SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/scsi/osd/osd_initiator.c

   1 /*
   2  * osd_initiator - Main body of the osd initiator library.
   3  *
   4  * Note: The file does not contain the advanced security functionality which
   5  * is only needed by the security_manager's initiators.
   6  *
   7  * Copyright (C) 2008 Panasas Inc.  All rights reserved.
   8  *
   9  * Authors:
  10  *   Boaz Harrosh <bharrosh@panasas.com>
  11  *   Benny Halevy <bhalevy@panasas.com>
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License version 2
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  *
  20  *  1. Redistributions of source code must retain the above copyright
  21  *     notice, this list of conditions and the following disclaimer.
  22  *  2. Redistributions in binary form must reproduce the above copyright
  23  *     notice, this list of conditions and the following disclaimer in the
  24  *     documentation and/or other materials provided with the distribution.
  25  *  3. Neither the name of the Panasas company nor the names of its
  26  *     contributors may be used to endorse or promote products derived
  27  *     from this software without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  30  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  31  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  32  * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  34  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  35  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  36  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  37  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  38  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  39  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  40  */
  41
  42 #include <scsi/osd_initiator.h>
  43 #include <scsi/osd_sec.h>
  44 #include <scsi/scsi_device.h>
  45
  46 #include "osd_debug.h"
  47
  48 #ifndef __unused
  49 #    define __unused                    __attribute__((unused))
  50 #endif
  51
  52 enum { OSD_REQ_RETRIES = 1 };
  53
  54 MODULE_AUTHOR("Boaz Harrosh <bharrosh@panasas.com>");
  55 MODULE_DESCRIPTION("open-osd initiator library libosd.ko");
  56 MODULE_LICENSE("GPL");
  57
  58 static inline void build_test(void)
  59 {
  60         /* structures were not packed */
  61         BUILD_BUG_ON(sizeof(struct osd_capability) != OSD_CAP_LEN);
  62         BUILD_BUG_ON(sizeof(struct osdv1_cdb) != OSDv1_TOTAL_CDB_LEN);
  63 }
  64
  65 static unsigned _osd_req_cdb_len(struct osd_request *or)
  66 {
  67         return OSDv1_TOTAL_CDB_LEN;
  68 }
  69
  70 static unsigned _osd_req_alist_elem_size(struct osd_request *or, unsigned len)
  71 {
  72         return osdv1_attr_list_elem_size(len);
  73 }
  74
  75 static unsigned _osd_req_alist_size(struct osd_request *or, void *list_head)
  76 {
  77         return osdv1_list_size(list_head);
  78 }
  79
  80 static unsigned _osd_req_sizeof_alist_header(struct osd_request *or)
  81 {
  82         return sizeof(struct osdv1_attributes_list_header);
  83 }
  84
  85 static void _osd_req_set_alist_type(struct osd_request *or,
  86         void *list, int list_type)
  87 {
  88         struct osdv1_attributes_list_header *attr_list = list;
  89
  90         memset(attr_list, 0, sizeof(*attr_list));
  91         attr_list->type = list_type;
  92 }
  93
  94 static bool _osd_req_is_alist_type(struct osd_request *or,
  95         void *list, int list_type)
  96 {
  97         if (!list)
  98                 return false;
  99
 100         if (1) {
 101                 struct osdv1_attributes_list_header *attr_list = list;
 102
 103                 return attr_list->type == list_type;
 104         }
 105 }
 106
 107 /* This is for List-objects not Attributes-Lists */
 108 static void _osd_req_encode_olist(struct osd_request *or,
 109         struct osd_obj_id_list *list)
 110 {
 111         struct osd_cdb_head *cdbh = osd_cdb_head(&or->cdb);
 112
 113         cdbh->v1.list_identifier = list->list_identifier;
 114         cdbh->v1.start_address = list->continuation_id;
 115 }
 116
 117 static osd_cdb_offset osd_req_encode_offset(struct osd_request *or,
 118         u64 offset, unsigned *padding)
 119 {
 120         return __osd_encode_offset(offset, padding,
 121                                   OSDv1_OFFSET_MIN_SHIFT, OSD_OFFSET_MAX_SHIFT);
 122 }
 123
 124 static struct osd_security_parameters *
 125 _osd_req_sec_params(struct osd_request *or)
 126 {
 127         struct osd_cdb *ocdb = &or->cdb;
 128
 129         return &ocdb->v1.sec_params;
 130 }
 131
 132 void osd_dev_init(struct osd_dev *osdd, struct scsi_device *scsi_device)
 133 {
 134         memset(osdd, 0, sizeof(*osdd));
 135         osdd->scsi_device = scsi_device;
 136         osdd->def_timeout = BLK_DEFAULT_SG_TIMEOUT;
 137         /* TODO: Allocate pools for osd_request attributes ... */
 138 }
 139 EXPORT_SYMBOL(osd_dev_init);
 140
 141 void osd_dev_fini(struct osd_dev *osdd)
 142 {
 143         /* TODO: De-allocate pools */
 144
 145         osdd->scsi_device = NULL;
 146 }
 147 EXPORT_SYMBOL(osd_dev_fini);
 148
 149 static struct osd_request *_osd_request_alloc(gfp_t gfp)
 150 {
 151         struct osd_request *or;
 152
 153         /* TODO: Use mempool with one saved request */
 154         or = kzalloc(sizeof(*or), gfp);
 155         return or;
 156 }
 157
 158 static void _osd_request_free(struct osd_request *or)
 159 {
 160         kfree(or);
 161 }
 162
 163 struct osd_request *osd_start_request(struct osd_dev *dev, gfp_t gfp)
 164 {
 165         struct osd_request *or;
 166
 167         or = _osd_request_alloc(gfp);
 168         if (!or)
 169                 return NULL;
 170
 171         or->osd_dev = dev;
 172         or->alloc_flags = gfp;
 173         or->timeout = dev->def_timeout;
 174         or->retries = OSD_REQ_RETRIES;
 175
 176         return or;
 177 }
 178 EXPORT_SYMBOL(osd_start_request);
 179
 180 /*
 181  * If osd_finalize_request() was called but the request was not executed through
 182  * the block layer, then we must release BIOs.
 183  */
 184 static void _abort_unexecuted_bios(struct request *rq)
 185 {
 186         struct bio *bio;
 187
 188         while ((bio = rq->bio) != NULL) {
 189                 rq->bio = bio->bi_next;
 190                 bio_endio(bio, 0);
 191         }
 192 }
 193
 194 static void _osd_free_seg(struct osd_request *or __unused,
 195         struct _osd_req_data_segment *seg)
 196 {
 197         if (!seg->buff || !seg->alloc_size)
 198                 return;
 199
 200         kfree(seg->buff);
 201         seg->buff = NULL;
 202         seg->alloc_size = 0;
 203 }
 204
 205 void osd_end_request(struct osd_request *or)
 206 {
 207         struct request *rq = or->request;
 208
 209         _osd_free_seg(or, &or->set_attr);
 210         _osd_free_seg(or, &or->enc_get_attr);
 211         _osd_free_seg(or, &or->get_attr);
 212
 213         if (rq) {
 214                 if (rq->next_rq) {
 215                         _abort_unexecuted_bios(rq->next_rq);
 216                         blk_put_request(rq->next_rq);
 217                 }
 218
 219                 _abort_unexecuted_bios(rq);
 220                 blk_put_request(rq);
 221         }
 222         _osd_request_free(or);
 223 }
 224 EXPORT_SYMBOL(osd_end_request);
 225
 226 int osd_execute_request(struct osd_request *or)
 227 {
 228         return blk_execute_rq(or->request->q, NULL, or->request, 0);
 229 }
 230 EXPORT_SYMBOL(osd_execute_request);
 231
 232 static void osd_request_async_done(struct request *req, int error)
 233 {
 234         struct osd_request *or = req->end_io_data;
 235
 236         or->async_error = error;
 237
 238         if (error)
 239                 OSD_DEBUG("osd_request_async_done error recieved %d\n", error);
 240
 241         if (or->async_done)
 242                 or->async_done(or, or->async_private);
 243         else
 244                 osd_end_request(or);
 245 }
 246
 247 int osd_execute_request_async(struct osd_request *or,
 248         osd_req_done_fn *done, void *private)
 249 {
 250         or->request->end_io_data = or;
 251         or->async_private = private;
 252         or->async_done = done;
 253
 254         blk_execute_rq_nowait(or->request->q, NULL, or->request, 0,
 255                               osd_request_async_done);
 256         return 0;
 257 }
 258 EXPORT_SYMBOL(osd_execute_request_async);
 259
 260 u8 sg_out_pad_buffer[1 << OSDv1_OFFSET_MIN_SHIFT];
 261 u8 sg_in_pad_buffer[1 << OSDv1_OFFSET_MIN_SHIFT];
 262
 263 static int _osd_realloc_seg(struct osd_request *or,
 264         struct _osd_req_data_segment *seg, unsigned max_bytes)
 265 {
 266         void *buff;
 267
 268         if (seg->alloc_size >= max_bytes)
 269                 return 0;
 270
 271         buff = krealloc(seg->buff, max_bytes, or->alloc_flags);
 272         if (!buff) {
 273                 OSD_ERR("Failed to Realloc %d-bytes was-%d\n", max_bytes,
 274                         seg->alloc_size);
 275                 return -ENOMEM;
 276         }
 277
 278         memset(buff + seg->alloc_size, 0, max_bytes - seg->alloc_size);
 279         seg->buff = buff;
 280         seg->alloc_size = max_bytes;
 281         return 0;
 282 }
 283
 284 static int _alloc_set_attr_list(struct osd_request *or,
 285         const struct osd_attr *oa, unsigned nelem, unsigned add_bytes)
 286 {
 287         unsigned total_bytes = add_bytes;
 288
 289         for (; nelem; --nelem, ++oa)
 290                 total_bytes += _osd_req_alist_elem_size(or, oa->len);
 291
 292         OSD_DEBUG("total_bytes=%d\n", total_bytes);
 293         return _osd_realloc_seg(or, &or->set_attr, total_bytes);
 294 }
 295
 296 static int _alloc_get_attr_desc(struct osd_request *or, unsigned max_bytes)
 297 {
 298         OSD_DEBUG("total_bytes=%d\n", max_bytes);
 299         return _osd_realloc_seg(or, &or->enc_get_attr, max_bytes);
 300 }
 301
 302 static int _alloc_get_attr_list(struct osd_request *or)
 303 {
 304         OSD_DEBUG("total_bytes=%d\n", or->get_attr.total_bytes);
 305         return _osd_realloc_seg(or, &or->get_attr, or->get_attr.total_bytes);
 306 }
 307
 308 /*
 309  * Common to all OSD commands
 310  */
 311
 312 static void _osdv1_req_encode_common(struct osd_request *or,
 313         __be16 act, const struct osd_obj_id *obj, u64 offset, u64 len)
 314 {
 315         struct osdv1_cdb *ocdb = &or->cdb.v1;
 316
 317         /*
 318          * For speed, the commands
 319          *      OSD_ACT_PERFORM_SCSI_COMMAND    , V1 0x8F7E, V2 0x8F7C
 320          *      OSD_ACT_SCSI_TASK_MANAGEMENT    , V1 0x8F7F, V2 0x8F7D
 321          * are not supported here. Should pass zero and set after the call
 322          */
 323         act &= cpu_to_be16(~0x0080); /* V1 action code */
 324
 325         OSD_DEBUG("OSDv1 execute opcode 0x%x\n", be16_to_cpu(act));
 326
 327         ocdb->h.varlen_cdb.opcode = VARIABLE_LENGTH_CMD;
 328         ocdb->h.varlen_cdb.additional_cdb_length = OSD_ADDITIONAL_CDB_LENGTH;
 329         ocdb->h.varlen_cdb.service_action = act;
 330
 331         ocdb->h.partition = cpu_to_be64(obj->partition);
 332         ocdb->h.object = cpu_to_be64(obj->id);
 333         ocdb->h.v1.length = cpu_to_be64(len);
 334         ocdb->h.v1.start_address = cpu_to_be64(offset);
 335 }
 336
 337 static void _osd_req_encode_common(struct osd_request *or,
 338         __be16 act, const struct osd_obj_id *obj, u64 offset, u64 len)
 339 {
 340         _osdv1_req_encode_common(or, act, obj, offset, len);
 341 }
 342
 343 /*
 344  * Device commands
 345  */
 346 void osd_req_format(struct osd_request *or, u64 tot_capacity)
 347 {
 348         _osd_req_encode_common(or, OSD_ACT_FORMAT_OSD, &osd_root_object, 0,
 349                                 tot_capacity);
 350 }
 351 EXPORT_SYMBOL(osd_req_format);
 352
 353 int osd_req_list_dev_partitions(struct osd_request *or,
 354         osd_id initial_id, struct osd_obj_id_list *list, unsigned nelem)
 355 {
 356         return osd_req_list_partition_objects(or, 0, initial_id, list, nelem);
 357 }
 358 EXPORT_SYMBOL(osd_req_list_dev_partitions);
 359
 360 static void _osd_req_encode_flush(struct osd_request *or,
 361         enum osd_options_flush_scope_values op)
 362 {
 363         struct osd_cdb_head *ocdb = osd_cdb_head(&or->cdb);
 364
 365         ocdb->command_specific_options = op;
 366 }
 367
 368 void osd_req_flush_obsd(struct osd_request *or,
 369         enum osd_options_flush_scope_values op)
 370 {
 371         _osd_req_encode_common(or, OSD_ACT_FLUSH_OSD, &osd_root_object, 0, 0);
 372         _osd_req_encode_flush(or, op);
 373 }
 374 EXPORT_SYMBOL(osd_req_flush_obsd);
 375
 376 /*
 377  * Partition commands
 378  */
 379 static void _osd_req_encode_partition(struct osd_request *or,
 380         __be16 act, osd_id partition)
 381 {
 382         struct osd_obj_id par = {
 383                 .partition = partition,
 384                 .id = 0,
 385         };
 386
 387         _osd_req_encode_common(or, act, &par, 0, 0);
 388 }
 389
 390 void osd_req_create_partition(struct osd_request *or, osd_id partition)
 391 {
 392         _osd_req_encode_partition(or, OSD_ACT_CREATE_PARTITION, partition);
 393 }
 394 EXPORT_SYMBOL(osd_req_create_partition);
 395
 396 void osd_req_remove_partition(struct osd_request *or, osd_id partition)
 397 {
 398         _osd_req_encode_partition(or, OSD_ACT_REMOVE_PARTITION, partition);
 399 }
 400 EXPORT_SYMBOL(osd_req_remove_partition);
 401
 402 static int _osd_req_list_objects(struct osd_request *or,
 403         __be16 action, const struct osd_obj_id *obj, osd_id initial_id,
 404         struct osd_obj_id_list *list, unsigned nelem)
 405 {
 406         struct request_queue *q = or->osd_dev->scsi_device->request_queue;
 407         u64 len = nelem * sizeof(osd_id) + sizeof(*list);
 408         struct bio *bio;
 409
 410         _osd_req_encode_common(or, action, obj, (u64)initial_id, len);
 411
 412         if (list->list_identifier)
 413                 _osd_req_encode_olist(or, list);
 414
 415         WARN_ON(or->in.bio);
 416         bio = bio_map_kern(q, list, len, or->alloc_flags);
 417         if (!bio) {
 418                 OSD_ERR("!!! Failed to allocate list_objects BIO\n");
 419                 return -ENOMEM;
 420         }
 421
 422         bio->bi_rw &= ~(1 << BIO_RW);
 423         or->in.bio = bio;
 424         or->in.total_bytes = bio->bi_size;
 425         return 0;
 426 }
 427
 428 int osd_req_list_partition_collections(struct osd_request *or,
 429         osd_id partition, osd_id initial_id, struct osd_obj_id_list *list,
 430         unsigned nelem)
 431 {
 432         struct osd_obj_id par = {
 433                 .partition = partition,
 434                 .id = 0,
 435         };
 436
 437         return osd_req_list_collection_objects(or, &par, initial_id, list,
 438                                                nelem);
 439 }
 440 EXPORT_SYMBOL(osd_req_list_partition_collections);
 441
 442 int osd_req_list_partition_objects(struct osd_request *or,
 443         osd_id partition, osd_id initial_id, struct osd_obj_id_list *list,
 444         unsigned nelem)
 445 {
 446         struct osd_obj_id par = {
 447                 .partition = partition,
 448                 .id = 0,
 449         };
 450
 451         return _osd_req_list_objects(or, OSD_ACT_LIST, &par, initial_id, list,
 452                                      nelem);
 453 }
 454 EXPORT_SYMBOL(osd_req_list_partition_objects);
 455
 456 void osd_req_flush_partition(struct osd_request *or,
 457         osd_id partition, enum osd_options_flush_scope_values op)
 458 {
 459         _osd_req_encode_partition(or, OSD_ACT_FLUSH_PARTITION, partition);
 460         _osd_req_encode_flush(or, op);
 461 }
 462 EXPORT_SYMBOL(osd_req_flush_partition);
 463
 464 /*
 465  * Collection commands
 466  */
 467 int osd_req_list_collection_objects(struct osd_request *or,
 468         const struct osd_obj_id *obj, osd_id initial_id,
 469         struct osd_obj_id_list *list, unsigned nelem)
 470 {
 471         return _osd_req_list_objects(or, OSD_ACT_LIST_COLLECTION, obj,
 472                                      initial_id, list, nelem);
 473 }
 474 EXPORT_SYMBOL(osd_req_list_collection_objects);
 475
 476 void osd_req_flush_collection(struct osd_request *or,
 477         const struct osd_obj_id *obj, enum osd_options_flush_scope_values op)
 478 {
 479         _osd_req_encode_common(or, OSD_ACT_FLUSH_PARTITION, obj, 0, 0);
 480         _osd_req_encode_flush(or, op);
 481 }
 482 EXPORT_SYMBOL(osd_req_flush_collection);
 483
 484 /*
 485  * Object commands
 486  */
 487 void osd_req_create_object(struct osd_request *or, struct osd_obj_id *obj)
 488 {
 489         _osd_req_encode_common(or, OSD_ACT_CREATE, obj, 0, 0);
 490 }
 491 EXPORT_SYMBOL(osd_req_create_object);
 492
 493 void osd_req_remove_object(struct osd_request *or, struct osd_obj_id *obj)
 494 {
 495         _osd_req_encode_common(or, OSD_ACT_REMOVE, obj, 0, 0);
 496 }
 497 EXPORT_SYMBOL(osd_req_remove_object);
 498
 499 void osd_req_write(struct osd_request *or,
 500         const struct osd_obj_id *obj, struct bio *bio, u64 offset)
 501 {
 502         _osd_req_encode_common(or, OSD_ACT_WRITE, obj, offset, bio->bi_size);
 503         WARN_ON(or->out.bio || or->out.total_bytes);
 504         bio->bi_rw |= (1 << BIO_RW);
 505         or->out.bio = bio;
 506         or->out.total_bytes = bio->bi_size;
 507 }
 508 EXPORT_SYMBOL(osd_req_write);
 509
 510 void osd_req_flush_object(struct osd_request *or,
 511         const struct osd_obj_id *obj, enum osd_options_flush_scope_values op,
 512         /*V2*/ u64 offset, /*V2*/ u64 len)
 513 {
 514         _osd_req_encode_common(or, OSD_ACT_FLUSH, obj, offset, len);
 515         _osd_req_encode_flush(or, op);
 516 }
 517 EXPORT_SYMBOL(osd_req_flush_object);
 518
 519 void osd_req_read(struct osd_request *or,
 520         const struct osd_obj_id *obj, struct bio *bio, u64 offset)
 521 {
 522         _osd_req_encode_common(or, OSD_ACT_READ, obj, offset, bio->bi_size);
 523         WARN_ON(or->in.bio || or->in.total_bytes);
 524         bio->bi_rw &= ~(1 << BIO_RW);
 525         or->in.bio = bio;
 526         or->in.total_bytes = bio->bi_size;
 527 }
 528 EXPORT_SYMBOL(osd_req_read);
 529
 530 void osd_req_get_attributes(struct osd_request *or,
 531         const struct osd_obj_id *obj)
 532 {
 533         _osd_req_encode_common(or, OSD_ACT_GET_ATTRIBUTES, obj, 0, 0);
 534 }
 535 EXPORT_SYMBOL(osd_req_get_attributes);
 536
 537 void osd_req_set_attributes(struct osd_request *or,
 538         const struct osd_obj_id *obj)
 539 {
 540         _osd_req_encode_common(or, OSD_ACT_SET_ATTRIBUTES, obj, 0, 0);
 541 }
 542 EXPORT_SYMBOL(osd_req_set_attributes);
 543
 544 /*
 545  * Attributes List-mode
 546  */
 547
 548 int osd_req_add_set_attr_list(struct osd_request *or,
 549         const struct osd_attr *oa, unsigned nelem)
 550 {
 551         unsigned total_bytes = or->set_attr.total_bytes;
 552         void *attr_last;
 553         int ret;
 554
 555         if (or->attributes_mode &&
 556             or->attributes_mode != OSD_CDB_GET_SET_ATTR_LISTS) {
 557                 WARN_ON(1);
 558                 return -EINVAL;
 559         }
 560         or->attributes_mode = OSD_CDB_GET_SET_ATTR_LISTS;
 561
 562         if (!total_bytes) { /* first-time: allocate and put list header */
 563                 total_bytes = _osd_req_sizeof_alist_header(or);
 564                 ret = _alloc_set_attr_list(or, oa, nelem, total_bytes);
 565                 if (ret)
 566                         return ret;
 567                 _osd_req_set_alist_type(or, or->set_attr.buff,
 568                                         OSD_ATTR_LIST_SET_RETRIEVE);
 569         }
 570         attr_last = or->set_attr.buff + total_bytes;
 571
 572         for (; nelem; --nelem) {
 573                 struct osd_attributes_list_element *attr;
 574                 unsigned elem_size = _osd_req_alist_elem_size(or, oa->len);
 575
 576                 total_bytes += elem_size;
 577                 if (unlikely(or->set_attr.alloc_size < total_bytes)) {
 578                         or->set_attr.total_bytes = total_bytes - elem_size;
 579                         ret = _alloc_set_attr_list(or, oa, nelem, total_bytes);
 580                         if (ret)
 581                                 return ret;
 582                         attr_last =
 583                                 or->set_attr.buff + or->set_attr.total_bytes;
 584                 }
 585
 586                 attr = attr_last;
 587                 attr->attr_page = cpu_to_be32(oa->attr_page);
 588                 attr->attr_id = cpu_to_be32(oa->attr_id);
 589                 attr->attr_bytes = cpu_to_be16(oa->len);
 590                 memcpy(attr->attr_val, oa->val_ptr, oa->len);
 591
 592                 attr_last += elem_size;
 593                 ++oa;
 594         }
 595
 596         or->set_attr.total_bytes = total_bytes;
 597         return 0;
 598 }
 599 EXPORT_SYMBOL(osd_req_add_set_attr_list);
 600
 601 static int _append_map_kern(struct request *req,
 602         void *buff, unsigned len, gfp_t flags)
 603 {
 604         struct bio *bio;
 605         int ret;
 606
 607         bio = bio_map_kern(req->q, buff, len, flags);
 608         if (IS_ERR(bio)) {
 609                 OSD_ERR("Failed bio_map_kern(%p, %d) => %ld\n", buff, len,
 610                         PTR_ERR(bio));
 611                 return PTR_ERR(bio);
 612         }
 613         ret = blk_rq_append_bio(req->q, req, bio);
 614         if (ret) {
 615                 OSD_ERR("Failed blk_rq_append_bio(%p) => %d\n", bio, ret);
 616                 bio_put(bio);
 617         }
 618         return ret;
 619 }
 620
 621 static int _req_append_segment(struct osd_request *or,
 622         unsigned padding, struct _osd_req_data_segment *seg,
 623         struct _osd_req_data_segment *last_seg, struct _osd_io_info *io)
 624 {
 625         void *pad_buff;
 626         int ret;
 627
 628         if (padding) {
 629                 /* check if we can just add it to last buffer */
 630                 if (last_seg &&
 631                     (padding <= last_seg->alloc_size - last_seg->total_bytes))
 632                         pad_buff = last_seg->buff + last_seg->total_bytes;
 633                 else
 634                         pad_buff = io->pad_buff;
 635
 636                 ret = _append_map_kern(io->req, pad_buff, padding,
 637                                        or->alloc_flags);
 638                 if (ret)
 639                         return ret;
 640                 io->total_bytes += padding;
 641         }
 642
 643         ret = _append_map_kern(io->req, seg->buff, seg->total_bytes,
 644                                or->alloc_flags);
 645         if (ret)
 646                 return ret;
 647
 648         io->total_bytes += seg->total_bytes;
 649         OSD_DEBUG("padding=%d buff=%p total_bytes=%d\n", padding, seg->buff,
 650                   seg->total_bytes);
 651         return 0;
 652 }
 653
 654 static int _osd_req_finalize_set_attr_list(struct osd_request *or)
 655 {
 656         struct osd_cdb_head *cdbh = osd_cdb_head(&or->cdb);
 657         unsigned padding;
 658         int ret;
 659
 660         if (!or->set_attr.total_bytes) {
 661                 cdbh->attrs_list.set_attr_offset = OSD_OFFSET_UNUSED;
 662                 return 0;
 663         }
 664
 665         cdbh->attrs_list.set_attr_bytes = cpu_to_be32(or->set_attr.total_bytes);
 666         cdbh->attrs_list.set_attr_offset =
 667                 osd_req_encode_offset(or, or->out.total_bytes, &padding);
 668
 669         ret = _req_append_segment(or, padding, &or->set_attr,
 670                                   or->out.last_seg, &or->out);
 671         if (ret)
 672                 return ret;
 673
 674         or->out.last_seg = &or->set_attr;
 675         return 0;
 676 }
 677
 678 int osd_req_add_get_attr_list(struct osd_request *or,
 679         const struct osd_attr *oa, unsigned nelem)
 680 {
 681         unsigned total_bytes = or->enc_get_attr.total_bytes;
 682         void *attr_last;
 683         int ret;
 684
 685         if (or->attributes_mode &&
 686             or->attributes_mode != OSD_CDB_GET_SET_ATTR_LISTS) {
 687                 WARN_ON(1);
 688                 return -EINVAL;
 689         }
 690         or->attributes_mode = OSD_CDB_GET_SET_ATTR_LISTS;
 691
 692         /* first time calc data-in list header size */
 693         if (!or->get_attr.total_bytes)
 694                 or->get_attr.total_bytes = _osd_req_sizeof_alist_header(or);
 695
 696         /* calc data-out info */
 697         if (!total_bytes) { /* first-time: allocate and put list header */
 698                 unsigned max_bytes;
 699
 700                 total_bytes = _osd_req_sizeof_alist_header(or);
 701                 max_bytes = total_bytes +
 702                         nelem * sizeof(struct osd_attributes_list_attrid);
 703                 ret = _alloc_get_attr_desc(or, max_bytes);
 704                 if (ret)
 705                         return ret;
 706
 707                 _osd_req_set_alist_type(or, or->enc_get_attr.buff,
 708                                         OSD_ATTR_LIST_GET);
 709         }
 710         attr_last = or->enc_get_attr.buff + total_bytes;
 711
 712         for (; nelem; --nelem) {
 713                 struct osd_attributes_list_attrid *attrid;
 714                 const unsigned cur_size = sizeof(*attrid);
 715
 716                 total_bytes += cur_size;
 717                 if (unlikely(or->enc_get_attr.alloc_size < total_bytes)) {
 718                         or->enc_get_attr.total_bytes = total_bytes - cur_size;
 719                         ret = _alloc_get_attr_desc(or,
 720                                         total_bytes + nelem * sizeof(*attrid));
 721                         if (ret)
 722                                 return ret;
 723                         attr_last = or->enc_get_attr.buff +
 724                                 or->enc_get_attr.total_bytes;
 725                 }
 726
 727                 attrid = attr_last;
 728                 attrid->attr_page = cpu_to_be32(oa->attr_page);
 729                 attrid->attr_id = cpu_to_be32(oa->attr_id);
 730
 731                 attr_last += cur_size;
 732
 733                 /* calc data-in size */
 734                 or->get_attr.total_bytes +=
 735                         _osd_req_alist_elem_size(or, oa->len);
 736                 ++oa;
 737         }
 738
 739         or->enc_get_attr.total_bytes = total_bytes;
 740
 741         OSD_DEBUG(
 742                "get_attr.total_bytes=%u(%u) enc_get_attr.total_bytes=%u(%Zu)\n",
 743                or->get_attr.total_bytes,
 744                or->get_attr.total_bytes - _osd_req_sizeof_alist_header(or),
 745                or->enc_get_attr.total_bytes,
 746                (or->enc_get_attr.total_bytes - _osd_req_sizeof_alist_header(or))
 747                         / sizeof(struct osd_attributes_list_attrid));
 748
 749         return 0;
 750 }
 751 EXPORT_SYMBOL(osd_req_add_get_attr_list);
 752
 753 static int _osd_req_finalize_get_attr_list(struct osd_request *or)
 754 {
 755         struct osd_cdb_head *cdbh = osd_cdb_head(&or->cdb);
 756         unsigned out_padding;
 757         unsigned in_padding;
 758         int ret;
 759
 760         if (!or->enc_get_attr.total_bytes) {
 761                 cdbh->attrs_list.get_attr_desc_offset = OSD_OFFSET_UNUSED;
 762                 cdbh->attrs_list.get_attr_offset = OSD_OFFSET_UNUSED;
 763                 return 0;
 764         }
 765
 766         ret = _alloc_get_attr_list(or);
 767         if (ret)
 768                 return ret;
 769
 770         /* The out-going buffer info update */
 771         OSD_DEBUG("out-going\n");
 772         cdbh->attrs_list.get_attr_desc_bytes =
 773                 cpu_to_be32(or->enc_get_attr.total_bytes);
 774
 775         cdbh->attrs_list.get_attr_desc_offset =
 776                 osd_req_encode_offset(or, or->out.total_bytes, &out_padding);
 777
 778         ret = _req_append_segment(or, out_padding, &or->enc_get_attr,
 779                                   or->out.last_seg, &or->out);
 780         if (ret)
 781                 return ret;
 782         or->out.last_seg = &or->enc_get_attr;
 783
 784         /* The incoming buffer info update */
 785         OSD_DEBUG("in-coming\n");
 786         cdbh->attrs_list.get_attr_alloc_length =
 787                 cpu_to_be32(or->get_attr.total_bytes);
 788
 789         cdbh->attrs_list.get_attr_offset =
 790                 osd_req_encode_offset(or, or->in.total_bytes, &in_padding);
 791
 792         ret = _req_append_segment(or, in_padding, &or->get_attr, NULL,
 793                                   &or->in);
 794         if (ret)
 795                 return ret;
 796         or->in.last_seg = &or->get_attr;
 797
 798         return 0;
 799 }
 800
 801 int osd_req_decode_get_attr_list(struct osd_request *or,
 802         struct osd_attr *oa, int *nelem, void **iterator)
 803 {
 804         unsigned cur_bytes, returned_bytes;
 805         int n;
 806         const unsigned sizeof_attr_list = _osd_req_sizeof_alist_header(or);
 807         void *cur_p;
 808
 809         if (!_osd_req_is_alist_type(or, or->get_attr.buff,
 810                                     OSD_ATTR_LIST_SET_RETRIEVE)) {
 811                 oa->attr_page = 0;
 812                 oa->attr_id = 0;
 813                 oa->val_ptr = NULL;
 814                 oa->len = 0;
 815                 *iterator = NULL;
 816                 return 0;
 817         }
 818
 819         if (*iterator) {
 820                 BUG_ON((*iterator < or->get_attr.buff) ||
 821                      (or->get_attr.buff + or->get_attr.alloc_size < *iterator));
 822                 cur_p = *iterator;
 823                 cur_bytes = (*iterator - or->get_attr.buff) - sizeof_attr_list;
 824                 returned_bytes = or->get_attr.total_bytes;
 825         } else { /* first time decode the list header */
 826                 cur_bytes = sizeof_attr_list;
 827                 returned_bytes = _osd_req_alist_size(or, or->get_attr.buff) +
 828                                         sizeof_attr_list;
 829
 830                 cur_p = or->get_attr.buff + sizeof_attr_list;
 831
 832                 if (returned_bytes > or->get_attr.alloc_size) {
 833                         OSD_DEBUG("target report: space was not big enough! "
 834                                   "Allocate=%u Needed=%u\n",
 835                                   or->get_attr.alloc_size,
 836                                   returned_bytes + sizeof_attr_list);
 837
 838                         returned_bytes =
 839                                 or->get_attr.alloc_size - sizeof_attr_list;
 840                 }
 841                 or->get_attr.total_bytes = returned_bytes;
 842         }
 843
 844         for (n = 0; (n < *nelem) && (cur_bytes < returned_bytes); ++n) {
 845                 struct osd_attributes_list_element *attr = cur_p;
 846                 unsigned inc;
 847
 848                 oa->len = be16_to_cpu(attr->attr_bytes);
 849                 inc = _osd_req_alist_elem_size(or, oa->len);
 850                 OSD_DEBUG("oa->len=%d inc=%d cur_bytes=%d\n",
 851                           oa->len, inc, cur_bytes);
 852                 cur_bytes += inc;
 853                 if (cur_bytes > returned_bytes) {
 854                         OSD_ERR("BAD FOOD from target. list not valid!"
 855                                 "c=%d r=%d n=%d\n",
 856                                 cur_bytes, returned_bytes, n);
 857                         oa->val_ptr = NULL;
 858                         break;
 859                 }
 860
 861                 oa->attr_page = be32_to_cpu(attr->attr_page);
 862                 oa->attr_id = be32_to_cpu(attr->attr_id);
 863                 oa->val_ptr = attr->attr_val;
 864
 865                 cur_p += inc;
 866                 ++oa;
 867         }
 868
 869         *iterator = (returned_bytes - cur_bytes) ? cur_p : NULL;
 870         *nelem = n;
 871         return returned_bytes - cur_bytes;
 872 }
 873 EXPORT_SYMBOL(osd_req_decode_get_attr_list);
 874
 875 /*
 876  * Attributes Page-mode
 877  */
 878
 879 int osd_req_add_get_attr_page(struct osd_request *or,
 880         u32 page_id, void *attar_page, unsigned max_page_len,
 881         const struct osd_attr *set_one_attr)
 882 {
 883         struct osd_cdb_head *cdbh = osd_cdb_head(&or->cdb);
 884
 885         if (or->attributes_mode &&
 886             or->attributes_mode != OSD_CDB_GET_ATTR_PAGE_SET_ONE) {
 887                 WARN_ON(1);
 888                 return -EINVAL;
 889         }
 890         or->attributes_mode = OSD_CDB_GET_ATTR_PAGE_SET_ONE;
 891
 892         or->get_attr.buff = attar_page;
 893         or->get_attr.total_bytes = max_page_len;
 894
 895         or->set_attr.buff = set_one_attr->val_ptr;
 896         or->set_attr.total_bytes = set_one_attr->len;
 897
 898         cdbh->attrs_page.get_attr_page = cpu_to_be32(page_id);
 899         cdbh->attrs_page.get_attr_alloc_length = cpu_to_be32(max_page_len);
 900         /* ocdb->attrs_page.get_attr_offset; */
 901
 902         cdbh->attrs_page.set_attr_page = cpu_to_be32(set_one_attr->attr_page);
 903         cdbh->attrs_page.set_attr_id = cpu_to_be32(set_one_attr->attr_id);
 904         cdbh->attrs_page.set_attr_length = cpu_to_be32(set_one_attr->len);
 905         /* ocdb->attrs_page.set_attr_offset; */
 906         return 0;
 907 }
 908 EXPORT_SYMBOL(osd_req_add_get_attr_page);
 909
 910 static int _osd_req_finalize_attr_page(struct osd_request *or)
 911 {
 912         struct osd_cdb_head *cdbh = osd_cdb_head(&or->cdb);
 913         unsigned in_padding, out_padding;
 914         int ret;
 915
 916         /* returned page */
 917         cdbh->attrs_page.get_attr_offset =
 918                 osd_req_encode_offset(or, or->in.total_bytes, &in_padding);
 919
 920         ret = _req_append_segment(or, in_padding, &or->get_attr, NULL,
 921                                   &or->in);
 922         if (ret)
 923                 return ret;
 924
 925         /* set one value */
 926         cdbh->attrs_page.set_attr_offset =
 927                 osd_req_encode_offset(or, or->out.total_bytes, &out_padding);
 928
 929         ret = _req_append_segment(or, out_padding, &or->enc_get_attr, NULL,
 930                                   &or->out);
 931         return ret;
 932 }
 933
 934 static int _osd_req_finalize_data_integrity(struct osd_request *or,
 935         bool has_in, bool has_out, const u8 *cap_key)
 936 {
 937         struct osd_security_parameters *sec_parms = _osd_req_sec_params(or);
 938         int ret;
 939
 940         if (!osd_is_sec_alldata(sec_parms))
 941                 return 0;
 942
 943         if (has_out) {
 944                 struct _osd_req_data_segment seg = {
 945                         .buff = &or->out_data_integ,
 946                         .total_bytes = sizeof(or->out_data_integ),
 947                 };
 948                 unsigned pad;
 949
 950                 or->out_data_integ.data_bytes = cpu_to_be64(
 951                         or->out.bio ? or->out.bio->bi_size : 0);
 952                 or->out_data_integ.set_attributes_bytes = cpu_to_be64(
 953                         or->set_attr.total_bytes);
 954                 or->out_data_integ.get_attributes_bytes = cpu_to_be64(
 955                         or->enc_get_attr.total_bytes);
 956
 957                 sec_parms->data_out_integrity_check_offset =
 958                         osd_req_encode_offset(or, or->out.total_bytes, &pad);
 959
 960                 ret = _req_append_segment(or, pad, &seg, or->out.last_seg,
 961                                           &or->out);
 962                 if (ret)
 963                         return ret;
 964                 or->out.last_seg = NULL;
 965
 966                 /* they are now all chained to request sign them all together */
 967                 osd_sec_sign_data(&or->out_data_integ, or->out.req->bio,
 968                                   cap_key);
 969         }
 970
 971         if (has_in) {
 972                 struct _osd_req_data_segment seg = {
 973                         .buff = &or->in_data_integ,
 974                         .total_bytes = sizeof(or->in_data_integ),
 975                 };
 976                 unsigned pad;
 977
 978                 sec_parms->data_in_integrity_check_offset =
 979                         osd_req_encode_offset(or, or->in.total_bytes, &pad);
 980
 981                 ret = _req_append_segment(or, pad, &seg, or->in.last_seg,
 982                                           &or->in);
 983                 if (ret)
 984                         return ret;
 985
 986                 or->in.last_seg = NULL;
 987         }
 988
 989         return 0;
 990 }
 991
 992 /*
 993  * osd_finalize_request and helpers
 994  */
 995
 996 static int _init_blk_request(struct osd_request *or,
 997         bool has_in, bool has_out)
 998 {
 999         gfp_t flags = or->alloc_flags;
1000         struct scsi_device *scsi_device = or->osd_dev->scsi_device;
1001         struct request_queue *q = scsi_device->request_queue;
1002         struct request *req;
1003         int ret = -ENOMEM;
1004
1005         req = blk_get_request(q, has_out, flags);
1006         if (!req)
1007                 goto out;
1008
1009         or->request = req;
1010         req->cmd_type = REQ_TYPE_BLOCK_PC;
1011         req->timeout = or->timeout;
1012         req->retries = or->retries;
1013         req->sense = or->sense;
1014         req->sense_len = 0;
1015
1016         if (has_out) {
1017                 or->out.req = req;
1018                 if (has_in) {
1019                         /* allocate bidi request */
1020                         req = blk_get_request(q, READ, flags);
1021                         if (!req) {
1022                                 OSD_DEBUG("blk_get_request for bidi failed\n");
1023                                 goto out;
1024                         }
1025                         req->cmd_type = REQ_TYPE_BLOCK_PC;
1026                         or->in.req = or->request->next_rq = req;
1027                 }
1028         } else if (has_in)
1029                 or->in.req = req;
1030
1031         ret = 0;
1032 out:
1033         OSD_DEBUG("or=%p has_in=%d has_out=%d => %d, %p\n",
1034                         or, has_in, has_out, ret, or->request);
1035         return ret;
1036 }
1037
1038 int osd_finalize_request(struct osd_request *or,
1039         u8 options, const void *cap, const u8 *cap_key)
1040 {
1041         struct osd_cdb_head *cdbh = osd_cdb_head(&or->cdb);
1042         bool has_in, has_out;
1043         int ret;
1044
1045         if (options & OSD_REQ_FUA)
1046                 cdbh->options |= OSD_CDB_FUA;
1047
1048         if (options & OSD_REQ_DPO)
1049                 cdbh->options |= OSD_CDB_DPO;
1050
1051         if (options & OSD_REQ_BYPASS_TIMESTAMPS)
1052                 cdbh->timestamp_control = OSD_CDB_BYPASS_TIMESTAMPS;
1053
1054         osd_set_caps(&or->cdb, cap);
1055
1056         has_in = or->in.bio || or->get_attr.total_bytes;
1057         has_out = or->out.bio || or->set_attr.total_bytes ||
1058                 or->enc_get_attr.total_bytes;
1059
1060         ret = _init_blk_request(or, has_in, has_out);
1061         if (ret) {
1062                 OSD_DEBUG("_init_blk_request failed\n");
1063                 return ret;
1064         }
1065
1066         if (or->out.bio) {
1067                 ret = blk_rq_append_bio(or->request->q, or->out.req,
1068                                         or->out.bio);
1069                 if (ret) {
1070                         OSD_DEBUG("blk_rq_append_bio out failed\n");
1071                         return ret;
1072                 }
1073                 OSD_DEBUG("out bytes=%llu (bytes_req=%u)\n",
1074                         _LLU(or->out.total_bytes), or->out.req->data_len);
1075         }
1076         if (or->in.bio) {
1077                 ret = blk_rq_append_bio(or->request->q, or->in.req, or->in.bio);
1078                 if (ret) {
1079                         OSD_DEBUG("blk_rq_append_bio in failed\n");
1080                         return ret;
1081                 }
1082                 OSD_DEBUG("in bytes=%llu (bytes_req=%u)\n",
1083                         _LLU(or->in.total_bytes), or->in.req->data_len);
1084         }
1085
1086         or->out.pad_buff = sg_out_pad_buffer;
1087         or->in.pad_buff = sg_in_pad_buffer;
1088
1089         if (!or->attributes_mode)
1090                 or->attributes_mode = OSD_CDB_GET_SET_ATTR_LISTS;
1091         cdbh->command_specific_options |= or->attributes_mode;
1092         if (or->attributes_mode == OSD_CDB_GET_ATTR_PAGE_SET_ONE) {
1093                 ret = _osd_req_finalize_attr_page(or);
1094         } else {
1095                 /* TODO: I think that for the GET_ATTR command these 2 should
1096                  * be reversed to keep them in execution order (for embeded
1097                  * targets with low memory footprint)
1098                  */
1099                 ret = _osd_req_finalize_set_attr_list(or);
1100                 if (ret) {
1101                         OSD_DEBUG("_osd_req_finalize_set_attr_list failed\n");
1102                         return ret;
1103                 }
1104
1105                 ret = _osd_req_finalize_get_attr_list(or);
1106                 if (ret) {
1107                         OSD_DEBUG("_osd_req_finalize_get_attr_list failed\n");
1108                         return ret;
1109                 }
1110         }
1111
1112         ret = _osd_req_finalize_data_integrity(or, has_in, has_out, cap_key);
1113         if (ret)
1114                 return ret;
1115
1116         osd_sec_sign_cdb(&or->cdb, cap_key);
1117
1118         or->request->cmd = or->cdb.buff;
1119         or->request->cmd_len = _osd_req_cdb_len(or);
1120
1121         return 0;
1122 }
1123 EXPORT_SYMBOL(osd_finalize_request);
1124
1125 /*
1126  * Implementation of osd_sec.h API
1127  * TODO: Move to a separate osd_sec.c file at a later stage.
1128  */
1129
1130 enum { OSD_SEC_CAP_V1_ALL_CAPS =
1131         OSD_SEC_CAP_APPEND | OSD_SEC_CAP_OBJ_MGMT | OSD_SEC_CAP_REMOVE   |
1132         OSD_SEC_CAP_CREATE | OSD_SEC_CAP_SET_ATTR | OSD_SEC_CAP_GET_ATTR |
1133         OSD_SEC_CAP_WRITE  | OSD_SEC_CAP_READ     | OSD_SEC_CAP_POL_SEC  |
1134         OSD_SEC_CAP_GLOBAL | OSD_SEC_CAP_DEV_MGMT
1135 };
1136
1137 void osd_sec_init_nosec_doall_caps(void *caps,
1138         const struct osd_obj_id *obj, bool is_collection, const bool is_v1)
1139 {
1140         struct osd_capability *cap = caps;
1141         u8 type;
1142         u8 descriptor_type;
1143
1144         if (likely(obj->id)) {
1145                 if (unlikely(is_collection)) {
1146                         type = OSD_SEC_OBJ_COLLECTION;
1147                         descriptor_type = is_v1 ? OSD_SEC_OBJ_DESC_OBJ :
1148                                                   OSD_SEC_OBJ_DESC_COL;
1149                 } else {
1150                         type = OSD_SEC_OBJ_USER;
1151                         descriptor_type = OSD_SEC_OBJ_DESC_OBJ;
1152                 }
1153                 WARN_ON(!obj->partition);
1154         } else {
1155                 type = obj->partition ? OSD_SEC_OBJ_PARTITION :
1156                                         OSD_SEC_OBJ_ROOT;
1157                 descriptor_type = OSD_SEC_OBJ_DESC_PAR;
1158         }
1159
1160         memset(cap, 0, sizeof(*cap));
1161
1162         cap->h.format = OSD_SEC_CAP_FORMAT_VER1;
1163         cap->h.integrity_algorithm__key_version = 0; /* MAKE_BYTE(0, 0); */
1164         cap->h.security_method = OSD_SEC_NOSEC;
1165 /*      cap->expiration_time;
1166         cap->AUDIT[30-10];
1167         cap->discriminator[42-30];
1168         cap->object_created_time; */
1169         cap->h.object_type = type;
1170         osd_sec_set_caps(&cap->h, OSD_SEC_CAP_V1_ALL_CAPS);
1171         cap->h.object_descriptor_type = descriptor_type;
1172         cap->od.obj_desc.policy_access_tag = 0;
1173         cap->od.obj_desc.allowed_partition_id = cpu_to_be64(obj->partition);
1174         cap->od.obj_desc.allowed_object_id = cpu_to_be64(obj->id);
1175 }
1176 EXPORT_SYMBOL(osd_sec_init_nosec_doall_caps);
1177
1178 void osd_set_caps(struct osd_cdb *cdb, const void *caps)
1179 {
1180         memcpy(&cdb->v1.caps, caps, OSDv1_CAP_LEN);
1181 }
1182
1183 bool osd_is_sec_alldata(struct osd_security_parameters *sec_parms __unused)
1184 {
1185         return false;
1186 }
1187
1188 void osd_sec_sign_cdb(struct osd_cdb *ocdb __unused, const u8 *cap_key __unused)
1189 {
1190 }
1191
1192 void osd_sec_sign_data(void *data_integ __unused,
1193                        struct bio *bio __unused, const u8 *cap_key __unused)
1194 {
1195 }
1196
1197 /*
1198  * Declared in osd_protocol.h
1199  * 4.12.5 Data-In and Data-Out buffer offsets
1200  * byte offset = mantissa * (2^(exponent+8))
1201  * Returns the smallest allowed encoded offset that contains given @offset
1202  * The actual encoded offset returned is @offset + *@padding.
1203  */
1204 osd_cdb_offset __osd_encode_offset(
1205         u64 offset, unsigned *padding, int min_shift, int max_shift)
1206 {
1207         u64 try_offset = -1, mod, align;
1208         osd_cdb_offset be32_offset;
1209         int shift;
1210
1211         *padding = 0;
1212         if (!offset)
1213                 return 0;
1214
1215         for (shift = min_shift; shift < max_shift; ++shift) {
1216                 try_offset = offset >> shift;
1217                 if (try_offset < (1 << OSD_OFFSET_MAX_BITS))
1218                         break;
1219         }
1220
1221         BUG_ON(shift == max_shift);
1222
1223         align = 1 << shift;
1224         mod = offset & (align - 1);
1225         if (mod) {
1226                 *padding = align - mod;
1227                 try_offset += 1;
1228         }
1229
1230         try_offset |= ((shift - 8) & 0xf) << 28;
1231         be32_offset = cpu_to_be32((u32)try_offset);
1232
1233         OSD_DEBUG("offset=%llu mantissa=%llu exp=%d encoded=%x pad=%d\n",
1234                  _LLU(offset), _LLU(try_offset & 0x0FFFFFFF), shift,
1235                  be32_offset, *padding);
1236         return be32_offset;
1237 }