drivers/infiniband/hw/mthca/mthca_memfree.c

   1 /*
   2  * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
   3  * Copyright (c) 2005 Cisco Systems.  All rights reserved.
   4  * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
   5  *
   6  * This software is available to you under a choice of one of two
   7  * licenses.  You may choose to be licensed under the terms of the GNU
   8  * General Public License (GPL) Version 2, available from the file
   9  * COPYING in the main directory of this source tree, or the
  10  * OpenIB.org BSD license below:
  11  *
  12  *     Redistribution and use in source and binary forms, with or
  13  *     without modification, are permitted provided that the following
  14  *     conditions are met:
  15  *
  16  *      - Redistributions of source code must retain the above
  17  *        copyright notice, this list of conditions and the following
  18  *        disclaimer.
  19  *
  20  *      - Redistributions in binary form must reproduce the above
  21  *        copyright notice, this list of conditions and the following
  22  *        disclaimer in the documentation and/or other materials
  23  *        provided with the distribution.
  24  *
  25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  29  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  30  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  31  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  32  * SOFTWARE.
  33  */
  34
  35 #include <linux/mm.h>
  36 #include <linux/scatterlist.h>
  37 #include <linux/sched.h>
  38 #include <linux/slab.h>
  39
  40 #include <asm/page.h>
  41
  42 #include "mthca_memfree.h"
  43 #include "mthca_dev.h"
  44 #include "mthca_cmd.h"
  45
  46 /*
  47  * We allocate in as big chunks as we can, up to a maximum of 256 KB
  48  * per chunk.
  49  */
  50 enum {
  51         MTHCA_ICM_ALLOC_SIZE   = 1 << 18,
  52         MTHCA_TABLE_CHUNK_SIZE = 1 << 18
  53 };
  54
  55 struct mthca_user_db_table {
  56         struct mutex mutex;
  57         struct {
  58                 u64                uvirt;
  59                 struct scatterlist mem;
  60                 int                refcount;
  61         } page[];
  62 };
  63
  64 static void mthca_free_icm_pages(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
  65 {
  66         int i;
  67
  68         if (chunk->nsg > 0)
  69                 pci_unmap_sg(dev->pdev, chunk->mem, chunk->npages,
  70                              PCI_DMA_BIDIRECTIONAL);
  71
  72         for (i = 0; i < chunk->npages; ++i)
  73                 __free_pages(sg_page(&chunk->mem[i]),
  74                              get_order(chunk->mem[i].length));
  75 }
  76
  77 static void mthca_free_icm_coherent(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
  78 {
  79         int i;
  80
  81         for (i = 0; i < chunk->npages; ++i) {
  82                 dma_free_coherent(&dev->pdev->dev, chunk->mem[i].length,
  83                                   lowmem_page_address(sg_page(&chunk->mem[i])),
  84                                   sg_dma_address(&chunk->mem[i]));
  85         }
  86 }
  87
  88 void mthca_free_icm(struct mthca_dev *dev, struct mthca_icm *icm, int coherent)
  89 {
  90         struct mthca_icm_chunk *chunk, *tmp;
  91
  92         if (!icm)
  93                 return;
  94
  95         list_for_each_entry_safe(chunk, tmp, &icm->chunk_list, list) {
  96                 if (coherent)
  97                         mthca_free_icm_coherent(dev, chunk);
  98                 else
  99                         mthca_free_icm_pages(dev, chunk);
 100
 101                 kfree(chunk);
 102         }
 103
 104         kfree(icm);
 105 }
 106
 107 static int mthca_alloc_icm_pages(struct scatterlist *mem, int order, gfp_t gfp_mask)
 108 {
 109         struct page *page;
 110
 111         /*
 112          * Use __GFP_ZERO because buggy firmware assumes ICM pages are
 113          * cleared, and subtle failures are seen if they aren't.
 114          */
 115         page = alloc_pages(gfp_mask | __GFP_ZERO, order);
 116         if (!page)
 117                 return -ENOMEM;
 118
 119         sg_set_page(mem, page, PAGE_SIZE << order, 0);
 120         return 0;
 121 }
 122
 123 static int mthca_alloc_icm_coherent(struct device *dev, struct scatterlist *mem,
 124                                     int order, gfp_t gfp_mask)
 125 {
 126         void *buf = dma_alloc_coherent(dev, PAGE_SIZE << order, &sg_dma_address(mem),
 127                                        gfp_mask);
 128         if (!buf)
 129                 return -ENOMEM;
 130
 131         sg_set_buf(mem, buf, PAGE_SIZE << order);
 132         BUG_ON(mem->offset);
 133         sg_dma_len(mem) = PAGE_SIZE << order;
 134         return 0;
 135 }
 136
 137 struct mthca_icm *mthca_alloc_icm(struct mthca_dev *dev, int npages,
 138                                   gfp_t gfp_mask, int coherent)
 139 {
 140         struct mthca_icm *icm;
 141         struct mthca_icm_chunk *chunk = NULL;
 142         int cur_order;
 143         int ret;
 144
 145         /* We use sg_set_buf for coherent allocs, which assumes low memory */
 146         BUG_ON(coherent && (gfp_mask & __GFP_HIGHMEM));
 147
 148         icm = kmalloc(sizeof *icm, gfp_mask & ~(__GFP_HIGHMEM | __GFP_NOWARN));
 149         if (!icm)
 150                 return icm;
 151
 152         icm->refcount = 0;
 153         INIT_LIST_HEAD(&icm->chunk_list);
 154
 155         cur_order = get_order(MTHCA_ICM_ALLOC_SIZE);
 156
 157         while (npages > 0) {
 158                 if (!chunk) {
 159                         chunk = kmalloc(sizeof *chunk,
 160                                         gfp_mask & ~(__GFP_HIGHMEM | __GFP_NOWARN));
 161                         if (!chunk)
 162                                 goto fail;
 163
 164                         sg_init_table(chunk->mem, MTHCA_ICM_CHUNK_LEN);
 165                         chunk->npages = 0;
 166                         chunk->nsg    = 0;
 167                         list_add_tail(&chunk->list, &icm->chunk_list);
 168                 }
 169
 170                 while (1 << cur_order > npages)
 171                         --cur_order;
 172
 173                 if (coherent)
 174                         ret = mthca_alloc_icm_coherent(&dev->pdev->dev,
 175                                                        &chunk->mem[chunk->npages],
 176                                                        cur_order, gfp_mask);
 177                 else
 178                         ret = mthca_alloc_icm_pages(&chunk->mem[chunk->npages],
 179                                                     cur_order, gfp_mask);
 180
 181                 if (!ret) {
 182                         ++chunk->npages;
 183
 184                         if (coherent)
 185                                 ++chunk->nsg;
 186                         else if (chunk->npages == MTHCA_ICM_CHUNK_LEN) {
 187                                 chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
 188                                                         chunk->npages,
 189                                                         PCI_DMA_BIDIRECTIONAL);
 190
 191                                 if (chunk->nsg <= 0)
 192                                         goto fail;
 193                         }
 194
 195                         if (chunk->npages == MTHCA_ICM_CHUNK_LEN)
 196                                 chunk = NULL;
 197
 198                         npages -= 1 << cur_order;
 199                 } else {
 200                         --cur_order;
 201                         if (cur_order < 0)
 202                                 goto fail;
 203                 }
 204         }
 205
 206         if (!coherent && chunk) {
 207                 chunk->nsg = pci_map_sg(dev->pdev, chunk->mem,
 208                                         chunk->npages,
 209                                         PCI_DMA_BIDIRECTIONAL);
 210
 211                 if (chunk->nsg <= 0)
 212                         goto fail;
 213         }
 214
 215         return icm;
 216
 217 fail:
 218         mthca_free_icm(dev, icm, coherent);
 219         return NULL;
 220 }
 221
 222 int mthca_table_get(struct mthca_dev *dev, struct mthca_icm_table *table, int obj)
 223 {
 224         int i = (obj & (table->num_obj - 1)) * table->obj_size / MTHCA_TABLE_CHUNK_SIZE;
 225         int ret = 0;
 226
 227         mutex_lock(&table->mutex);
 228
 229         if (table->icm[i]) {
 230                 ++table->icm[i]->refcount;
 231                 goto out;
 232         }
 233
 234         table->icm[i] = mthca_alloc_icm(dev, MTHCA_TABLE_CHUNK_SIZE >> PAGE_SHIFT,
 235                                         (table->lowmem ? GFP_KERNEL : GFP_HIGHUSER) |
 236                                         __GFP_NOWARN, table->coherent);
 237         if (!table->icm[i]) {
 238                 ret = -ENOMEM;
 239                 goto out;
 240         }
 241
 242         if (mthca_MAP_ICM(dev, table->icm[i],
 243                           table->virt + i * MTHCA_TABLE_CHUNK_SIZE)) {
 244                 mthca_free_icm(dev, table->icm[i], table->coherent);
 245                 table->icm[i] = NULL;
 246                 ret = -ENOMEM;
 247                 goto out;
 248         }
 249
 250         ++table->icm[i]->refcount;
 251
 252 out:
 253         mutex_unlock(&table->mutex);
 254         return ret;
 255 }
 256
 257 void mthca_table_put(struct mthca_dev *dev, struct mthca_icm_table *table, int obj)
 258 {
 259         int i;
 260
 261         if (!mthca_is_memfree(dev))
 262                 return;
 263
 264         i = (obj & (table->num_obj - 1)) * table->obj_size / MTHCA_TABLE_CHUNK_SIZE;
 265
 266         mutex_lock(&table->mutex);
 267
 268         if (--table->icm[i]->refcount == 0) {
 269                 mthca_UNMAP_ICM(dev, table->virt + i * MTHCA_TABLE_CHUNK_SIZE,
 270                                 MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
 271                 mthca_free_icm(dev, table->icm[i], table->coherent);
 272                 table->icm[i] = NULL;
 273         }
 274
 275         mutex_unlock(&table->mutex);
 276 }
 277
 278 void *mthca_table_find(struct mthca_icm_table *table, int obj, dma_addr_t *dma_handle)
 279 {
 280         int idx, offset, dma_offset, i;
 281         struct mthca_icm_chunk *chunk;
 282         struct mthca_icm *icm;
 283         struct page *page = NULL;
 284
 285         if (!table->lowmem)
 286                 return NULL;
 287
 288         mutex_lock(&table->mutex);
 289
 290         idx = (obj & (table->num_obj - 1)) * table->obj_size;
 291         icm = table->icm[idx / MTHCA_TABLE_CHUNK_SIZE];
 292         dma_offset = offset = idx % MTHCA_TABLE_CHUNK_SIZE;
 293
 294         if (!icm)
 295                 goto out;
 296
 297         list_for_each_entry(chunk, &icm->chunk_list, list) {
 298                 for (i = 0; i < chunk->npages; ++i) {
 299                         if (dma_handle && dma_offset >= 0) {
 300                                 if (sg_dma_len(&chunk->mem[i]) > dma_offset)
 301                                         *dma_handle = sg_dma_address(&chunk->mem[i]) +
 302                                                 dma_offset;
 303                                 dma_offset -= sg_dma_len(&chunk->mem[i]);
 304                         }
 305                         /* DMA mapping can merge pages but not split them,
 306                          * so if we found the page, dma_handle has already
 307                          * been assigned to. */
 308                         if (chunk->mem[i].length > offset) {
 309                                 page = sg_page(&chunk->mem[i]);
 310                                 goto out;
 311                         }
 312                         offset -= chunk->mem[i].length;
 313                 }
 314         }
 315
 316 out:
 317         mutex_unlock(&table->mutex);
 318         return page ? lowmem_page_address(page) + offset : NULL;
 319 }
 320
 321 int mthca_table_get_range(struct mthca_dev *dev, struct mthca_icm_table *table,
 322                           int start, int end)
 323 {
 324         int inc = MTHCA_TABLE_CHUNK_SIZE / table->obj_size;
 325         int i, err;
 326
 327         for (i = start; i <= end; i += inc) {
 328                 err = mthca_table_get(dev, table, i);
 329                 if (err)
 330                         goto fail;
 331         }
 332
 333         return 0;
 334
 335 fail:
 336         while (i > start) {
 337                 i -= inc;
 338                 mthca_table_put(dev, table, i);
 339         }
 340
 341         return err;
 342 }
 343
 344 void mthca_table_put_range(struct mthca_dev *dev, struct mthca_icm_table *table,
 345                            int start, int end)
 346 {
 347         int i;
 348
 349         if (!mthca_is_memfree(dev))
 350                 return;
 351
 352         for (i = start; i <= end; i += MTHCA_TABLE_CHUNK_SIZE / table->obj_size)
 353                 mthca_table_put(dev, table, i);
 354 }
 355
 356 struct mthca_icm_table *mthca_alloc_icm_table(struct mthca_dev *dev,
 357                                               u64 virt, int obj_size,
 358                                               int nobj, int reserved,
 359                                               int use_lowmem, int use_coherent)
 360 {
 361         struct mthca_icm_table *table;
 362         int obj_per_chunk;
 363         int num_icm;
 364         unsigned chunk_size;
 365         int i;
 366
 367         obj_per_chunk = MTHCA_TABLE_CHUNK_SIZE / obj_size;
 368         num_icm = DIV_ROUND_UP(nobj, obj_per_chunk);
 369
 370         table = kmalloc(struct_size(table, icm, num_icm), GFP_KERNEL);
 371         if (!table)
 372                 return NULL;
 373
 374         table->virt     = virt;
 375         table->num_icm  = num_icm;
 376         table->num_obj  = nobj;
 377         table->obj_size = obj_size;
 378         table->lowmem   = use_lowmem;
 379         table->coherent = use_coherent;
 380         mutex_init(&table->mutex);
 381
 382         for (i = 0; i < num_icm; ++i)
 383                 table->icm[i] = NULL;
 384
 385         for (i = 0; i * MTHCA_TABLE_CHUNK_SIZE < reserved * obj_size; ++i) {
 386                 chunk_size = MTHCA_TABLE_CHUNK_SIZE;
 387                 if ((i + 1) * MTHCA_TABLE_CHUNK_SIZE > nobj * obj_size)
 388                         chunk_size = nobj * obj_size - i * MTHCA_TABLE_CHUNK_SIZE;
 389
 390                 table->icm[i] = mthca_alloc_icm(dev, chunk_size >> PAGE_SHIFT,
 391                                                 (use_lowmem ? GFP_KERNEL : GFP_HIGHUSER) |
 392                                                 __GFP_NOWARN, use_coherent);
 393                 if (!table->icm[i])
 394                         goto err;
 395                 if (mthca_MAP_ICM(dev, table->icm[i],
 396                                   virt + i * MTHCA_TABLE_CHUNK_SIZE)) {
 397                         mthca_free_icm(dev, table->icm[i], table->coherent);
 398                         table->icm[i] = NULL;
 399                         goto err;
 400                 }
 401
 402                 /*
 403                  * Add a reference to this ICM chunk so that it never
 404                  * gets freed (since it contains reserved firmware objects).
 405                  */
 406                 ++table->icm[i]->refcount;
 407         }
 408
 409         return table;
 410
 411 err:
 412         for (i = 0; i < num_icm; ++i)
 413                 if (table->icm[i]) {
 414                         mthca_UNMAP_ICM(dev, virt + i * MTHCA_TABLE_CHUNK_SIZE,
 415                                         MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
 416                         mthca_free_icm(dev, table->icm[i], table->coherent);
 417                 }
 418
 419         kfree(table);
 420
 421         return NULL;
 422 }
 423
 424 void mthca_free_icm_table(struct mthca_dev *dev, struct mthca_icm_table *table)
 425 {
 426         int i;
 427
 428         for (i = 0; i < table->num_icm; ++i)
 429                 if (table->icm[i]) {
 430                         mthca_UNMAP_ICM(dev,
 431                                         table->virt + i * MTHCA_TABLE_CHUNK_SIZE,
 432                                         MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
 433                         mthca_free_icm(dev, table->icm[i], table->coherent);
 434                 }
 435
 436         kfree(table);
 437 }
 438
 439 static u64 mthca_uarc_virt(struct mthca_dev *dev, struct mthca_uar *uar, int page)
 440 {
 441         return dev->uar_table.uarc_base +
 442                 uar->index * dev->uar_table.uarc_size +
 443                 page * MTHCA_ICM_PAGE_SIZE;
 444 }
 445
 446 int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
 447                       struct mthca_user_db_table *db_tab, int index, u64 uaddr)
 448 {
 449         struct page *pages[1];
 450         int ret = 0;
 451         int i;
 452
 453         if (!mthca_is_memfree(dev))
 454                 return 0;
 455
 456         if (index < 0 || index > dev->uar_table.uarc_size / 8)
 457                 return -EINVAL;
 458
 459         mutex_lock(&db_tab->mutex);
 460
 461         i = index / MTHCA_DB_REC_PER_PAGE;
 462
 463         if ((db_tab->page[i].refcount >= MTHCA_DB_REC_PER_PAGE)       ||
 464             (db_tab->page[i].uvirt && db_tab->page[i].uvirt != uaddr) ||
 465             (uaddr & 4095)) {
 466                 ret = -EINVAL;
 467                 goto out;
 468         }
 469
 470         if (db_tab->page[i].refcount) {
 471                 ++db_tab->page[i].refcount;
 472                 goto out;
 473         }
 474
 475         ret = pin_user_pages_fast(uaddr & PAGE_MASK, 1,
 476                                   FOLL_WRITE | FOLL_LONGTERM, pages);
 477         if (ret < 0)
 478                 goto out;
 479
 480         sg_set_page(&db_tab->page[i].mem, pages[0], MTHCA_ICM_PAGE_SIZE,
 481                         uaddr & ~PAGE_MASK);
 482
 483         ret = pci_map_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
 484         if (ret < 0) {
 485                 unpin_user_page(pages[0]);
 486                 goto out;
 487         }
 488
 489         ret = mthca_MAP_ICM_page(dev, sg_dma_address(&db_tab->page[i].mem),
 490                                  mthca_uarc_virt(dev, uar, i));
 491         if (ret) {
 492                 pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
 493                 unpin_user_page(sg_page(&db_tab->page[i].mem));
 494                 goto out;
 495         }
 496
 497         db_tab->page[i].uvirt    = uaddr;
 498         db_tab->page[i].refcount = 1;
 499
 500 out:
 501         mutex_unlock(&db_tab->mutex);
 502         return ret;
 503 }
 504
 505 void mthca_unmap_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
 506                          struct mthca_user_db_table *db_tab, int index)
 507 {
 508         if (!mthca_is_memfree(dev))
 509                 return;
 510
 511         /*
 512          * To make our bookkeeping simpler, we don't unmap DB
 513          * pages until we clean up the whole db table.
 514          */
 515
 516         mutex_lock(&db_tab->mutex);
 517
 518         --db_tab->page[index / MTHCA_DB_REC_PER_PAGE].refcount;
 519
 520         mutex_unlock(&db_tab->mutex);
 521 }
 522
 523 struct mthca_user_db_table *mthca_init_user_db_tab(struct mthca_dev *dev)
 524 {
 525         struct mthca_user_db_table *db_tab;
 526         int npages;
 527         int i;
 528
 529         if (!mthca_is_memfree(dev))
 530                 return NULL;
 531
 532         npages = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
 533         db_tab = kmalloc(struct_size(db_tab, page, npages), GFP_KERNEL);
 534         if (!db_tab)
 535                 return ERR_PTR(-ENOMEM);
 536
 537         mutex_init(&db_tab->mutex);
 538         for (i = 0; i < npages; ++i) {
 539                 db_tab->page[i].refcount = 0;
 540                 db_tab->page[i].uvirt    = 0;
 541                 sg_init_table(&db_tab->page[i].mem, 1);
 542         }
 543
 544         return db_tab;
 545 }
 546
 547 void mthca_cleanup_user_db_tab(struct mthca_dev *dev, struct mthca_uar *uar,
 548                                struct mthca_user_db_table *db_tab)
 549 {
 550         int i;
 551
 552         if (!mthca_is_memfree(dev))
 553                 return;
 554
 555         for (i = 0; i < dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE; ++i) {
 556                 if (db_tab->page[i].uvirt) {
 557                         mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, uar, i), 1);
 558                         pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
 559                         unpin_user_page(sg_page(&db_tab->page[i].mem));
 560                 }
 561         }
 562
 563         kfree(db_tab);
 564 }
 565
 566 int mthca_alloc_db(struct mthca_dev *dev, enum mthca_db_type type,
 567                    u32 qn, __be32 **db)
 568 {
 569         int group;
 570         int start, end, dir;
 571         int i, j;
 572         struct mthca_db_page *page;
 573         int ret = 0;
 574
 575         mutex_lock(&dev->db_tab->mutex);
 576
 577         switch (type) {
 578         case MTHCA_DB_TYPE_CQ_ARM:
 579         case MTHCA_DB_TYPE_SQ:
 580                 group = 0;
 581                 start = 0;
 582                 end   = dev->db_tab->max_group1;
 583                 dir   = 1;
 584                 break;
 585
 586         case MTHCA_DB_TYPE_CQ_SET_CI:
 587         case MTHCA_DB_TYPE_RQ:
 588         case MTHCA_DB_TYPE_SRQ:
 589                 group = 1;
 590                 start = dev->db_tab->npages - 1;
 591                 end   = dev->db_tab->min_group2;
 592                 dir   = -1;
 593                 break;
 594
 595         default:
 596                 ret = -EINVAL;
 597                 goto out;
 598         }
 599
 600         for (i = start; i != end; i += dir)
 601                 if (dev->db_tab->page[i].db_rec &&
 602                     !bitmap_full(dev->db_tab->page[i].used,
 603                                  MTHCA_DB_REC_PER_PAGE)) {
 604                         page = dev->db_tab->page + i;
 605                         goto found;
 606                 }
 607
 608         for (i = start; i != end; i += dir)
 609                 if (!dev->db_tab->page[i].db_rec) {
 610                         page = dev->db_tab->page + i;
 611                         goto alloc;
 612                 }
 613
 614         if (dev->db_tab->max_group1 >= dev->db_tab->min_group2 - 1) {
 615                 ret = -ENOMEM;
 616                 goto out;
 617         }
 618
 619         if (group == 0)
 620                 ++dev->db_tab->max_group1;
 621         else
 622                 --dev->db_tab->min_group2;
 623
 624         page = dev->db_tab->page + end;
 625
 626 alloc:
 627         page->db_rec = dma_alloc_coherent(&dev->pdev->dev,
 628                                           MTHCA_ICM_PAGE_SIZE, &page->mapping,
 629                                           GFP_KERNEL);
 630         if (!page->db_rec) {
 631                 ret = -ENOMEM;
 632                 goto out;
 633         }
 634
 635         ret = mthca_MAP_ICM_page(dev, page->mapping,
 636                                  mthca_uarc_virt(dev, &dev->driver_uar, i));
 637         if (ret) {
 638                 dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
 639                                   page->db_rec, page->mapping);
 640                 goto out;
 641         }
 642
 643         bitmap_zero(page->used, MTHCA_DB_REC_PER_PAGE);
 644
 645 found:
 646         j = find_first_zero_bit(page->used, MTHCA_DB_REC_PER_PAGE);
 647         set_bit(j, page->used);
 648
 649         if (group == 1)
 650                 j = MTHCA_DB_REC_PER_PAGE - 1 - j;
 651
 652         ret = i * MTHCA_DB_REC_PER_PAGE + j;
 653
 654         page->db_rec[j] = cpu_to_be64((qn << 8) | (type << 5));
 655
 656         *db = (__be32 *) &page->db_rec[j];
 657
 658 out:
 659         mutex_unlock(&dev->db_tab->mutex);
 660
 661         return ret;
 662 }
 663
 664 void mthca_free_db(struct mthca_dev *dev, int type, int db_index)
 665 {
 666         int i, j;
 667         struct mthca_db_page *page;
 668
 669         i = db_index / MTHCA_DB_REC_PER_PAGE;
 670         j = db_index % MTHCA_DB_REC_PER_PAGE;
 671
 672         page = dev->db_tab->page + i;
 673
 674         mutex_lock(&dev->db_tab->mutex);
 675
 676         page->db_rec[j] = 0;
 677         if (i >= dev->db_tab->min_group2)
 678                 j = MTHCA_DB_REC_PER_PAGE - 1 - j;
 679         clear_bit(j, page->used);
 680
 681         if (bitmap_empty(page->used, MTHCA_DB_REC_PER_PAGE) &&
 682             i >= dev->db_tab->max_group1 - 1) {
 683                 mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1);
 684
 685                 dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
 686                                   page->db_rec, page->mapping);
 687                 page->db_rec = NULL;
 688
 689                 if (i == dev->db_tab->max_group1) {
 690                         --dev->db_tab->max_group1;
 691                         /* XXX may be able to unmap more pages now */
 692                 }
 693                 if (i == dev->db_tab->min_group2)
 694                         ++dev->db_tab->min_group2;
 695         }
 696
 697         mutex_unlock(&dev->db_tab->mutex);
 698 }
 699
 700 int mthca_init_db_tab(struct mthca_dev *dev)
 701 {
 702         int i;
 703
 704         if (!mthca_is_memfree(dev))
 705                 return 0;
 706
 707         dev->db_tab = kmalloc(sizeof *dev->db_tab, GFP_KERNEL);
 708         if (!dev->db_tab)
 709                 return -ENOMEM;
 710
 711         mutex_init(&dev->db_tab->mutex);
 712
 713         dev->db_tab->npages     = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
 714         dev->db_tab->max_group1 = 0;
 715         dev->db_tab->min_group2 = dev->db_tab->npages - 1;
 716
 717         dev->db_tab->page = kmalloc_array(dev->db_tab->npages,
 718                                           sizeof(*dev->db_tab->page),
 719                                           GFP_KERNEL);
 720         if (!dev->db_tab->page) {
 721                 kfree(dev->db_tab);
 722                 return -ENOMEM;
 723         }
 724
 725         for (i = 0; i < dev->db_tab->npages; ++i)
 726                 dev->db_tab->page[i].db_rec = NULL;
 727
 728         return 0;
 729 }
 730
 731 void mthca_cleanup_db_tab(struct mthca_dev *dev)
 732 {
 733         int i;
 734
 735         if (!mthca_is_memfree(dev))
 736                 return;
 737
 738         /*
 739          * Because we don't always free our UARC pages when they
 740          * become empty to make mthca_free_db() simpler we need to
 741          * make a sweep through the doorbell pages and free any
 742          * leftover pages now.
 743          */
 744         for (i = 0; i < dev->db_tab->npages; ++i) {
 745                 if (!dev->db_tab->page[i].db_rec)
 746                         continue;
 747
 748                 if (!bitmap_empty(dev->db_tab->page[i].used, MTHCA_DB_REC_PER_PAGE))
 749                         mthca_warn(dev, "Kernel UARC page %d not empty\n", i);
 750
 751                 mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1);
 752
 753                 dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
 754                                   dev->db_tab->page[i].db_rec,
 755                                   dev->db_tab->page[i].mapping);
 756         }
 757
 758         kfree(dev->db_tab->page);
 759         kfree(dev->db_tab);
 760 }