1 /************************************************************************** 2 * 3 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice (including the 15 * next paragraph) shall be included in all copies or substantial portions 16 * of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 24 * USE OR OTHER DEALINGS IN THE SOFTWARE. 25 * 26 **************************************************************************/ 27 /* 28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com> 29 */ 30 31 #ifndef _TTM_BO_API_H_ 32 #define _TTM_BO_API_H_ 33 34 #include <drm/drmP.h> 35 #include <drm/drm_hashtab.h> 36 #include <drm/drm_vma_manager.h> 37 #include <linux/kref.h> 38 #include <linux/list.h> 39 #include <linux/wait.h> 40 #include <linux/mutex.h> 41 #include <linux/mm.h> 42 #include <linux/bitmap.h> 43 #include <linux/reservation.h> 44 45 struct ttm_bo_device; 46 47 struct drm_mm_node; 48 49 struct ttm_placement; 50 51 /** 52 * struct ttm_bus_placement 53 * 54 * @addr: mapped virtual address 55 * @base: bus base address 56 * @is_iomem: is this io memory ? 57 * @size: size in byte 58 * @offset: offset from the base address 59 * @io_reserved_vm: The VM system has a refcount in @io_reserved_count 60 * @io_reserved_count: Refcounting the numbers of callers to ttm_mem_io_reserve 61 * 62 * Structure indicating the bus placement of an object. 63 */ 64 struct ttm_bus_placement { 65 void *addr; 66 unsigned long base; 67 unsigned long size; 68 unsigned long offset; 69 bool is_iomem; 70 bool io_reserved_vm; 71 uint64_t io_reserved_count; 72 }; 73 74 75 /** 76 * struct ttm_mem_reg 77 * 78 * @mm_node: Memory manager node. 79 * @size: Requested size of memory region. 80 * @num_pages: Actual size of memory region in pages. 81 * @page_alignment: Page alignment. 82 * @placement: Placement flags. 83 * @bus: Placement on io bus accessible to the CPU 84 * 85 * Structure indicating the placement and space resources used by a 86 * buffer object. 87 */ 88 89 struct ttm_mem_reg { 90 void *mm_node; 91 unsigned long start; 92 unsigned long size; 93 unsigned long num_pages; 94 uint32_t page_alignment; 95 uint32_t mem_type; 96 uint32_t placement; 97 struct ttm_bus_placement bus; 98 }; 99 100 /** 101 * enum ttm_bo_type 102 * 103 * @ttm_bo_type_device: These are 'normal' buffers that can 104 * be mmapped by user space. Each of these bos occupy a slot in the 105 * device address space, that can be used for normal vm operations. 106 * 107 * @ttm_bo_type_kernel: These buffers are like ttm_bo_type_device buffers, 108 * but they cannot be accessed from user-space. For kernel-only use. 109 * 110 * @ttm_bo_type_sg: Buffer made from dmabuf sg table shared with another 111 * driver. 112 */ 113 114 enum ttm_bo_type { 115 ttm_bo_type_device, 116 ttm_bo_type_kernel, 117 ttm_bo_type_sg 118 }; 119 120 struct ttm_tt; 121 122 /** 123 * struct ttm_buffer_object 124 * 125 * @bdev: Pointer to the buffer object device structure. 126 * @type: The bo type. 127 * @destroy: Destruction function. If NULL, kfree is used. 128 * @num_pages: Actual number of pages. 129 * @acc_size: Accounted size for this object. 130 * @kref: Reference count of this buffer object. When this refcount reaches 131 * zero, the object is put on the delayed delete list. 132 * @list_kref: List reference count of this buffer object. This member is 133 * used to avoid destruction while the buffer object is still on a list. 134 * Lru lists may keep one refcount, the delayed delete list, and kref != 0 135 * keeps one refcount. When this refcount reaches zero, 136 * the object is destroyed. 137 * @mem: structure describing current placement. 138 * @persistent_swap_storage: Usually the swap storage is deleted for buffers 139 * pinned in physical memory. If this behaviour is not desired, this member 140 * holds a pointer to a persistent shmem object. 141 * @ttm: TTM structure holding system pages. 142 * @evicted: Whether the object was evicted without user-space knowing. 143 * @cpu_writes: For synchronization. Number of cpu writers. 144 * @lru: List head for the lru list. 145 * @ddestroy: List head for the delayed destroy list. 146 * @swap: List head for swap LRU list. 147 * @moving: Fence set when BO is moving 148 * @vma_node: Address space manager node. 149 * @offset: The current GPU offset, which can have different meanings 150 * depending on the memory type. For SYSTEM type memory, it should be 0. 151 * @cur_placement: Hint of current placement. 152 * @wu_mutex: Wait unreserved mutex. 153 * 154 * Base class for TTM buffer object, that deals with data placement and CPU 155 * mappings. GPU mappings are really up to the driver, but for simpler GPUs 156 * the driver can usually use the placement offset @offset directly as the 157 * GPU virtual address. For drivers implementing multiple 158 * GPU memory manager contexts, the driver should manage the address space 159 * in these contexts separately and use these objects to get the correct 160 * placement and caching for these GPU maps. This makes it possible to use 161 * these objects for even quite elaborate memory management schemes. 162 * The destroy member, the API visibility of this object makes it possible 163 * to derive driver specific types. 164 */ 165 166 struct ttm_buffer_object { 167 /** 168 * Members constant at init. 169 */ 170 171 struct ttm_bo_global *glob; 172 struct ttm_bo_device *bdev; 173 enum ttm_bo_type type; 174 void (*destroy) (struct ttm_buffer_object *); 175 unsigned long num_pages; 176 size_t acc_size; 177 178 /** 179 * Members not needing protection. 180 */ 181 182 struct kref kref; 183 struct kref list_kref; 184 185 /** 186 * Members protected by the bo::resv::reserved lock. 187 */ 188 189 struct ttm_mem_reg mem; 190 struct vm_object *persistent_swap_storage; 191 struct ttm_tt *ttm; 192 bool evicted; 193 194 /** 195 * Members protected by the bo::reserved lock only when written to. 196 */ 197 198 atomic_t cpu_writers; 199 200 /** 201 * Members protected by the bdev::lru_lock. 202 */ 203 204 struct list_head lru; 205 struct list_head ddestroy; 206 struct list_head swap; 207 struct list_head io_reserve_lru; 208 209 /** 210 * Members protected by a bo reservation. 211 */ 212 213 struct fence *moving; 214 215 RB_ENTRY(ttm_buffer_object) vm_rb; /* DragonFly */ 216 struct drm_vma_offset_node vma_node; 217 218 /** 219 * Special members that are protected by the reserve lock 220 * and the bo::lock when written to. Can be read with 221 * either of these locks held. 222 */ 223 224 uint64_t offset; /* GPU address space is independent of CPU word size */ 225 uint32_t cur_placement; 226 227 struct sg_table *sg; 228 229 struct reservation_object *resv; 230 struct reservation_object ttm_resv; 231 struct lock wu_mutex; 232 }; 233 234 /** 235 * struct ttm_bo_kmap_obj 236 * 237 * @virtual: The current kernel virtual address. 238 * @page: The page when kmap'ing a single page. 239 * @bo_kmap_type: Type of bo_kmap. 240 * 241 * Object describing a kernel mapping. Since a TTM bo may be located 242 * in various memory types with various caching policies, the 243 * mapping can either be an ioremap, a vmap, a kmap or part of a 244 * premapped region. 245 */ 246 247 #define TTM_BO_MAP_IOMEM_MASK 0x80 248 struct ttm_bo_kmap_obj { 249 void *virtual; 250 struct page *page; 251 enum { 252 ttm_bo_map_iomap = 1 | TTM_BO_MAP_IOMEM_MASK, 253 ttm_bo_map_vmap = 2, 254 ttm_bo_map_kmap = 3, 255 ttm_bo_map_premapped = 4 | TTM_BO_MAP_IOMEM_MASK, 256 } bo_kmap_type; 257 struct ttm_buffer_object *bo; 258 }; 259 260 /** 261 * ttm_bo_reference - reference a struct ttm_buffer_object 262 * 263 * @bo: The buffer object. 264 * 265 * Returns a refcounted pointer to a buffer object. 266 */ 267 268 static inline struct ttm_buffer_object * 269 ttm_bo_reference(struct ttm_buffer_object *bo) 270 { 271 kref_get(&bo->kref); 272 return bo; 273 } 274 275 /** 276 * ttm_bo_wait - wait for buffer idle. 277 * 278 * @bo: The buffer object. 279 * @interruptible: Use interruptible wait. 280 * @no_wait: Return immediately if buffer is busy. 281 * 282 * This function must be called with the bo::mutex held, and makes 283 * sure any previous rendering to the buffer is completed. 284 * Note: It might be necessary to block validations before the 285 * wait by reserving the buffer. 286 * Returns -EBUSY if no_wait is true and the buffer is busy. 287 * Returns -ERESTARTSYS if interrupted by a signal. 288 */ 289 extern int ttm_bo_wait(struct ttm_buffer_object *bo, 290 bool interruptible, bool no_wait); 291 292 /** 293 * ttm_bo_mem_compat - Check if proposed placement is compatible with a bo 294 * 295 * @placement: Return immediately if buffer is busy. 296 * @mem: The struct ttm_mem_reg indicating the region where the bo resides 297 * @new_flags: Describes compatible placement found 298 * 299 * Returns true if the placement is compatible 300 */ 301 extern bool ttm_bo_mem_compat(struct ttm_placement *placement, 302 struct ttm_mem_reg *mem, 303 uint32_t *new_flags); 304 305 /** 306 * ttm_bo_validate 307 * 308 * @bo: The buffer object. 309 * @placement: Proposed placement for the buffer object. 310 * @interruptible: Sleep interruptible if sleeping. 311 * @no_wait_gpu: Return immediately if the GPU is busy. 312 * 313 * Changes placement and caching policy of the buffer object 314 * according proposed placement. 315 * Returns 316 * -EINVAL on invalid proposed placement. 317 * -ENOMEM on out-of-memory condition. 318 * -EBUSY if no_wait is true and buffer busy. 319 * -ERESTARTSYS if interrupted by a signal. 320 */ 321 extern int ttm_bo_validate(struct ttm_buffer_object *bo, 322 struct ttm_placement *placement, 323 bool interruptible, 324 bool no_wait_gpu); 325 326 /** 327 * ttm_bo_unref 328 * 329 * @bo: The buffer object. 330 * 331 * Unreference and clear a pointer to a buffer object. 332 */ 333 extern void ttm_bo_unref(struct ttm_buffer_object **bo); 334 335 336 /** 337 * ttm_bo_list_ref_sub 338 * 339 * @bo: The buffer object. 340 * @count: The number of references with which to decrease @bo::list_kref; 341 * @never_free: The refcount should not reach zero with this operation. 342 * 343 * Release @count lru list references to this buffer object. 344 */ 345 extern void ttm_bo_list_ref_sub(struct ttm_buffer_object *bo, int count, 346 bool never_free); 347 348 /** 349 * ttm_bo_add_to_lru 350 * 351 * @bo: The buffer object. 352 * 353 * Add this bo to the relevant mem type lru and, if it's backed by 354 * system pages (ttms) to the swap list. 355 * This function must be called with struct ttm_bo_global::lru_lock held, and 356 * is typically called immediately prior to unreserving a bo. 357 */ 358 extern void ttm_bo_add_to_lru(struct ttm_buffer_object *bo); 359 360 /** 361 * ttm_bo_del_from_lru 362 * 363 * @bo: The buffer object. 364 * 365 * Remove this bo from all lru lists used to lookup and reserve an object. 366 * This function must be called with struct ttm_bo_global::lru_lock held, 367 * and is usually called just immediately after the bo has been reserved to 368 * avoid recursive reservation from lru lists. 369 */ 370 extern int ttm_bo_del_from_lru(struct ttm_buffer_object *bo); 371 372 /** 373 * ttm_bo_move_to_lru_tail 374 * 375 * @bo: The buffer object. 376 * 377 * Move this BO to the tail of all lru lists used to lookup and reserve an 378 * object. This function must be called with struct ttm_bo_global::lru_lock 379 * held, and is used to make a BO less likely to be considered for eviction. 380 */ 381 extern void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo); 382 383 /** 384 * ttm_bo_lock_delayed_workqueue 385 * 386 * Prevent the delayed workqueue from running. 387 * Returns 388 * True if the workqueue was queued at the time 389 */ 390 extern int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev); 391 392 /** 393 * ttm_bo_unlock_delayed_workqueue 394 * 395 * Allows the delayed workqueue to run. 396 */ 397 extern void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev, 398 int resched); 399 400 /** 401 * ttm_bo_synccpu_write_grab 402 * 403 * @bo: The buffer object: 404 * @no_wait: Return immediately if buffer is busy. 405 * 406 * Synchronizes a buffer object for CPU RW access. This means 407 * command submission that affects the buffer will return -EBUSY 408 * until ttm_bo_synccpu_write_release is called. 409 * 410 * Returns 411 * -EBUSY if the buffer is busy and no_wait is true. 412 * -ERESTARTSYS if interrupted by a signal. 413 */ 414 extern int 415 ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait); 416 417 /** 418 * ttm_bo_synccpu_write_release: 419 * 420 * @bo : The buffer object. 421 * 422 * Releases a synccpu lock. 423 */ 424 extern void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo); 425 426 /** 427 * ttm_bo_acc_size 428 * 429 * @bdev: Pointer to a ttm_bo_device struct. 430 * @bo_size: size of the buffer object in byte. 431 * @struct_size: size of the structure holding buffer object datas 432 * 433 * Returns size to account for a buffer object 434 */ 435 size_t ttm_bo_acc_size(struct ttm_bo_device *bdev, 436 unsigned long bo_size, 437 unsigned struct_size); 438 size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev, 439 unsigned long bo_size, 440 unsigned struct_size); 441 442 /** 443 * ttm_bo_init 444 * 445 * @bdev: Pointer to a ttm_bo_device struct. 446 * @bo: Pointer to a ttm_buffer_object to be initialized. 447 * @size: Requested size of buffer object. 448 * @type: Requested type of buffer object. 449 * @flags: Initial placement flags. 450 * @page_alignment: Data alignment in pages. 451 * @interruptible: If needing to sleep to wait for GPU resources, 452 * sleep interruptible. 453 * @persistent_swap_storage: Usually the swap storage is deleted for buffers 454 * pinned in physical memory. If this behaviour is not desired, this member 455 * holds a pointer to a persistent shmem object. Typically, this would 456 * point to the shmem object backing a GEM object if TTM is used to back a 457 * GEM user interface. 458 * @acc_size: Accounted size for this object. 459 * @resv: Pointer to a reservation_object, or NULL to let ttm allocate one. 460 * @destroy: Destroy function. Use NULL for kfree(). 461 * 462 * This function initializes a pre-allocated struct ttm_buffer_object. 463 * As this object may be part of a larger structure, this function, 464 * together with the @destroy function, 465 * enables driver-specific objects derived from a ttm_buffer_object. 466 * On successful return, the object kref and list_kref are set to 1. 467 * If a failure occurs, the function will call the @destroy function, or 468 * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is 469 * illegal and will likely cause memory corruption. 470 * 471 * Returns 472 * -ENOMEM: Out of memory. 473 * -EINVAL: Invalid placement flags. 474 * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources. 475 */ 476 477 extern int ttm_bo_init(struct ttm_bo_device *bdev, 478 struct ttm_buffer_object *bo, 479 unsigned long size, 480 enum ttm_bo_type type, 481 struct ttm_placement *placement, 482 uint32_t page_alignment, 483 bool interrubtible, 484 struct vm_object *persistent_swap_storage, 485 size_t acc_size, 486 struct sg_table *sg, 487 struct reservation_object *resv, 488 void (*destroy) (struct ttm_buffer_object *)); 489 490 /** 491 * ttm_bo_create 492 * 493 * @bdev: Pointer to a ttm_bo_device struct. 494 * @size: Requested size of buffer object. 495 * @type: Requested type of buffer object. 496 * @placement: Initial placement. 497 * @page_alignment: Data alignment in pages. 498 * @interruptible: If needing to sleep while waiting for GPU resources, 499 * sleep interruptible. 500 * @persistent_swap_storage: Usually the swap storage is deleted for buffers 501 * pinned in physical memory. If this behaviour is not desired, this member 502 * holds a pointer to a persistent shmem object. Typically, this would 503 * point to the shmem object backing a GEM object if TTM is used to back a 504 * GEM user interface. 505 * @p_bo: On successful completion *p_bo points to the created object. 506 * 507 * This function allocates a ttm_buffer_object, and then calls ttm_bo_init 508 * on that object. The destroy function is set to kfree(). 509 * Returns 510 * -ENOMEM: Out of memory. 511 * -EINVAL: Invalid placement flags. 512 * -ERESTARTSYS: Interrupted by signal while waiting for resources. 513 */ 514 515 extern int ttm_bo_create(struct ttm_bo_device *bdev, 516 unsigned long size, 517 enum ttm_bo_type type, 518 struct ttm_placement *placement, 519 uint32_t page_alignment, 520 bool interruptible, 521 struct vm_object *persistent_swap_storage, 522 struct ttm_buffer_object **p_bo); 523 524 /** 525 * ttm_bo_init_mm 526 * 527 * @bdev: Pointer to a ttm_bo_device struct. 528 * @mem_type: The memory type. 529 * @p_size: size managed area in pages. 530 * 531 * Initialize a manager for a given memory type. 532 * Note: if part of driver firstopen, it must be protected from a 533 * potentially racing lastclose. 534 * Returns: 535 * -EINVAL: invalid size or memory type. 536 * -ENOMEM: Not enough memory. 537 * May also return driver-specified errors. 538 */ 539 540 extern int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type, 541 unsigned long p_size); 542 /** 543 * ttm_bo_clean_mm 544 * 545 * @bdev: Pointer to a ttm_bo_device struct. 546 * @mem_type: The memory type. 547 * 548 * Take down a manager for a given memory type after first walking 549 * the LRU list to evict any buffers left alive. 550 * 551 * Normally, this function is part of lastclose() or unload(), and at that 552 * point there shouldn't be any buffers left created by user-space, since 553 * there should've been removed by the file descriptor release() method. 554 * However, before this function is run, make sure to signal all sync objects, 555 * and verify that the delayed delete queue is empty. The driver must also 556 * make sure that there are no NO_EVICT buffers present in this memory type 557 * when the call is made. 558 * 559 * If this function is part of a VT switch, the caller must make sure that 560 * there are no appications currently validating buffers before this 561 * function is called. The caller can do that by first taking the 562 * struct ttm_bo_device::ttm_lock in write mode. 563 * 564 * Returns: 565 * -EINVAL: invalid or uninitialized memory type. 566 * -EBUSY: There are still buffers left in this memory type. 567 */ 568 569 extern int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type); 570 571 /** 572 * ttm_bo_evict_mm 573 * 574 * @bdev: Pointer to a ttm_bo_device struct. 575 * @mem_type: The memory type. 576 * 577 * Evicts all buffers on the lru list of the memory type. 578 * This is normally part of a VT switch or an 579 * out-of-memory-space-due-to-fragmentation handler. 580 * The caller must make sure that there are no other processes 581 * currently validating buffers, and can do that by taking the 582 * struct ttm_bo_device::ttm_lock in write mode. 583 * 584 * Returns: 585 * -EINVAL: Invalid or uninitialized memory type. 586 * -ERESTARTSYS: The call was interrupted by a signal while waiting to 587 * evict a buffer. 588 */ 589 590 extern int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type); 591 592 /** 593 * ttm_kmap_obj_virtual 594 * 595 * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap. 596 * @is_iomem: Pointer to an integer that on return indicates 1 if the 597 * virtual map is io memory, 0 if normal memory. 598 * 599 * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap. 600 * If *is_iomem is 1 on return, the virtual address points to an io memory area, 601 * that should strictly be accessed by the iowriteXX() and similar functions. 602 */ 603 604 static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map, 605 bool *is_iomem) 606 { 607 *is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK); 608 return map->virtual; 609 } 610 611 /** 612 * ttm_bo_kmap 613 * 614 * @bo: The buffer object. 615 * @start_page: The first page to map. 616 * @num_pages: Number of pages to map. 617 * @map: pointer to a struct ttm_bo_kmap_obj representing the map. 618 * 619 * Sets up a kernel virtual mapping, using ioremap, vmap or kmap to the 620 * data in the buffer object. The ttm_kmap_obj_virtual function can then be 621 * used to obtain a virtual address to the data. 622 * 623 * Returns 624 * -ENOMEM: Out of memory. 625 * -EINVAL: Invalid range. 626 */ 627 628 extern int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page, 629 unsigned long num_pages, struct ttm_bo_kmap_obj *map); 630 631 /** 632 * ttm_bo_kunmap 633 * 634 * @map: Object describing the map to unmap. 635 * 636 * Unmaps a kernel map set up by ttm_bo_kmap. 637 */ 638 639 extern void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map); 640 641 /** 642 * ttm_fbdev_mmap - mmap fbdev memory backed by a ttm buffer object. 643 * 644 * @vma: vma as input from the fbdev mmap method. 645 * @bo: The bo backing the address space. The address space will 646 * have the same size as the bo, and start at offset 0. 647 * 648 * This function is intended to be called by the fbdev mmap method 649 * if the fbdev address space is to be backed by a bo. 650 */ 651 652 extern int ttm_fbdev_mmap(struct vm_area_struct *vma, 653 struct ttm_buffer_object *bo); 654 655 /** 656 * ttm_bo_mmap - mmap out of the ttm device address space. 657 * 658 * @filp: filp as input from the mmap method. 659 * @vma: vma as input from the mmap method. 660 * @bdev: Pointer to the ttm_bo_device with the address space manager. 661 * 662 * This function is intended to be called by the device mmap method. 663 * if the device address space is to be backed by the bo manager. 664 */ 665 666 extern int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma, 667 struct ttm_bo_device *bdev); 668 669 /** 670 * ttm_bo_io 671 * 672 * @bdev: Pointer to the struct ttm_bo_device. 673 * @filp: Pointer to the struct file attempting to read / write. 674 * @wbuf: User-space pointer to address of buffer to write. NULL on read. 675 * @rbuf: User-space pointer to address of buffer to read into. 676 * Null on write. 677 * @count: Number of bytes to read / write. 678 * @f_pos: Pointer to current file position. 679 * @write: 1 for read, 0 for write. 680 * 681 * This function implements read / write into ttm buffer objects, and is 682 * intended to 683 * be called from the fops::read and fops::write method. 684 * Returns: 685 * See man (2) write, man(2) read. In particular, 686 * the function may return -ERESTARTSYS if 687 * interrupted by a signal. 688 */ 689 690 extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp, 691 const char __user *wbuf, char __user *rbuf, 692 size_t count, loff_t *f_pos, bool write); 693 694 extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev); 695 extern int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo); 696 #endif 697