof(((struct gendisk *)0)->disk_name)
  73 };
  74
  75 static DEFINE_SPINLOCK(viodasd_spinlock);
  76
  77 #define VIOMAXREQ               16
  78 #define VIOMAXBLOCKDMA          12
  79
  80 #define DEVICE_NO(cell) ((struct viodasd_device *)(cell) - &viodasd_devices[0])
  81
  82 struct open_data {
  83         u64     disk_size;
  84         u16     max_disk;
  85         u16     cylinders;
  86         u16     tracks;
  87         u16     sectors;
  88         u16     bytes_per_sector;
  89 };
  90
  91 struct rw_data {
  92         u64     offset;
  93         struct {
  94                 u32     token;
  95                 u32     reserved;
  96                 u64     len;
  97         } dma_info[VIOMAXBLOCKDMA];
  98 };
  99
 100 struct vioblocklpevent {
 101         struct HvLpEvent        event;
 102         u32                     reserved;
 103         u16                     version;
 104         u16                     sub_result;
 105         u16                     disk;
 106         u16                     flags;
 107         union {
 108                 struct open_data        open_data;
 109                 struct rw_data          rw_data;
 110                 u64                     changed;
 111         } u;
 112 };
 113
 114 #define vioblockflags_ro   0x0001
 115
 116 enum vioblocksubtype {
 117         vioblockopen = 0x0001,
 118         vioblockclose = 0x0002,
 119         vioblockread = 0x0003,
 120         vioblockwrite = 0x0004,
 121         vioblockflush = 0x0005,
 122         vioblockcheck = 0x0007
 123 };
 124
 125 struct viodasd_waitevent {
 126         struct completion       com;
 127         int                     rc;
 128         u16                     sub_result;
 129         int                     max_disk;       /* open */
 130 };
 131
 132 static const struct vio_error_entry viodasd_err_table[] = {
 133         { 0x0201, EINVAL, "Invalid Range" },
 134         { 0x0202, EINVAL, "Invalid Token" },
 135         { 0x0203, EIO, "DMA Error" },
 136         { 0x0204, EIO, "Use Error" },
 137         { 0x0205, EIO, "Release Error" },
 138         { 0x0206, EINVAL, "Invalid Disk" },
 139         { 0x0207, EBUSY, "Cant Lock" },
 140         { 0x0208, EIO, "Already Locked" },
 141         { 0x0209, EIO, "Already Unlocked" },
 142         { 0x020A, EIO, "Invalid Arg" },
 143         { 0x020B, EIO, "Bad IFS File" },
 144         { 0x020C, EROFS, "Read Only Device" },
 145         { 0x02FF, EIO, "Internal Error" },
 146         { 0x0000, 0, NULL },
 147 };
 148
 149 /*
 150  * Figure out the biggest I/O request (in sectors) we can accept
 151  */
 152 #define VIODASD_MAXSECTORS (4096 / 512 * VIOMAXBLOCKDMA)
 153
 154 /*
 155  * Number of disk I/O requests we've sent to OS/400
 156  */
 157 static int num_req_outstanding;
 158
 159 /*
 160  * This is our internal structure for keeping track of disk devices
 161  */
 162 struct viodasd_device {
 163         u16             cylinders;
 164         u16             tracks;
 165         u16             sectors;
 166         u16             bytes_per_sector;
 167         u64             size;
 168         int             read_only;
 169         spinlock_t      q_lock;
 170         struct gendisk  *disk;
 171         struct device   *dev;
 172 } viodasd_devices[MAX_DISKNO];
 173
 174 /*
 175  * External open entry point.
 176  */
 177 static int viodasd_open(struct inode *ino, struct file *fil)
 178 {
 179         struct viodasd_device *d = ino->i_bdev->bd_disk->private_data;
 180         HvLpEvent_Rc hvrc;
 181         struct viodasd_waitevent we;
 182         u16 flags = 0;
 183
 184         if (d->read_only) {
 185                 if ((fil != NULL) && (fil->f_mode & FMODE_WRITE))
 186                         return -EROFS;
 187                 flags = vioblockflags_ro;
 188         }
 189
 190         init_completion(&we.com);
 191
 192         /* Send the open event to OS/400 */
 193         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 194                         HvLpEvent_Type_VirtualIo,
 195                         viomajorsubtype_blockio | vioblockopen,
 196                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
 197                         viopath_sourceinst(viopath_hostLp),
 198                         viopath_targetinst(viopath_hostLp),
 199                         (u64)(unsigned long)&we, VIOVERSION << 16,
 200                         ((u64)DEVICE_NO(d) << 48) | ((u64)flags << 32),
 201                         0, 0, 0);
 202         if (hvrc != 0) {
 203                 printk(VIOD_KERN_WARNING "HV open failed %d\n", (int)hvrc);
 204                 return -EIO;
 205         }
 206
 207         wait_for_completion(&we.com);
 208
 209         /* Check the return code */
 210         if (we.rc != 0) {
 211                 const struct vio_error_entry *err =
 212                         vio_lookup_rc(viodasd_err_table, we.sub_result);
 213
 214                 printk(VIOD_KERN_WARNING
 215                                 "bad rc opening disk: %d:0x%04x (%s)\n",
 216                                 (int)we.rc, we.sub_result, err->msg);
 217                 return -EIO;
 218         }
 219
 220         return 0;
 221 }
 222
 223 /*
 224  * External release entry point.
 225  */
 226 static int viodasd_release(struct inode *ino, struct file *fil)
 227 {
 228         struct viodasd_device *d = ino->i_bdev->bd_disk->private_data;
 229         HvLpEvent_Rc hvrc;
 230
 231         /* Send the event to OS/400.  We DON'T expect a response */
 232         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 233                         HvLpEvent_Type_VirtualIo,
 234                         viomajorsubtype_blockio | vioblockclose,
 235                         HvLpEvent_AckInd_NoAck, HvLpEvent_AckType_ImmediateAck,
 236                         viopath_sourceinst(viopath_hostLp),
 237                         viopath_targetinst(viopath_hostLp),
 238                         0, VIOVERSION << 16,
 239                         ((u64)DEVICE_NO(d) << 48) /* | ((u64)flags << 32) */,
 240                         0, 0, 0);
 241         if (hvrc != 0)
 242                 printk(VIOD_KERN_WARNING "HV close call failed %d\n",
 243                                 (int)hvrc);
 244         return 0;
 245 }
 246
 247
 248 /* External ioctl entry point.
 249  */
 250 static int viodasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 251 {
 252         struct gendisk *disk = bdev->bd_disk;
 253         struct viodasd_device *d = disk->private_data;
 254
 255         geo->sectors = d->sectors ? d->sectors : 32;
 256         geo->heads = d->tracks ? d->tracks  : 64;
 257         geo->cylinders = d->cylinders ? d->cylinders :
 258                 get_capacity(disk) / (geo->sectors * geo->heads);
 259
 260         return 0;
 261 }
 262
 263 /*
 264  * Our file operations table
 265  */
 266 static struct block_device_operations viodasd_fops = {
 267         .owner = THIS_MODULE,
 268         .open = viodasd_open,
 269         .release = viodasd_release,
 270         .getgeo = viodasd_getgeo,
 271 };
 272
 273 /*
 274  * End a request
 275  */
 276 static void viodasd_end_request(struct request *req, int uptodate,
 277                 int num_sectors)
 278 {
 279         if (end_that_request_first(req, uptodate, num_sectors))
 280                 return;
 281         add_disk_randomness(req->rq_disk);
 282         end_that_request_last(req, uptodate);
 283 }
 284
 285 /*
 286  * Send an actual I/O request to OS/400
 287  */
 288 static int send_request(struct request *req)
 289 {
 290         u64 start;
 291         int direction;
 292         int nsg;
 293         u16 viocmd;
 294         HvLpEvent_Rc hvrc;
 295         struct vioblocklpevent *bevent;
 296         struct HvLpEvent *hev;
 297         struct scatterlist sg[VIOMAXBLOCKDMA];
 298         int sgindex;
 299         int statindex;
 300         struct viodasd_device *d;
 301         unsigned long flags;
 302
 303         start = (u64)req->sector << 9;
 304
 305         if (rq_data_dir(req) == READ) {
 306                 direction = DMA_FROM_DEVICE;
 307                 viocmd = viomajorsubtype_blockio | vioblockread;
 308                 statindex = 0;
 309         } else {
 310                 direction = DMA_TO_DEVICE;
 311                 viocmd = viomajorsubtype_blockio | vioblockwrite;
 312                 statindex = 1;
 313         }
 314
 315         d = req->rq_disk->private_data;
 316
 317         /* Now build the scatter-gather list */
 318         nsg = blk_rq_map_sg(req->q, req, sg);
 319         nsg = dma_map_sg(d->dev, sg, nsg, direction);
 320
 321         spin_lock_irqsave(&viodasd_spinlock, flags);
 322         num_req_outstanding++;
 323
 324         /* This optimization handles a single DMA block */
 325         if (nsg == 1)
 326                 hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 327                                 HvLpEvent_Type_VirtualIo, viocmd,
 328                                 HvLpEvent_AckInd_DoAck,
 329                                 HvLpEvent_AckType_ImmediateAck,
 330                                 viopath_sourceinst(viopath_hostLp),
 331                                 viopath_targetinst(viopath_hostLp),
 332                                 (u64)(unsigned long)req, VIOVERSION << 16,
 333                                 ((u64)DEVICE_NO(d) << 48), start,
 334                                 ((u64)sg_dma_address(&sg[0])) << 32,
 335                                 sg_dma_len(&sg[0]));
 336         else {
 337                 bevent = (struct vioblocklpevent *)
 338                         vio_get_event_buffer(viomajorsubtype_blockio);
 339                 if (bevent == NULL) {
 340                         printk(VIOD_KERN_WARNING
 341                                "error allocating disk event buffer\n");
 342                         goto error_ret;
 343                 }
 344
 345                 /*
 346                  * Now build up the actual request.  Note that we store
 347                  * the pointer to the request in the correlation
 348                  * token so we can match the response up later
 349                  */
 350                 memset(bevent, 0, sizeof(struct vioblocklpevent));
 351                 hev = &bevent->event;
 352                 hev->flags = HV_LP_EVENT_VALID | HV_LP_EVENT_DO_ACK |
 353                         HV_LP_EVENT_INT;
 354                 hev->xType = HvLpEvent_Type_VirtualIo;
 355                 hev->xSubtype = viocmd;
 356                 hev->xSourceLp = HvLpConfig_getLpIndex();
 357                 hev->xTargetLp = viopath_hostLp;
 358                 hev->xSizeMinus1 =
 359                         offsetof(struct vioblocklpevent, u.rw_data.dma_info) +
 360                         (sizeof(bevent->u.rw_data.dma_info[0]) * nsg) - 1;
 361                 hev->xSourceInstanceId = viopath_sourceinst(viopath_hostLp);
 362                 hev->xTargetInstanceId = viopath_targetinst(viopath_hostLp);
 363                 hev->xCorrelationToken = (u64)req;
 364                 bevent->version = VIOVERSION;
 365                 bevent->disk = DEVICE_NO(d);
 366                 bevent->u.rw_data.offset = start;
 367
 368                 /*
 369                  * Copy just the dma information from the sg list
 370                  * into the request
 371                  */
 372                 for (sgindex = 0; sgindex < nsg; sgindex++) {
 373                         bevent->u.rw_data.dma_info[sgindex].token =
 374                                 sg_dma_address(&sg[sgindex]);
 375                         bevent->u.rw_data.dma_info[sgindex].len =
 376                                 sg_dma_len(&sg[sgindex]);
 377                 }
 378
 379                 /* Send the request */
 380                 hvrc = HvCallEvent_signalLpEvent(&bevent->event);
 381                 vio_free_event_buffer(viomajorsubtype_blockio, bevent);
 382         }
 383
 384         if (hvrc != HvLpEvent_Rc_Good) {
 385                 printk(VIOD_KERN_WARNING
 386                        "error sending disk event to OS/400 (rc %d)\n",
 387                        (int)hvrc);
 388                 goto error_ret;
 389         }
 390         spin_unlock_irqrestore(&viodasd_spinlock, flags);
 391         return 0;
 392
 393 error_ret:
 394         num_req_outstanding--;
 395         spin_unlock_irqrestore(&viodasd_spinlock, flags);
 396         dma_unmap_sg(d->dev, sg, nsg, direction);
 397         return -1;
 398 }
 399
 400 /*
 401  * This is the external request processing routine
 402  */
 403 static void do_viodasd_request(request_queue_t *q)
 404 {
 405         struct request *req;
 406
 407         /*
 408          * If we already have the maximum number of requests
 409          * outstanding to OS/400 just bail out. We'll come
 410          * back later.
 411          */
 412         while (num_req_outstanding < VIOMAXREQ) {
 413                 req = elv_next_request(q);
 414                 if (req == NULL)
 415                         return;
 416                 /* dequeue the current request from the queue */
 417                 blkdev_dequeue_request(req);
 418                 /* check that request contains a valid command */
 419                 if (!blk_fs_request(req)) {
 420                         viodasd_end_request(req, 0, req->hard_nr_sectors);
 421                         continue;
 422                 }
 423                 /* Try sending the request */
 424                 if (send_request(req) != 0)
 425                         viodasd_end_request(req, 0, req->hard_nr_sectors);
 426         }
 427 }
 428
 429 /*
 430  * Probe a single disk and fill in the viodasd_device structure
 431  * for it.
 432  */
 433 static void probe_disk(struct viodasd_device *d)
 434 {
 435         HvLpEvent_Rc hvrc;
 436         struct viodasd_waitevent we;
 437         int dev_no = DEVICE_NO(d);
 438         struct gendisk *g;
 439         struct request_queue *q;
 440         u16 flags = 0;
 441
 442 retry:
 443         init_completion(&we.com);
 444
 445         /* Send the open event to OS/400 */
 446         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 447                         HvLpEvent_Type_VirtualIo,
 448                         viomajorsubtype_blockio | vioblockopen,
 449                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
 450                         viopath_sourceinst(viopath_hostLp),
 451                         viopath_targetinst(viopath_hostLp),
 452                         (u64)(unsigned long)&we, VIOVERSION << 16,
 453                         ((u64)dev_no << 48) | ((u64)flags<< 32),
 454                         0, 0, 0);
 455         if (hvrc != 0) {
 456                 printk(VIOD_KERN_WARNING "bad rc on HV open %d\n", (int)hvrc);
 457                 return;
 458         }
 459
 460         wait_for_completion(&we.com);
 461
 462         if (we.rc != 0) {
 463                 if (flags != 0)
 464                         return;
 465                 /* try again with read only flag set */
 466                 flags = vioblockflags_ro;
 467                 goto retry;
 468         }
 469         if (we.max_disk > (MAX_DISKNO - 1)) {
 470                 static int warned;
 471
 472                 if (warned == 0) {
 473                         warned++;
 474                         printk(VIOD_KERN_INFO
 475                                 "Only examining the first %d "
 476                                 "of %d disks connected\n",
 477                                 MAX_DISKNO, we.max_disk + 1);
 478                 }
 479         }
 480
 481         /* Send the close event to OS/400.  We DON'T expect a response */
 482         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 483                         HvLpEvent_Type_VirtualIo,
 484                         viomajorsubtype_blockio | vioblockclose,
 485                         HvLpEvent_AckInd_NoAck, HvLpEvent_AckType_ImmediateAck,
 486                         viopath_sourceinst(viopath_hostLp),
 487                         viopath_targetinst(viopath_hostLp),
 488                         0, VIOVERSION << 16,
 489                         ((u64)dev_no << 48) | ((u64)flags << 32),
 490                         0, 0, 0);
 491         if (hvrc != 0) {
 492                 printk(VIOD_KERN_WARNING
 493                        "bad rc sending event to OS/400 %d\n", (int)hvrc);
 494                 return;
 495         }
 496         /* create the request queue for the disk */
 497         spin_lock_init(&d->q_lock);
 498         q = blk_init_queue(do_viodasd_request, &d->q_lock);
 499         if (q == NULL) {
 500                 printk(VIOD_KERN_WARNING "cannot allocate queue for disk %d\n",
 501                                 dev_no);
 502                 return;
 503         }
 504         g = alloc_disk(1 << PARTITION_SHIFT);
 505         if (g == NULL) {
 506                 printk(VIOD_KERN_WARNING
 507                                 "cannot allocate disk structure for disk %d\n",
 508                                 dev_no);
 509                 blk_cleanup_queue(q);
 510                 return;
 511         }
 512
 513         d->disk = g;
 514         blk_queue_max_hw_segments(q, VIOMAXBLOCKDMA);
 515         blk_queue_max_phys_segments(q, VIOMAXBLOCKDMA);
 516         blk_queue_max_sectors(q, VIODASD_MAXSECTORS);
 517         g->major = VIODASD_MAJOR;
 518         g->first_minor = dev_no << PARTITION_SHIFT;
 519         if (dev_no >= 26)
 520                 snprintf(g->disk_name, sizeof(g->disk_name),
 521                                 VIOD_GENHD_NAME "%c%c",
 522                                 'a' + (dev_no / 26) - 1, 'a' + (dev_no % 26));
 523         else
 524                 snprintf(g->disk_name, sizeof(g->disk_name),
 525                                 VIOD_GENHD_NAME "%c", 'a' + (dev_no % 26));
 526         g->fops = &viodasd_fops;
 527         g->queue = q;
 528         g->private_data = d;
 529         g->driverfs_dev = d->dev;
 530         set_capacity(g, d->size >> 9);
 531
 532         printk(VIOD_KERN_INFO "disk %d: %lu sectors (%lu MB) "
 533                         "CHS=%d/%d/%d sector size %d%s\n",
 534                         dev_no, (unsigned long)(d->size >> 9),
 535                         (unsigned long)(d->size >> 20),
 536                         (int)d->cylinders, (int)d->tracks,
 537                         (int)d->sectors, (int)d->bytes_per_sector,
 538                         d->read_only ? " (RO)" : "");
 539
 540         /* register us in the global list */
 541         add_disk(g);
 542 }
 543
 544 /* returns the total number of scatterlist elements converted */
 545 static int block_event_to_scatterlist(const struct vioblocklpevent *bevent,
 546                 struct scatterlist *sg, int *total_len)
 547 {
 548         int i, numsg;
 549         const struct rw_data *rw_data = &bevent->u.rw_data;
 550         static const int offset =
 551                 offsetof(struct vioblocklpevent, u.rw_data.dma_info);
 552         static const int element_size = sizeof(rw_data->dma_info[0]);
 553
 554         numsg = ((bevent->event.xSizeMinus1 + 1) - offset) / element_size;
 555         if (numsg > VIOMAXBLOCKDMA)
 556                 numsg = VIOMAXBLOCKDMA;
 557
 558         *total_len = 0;
 559         memset(sg, 0, sizeof(sg[0]) * VIOMAXBLOCKDMA);
 560
 561         for (i = 0; (i < numsg) && (rw_data->dma_info[i].len > 0); ++i) {
 562                 sg_dma_address(&sg[i]) = rw_data->dma_info[i].token;
 563                 sg_dma_len(&sg[i]) = rw_data->dma_info[i].len;
 564                 *total_len += rw_data->dma_info[i].len;
 565         }
 566         return i;
 567 }
 568
 569 /*
 570  * Restart all queues, starting with the one _after_ the disk given,
 571  * thus reducing the chance of starvation of higher numbered disks.
 572  */
 573 static void viodasd_restart_all_queues_starting_from(int first_index)
 574 {
 575         int i;
 576
 577         for (i = first_index + 1; i < MAX_DISKNO; ++i)
 578                 if (viodasd_devices[i].disk)
 579                         blk_run_queue(viodasd_devices[i].disk->queue);
 580         for (i = 0; i <= first_index; ++i)
 581                 if (viodasd_devices[i].disk)
 582                         blk_run_queue(viodasd_devices[i].disk->queue);
 583 }
 584
 585 /*
 586  * For read and write requests, decrement the number of outstanding requests,
 587  * Free the DMA buffers we allocated.
 588  */
 589 static int viodasd_handle_read_write(struct vioblocklpevent *bevent)
 590 {
 591         int num_sg, num_sect, pci_direction, total_len;
 592         struct request *req;
 593         struct scatterlist sg[VIOMAXBLOCKDMA];
 594         struct HvLpEvent *event = &bevent->event;
 595         unsigned long irq_flags;
 596         struct viodasd_device *d;
 597         int error;
 598         spinlock_t *qlock;
 599
 600         num_sg = block_event_to_scatterlist(bevent, sg, &total_len);
 601         num_sect = total_len >> 9;
 602         if (event->xSubtype == (viomajorsubtype_blockio | vioblockread))
 603                 pci_direction = DMA_FROM_DEVICE;
 604         else
 605                 pci_direction = DMA_TO_DEVICE;
 606         req = (struct request *)bevent->event.xCorrelationToken;
 607         d = req->rq_disk->private_data;
 608
 609         dma_unmap_sg(d->dev, sg, num_sg, pci_direction);
 610
 611         /*
 612          * Since this is running in interrupt mode, we need to make sure
 613          * we're not stepping on any global I/O operations
 614          */
 615         spin_lock_irqsave(&viodasd_spinlock, irq_flags);
 616         num_req_outstanding--;
 617         spin_unlock_irqrestore(&viodasd_spinlock, irq_flags);
 618
 619         error = event->xRc != HvLpEvent_Rc_Good;
 620         if (error) {
 621                 const struct vio_error_entry *err;
 622                 err = vio_lookup_rc(viodasd_err_table, bevent->sub_result);
 623                 printk(VIOD_KERN_WARNING "read/write error %d:0x%04x (%s)\n",
 624                                 event->xRc, bevent->sub_result, err->msg);
 625                 num_sect = req->hard_nr_sectors;
 626         }
 627         qlock = req->q->queue_lock;
 628         spin_lock_irqsave(qlock, irq_flags);
 629         viodasd_end_request(req, !error, num_sect);
 630         spin_unlock_irqrestore(qlock, irq_flags);
 631
 632         /* Finally, try to get more requests off of this device's queue */
 633         viodasd_restart_all_queues_starting_from(DEVICE_NO(d));
 634
 635         return 0;
 636 }
 637
 638 /* This routine handles incoming block LP events */
 639 static void handle_block_event(struct HvLpEvent *event)
 640 {
 641         struct vioblocklpevent *bevent = (struct vioblocklpevent *)event;
 642         struct viodasd_waitevent *pwe;
 643
 644         if (event == NULL)
 645                 /* Notification that a partition went away! */
 646                 return;
 647         /* First, we should NEVER get an int here...only acks */
 648         if (hvlpevent_is_int(event)) {
 649                 printk(VIOD_KERN_WARNING
 650                        "Yikes! got an int in viodasd event handler!\n");
 651                 if (hvlpevent_need_ack(event)) {
 652                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 653                         HvCallEvent_ackLpEvent(event);
 654                 }
 655         }
 656
 657         switch (event->xSubtype & VIOMINOR_SUBTYPE_MASK) {
 658         case vioblockopen:
 659                 /*
 660                  * Handle a response to an open request.  We get all the
 661                  * disk information in the response, so update it.  The
 662                  * correlation token contains a pointer to a waitevent
 663                  * structure that has a completion in it.  update the
 664                  * return code in the waitevent structure and post the
 665                  * completion to wake up the guy who sent the request
 666                  */
 667                 pwe = (struct viodasd_waitevent *)event->xCorrelationToken;
 668                 pwe->rc = event->xRc;
 669                 pwe->sub_result = bevent->sub_result;
 670                 if (event->xRc == HvLpEvent_Rc_Good) {
 671                         const struct open_data *data = &bevent->u.open_data;
 672                         struct viodasd_device *device =
 673                                 &viodasd_devices[bevent->disk];
 674                         device->read_only =
 675                                 bevent->flags & vioblockflags_ro;
 676                         device->size = data->disk_size;
 677                         device->cylinders = data->cylinders;
 678                         device->tracks = data->tracks;
 679                         device->sectors = data->sectors;
 680                         device->bytes_per_sector = data->bytes_per_sector;
 681                         pwe->max_disk = data->max_disk;
 682                 }
 683                 complete(&pwe->com);
 684                 break;
 685         case vioblockclose:
 686                 break;
 687         case vioblockread:
 688         case vioblockwrite:
 689                 viodasd_handle_read_write(bevent);
 690                 break;
 691
 692         default:
 693                 printk(VIOD_KERN_WARNING "invalid subtype!");
 694                 if (hvlpevent_need_ack(event)) {
 695                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 696                         HvCallEvent_ackLpEvent(event);
 697                 }
 698         }
 699 }
 700
 701 /*
 702  * Get the driver to reprobe for more disks.
 703  */
 704 static ssize_t probe_disks(struct device_driver *drv, const char *buf,
 705                 size_t count)
 706 {
 707         struct viodasd_device *d;
 708
 709         for (d = viodasd_devices; d < &viodasd_devices[MAX_DISKNO]; d++) {
 710                 if (d->disk == NULL)
 711                         probe_disk(d);
 712         }
 713         return count;
 714 }
 715 static DRIVER_ATTR(probe, S_IWUSR, NULL, probe_disks);
 716
 717 static int viodasd_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 718 {
 719         struct viodasd_device *d = &viodasd_devices[vdev->unit_address];
 720
 721         d->dev = &vdev->dev;
 722         probe_disk(d);
 723         if (d->disk == NULL)
 724                 return -ENODEV;
 725         return 0;
 726 }
 727
 728 static int viodasd_remove(struct vio_dev *vdev)
 729 {
 730         struct viodasd_device *d;
 731
 732         d = &viodasd_devices[vdev->unit_address];
 733         if (d->disk) {
 734                 del_gendisk(d->disk);
 735                 blk_cleanup_queue(d->disk->queue);
 736                 put_disk(d->disk);
 737                 d->disk = NULL;
 738         }
 739         d->dev = NULL;
 740         return 0;
 741 }
 742
 743 /**
 744  * viodasd_device_table: Used by vio.c to match devices that we
 745  * support.
 746  */
 747 static struct vio_device_id viodasd_device_table[] __devinitdata = {
 748         { "block", "IBM,iSeries-viodasd" },
 749         { "", "" }
 750 };
 751 MODULE_DEVICE_TABLE(vio, viodasd_device_table);
 752
 753 static struct vio_driver viodasd_driver = {
 754         .id_table = viodasd_device_table,
 755         .probe = viodasd_probe,
 756         .remove = viodasd_remove,
 757         .driver = {
 758                 .name = "viodasd",
 759                 .owner = THIS_MODULE,
 760         }
 761 };
 762
 763 static int need_delete_probe;
 764
 765 /*
 766  * Initialize the whole device driver.  Handle module and non-module
 767  * versions
 768  */
 769 static int __init viodasd_init(void)
 770 {
 771         int rc;
 772
 773         if (!firmware_has_feature(FW_FEATURE_ISERIES)) {
 774                 rc = -ENODEV;
 775                 goto early_fail;
 776         }
 777
 778         /* Try to open to our host lp */
 779         if (viopath_hostLp == HvLpIndexInvalid)
 780                 vio_set_hostlp();
 781
 782         if (viopath_hostLp == HvLpIndexInvalid) {
 783                 printk(VIOD_KERN_WARNING "invalid hosting partition\n");
 784                 rc = -EIO;
 785                 goto early_fail;
 786         }
 787
 788         printk(VIOD_KERN_INFO "vers " VIOD_VERS ", hosting partition %d\n",
 789                         viopath_hostLp);
 790
 791         /* register the block device */
 792         rc =  register_blkdev(VIODASD_MAJOR, VIOD_GENHD_NAME);
 793         if (rc) {
 794                 printk(VIOD_KERN_WARNING
 795                                 "Unable to get major number %d for %s\n",
 796                                 VIODASD_MAJOR, VIOD_GENHD_NAME);
 797                 goto early_fail;
 798         }
 799         /* Actually open the path to the hosting partition */
 800         rc = viopath_open(viopath_hostLp, viomajorsubtype_blockio,
 801                                 VIOMAXREQ + 2);
 802         if (rc) {
 803                 printk(VIOD_KERN_WARNING
 804                        "error opening path to host partition %d\n",
 805                        viopath_hostLp);
 806                 goto unregister_blk;
 807         }
 808
 809         /* Initialize our request handler */
 810         vio_setHandler(viomajorsubtype_blockio, handle_block_event);
 811
 812         rc = vio_register_driver(&viodasd_driver);
 813         if (rc) {
 814                 printk(VIOD_KERN_WARNING "vio_register_driver failed\n");
 815                 goto unset_handler;
 816         }
 817
 818         /*
 819          * If this call fails, it just means that we cannot dynamically
 820          * add virtual disks, but the driver will still work fine for
 821          * all existing disk, so ignore the failure.
 822          */
 823         if (!driver_create_file(&viodasd_driver.driver, &driver_attr_probe))
 824                 need_delete_probe = 1;
 825
 826         return 0;
 827
 828 unset_handler:
 829         vio_clearHandler(viomajorsubtype_blockio);
 830         viopath_close(viopath_hostLp, viomajorsubtype_blockio, VIOMAXREQ + 2);
 831 unregister_blk:
 832         unregister_blkdev(VIODASD_MAJOR, VIOD_GENHD_NAME);
 833 early_fail:
 834         return rc;
 835 }
 836 module_init(viodasd_init);
 837
 838 void __exit viodasd_exit(void)
 839 {
 840         if (need_delete_probe)
 841                 driver_remove_file(&viodasd_driver.driver, &driver_attr_probe);
 842         vio_unregister_driver(&viodasd_driver);
 843         vio_clearHandler(viomajorsubtype_blockio);
 844         viopath_close(viopath_hostLp, viomajorsubtype_blockio, VIOMAXREQ + 2);
 845         unregister_blkdev(VIODASD_MAJOR, VIOD_GENHD_NAME);
 846 }
 847 module_exit(viodasd_exit);