root/drivers/gpu/drm/drm_prime.c

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DEFINITIONS

This source file includes following definitions.
  1. drm_prime_add_buf_handle
  2. drm_prime_lookup_buf_by_handle
  3. drm_prime_lookup_buf_handle
  4. drm_prime_remove_buf_handle_locked
  5. drm_prime_init_file_private
  6. drm_prime_destroy_file_private
  7. drm_gem_dmabuf_export
  8. drm_gem_dmabuf_release
  9. drm_gem_prime_fd_to_handle
  10. drm_prime_fd_to_handle_ioctl
  11. export_and_register_object
  12. drm_gem_prime_handle_to_fd
  13. drm_prime_handle_to_fd_ioctl
  14. drm_gem_map_attach
  15. drm_gem_map_detach
  16. drm_gem_map_dma_buf
  17. drm_gem_unmap_dma_buf
  18. drm_gem_dmabuf_vmap
  19. drm_gem_dmabuf_vunmap
  20. drm_gem_prime_mmap
  21. drm_gem_dmabuf_mmap
  22. drm_prime_pages_to_sg
  23. drm_gem_prime_export
  24. drm_gem_prime_import_dev
  25. drm_gem_prime_import
  26. drm_prime_sg_to_page_addr_arrays
  27. drm_prime_gem_destroy

   1 /*
   2  * Copyright © 2012 Red Hat
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *      Dave Airlie <airlied@redhat.com>
  25  *      Rob Clark <rob.clark@linaro.org>
  26  *
  27  */
  28 
  29 #include <linux/export.h>
  30 #include <linux/dma-buf.h>
  31 #include <linux/rbtree.h>
  32 
  33 #include <drm/drm.h>
  34 #include <drm/drm_drv.h>
  35 #include <drm/drm_file.h>
  36 #include <drm/drm_framebuffer.h>
  37 #include <drm/drm_gem.h>
  38 #include <drm/drm_prime.h>
  39 
  40 #include "drm_internal.h"
  41 
  42 /**
  43  * DOC: overview and lifetime rules
  44  *
  45  * Similar to GEM global names, PRIME file descriptors are also used to share
  46  * buffer objects across processes. They offer additional security: as file
  47  * descriptors must be explicitly sent over UNIX domain sockets to be shared
  48  * between applications, they can't be guessed like the globally unique GEM
  49  * names.
  50  *
  51  * Drivers that support the PRIME API implement the
  52  * &drm_driver.prime_handle_to_fd and &drm_driver.prime_fd_to_handle operations.
  53  * GEM based drivers must use drm_gem_prime_handle_to_fd() and
  54  * drm_gem_prime_fd_to_handle() to implement these. For GEM based drivers the
  55  * actual driver interfaces is provided through the &drm_gem_object_funcs.export
  56  * and &drm_driver.gem_prime_import hooks.
  57  *
  58  * &dma_buf_ops implementations for GEM drivers are all individually exported
  59  * for drivers which need to overwrite or reimplement some of them.
  60  *
  61  * Reference Counting for GEM Drivers
  62  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  63  *
  64  * On the export the &dma_buf holds a reference to the exported buffer object,
  65  * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
  66  * IOCTL, when it first calls &drm_gem_object_funcs.export
  67  * and stores the exporting GEM object in the &dma_buf.priv field. This
  68  * reference needs to be released when the final reference to the &dma_buf
  69  * itself is dropped and its &dma_buf_ops.release function is called.  For
  70  * GEM-based drivers, the &dma_buf should be exported using
  71  * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
  72  *
  73  * Thus the chain of references always flows in one direction, avoiding loops:
  74  * importing GEM object -> dma-buf -> exported GEM bo. A further complication
  75  * are the lookup caches for import and export. These are required to guarantee
  76  * that any given object will always have only one uniqe userspace handle. This
  77  * is required to allow userspace to detect duplicated imports, since some GEM
  78  * drivers do fail command submissions if a given buffer object is listed more
  79  * than once. These import and export caches in &drm_prime_file_private only
  80  * retain a weak reference, which is cleaned up when the corresponding object is
  81  * released.
  82  *
  83  * Self-importing: If userspace is using PRIME as a replacement for flink then
  84  * it will get a fd->handle request for a GEM object that it created.  Drivers
  85  * should detect this situation and return back the underlying object from the
  86  * dma-buf private. For GEM based drivers this is handled in
  87  * drm_gem_prime_import() already.
  88  */
  89 
  90 struct drm_prime_member {
  91         struct dma_buf *dma_buf;
  92         uint32_t handle;
  93 
  94         struct rb_node dmabuf_rb;
  95         struct rb_node handle_rb;
  96 };
  97 
  98 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
  99                                     struct dma_buf *dma_buf, uint32_t handle)
 100 {
 101         struct drm_prime_member *member;
 102         struct rb_node **p, *rb;
 103 
 104         member = kmalloc(sizeof(*member), GFP_KERNEL);
 105         if (!member)
 106                 return -ENOMEM;
 107 
 108         get_dma_buf(dma_buf);
 109         member->dma_buf = dma_buf;
 110         member->handle = handle;
 111 
 112         rb = NULL;
 113         p = &prime_fpriv->dmabufs.rb_node;
 114         while (*p) {
 115                 struct drm_prime_member *pos;
 116 
 117                 rb = *p;
 118                 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
 119                 if (dma_buf > pos->dma_buf)
 120                         p = &rb->rb_right;
 121                 else
 122                         p = &rb->rb_left;
 123         }
 124         rb_link_node(&member->dmabuf_rb, rb, p);
 125         rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
 126 
 127         rb = NULL;
 128         p = &prime_fpriv->handles.rb_node;
 129         while (*p) {
 130                 struct drm_prime_member *pos;
 131 
 132                 rb = *p;
 133                 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
 134                 if (handle > pos->handle)
 135                         p = &rb->rb_right;
 136                 else
 137                         p = &rb->rb_left;
 138         }
 139         rb_link_node(&member->handle_rb, rb, p);
 140         rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
 141 
 142         return 0;
 143 }
 144 
 145 static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
 146                                                       uint32_t handle)
 147 {
 148         struct rb_node *rb;
 149 
 150         rb = prime_fpriv->handles.rb_node;
 151         while (rb) {
 152                 struct drm_prime_member *member;
 153 
 154                 member = rb_entry(rb, struct drm_prime_member, handle_rb);
 155                 if (member->handle == handle)
 156                         return member->dma_buf;
 157                 else if (member->handle < handle)
 158                         rb = rb->rb_right;
 159                 else
 160                         rb = rb->rb_left;
 161         }
 162 
 163         return NULL;
 164 }
 165 
 166 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
 167                                        struct dma_buf *dma_buf,
 168                                        uint32_t *handle)
 169 {
 170         struct rb_node *rb;
 171 
 172         rb = prime_fpriv->dmabufs.rb_node;
 173         while (rb) {
 174                 struct drm_prime_member *member;
 175 
 176                 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
 177                 if (member->dma_buf == dma_buf) {
 178                         *handle = member->handle;
 179                         return 0;
 180                 } else if (member->dma_buf < dma_buf) {
 181                         rb = rb->rb_right;
 182                 } else {
 183                         rb = rb->rb_left;
 184                 }
 185         }
 186 
 187         return -ENOENT;
 188 }
 189 
 190 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
 191                                         struct dma_buf *dma_buf)
 192 {
 193         struct rb_node *rb;
 194 
 195         rb = prime_fpriv->dmabufs.rb_node;
 196         while (rb) {
 197                 struct drm_prime_member *member;
 198 
 199                 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
 200                 if (member->dma_buf == dma_buf) {
 201                         rb_erase(&member->handle_rb, &prime_fpriv->handles);
 202                         rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
 203 
 204                         dma_buf_put(dma_buf);
 205                         kfree(member);
 206                         return;
 207                 } else if (member->dma_buf < dma_buf) {
 208                         rb = rb->rb_right;
 209                 } else {
 210                         rb = rb->rb_left;
 211                 }
 212         }
 213 }
 214 
 215 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 216 {
 217         mutex_init(&prime_fpriv->lock);
 218         prime_fpriv->dmabufs = RB_ROOT;
 219         prime_fpriv->handles = RB_ROOT;
 220 }
 221 
 222 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 223 {
 224         /* by now drm_gem_release should've made sure the list is empty */
 225         WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
 226 }
 227 
 228 /**
 229  * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
 230  * @dev: parent device for the exported dmabuf
 231  * @exp_info: the export information used by dma_buf_export()
 232  *
 233  * This wraps dma_buf_export() for use by generic GEM drivers that are using
 234  * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
 235  * a reference to the &drm_device and the exported &drm_gem_object (stored in
 236  * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
 237  *
 238  * Returns the new dmabuf.
 239  */
 240 struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
 241                                       struct dma_buf_export_info *exp_info)
 242 {
 243         struct dma_buf *dma_buf;
 244 
 245         dma_buf = dma_buf_export(exp_info);
 246         if (IS_ERR(dma_buf))
 247                 return dma_buf;
 248 
 249         drm_dev_get(dev);
 250         drm_gem_object_get(exp_info->priv);
 251 
 252         return dma_buf;
 253 }
 254 EXPORT_SYMBOL(drm_gem_dmabuf_export);
 255 
 256 /**
 257  * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
 258  * @dma_buf: buffer to be released
 259  *
 260  * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
 261  * must use this in their &dma_buf_ops structure as the release callback.
 262  * drm_gem_dmabuf_release() should be used in conjunction with
 263  * drm_gem_dmabuf_export().
 264  */
 265 void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
 266 {
 267         struct drm_gem_object *obj = dma_buf->priv;
 268         struct drm_device *dev = obj->dev;
 269 
 270         /* drop the reference on the export fd holds */
 271         drm_gem_object_put_unlocked(obj);
 272 
 273         drm_dev_put(dev);
 274 }
 275 EXPORT_SYMBOL(drm_gem_dmabuf_release);
 276 
 277 /**
 278  * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
 279  * @dev: dev to export the buffer from
 280  * @file_priv: drm file-private structure
 281  * @prime_fd: fd id of the dma-buf which should be imported
 282  * @handle: pointer to storage for the handle of the imported buffer object
 283  *
 284  * This is the PRIME import function which must be used mandatorily by GEM
 285  * drivers to ensure correct lifetime management of the underlying GEM object.
 286  * The actual importing of GEM object from the dma-buf is done through the
 287  * &drm_driver.gem_prime_import driver callback.
 288  *
 289  * Returns 0 on success or a negative error code on failure.
 290  */
 291 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 292                                struct drm_file *file_priv, int prime_fd,
 293                                uint32_t *handle)
 294 {
 295         struct dma_buf *dma_buf;
 296         struct drm_gem_object *obj;
 297         int ret;
 298 
 299         dma_buf = dma_buf_get(prime_fd);
 300         if (IS_ERR(dma_buf))
 301                 return PTR_ERR(dma_buf);
 302 
 303         mutex_lock(&file_priv->prime.lock);
 304 
 305         ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 306                         dma_buf, handle);
 307         if (ret == 0)
 308                 goto out_put;
 309 
 310         /* never seen this one, need to import */
 311         mutex_lock(&dev->object_name_lock);
 312         if (dev->driver->gem_prime_import)
 313                 obj = dev->driver->gem_prime_import(dev, dma_buf);
 314         else
 315                 obj = drm_gem_prime_import(dev, dma_buf);
 316         if (IS_ERR(obj)) {
 317                 ret = PTR_ERR(obj);
 318                 goto out_unlock;
 319         }
 320 
 321         if (obj->dma_buf) {
 322                 WARN_ON(obj->dma_buf != dma_buf);
 323         } else {
 324                 obj->dma_buf = dma_buf;
 325                 get_dma_buf(dma_buf);
 326         }
 327 
 328         /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
 329         ret = drm_gem_handle_create_tail(file_priv, obj, handle);
 330         drm_gem_object_put_unlocked(obj);
 331         if (ret)
 332                 goto out_put;
 333 
 334         ret = drm_prime_add_buf_handle(&file_priv->prime,
 335                         dma_buf, *handle);
 336         mutex_unlock(&file_priv->prime.lock);
 337         if (ret)
 338                 goto fail;
 339 
 340         dma_buf_put(dma_buf);
 341 
 342         return 0;
 343 
 344 fail:
 345         /* hmm, if driver attached, we are relying on the free-object path
 346          * to detach.. which seems ok..
 347          */
 348         drm_gem_handle_delete(file_priv, *handle);
 349         dma_buf_put(dma_buf);
 350         return ret;
 351 
 352 out_unlock:
 353         mutex_unlock(&dev->object_name_lock);
 354 out_put:
 355         mutex_unlock(&file_priv->prime.lock);
 356         dma_buf_put(dma_buf);
 357         return ret;
 358 }
 359 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 360 
 361 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 362                                  struct drm_file *file_priv)
 363 {
 364         struct drm_prime_handle *args = data;
 365 
 366         if (!dev->driver->prime_fd_to_handle)
 367                 return -ENOSYS;
 368 
 369         return dev->driver->prime_fd_to_handle(dev, file_priv,
 370                         args->fd, &args->handle);
 371 }
 372 
 373 static struct dma_buf *export_and_register_object(struct drm_device *dev,
 374                                                   struct drm_gem_object *obj,
 375                                                   uint32_t flags)
 376 {
 377         struct dma_buf *dmabuf;
 378 
 379         /* prevent races with concurrent gem_close. */
 380         if (obj->handle_count == 0) {
 381                 dmabuf = ERR_PTR(-ENOENT);
 382                 return dmabuf;
 383         }
 384 
 385         if (obj->funcs && obj->funcs->export)
 386                 dmabuf = obj->funcs->export(obj, flags);
 387         else if (dev->driver->gem_prime_export)
 388                 dmabuf = dev->driver->gem_prime_export(obj, flags);
 389         else
 390                 dmabuf = drm_gem_prime_export(obj, flags);
 391         if (IS_ERR(dmabuf)) {
 392                 /* normally the created dma-buf takes ownership of the ref,
 393                  * but if that fails then drop the ref
 394                  */
 395                 return dmabuf;
 396         }
 397 
 398         /*
 399          * Note that callers do not need to clean up the export cache
 400          * since the check for obj->handle_count guarantees that someone
 401          * will clean it up.
 402          */
 403         obj->dma_buf = dmabuf;
 404         get_dma_buf(obj->dma_buf);
 405 
 406         return dmabuf;
 407 }
 408 
 409 /**
 410  * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
 411  * @dev: dev to export the buffer from
 412  * @file_priv: drm file-private structure
 413  * @handle: buffer handle to export
 414  * @flags: flags like DRM_CLOEXEC
 415  * @prime_fd: pointer to storage for the fd id of the create dma-buf
 416  *
 417  * This is the PRIME export function which must be used mandatorily by GEM
 418  * drivers to ensure correct lifetime management of the underlying GEM object.
 419  * The actual exporting from GEM object to a dma-buf is done through the
 420  * &drm_driver.gem_prime_export driver callback.
 421  */
 422 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 423                                struct drm_file *file_priv, uint32_t handle,
 424                                uint32_t flags,
 425                                int *prime_fd)
 426 {
 427         struct drm_gem_object *obj;
 428         int ret = 0;
 429         struct dma_buf *dmabuf;
 430 
 431         mutex_lock(&file_priv->prime.lock);
 432         obj = drm_gem_object_lookup(file_priv, handle);
 433         if (!obj)  {
 434                 ret = -ENOENT;
 435                 goto out_unlock;
 436         }
 437 
 438         dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
 439         if (dmabuf) {
 440                 get_dma_buf(dmabuf);
 441                 goto out_have_handle;
 442         }
 443 
 444         mutex_lock(&dev->object_name_lock);
 445         /* re-export the original imported object */
 446         if (obj->import_attach) {
 447                 dmabuf = obj->import_attach->dmabuf;
 448                 get_dma_buf(dmabuf);
 449                 goto out_have_obj;
 450         }
 451 
 452         if (obj->dma_buf) {
 453                 get_dma_buf(obj->dma_buf);
 454                 dmabuf = obj->dma_buf;
 455                 goto out_have_obj;
 456         }
 457 
 458         dmabuf = export_and_register_object(dev, obj, flags);
 459         if (IS_ERR(dmabuf)) {
 460                 /* normally the created dma-buf takes ownership of the ref,
 461                  * but if that fails then drop the ref
 462                  */
 463                 ret = PTR_ERR(dmabuf);
 464                 mutex_unlock(&dev->object_name_lock);
 465                 goto out;
 466         }
 467 
 468 out_have_obj:
 469         /*
 470          * If we've exported this buffer then cheat and add it to the import list
 471          * so we get the correct handle back. We must do this under the
 472          * protection of dev->object_name_lock to ensure that a racing gem close
 473          * ioctl doesn't miss to remove this buffer handle from the cache.
 474          */
 475         ret = drm_prime_add_buf_handle(&file_priv->prime,
 476                                        dmabuf, handle);
 477         mutex_unlock(&dev->object_name_lock);
 478         if (ret)
 479                 goto fail_put_dmabuf;
 480 
 481 out_have_handle:
 482         ret = dma_buf_fd(dmabuf, flags);
 483         /*
 484          * We must _not_ remove the buffer from the handle cache since the newly
 485          * created dma buf is already linked in the global obj->dma_buf pointer,
 486          * and that is invariant as long as a userspace gem handle exists.
 487          * Closing the handle will clean out the cache anyway, so we don't leak.
 488          */
 489         if (ret < 0) {
 490                 goto fail_put_dmabuf;
 491         } else {
 492                 *prime_fd = ret;
 493                 ret = 0;
 494         }
 495 
 496         goto out;
 497 
 498 fail_put_dmabuf:
 499         dma_buf_put(dmabuf);
 500 out:
 501         drm_gem_object_put_unlocked(obj);
 502 out_unlock:
 503         mutex_unlock(&file_priv->prime.lock);
 504 
 505         return ret;
 506 }
 507 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 508 
 509 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 510                                  struct drm_file *file_priv)
 511 {
 512         struct drm_prime_handle *args = data;
 513 
 514         if (!dev->driver->prime_handle_to_fd)
 515                 return -ENOSYS;
 516 
 517         /* check flags are valid */
 518         if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
 519                 return -EINVAL;
 520 
 521         return dev->driver->prime_handle_to_fd(dev, file_priv,
 522                         args->handle, args->flags, &args->fd);
 523 }
 524 
 525 /**
 526  * DOC: PRIME Helpers
 527  *
 528  * Drivers can implement &drm_gem_object_funcs.export and
 529  * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
 530  * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
 531  * implement dma-buf support in terms of some lower-level helpers, which are
 532  * again exported for drivers to use individually:
 533  *
 534  * Exporting buffers
 535  * ~~~~~~~~~~~~~~~~~
 536  *
 537  * Optional pinning of buffers is handled at dma-buf attach and detach time in
 538  * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
 539  * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
 540  * &drm_gem_object_funcs.get_sg_table.
 541  *
 542  * For kernel-internal access there's drm_gem_dmabuf_vmap() and
 543  * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
 544  * drm_gem_dmabuf_mmap().
 545  *
 546  * Note that these export helpers can only be used if the underlying backing
 547  * storage is fully coherent and either permanently pinned, or it is safe to pin
 548  * it indefinitely.
 549  *
 550  * FIXME: The underlying helper functions are named rather inconsistently.
 551  *
 552  * Exporting buffers
 553  * ~~~~~~~~~~~~~~~~~
 554  *
 555  * Importing dma-bufs using drm_gem_prime_import() relies on
 556  * &drm_driver.gem_prime_import_sg_table.
 557  *
 558  * Note that similarly to the export helpers this permanently pins the
 559  * underlying backing storage. Which is ok for scanout, but is not the best
 560  * option for sharing lots of buffers for rendering.
 561  */
 562 
 563 /**
 564  * drm_gem_map_attach - dma_buf attach implementation for GEM
 565  * @dma_buf: buffer to attach device to
 566  * @attach: buffer attachment data
 567  *
 568  * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
 569  * used as the &dma_buf_ops.attach callback. Must be used together with
 570  * drm_gem_map_detach().
 571  *
 572  * Returns 0 on success, negative error code on failure.
 573  */
 574 int drm_gem_map_attach(struct dma_buf *dma_buf,
 575                        struct dma_buf_attachment *attach)
 576 {
 577         struct drm_gem_object *obj = dma_buf->priv;
 578 
 579         return drm_gem_pin(obj);
 580 }
 581 EXPORT_SYMBOL(drm_gem_map_attach);
 582 
 583 /**
 584  * drm_gem_map_detach - dma_buf detach implementation for GEM
 585  * @dma_buf: buffer to detach from
 586  * @attach: attachment to be detached
 587  *
 588  * Calls &drm_gem_object_funcs.pin for device specific handling.  Cleans up
 589  * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
 590  * &dma_buf_ops.detach callback.
 591  */
 592 void drm_gem_map_detach(struct dma_buf *dma_buf,
 593                         struct dma_buf_attachment *attach)
 594 {
 595         struct drm_gem_object *obj = dma_buf->priv;
 596 
 597         drm_gem_unpin(obj);
 598 }
 599 EXPORT_SYMBOL(drm_gem_map_detach);
 600 
 601 /**
 602  * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
 603  * @attach: attachment whose scatterlist is to be returned
 604  * @dir: direction of DMA transfer
 605  *
 606  * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
 607  * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
 608  * with drm_gem_unmap_dma_buf().
 609  *
 610  * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
 611  * on error. May return -EINTR if it is interrupted by a signal.
 612  */
 613 struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
 614                                      enum dma_data_direction dir)
 615 {
 616         struct drm_gem_object *obj = attach->dmabuf->priv;
 617         struct sg_table *sgt;
 618 
 619         if (WARN_ON(dir == DMA_NONE))
 620                 return ERR_PTR(-EINVAL);
 621 
 622         if (obj->funcs)
 623                 sgt = obj->funcs->get_sg_table(obj);
 624         else
 625                 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
 626 
 627         if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
 628                               DMA_ATTR_SKIP_CPU_SYNC)) {
 629                 sg_free_table(sgt);
 630                 kfree(sgt);
 631                 sgt = ERR_PTR(-ENOMEM);
 632         }
 633 
 634         return sgt;
 635 }
 636 EXPORT_SYMBOL(drm_gem_map_dma_buf);
 637 
 638 /**
 639  * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
 640  * @attach: attachment to unmap buffer from
 641  * @sgt: scatterlist info of the buffer to unmap
 642  * @dir: direction of DMA transfer
 643  *
 644  * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
 645  */
 646 void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 647                            struct sg_table *sgt,
 648                            enum dma_data_direction dir)
 649 {
 650         if (!sgt)
 651                 return;
 652 
 653         dma_unmap_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
 654                            DMA_ATTR_SKIP_CPU_SYNC);
 655         sg_free_table(sgt);
 656         kfree(sgt);
 657 }
 658 EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
 659 
 660 /**
 661  * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
 662  * @dma_buf: buffer to be mapped
 663  *
 664  * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
 665  * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
 666  *
 667  * Returns the kernel virtual address or NULL on failure.
 668  */
 669 void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 670 {
 671         struct drm_gem_object *obj = dma_buf->priv;
 672         void *vaddr;
 673 
 674         vaddr = drm_gem_vmap(obj);
 675         if (IS_ERR(vaddr))
 676                 vaddr = NULL;
 677 
 678         return vaddr;
 679 }
 680 EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
 681 
 682 /**
 683  * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
 684  * @dma_buf: buffer to be unmapped
 685  * @vaddr: the virtual address of the buffer
 686  *
 687  * Releases a kernel virtual mapping. This can be used as the
 688  * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
 689  */
 690 void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 691 {
 692         struct drm_gem_object *obj = dma_buf->priv;
 693 
 694         drm_gem_vunmap(obj, vaddr);
 695 }
 696 EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
 697 
 698 /**
 699  * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
 700  * @obj: GEM object
 701  * @vma: Virtual address range
 702  *
 703  * This function sets up a userspace mapping for PRIME exported buffers using
 704  * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
 705  * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
 706  * called to set up the mapping.
 707  *
 708  * Drivers can use this as their &drm_driver.gem_prime_mmap callback.
 709  */
 710 int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 711 {
 712         struct drm_file *priv;
 713         struct file *fil;
 714         int ret;
 715 
 716         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 717         fil = kzalloc(sizeof(*fil), GFP_KERNEL);
 718         if (!priv || !fil) {
 719                 ret = -ENOMEM;
 720                 goto out;
 721         }
 722 
 723         /* Used by drm_gem_mmap() to lookup the GEM object */
 724         priv->minor = obj->dev->primary;
 725         fil->private_data = priv;
 726 
 727         ret = drm_vma_node_allow(&obj->vma_node, priv);
 728         if (ret)
 729                 goto out;
 730 
 731         vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
 732 
 733         ret = obj->dev->driver->fops->mmap(fil, vma);
 734 
 735         drm_vma_node_revoke(&obj->vma_node, priv);
 736 out:
 737         kfree(priv);
 738         kfree(fil);
 739 
 740         return ret;
 741 }
 742 EXPORT_SYMBOL(drm_gem_prime_mmap);
 743 
 744 /**
 745  * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
 746  * @dma_buf: buffer to be mapped
 747  * @vma: virtual address range
 748  *
 749  * Provides memory mapping for the buffer. This can be used as the
 750  * &dma_buf_ops.mmap callback. It just forwards to &drm_driver.gem_prime_mmap,
 751  * which should be set to drm_gem_prime_mmap().
 752  *
 753  * FIXME: There's really no point to this wrapper, drivers which need anything
 754  * else but drm_gem_prime_mmap can roll their own &dma_buf_ops.mmap callback.
 755  *
 756  * Returns 0 on success or a negative error code on failure.
 757  */
 758 int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
 759 {
 760         struct drm_gem_object *obj = dma_buf->priv;
 761         struct drm_device *dev = obj->dev;
 762 
 763         if (!dev->driver->gem_prime_mmap)
 764                 return -ENOSYS;
 765 
 766         return dev->driver->gem_prime_mmap(obj, vma);
 767 }
 768 EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
 769 
 770 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 771         .cache_sgt_mapping = true,
 772         .attach = drm_gem_map_attach,
 773         .detach = drm_gem_map_detach,
 774         .map_dma_buf = drm_gem_map_dma_buf,
 775         .unmap_dma_buf = drm_gem_unmap_dma_buf,
 776         .release = drm_gem_dmabuf_release,
 777         .mmap = drm_gem_dmabuf_mmap,
 778         .vmap = drm_gem_dmabuf_vmap,
 779         .vunmap = drm_gem_dmabuf_vunmap,
 780 };
 781 
 782 /**
 783  * drm_prime_pages_to_sg - converts a page array into an sg list
 784  * @pages: pointer to the array of page pointers to convert
 785  * @nr_pages: length of the page vector
 786  *
 787  * This helper creates an sg table object from a set of pages
 788  * the driver is responsible for mapping the pages into the
 789  * importers address space for use with dma_buf itself.
 790  *
 791  * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
 792  */
 793 struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages)
 794 {
 795         struct sg_table *sg = NULL;
 796         int ret;
 797 
 798         sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 799         if (!sg) {
 800                 ret = -ENOMEM;
 801                 goto out;
 802         }
 803 
 804         ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 805                                 nr_pages << PAGE_SHIFT, GFP_KERNEL);
 806         if (ret)
 807                 goto out;
 808 
 809         return sg;
 810 out:
 811         kfree(sg);
 812         return ERR_PTR(ret);
 813 }
 814 EXPORT_SYMBOL(drm_prime_pages_to_sg);
 815 
 816 /**
 817  * drm_gem_prime_export - helper library implementation of the export callback
 818  * @obj: GEM object to export
 819  * @flags: flags like DRM_CLOEXEC and DRM_RDWR
 820  *
 821  * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
 822  * using the PRIME helpers. It is used as the default in
 823  * drm_gem_prime_handle_to_fd().
 824  */
 825 struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
 826                                      int flags)
 827 {
 828         struct drm_device *dev = obj->dev;
 829         struct dma_buf_export_info exp_info = {
 830                 .exp_name = KBUILD_MODNAME, /* white lie for debug */
 831                 .owner = dev->driver->fops->owner,
 832                 .ops = &drm_gem_prime_dmabuf_ops,
 833                 .size = obj->size,
 834                 .flags = flags,
 835                 .priv = obj,
 836                 .resv = obj->resv,
 837         };
 838 
 839         return drm_gem_dmabuf_export(dev, &exp_info);
 840 }
 841 EXPORT_SYMBOL(drm_gem_prime_export);
 842 
 843 /**
 844  * drm_gem_prime_import_dev - core implementation of the import callback
 845  * @dev: drm_device to import into
 846  * @dma_buf: dma-buf object to import
 847  * @attach_dev: struct device to dma_buf attach
 848  *
 849  * This is the core of drm_gem_prime_import(). It's designed to be called by
 850  * drivers who want to use a different device structure than &drm_device.dev for
 851  * attaching via dma_buf. This function calls
 852  * &drm_driver.gem_prime_import_sg_table internally.
 853  *
 854  * Drivers must arrange to call drm_prime_gem_destroy() from their
 855  * &drm_gem_object_funcs.free hook when using this function.
 856  */
 857 struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
 858                                             struct dma_buf *dma_buf,
 859                                             struct device *attach_dev)
 860 {
 861         struct dma_buf_attachment *attach;
 862         struct sg_table *sgt;
 863         struct drm_gem_object *obj;
 864         int ret;
 865 
 866         if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 867                 obj = dma_buf->priv;
 868                 if (obj->dev == dev) {
 869                         /*
 870                          * Importing dmabuf exported from out own gem increases
 871                          * refcount on gem itself instead of f_count of dmabuf.
 872                          */
 873                         drm_gem_object_get(obj);
 874                         return obj;
 875                 }
 876         }
 877 
 878         if (!dev->driver->gem_prime_import_sg_table)
 879                 return ERR_PTR(-EINVAL);
 880 
 881         attach = dma_buf_attach(dma_buf, attach_dev);
 882         if (IS_ERR(attach))
 883                 return ERR_CAST(attach);
 884 
 885         get_dma_buf(dma_buf);
 886 
 887         sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 888         if (IS_ERR(sgt)) {
 889                 ret = PTR_ERR(sgt);
 890                 goto fail_detach;
 891         }
 892 
 893         obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
 894         if (IS_ERR(obj)) {
 895                 ret = PTR_ERR(obj);
 896                 goto fail_unmap;
 897         }
 898 
 899         obj->import_attach = attach;
 900         obj->resv = dma_buf->resv;
 901 
 902         return obj;
 903 
 904 fail_unmap:
 905         dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 906 fail_detach:
 907         dma_buf_detach(dma_buf, attach);
 908         dma_buf_put(dma_buf);
 909 
 910         return ERR_PTR(ret);
 911 }
 912 EXPORT_SYMBOL(drm_gem_prime_import_dev);
 913 
 914 /**
 915  * drm_gem_prime_import - helper library implementation of the import callback
 916  * @dev: drm_device to import into
 917  * @dma_buf: dma-buf object to import
 918  *
 919  * This is the implementation of the gem_prime_import functions for GEM drivers
 920  * using the PRIME helpers. Drivers can use this as their
 921  * &drm_driver.gem_prime_import implementation. It is used as the default
 922  * implementation in drm_gem_prime_fd_to_handle().
 923  *
 924  * Drivers must arrange to call drm_prime_gem_destroy() from their
 925  * &drm_gem_object_funcs.free hook when using this function.
 926  */
 927 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 928                                             struct dma_buf *dma_buf)
 929 {
 930         return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
 931 }
 932 EXPORT_SYMBOL(drm_gem_prime_import);
 933 
 934 /**
 935  * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
 936  * @sgt: scatter-gather table to convert
 937  * @pages: optional array of page pointers to store the page array in
 938  * @addrs: optional array to store the dma bus address of each page
 939  * @max_entries: size of both the passed-in arrays
 940  *
 941  * Exports an sg table into an array of pages and addresses. This is currently
 942  * required by the TTM driver in order to do correct fault handling.
 943  *
 944  * Drivers can use this in their &drm_driver.gem_prime_import_sg_table
 945  * implementation.
 946  */
 947 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 948                                      dma_addr_t *addrs, int max_entries)
 949 {
 950         unsigned count;
 951         struct scatterlist *sg;
 952         struct page *page;
 953         u32 len, index;
 954         dma_addr_t addr;
 955 
 956         index = 0;
 957         for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 958                 len = sg->length;
 959                 page = sg_page(sg);
 960                 addr = sg_dma_address(sg);
 961 
 962                 while (len > 0) {
 963                         if (WARN_ON(index >= max_entries))
 964                                 return -1;
 965                         if (pages)
 966                                 pages[index] = page;
 967                         if (addrs)
 968                                 addrs[index] = addr;
 969 
 970                         page++;
 971                         addr += PAGE_SIZE;
 972                         len -= PAGE_SIZE;
 973                         index++;
 974                 }
 975         }
 976         return 0;
 977 }
 978 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 979 
 980 /**
 981  * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
 982  * @obj: GEM object which was created from a dma-buf
 983  * @sg: the sg-table which was pinned at import time
 984  *
 985  * This is the cleanup functions which GEM drivers need to call when they use
 986  * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
 987  */
 988 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 989 {
 990         struct dma_buf_attachment *attach;
 991         struct dma_buf *dma_buf;
 992         attach = obj->import_attach;
 993         if (sg)
 994                 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 995         dma_buf = attach->dmabuf;
 996         dma_buf_detach(attach->dmabuf, attach);
 997         /* remove the reference */
 998         dma_buf_put(dma_buf);
 999 }
1000 EXPORT_SYMBOL(drm_prime_gem_destroy);

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