drivers/media/common/videobuf2/videobuf2-dma-sg.c

   1 /*
   2  * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  *
   6  * Author: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/mm.h>
  15 #include <linux/refcount.h>
  16 #include <linux/scatterlist.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19 #include <linux/vmalloc.h>
  20
  21 #include <media/videobuf2-v4l2.h>
  22 #include <media/videobuf2-memops.h>
  23 #include <media/videobuf2-dma-sg.h>
  24
  25 static int debug;
  26 module_param(debug, int, 0644);
  27
  28 #define dprintk(level, fmt, arg...)                                     \
  29         do {                                                            \
  30                 if (debug >= level)                                     \
  31                         printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg);  \
  32         } while (0)
  33
  34 struct vb2_dma_sg_buf {
  35         struct device                   *dev;
  36         void                            *vaddr;
  37         struct page                     **pages;
  38         struct frame_vector             *vec;
  39         int                             offset;
  40         enum dma_data_direction         dma_dir;
  41         struct sg_table                 sg_table;
  42         /*
  43          * This will point to sg_table when used with the MMAP or USERPTR
  44          * memory model, and to the dma_buf sglist when used with the
  45          * DMABUF memory model.
  46          */
  47         struct sg_table                 *dma_sgt;
  48         size_t                          size;
  49         unsigned int                    num_pages;
  50         refcount_t                      refcount;
  51         struct vb2_vmarea_handler       handler;
  52
  53         struct dma_buf_attachment       *db_attach;
  54 };
  55
  56 static void vb2_dma_sg_put(void *buf_priv);
  57
  58 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
  59                 gfp_t gfp_flags)
  60 {
  61         unsigned int last_page = 0;
  62         unsigned long size = buf->size;
  63
  64         while (size > 0) {
  65                 struct page *pages;
  66                 int order;
  67                 int i;
  68
  69                 order = get_order(size);
  70                 /* Don't over allocate*/
  71                 if ((PAGE_SIZE << order) > size)
  72                         order--;
  73
  74                 pages = NULL;
  75                 while (!pages) {
  76                         pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
  77                                         __GFP_NOWARN | gfp_flags, order);
  78                         if (pages)
  79                                 break;
  80
  81                         if (order == 0) {
  82                                 while (last_page--)
  83                                         __free_page(buf->pages[last_page]);
  84                                 return -ENOMEM;
  85                         }
  86                         order--;
  87                 }
  88
  89                 split_page(pages, order);
  90                 for (i = 0; i < (1 << order); i++)
  91                         buf->pages[last_page++] = &pages[i];
  92
  93                 size -= PAGE_SIZE << order;
  94         }
  95
  96         return 0;
  97 }
  98
  99 static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
 100                               unsigned long size, enum dma_data_direction dma_dir,
 101                               gfp_t gfp_flags)
 102 {
 103         struct vb2_dma_sg_buf *buf;
 104         struct sg_table *sgt;
 105         int ret;
 106         int num_pages;
 107
 108         if (WARN_ON(!dev))
 109                 return ERR_PTR(-EINVAL);
 110
 111         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 112         if (!buf)
 113                 return ERR_PTR(-ENOMEM);
 114
 115         buf->vaddr = NULL;
 116         buf->dma_dir = dma_dir;
 117         buf->offset = 0;
 118         buf->size = size;
 119         /* size is already page aligned */
 120         buf->num_pages = size >> PAGE_SHIFT;
 121         buf->dma_sgt = &buf->sg_table;
 122
 123         /*
 124          * NOTE: dma-sg allocates memory using the page allocator directly, so
 125          * there is no memory consistency guarantee, hence dma-sg ignores DMA
 126          * attributes passed from the upper layer.
 127          */
 128         buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *),
 129                                     GFP_KERNEL | __GFP_ZERO);
 130         if (!buf->pages)
 131                 goto fail_pages_array_alloc;
 132
 133         ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
 134         if (ret)
 135                 goto fail_pages_alloc;
 136
 137         ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 138                         buf->num_pages, 0, size, GFP_KERNEL);
 139         if (ret)
 140                 goto fail_table_alloc;
 141
 142         /* Prevent the device from being released while the buffer is used */
 143         buf->dev = get_device(dev);
 144
 145         sgt = &buf->sg_table;
 146         /*
 147          * No need to sync to the device, this will happen later when the
 148          * prepare() memop is called.
 149          */
 150         if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
 151                             DMA_ATTR_SKIP_CPU_SYNC))
 152                 goto fail_map;
 153
 154         buf->handler.refcount = &buf->refcount;
 155         buf->handler.put = vb2_dma_sg_put;
 156         buf->handler.arg = buf;
 157
 158         refcount_set(&buf->refcount, 1);
 159
 160         dprintk(1, "%s: Allocated buffer of %d pages\n",
 161                 __func__, buf->num_pages);
 162         return buf;
 163
 164 fail_map:
 165         put_device(buf->dev);
 166         sg_free_table(buf->dma_sgt);
 167 fail_table_alloc:
 168         num_pages = buf->num_pages;
 169         while (num_pages--)
 170                 __free_page(buf->pages[num_pages]);
 171 fail_pages_alloc:
 172         kvfree(buf->pages);
 173 fail_pages_array_alloc:
 174         kfree(buf);
 175         return ERR_PTR(-ENOMEM);
 176 }
 177
 178 static void vb2_dma_sg_put(void *buf_priv)
 179 {
 180         struct vb2_dma_sg_buf *buf = buf_priv;
 181         struct sg_table *sgt = &buf->sg_table;
 182         int i = buf->num_pages;
 183
 184         if (refcount_dec_and_test(&buf->refcount)) {
 185                 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
 186                         buf->num_pages);
 187                 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,
 188                                   DMA_ATTR_SKIP_CPU_SYNC);
 189                 if (buf->vaddr)
 190                         vm_unmap_ram(buf->vaddr, buf->num_pages);
 191                 sg_free_table(buf->dma_sgt);
 192                 while (--i >= 0)
 193                         __free_page(buf->pages[i]);
 194                 kvfree(buf->pages);
 195                 put_device(buf->dev);
 196                 kfree(buf);
 197         }
 198 }
 199
 200 static void vb2_dma_sg_prepare(void *buf_priv)
 201 {
 202         struct vb2_dma_sg_buf *buf = buf_priv;
 203         struct sg_table *sgt = buf->dma_sgt;
 204
 205         dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
 206 }
 207
 208 static void vb2_dma_sg_finish(void *buf_priv)
 209 {
 210         struct vb2_dma_sg_buf *buf = buf_priv;
 211         struct sg_table *sgt = buf->dma_sgt;
 212
 213         dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
 214 }
 215
 216 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
 217                                     unsigned long size,
 218                                     enum dma_data_direction dma_dir)
 219 {
 220         struct vb2_dma_sg_buf *buf;
 221         struct sg_table *sgt;
 222         struct frame_vector *vec;
 223
 224         if (WARN_ON(!dev))
 225                 return ERR_PTR(-EINVAL);
 226
 227         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 228         if (!buf)
 229                 return ERR_PTR(-ENOMEM);
 230
 231         buf->vaddr = NULL;
 232         buf->dev = dev;
 233         buf->dma_dir = dma_dir;
 234         buf->offset = vaddr & ~PAGE_MASK;
 235         buf->size = size;
 236         buf->dma_sgt = &buf->sg_table;
 237         vec = vb2_create_framevec(vaddr, size);
 238         if (IS_ERR(vec))
 239                 goto userptr_fail_pfnvec;
 240         buf->vec = vec;
 241
 242         buf->pages = frame_vector_pages(vec);
 243         if (IS_ERR(buf->pages))
 244                 goto userptr_fail_sgtable;
 245         buf->num_pages = frame_vector_count(vec);
 246
 247         if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
 248                         buf->num_pages, buf->offset, size, 0))
 249                 goto userptr_fail_sgtable;
 250
 251         sgt = &buf->sg_table;
 252         /*
 253          * No need to sync to the device, this will happen later when the
 254          * prepare() memop is called.
 255          */
 256         if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
 257                             DMA_ATTR_SKIP_CPU_SYNC))
 258                 goto userptr_fail_map;
 259
 260         return buf;
 261
 262 userptr_fail_map:
 263         sg_free_table(&buf->sg_table);
 264 userptr_fail_sgtable:
 265         vb2_destroy_framevec(vec);
 266 userptr_fail_pfnvec:
 267         kfree(buf);
 268         return ERR_PTR(-ENOMEM);
 269 }
 270
 271 /*
 272  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
 273  *               be used
 274  */
 275 static void vb2_dma_sg_put_userptr(void *buf_priv)
 276 {
 277         struct vb2_dma_sg_buf *buf = buf_priv;
 278         struct sg_table *sgt = &buf->sg_table;
 279         int i = buf->num_pages;
 280
 281         dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
 282                __func__, buf->num_pages);
 283         dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 284         if (buf->vaddr)
 285                 vm_unmap_ram(buf->vaddr, buf->num_pages);
 286         sg_free_table(buf->dma_sgt);
 287         if (buf->dma_dir == DMA_FROM_DEVICE ||
 288             buf->dma_dir == DMA_BIDIRECTIONAL)
 289                 while (--i >= 0)
 290                         set_page_dirty_lock(buf->pages[i]);
 291         vb2_destroy_framevec(buf->vec);
 292         kfree(buf);
 293 }
 294
 295 static void *vb2_dma_sg_vaddr(void *buf_priv)
 296 {
 297         struct vb2_dma_sg_buf *buf = buf_priv;
 298
 299         BUG_ON(!buf);
 300
 301         if (!buf->vaddr) {
 302                 if (buf->db_attach)
 303                         buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
 304                 else
 305                         buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1);
 306         }
 307
 308         /* add offset in case userptr is not page-aligned */
 309         return buf->vaddr ? buf->vaddr + buf->offset : NULL;
 310 }
 311
 312 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
 313 {
 314         struct vb2_dma_sg_buf *buf = buf_priv;
 315
 316         return refcount_read(&buf->refcount);
 317 }
 318
 319 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
 320 {
 321         struct vb2_dma_sg_buf *buf = buf_priv;
 322         int err;
 323
 324         if (!buf) {
 325                 printk(KERN_ERR "No memory to map\n");
 326                 return -EINVAL;
 327         }
 328
 329         err = vm_map_pages(vma, buf->pages, buf->num_pages);
 330         if (err) {
 331                 printk(KERN_ERR "Remapping memory, error: %d\n", err);
 332                 return err;
 333         }
 334
 335         /*
 336          * Use common vm_area operations to track buffer refcount.
 337          */
 338         vma->vm_private_data    = &buf->handler;
 339         vma->vm_ops             = &vb2_common_vm_ops;
 340
 341         vma->vm_ops->open(vma);
 342
 343         return 0;
 344 }
 345
 346 /*********************************************/
 347 /*         DMABUF ops for exporters          */
 348 /*********************************************/
 349
 350 struct vb2_dma_sg_attachment {
 351         struct sg_table sgt;
 352         enum dma_data_direction dma_dir;
 353 };
 354
 355 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf,
 356         struct dma_buf_attachment *dbuf_attach)
 357 {
 358         struct vb2_dma_sg_attachment *attach;
 359         unsigned int i;
 360         struct scatterlist *rd, *wr;
 361         struct sg_table *sgt;
 362         struct vb2_dma_sg_buf *buf = dbuf->priv;
 363         int ret;
 364
 365         attach = kzalloc(sizeof(*attach), GFP_KERNEL);
 366         if (!attach)
 367                 return -ENOMEM;
 368
 369         sgt = &attach->sgt;
 370         /* Copy the buf->base_sgt scatter list to the attachment, as we can't
 371          * map the same scatter list to multiple attachments at the same time.
 372          */
 373         ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
 374         if (ret) {
 375                 kfree(attach);
 376                 return -ENOMEM;
 377         }
 378
 379         rd = buf->dma_sgt->sgl;
 380         wr = sgt->sgl;
 381         for (i = 0; i < sgt->orig_nents; ++i) {
 382                 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
 383                 rd = sg_next(rd);
 384                 wr = sg_next(wr);
 385         }
 386
 387         attach->dma_dir = DMA_NONE;
 388         dbuf_attach->priv = attach;
 389
 390         return 0;
 391 }
 392
 393 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
 394         struct dma_buf_attachment *db_attach)
 395 {
 396         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 397         struct sg_table *sgt;
 398
 399         if (!attach)
 400                 return;
 401
 402         sgt = &attach->sgt;
 403
 404         /* release the scatterlist cache */
 405         if (attach->dma_dir != DMA_NONE)
 406                 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
 407         sg_free_table(sgt);
 408         kfree(attach);
 409         db_attach->priv = NULL;
 410 }
 411
 412 static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
 413         struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
 414 {
 415         struct vb2_dma_sg_attachment *attach = db_attach->priv;
 416         /* stealing dmabuf mutex to serialize map/unmap operations */
 417         struct mutex *lock = &db_attach->dmabuf->lock;
 418         struct sg_table *sgt;
 419
 420         mutex_lock(lock);
 421
 422         sgt = &attach->sgt;
 423         /* return previously mapped sg table */
 424         if (attach->dma_dir == dma_dir) {
 425                 mutex_unlock(lock);
 426                 return sgt;
 427         }
 428
 429         /* release any previous cache */
 430         if (attach->dma_dir != DMA_NONE) {
 431                 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
 432                 attach->dma_dir = DMA_NONE;
 433         }
 434
 435         /* mapping to the client with new direction */
 436         if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
 437                 pr_err("failed to map scatterlist\n");
 438                 mutex_unlock(lock);
 439                 return ERR_PTR(-EIO);
 440         }
 441
 442         attach->dma_dir = dma_dir;
 443
 444         mutex_unlock(lock);
 445
 446         return sgt;
 447 }
 448
 449 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
 450         struct sg_table *sgt, enum dma_data_direction dma_dir)
 451 {
 452         /* nothing to be done here */
 453 }
 454
 455 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
 456 {
 457         /* drop reference obtained in vb2_dma_sg_get_dmabuf */
 458         vb2_dma_sg_put(dbuf->priv);
 459 }
 460
 461 static int
 462 vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
 463                                        enum dma_data_direction direction)
 464 {
 465         struct vb2_dma_sg_buf *buf = dbuf->priv;
 466         struct sg_table *sgt = buf->dma_sgt;
 467
 468         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 469         return 0;
 470 }
 471
 472 static int
 473 vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
 474                                      enum dma_data_direction direction)
 475 {
 476         struct vb2_dma_sg_buf *buf = dbuf->priv;
 477         struct sg_table *sgt = buf->dma_sgt;
 478
 479         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 480         return 0;
 481 }
 482
 483 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
 484 {
 485         struct vb2_dma_sg_buf *buf = dbuf->priv;
 486
 487         return vb2_dma_sg_vaddr(buf);
 488 }
 489
 490 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
 491         struct vm_area_struct *vma)
 492 {
 493         return vb2_dma_sg_mmap(dbuf->priv, vma);
 494 }
 495
 496 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
 497         .attach = vb2_dma_sg_dmabuf_ops_attach,
 498         .detach = vb2_dma_sg_dmabuf_ops_detach,
 499         .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
 500         .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
 501         .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access,
 502         .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access,
 503         .vmap = vb2_dma_sg_dmabuf_ops_vmap,
 504         .mmap = vb2_dma_sg_dmabuf_ops_mmap,
 505         .release = vb2_dma_sg_dmabuf_ops_release,
 506 };
 507
 508 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
 509 {
 510         struct vb2_dma_sg_buf *buf = buf_priv;
 511         struct dma_buf *dbuf;
 512         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 513
 514         exp_info.ops = &vb2_dma_sg_dmabuf_ops;
 515         exp_info.size = buf->size;
 516         exp_info.flags = flags;
 517         exp_info.priv = buf;
 518
 519         if (WARN_ON(!buf->dma_sgt))
 520                 return NULL;
 521
 522         dbuf = dma_buf_export(&exp_info);
 523         if (IS_ERR(dbuf))
 524                 return NULL;
 525
 526         /* dmabuf keeps reference to vb2 buffer */
 527         refcount_inc(&buf->refcount);
 528
 529         return dbuf;
 530 }
 531
 532 /*********************************************/
 533 /*       callbacks for DMABUF buffers        */
 534 /*********************************************/
 535
 536 static int vb2_dma_sg_map_dmabuf(void *mem_priv)
 537 {
 538         struct vb2_dma_sg_buf *buf = mem_priv;
 539         struct sg_table *sgt;
 540
 541         if (WARN_ON(!buf->db_attach)) {
 542                 pr_err("trying to pin a non attached buffer\n");
 543                 return -EINVAL;
 544         }
 545
 546         if (WARN_ON(buf->dma_sgt)) {
 547                 pr_err("dmabuf buffer is already pinned\n");
 548                 return 0;
 549         }
 550
 551         /* get the associated scatterlist for this buffer */
 552         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 553         if (IS_ERR(sgt)) {
 554                 pr_err("Error getting dmabuf scatterlist\n");
 555                 return -EINVAL;
 556         }
 557
 558         buf->dma_sgt = sgt;
 559         buf->vaddr = NULL;
 560
 561         return 0;
 562 }
 563
 564 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
 565 {
 566         struct vb2_dma_sg_buf *buf = mem_priv;
 567         struct sg_table *sgt = buf->dma_sgt;
 568
 569         if (WARN_ON(!buf->db_attach)) {
 570                 pr_err("trying to unpin a not attached buffer\n");
 571                 return;
 572         }
 573
 574         if (WARN_ON(!sgt)) {
 575                 pr_err("dmabuf buffer is already unpinned\n");
 576                 return;
 577         }
 578
 579         if (buf->vaddr) {
 580                 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
 581                 buf->vaddr = NULL;
 582         }
 583         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 584
 585         buf->dma_sgt = NULL;
 586 }
 587
 588 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
 589 {
 590         struct vb2_dma_sg_buf *buf = mem_priv;
 591
 592         /* if vb2 works correctly you should never detach mapped buffer */
 593         if (WARN_ON(buf->dma_sgt))
 594                 vb2_dma_sg_unmap_dmabuf(buf);
 595
 596         /* detach this attachment */
 597         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 598         kfree(buf);
 599 }
 600
 601 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
 602         unsigned long size, enum dma_data_direction dma_dir)
 603 {
 604         struct vb2_dma_sg_buf *buf;
 605         struct dma_buf_attachment *dba;
 606
 607         if (WARN_ON(!dev))
 608                 return ERR_PTR(-EINVAL);
 609
 610         if (dbuf->size < size)
 611                 return ERR_PTR(-EFAULT);
 612
 613         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 614         if (!buf)
 615                 return ERR_PTR(-ENOMEM);
 616
 617         buf->dev = dev;
 618         /* create attachment for the dmabuf with the user device */
 619         dba = dma_buf_attach(dbuf, buf->dev);
 620         if (IS_ERR(dba)) {
 621                 pr_err("failed to attach dmabuf\n");
 622                 kfree(buf);
 623                 return dba;
 624         }
 625
 626         buf->dma_dir = dma_dir;
 627         buf->size = size;
 628         buf->db_attach = dba;
 629
 630         return buf;
 631 }
 632
 633 static void *vb2_dma_sg_cookie(void *buf_priv)
 634 {
 635         struct vb2_dma_sg_buf *buf = buf_priv;
 636
 637         return buf->dma_sgt;
 638 }
 639
 640 const struct vb2_mem_ops vb2_dma_sg_memops = {
 641         .alloc          = vb2_dma_sg_alloc,
 642         .put            = vb2_dma_sg_put,
 643         .get_userptr    = vb2_dma_sg_get_userptr,
 644         .put_userptr    = vb2_dma_sg_put_userptr,
 645         .prepare        = vb2_dma_sg_prepare,
 646         .finish         = vb2_dma_sg_finish,
 647         .vaddr          = vb2_dma_sg_vaddr,
 648         .mmap           = vb2_dma_sg_mmap,
 649         .num_users      = vb2_dma_sg_num_users,
 650         .get_dmabuf     = vb2_dma_sg_get_dmabuf,
 651         .map_dmabuf     = vb2_dma_sg_map_dmabuf,
 652         .unmap_dmabuf   = vb2_dma_sg_unmap_dmabuf,
 653         .attach_dmabuf  = vb2_dma_sg_attach_dmabuf,
 654         .detach_dmabuf  = vb2_dma_sg_detach_dmabuf,
 655         .cookie         = vb2_dma_sg_cookie,
 656 };
 657 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
 658
 659 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
 660 MODULE_AUTHOR("Andrzej Pietrasiewicz");
 661 MODULE_LICENSE("GPL");