1 /*
2 * Copyright © 2008 Intel Corporation
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 * Eric Anholt <eric@anholt.net>
25 *
26 */
27
28 #include <linux/dma-buf.h>
29 #include <linux/file.h>
30 #include <linux/fs.h>
31 #include <linux/iosys-map.h>
32 #include <linux/mem_encrypt.h>
33 #include <linux/mm.h>
34 #include <linux/mman.h>
35 #include <linux/module.h>
36 #include <linux/pagemap.h>
37 #include <linux/pagevec.h>
38 #include <linux/shmem_fs.h>
39 #include <linux/slab.h>
40 #include <linux/string_helpers.h>
41 #include <linux/types.h>
42 #include <linux/uaccess.h>
43
44 #include <drm/drm.h>
45 #include <drm/drm_device.h>
46 #include <drm/drm_drv.h>
47 #include <drm/drm_file.h>
48 #include <drm/drm_gem.h>
49 #include <drm/drm_managed.h>
50 #include <drm/drm_print.h>
51 #include <drm/drm_vma_manager.h>
52
53 #include "drm_internal.h"
54
55 /** @file drm_gem.c
56 *
57 * This file provides some of the base ioctls and library routines for
58 * the graphics memory manager implemented by each device driver.
59 *
60 * Because various devices have different requirements in terms of
61 * synchronization and migration strategies, implementing that is left up to
62 * the driver, and all that the general API provides should be generic --
63 * allocating objects, reading/writing data with the cpu, freeing objects.
64 * Even there, platform-dependent optimizations for reading/writing data with
65 * the CPU mean we'll likely hook those out to driver-specific calls. However,
66 * the DRI2 implementation wants to have at least allocate/mmap be generic.
67 *
68 * The goal was to have swap-backed object allocation managed through
69 * struct file. However, file descriptors as handles to a struct file have
70 * two major failings:
71 * - Process limits prevent more than 1024 or so being used at a time by
72 * default.
73 * - Inability to allocate high fds will aggravate the X Server's select()
74 * handling, and likely that of many GL client applications as well.
75 *
76 * This led to a plan of using our own integer IDs (called handles, following
77 * DRM terminology) to mimic fds, and implement the fd syscalls we need as
78 * ioctls. The objects themselves will still include the struct file so
79 * that we can transition to fds if the required kernel infrastructure shows
80 * up at a later date, and as our interface with shmfs for memory allocation.
81 */
82
83 static void
drm_gem_init_release(struct drm_device * dev,void * ptr)84 drm_gem_init_release(struct drm_device *dev, void *ptr)
85 {
86 drm_vma_offset_manager_destroy(dev->vma_offset_manager);
87 }
88
89 /**
90 * drm_gem_init - Initialize the GEM device fields
91 * @dev: drm_devic structure to initialize
92 */
93 int
drm_gem_init(struct drm_device * dev)94 drm_gem_init(struct drm_device *dev)
95 {
96 struct drm_vma_offset_manager *vma_offset_manager;
97
98 mutex_init(&dev->object_name_lock);
99 idr_init_base(&dev->object_name_idr, 1);
100
101 vma_offset_manager = drmm_kzalloc(dev, sizeof(*vma_offset_manager),
102 GFP_KERNEL);
103 if (!vma_offset_manager) {
104 DRM_ERROR("out of memory\n");
105 return -ENOMEM;
106 }
107
108 dev->vma_offset_manager = vma_offset_manager;
109 drm_vma_offset_manager_init(vma_offset_manager,
110 DRM_FILE_PAGE_OFFSET_START,
111 DRM_FILE_PAGE_OFFSET_SIZE);
112
113 return drmm_add_action(dev, drm_gem_init_release, NULL);
114 }
115
116 /**
117 * drm_gem_object_init - initialize an allocated shmem-backed GEM object
118 * @dev: drm_device the object should be initialized for
119 * @obj: drm_gem_object to initialize
120 * @size: object size
121 *
122 * Initialize an already allocated GEM object of the specified size with
123 * shmfs backing store.
124 */
drm_gem_object_init(struct drm_device * dev,struct drm_gem_object * obj,size_t size)125 int drm_gem_object_init(struct drm_device *dev,
126 struct drm_gem_object *obj, size_t size)
127 {
128 struct file *filp;
129
130 drm_gem_private_object_init(dev, obj, size);
131
132 filp = shmem_file_setup("drm mm object", size, VM_NORESERVE);
133 if (IS_ERR(filp))
134 return PTR_ERR(filp);
135
136 obj->filp = filp;
137
138 return 0;
139 }
140 EXPORT_SYMBOL(drm_gem_object_init);
141
142 /**
143 * drm_gem_private_object_init - initialize an allocated private GEM object
144 * @dev: drm_device the object should be initialized for
145 * @obj: drm_gem_object to initialize
146 * @size: object size
147 *
148 * Initialize an already allocated GEM object of the specified size with
149 * no GEM provided backing store. Instead the caller is responsible for
150 * backing the object and handling it.
151 */
drm_gem_private_object_init(struct drm_device * dev,struct drm_gem_object * obj,size_t size)152 void drm_gem_private_object_init(struct drm_device *dev,
153 struct drm_gem_object *obj, size_t size)
154 {
155 BUG_ON((size & (PAGE_SIZE - 1)) != 0);
156
157 obj->dev = dev;
158 obj->filp = NULL;
159
160 kref_init(&obj->refcount);
161 obj->handle_count = 0;
162 obj->size = size;
163 dma_resv_init(&obj->_resv);
164 if (!obj->resv)
165 obj->resv = &obj->_resv;
166
167 drm_vma_node_reset(&obj->vma_node);
168 INIT_LIST_HEAD(&obj->lru_node);
169 }
170 EXPORT_SYMBOL(drm_gem_private_object_init);
171
172 /**
173 * drm_gem_object_handle_free - release resources bound to userspace handles
174 * @obj: GEM object to clean up.
175 *
176 * Called after the last handle to the object has been closed
177 *
178 * Removes any name for the object. Note that this must be
179 * called before drm_gem_object_free or we'll be touching
180 * freed memory
181 */
drm_gem_object_handle_free(struct drm_gem_object * obj)182 static void drm_gem_object_handle_free(struct drm_gem_object *obj)
183 {
184 struct drm_device *dev = obj->dev;
185
186 /* Remove any name for this object */
187 if (obj->name) {
188 idr_remove(&dev->object_name_idr, obj->name);
189 obj->name = 0;
190 }
191 }
192
drm_gem_object_exported_dma_buf_free(struct drm_gem_object * obj)193 static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj)
194 {
195 /* Unbreak the reference cycle if we have an exported dma_buf. */
196 if (obj->dma_buf) {
197 dma_buf_put(obj->dma_buf);
198 obj->dma_buf = NULL;
199 }
200 }
201
202 static void
drm_gem_object_handle_put_unlocked(struct drm_gem_object * obj)203 drm_gem_object_handle_put_unlocked(struct drm_gem_object *obj)
204 {
205 struct drm_device *dev = obj->dev;
206 bool final = false;
207
208 if (WARN_ON(READ_ONCE(obj->handle_count) == 0))
209 return;
210
211 /*
212 * Must bump handle count first as this may be the last
213 * ref, in which case the object would disappear before we
214 * checked for a name
215 */
216
217 mutex_lock(&dev->object_name_lock);
218 if (--obj->handle_count == 0) {
219 drm_gem_object_handle_free(obj);
220 drm_gem_object_exported_dma_buf_free(obj);
221 final = true;
222 }
223 mutex_unlock(&dev->object_name_lock);
224
225 if (final)
226 drm_gem_object_put(obj);
227 }
228
229 /*
230 * Called at device or object close to release the file's
231 * handle references on objects.
232 */
233 static int
drm_gem_object_release_handle(int id,void * ptr,void * data)234 drm_gem_object_release_handle(int id, void *ptr, void *data)
235 {
236 struct drm_file *file_priv = data;
237 struct drm_gem_object *obj = ptr;
238
239 if (obj->funcs->close)
240 obj->funcs->close(obj, file_priv);
241
242 drm_prime_remove_buf_handle(&file_priv->prime, id);
243 drm_vma_node_revoke(&obj->vma_node, file_priv);
244
245 drm_gem_object_handle_put_unlocked(obj);
246
247 return 0;
248 }
249
250 /**
251 * drm_gem_handle_delete - deletes the given file-private handle
252 * @filp: drm file-private structure to use for the handle look up
253 * @handle: userspace handle to delete
254 *
255 * Removes the GEM handle from the @filp lookup table which has been added with
256 * drm_gem_handle_create(). If this is the last handle also cleans up linked
257 * resources like GEM names.
258 */
259 int
drm_gem_handle_delete(struct drm_file * filp,u32 handle)260 drm_gem_handle_delete(struct drm_file *filp, u32 handle)
261 {
262 struct drm_gem_object *obj;
263
264 spin_lock(&filp->table_lock);
265
266 /* Check if we currently have a reference on the object */
267 obj = idr_replace(&filp->object_idr, NULL, handle);
268 spin_unlock(&filp->table_lock);
269 if (IS_ERR_OR_NULL(obj))
270 return -EINVAL;
271
272 /* Release driver's reference and decrement refcount. */
273 drm_gem_object_release_handle(handle, obj, filp);
274
275 /* And finally make the handle available for future allocations. */
276 spin_lock(&filp->table_lock);
277 idr_remove(&filp->object_idr, handle);
278 spin_unlock(&filp->table_lock);
279
280 return 0;
281 }
282 EXPORT_SYMBOL(drm_gem_handle_delete);
283
284 /**
285 * drm_gem_dumb_map_offset - return the fake mmap offset for a gem object
286 * @file: drm file-private structure containing the gem object
287 * @dev: corresponding drm_device
288 * @handle: gem object handle
289 * @offset: return location for the fake mmap offset
290 *
291 * This implements the &drm_driver.dumb_map_offset kms driver callback for
292 * drivers which use gem to manage their backing storage.
293 *
294 * Returns:
295 * 0 on success or a negative error code on failure.
296 */
drm_gem_dumb_map_offset(struct drm_file * file,struct drm_device * dev,u32 handle,u64 * offset)297 int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
298 u32 handle, u64 *offset)
299 {
300 struct drm_gem_object *obj;
301 int ret;
302
303 obj = drm_gem_object_lookup(file, handle);
304 if (!obj)
305 return -ENOENT;
306
307 /* Don't allow imported objects to be mapped */
308 if (obj->import_attach) {
309 ret = -EINVAL;
310 goto out;
311 }
312
313 ret = drm_gem_create_mmap_offset(obj);
314 if (ret)
315 goto out;
316
317 *offset = drm_vma_node_offset_addr(&obj->vma_node);
318 out:
319 drm_gem_object_put(obj);
320
321 return ret;
322 }
323 EXPORT_SYMBOL_GPL(drm_gem_dumb_map_offset);
324
drm_gem_dumb_destroy(struct drm_file * file,struct drm_device * dev,u32 handle)325 int drm_gem_dumb_destroy(struct drm_file *file,
326 struct drm_device *dev,
327 u32 handle)
328 {
329 return drm_gem_handle_delete(file, handle);
330 }
331
332 /**
333 * drm_gem_handle_create_tail - internal functions to create a handle
334 * @file_priv: drm file-private structure to register the handle for
335 * @obj: object to register
336 * @handlep: pointer to return the created handle to the caller
337 *
338 * This expects the &drm_device.object_name_lock to be held already and will
339 * drop it before returning. Used to avoid races in establishing new handles
340 * when importing an object from either an flink name or a dma-buf.
341 *
342 * Handles must be release again through drm_gem_handle_delete(). This is done
343 * when userspace closes @file_priv for all attached handles, or through the
344 * GEM_CLOSE ioctl for individual handles.
345 */
346 int
drm_gem_handle_create_tail(struct drm_file * file_priv,struct drm_gem_object * obj,u32 * handlep)347 drm_gem_handle_create_tail(struct drm_file *file_priv,
348 struct drm_gem_object *obj,
349 u32 *handlep)
350 {
351 struct drm_device *dev = obj->dev;
352 u32 handle;
353 int ret;
354
355 WARN_ON(!mutex_is_locked(&dev->object_name_lock));
356 if (obj->handle_count++ == 0)
357 drm_gem_object_get(obj);
358
359 /*
360 * Get the user-visible handle using idr. Preload and perform
361 * allocation under our spinlock.
362 */
363 idr_preload(GFP_KERNEL);
364 spin_lock(&file_priv->table_lock);
365
366 ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
367
368 spin_unlock(&file_priv->table_lock);
369 idr_preload_end();
370
371 mutex_unlock(&dev->object_name_lock);
372 if (ret < 0)
373 goto err_unref;
374
375 handle = ret;
376
377 ret = drm_vma_node_allow(&obj->vma_node, file_priv);
378 if (ret)
379 goto err_remove;
380
381 if (obj->funcs->open) {
382 ret = obj->funcs->open(obj, file_priv);
383 if (ret)
384 goto err_revoke;
385 }
386
387 *handlep = handle;
388 return 0;
389
390 err_revoke:
391 drm_vma_node_revoke(&obj->vma_node, file_priv);
392 err_remove:
393 spin_lock(&file_priv->table_lock);
394 idr_remove(&file_priv->object_idr, handle);
395 spin_unlock(&file_priv->table_lock);
396 err_unref:
397 drm_gem_object_handle_put_unlocked(obj);
398 return ret;
399 }
400
401 /**
402 * drm_gem_handle_create - create a gem handle for an object
403 * @file_priv: drm file-private structure to register the handle for
404 * @obj: object to register
405 * @handlep: pointer to return the created handle to the caller
406 *
407 * Create a handle for this object. This adds a handle reference to the object,
408 * which includes a regular reference count. Callers will likely want to
409 * dereference the object afterwards.
410 *
411 * Since this publishes @obj to userspace it must be fully set up by this point,
412 * drivers must call this last in their buffer object creation callbacks.
413 */
drm_gem_handle_create(struct drm_file * file_priv,struct drm_gem_object * obj,u32 * handlep)414 int drm_gem_handle_create(struct drm_file *file_priv,
415 struct drm_gem_object *obj,
416 u32 *handlep)
417 {
418 mutex_lock(&obj->dev->object_name_lock);
419
420 return drm_gem_handle_create_tail(file_priv, obj, handlep);
421 }
422 EXPORT_SYMBOL(drm_gem_handle_create);
423
424
425 /**
426 * drm_gem_free_mmap_offset - release a fake mmap offset for an object
427 * @obj: obj in question
428 *
429 * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
430 *
431 * Note that drm_gem_object_release() already calls this function, so drivers
432 * don't have to take care of releasing the mmap offset themselves when freeing
433 * the GEM object.
434 */
435 void
drm_gem_free_mmap_offset(struct drm_gem_object * obj)436 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
437 {
438 struct drm_device *dev = obj->dev;
439
440 drm_vma_offset_remove(dev->vma_offset_manager, &obj->vma_node);
441 }
442 EXPORT_SYMBOL(drm_gem_free_mmap_offset);
443
444 /**
445 * drm_gem_create_mmap_offset_size - create a fake mmap offset for an object
446 * @obj: obj in question
447 * @size: the virtual size
448 *
449 * GEM memory mapping works by handing back to userspace a fake mmap offset
450 * it can use in a subsequent mmap(2) call. The DRM core code then looks
451 * up the object based on the offset and sets up the various memory mapping
452 * structures.
453 *
454 * This routine allocates and attaches a fake offset for @obj, in cases where
455 * the virtual size differs from the physical size (ie. &drm_gem_object.size).
456 * Otherwise just use drm_gem_create_mmap_offset().
457 *
458 * This function is idempotent and handles an already allocated mmap offset
459 * transparently. Drivers do not need to check for this case.
460 */
461 int
drm_gem_create_mmap_offset_size(struct drm_gem_object * obj,size_t size)462 drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
463 {
464 struct drm_device *dev = obj->dev;
465
466 return drm_vma_offset_add(dev->vma_offset_manager, &obj->vma_node,
467 size / PAGE_SIZE);
468 }
469 EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
470
471 /**
472 * drm_gem_create_mmap_offset - create a fake mmap offset for an object
473 * @obj: obj in question
474 *
475 * GEM memory mapping works by handing back to userspace a fake mmap offset
476 * it can use in a subsequent mmap(2) call. The DRM core code then looks
477 * up the object based on the offset and sets up the various memory mapping
478 * structures.
479 *
480 * This routine allocates and attaches a fake offset for @obj.
481 *
482 * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release
483 * the fake offset again.
484 */
drm_gem_create_mmap_offset(struct drm_gem_object * obj)485 int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
486 {
487 return drm_gem_create_mmap_offset_size(obj, obj->size);
488 }
489 EXPORT_SYMBOL(drm_gem_create_mmap_offset);
490
491 /*
492 * Move pages to appropriate lru and release the pagevec, decrementing the
493 * ref count of those pages.
494 */
drm_gem_check_release_pagevec(struct pagevec * pvec)495 static void drm_gem_check_release_pagevec(struct pagevec *pvec)
496 {
497 check_move_unevictable_pages(pvec);
498 __pagevec_release(pvec);
499 cond_resched();
500 }
501
502 /**
503 * drm_gem_get_pages - helper to allocate backing pages for a GEM object
504 * from shmem
505 * @obj: obj in question
506 *
507 * This reads the page-array of the shmem-backing storage of the given gem
508 * object. An array of pages is returned. If a page is not allocated or
509 * swapped-out, this will allocate/swap-in the required pages. Note that the
510 * whole object is covered by the page-array and pinned in memory.
511 *
512 * Use drm_gem_put_pages() to release the array and unpin all pages.
513 *
514 * This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask()).
515 * If you require other GFP-masks, you have to do those allocations yourself.
516 *
517 * Note that you are not allowed to change gfp-zones during runtime. That is,
518 * shmem_read_mapping_page_gfp() must be called with the same gfp_zone(gfp) as
519 * set during initialization. If you have special zone constraints, set them
520 * after drm_gem_object_init() via mapping_set_gfp_mask(). shmem-core takes care
521 * to keep pages in the required zone during swap-in.
522 *
523 * This function is only valid on objects initialized with
524 * drm_gem_object_init(), but not for those initialized with
525 * drm_gem_private_object_init() only.
526 */
drm_gem_get_pages(struct drm_gem_object * obj)527 struct page **drm_gem_get_pages(struct drm_gem_object *obj)
528 {
529 struct address_space *mapping;
530 struct page *p, **pages;
531 struct pagevec pvec;
532 int i, npages;
533
534
535 if (WARN_ON(!obj->filp))
536 return ERR_PTR(-EINVAL);
537
538 /* This is the shared memory object that backs the GEM resource */
539 mapping = obj->filp->f_mapping;
540
541 /* We already BUG_ON() for non-page-aligned sizes in
542 * drm_gem_object_init(), so we should never hit this unless
543 * driver author is doing something really wrong:
544 */
545 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
546
547 npages = obj->size >> PAGE_SHIFT;
548
549 pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
550 if (pages == NULL)
551 return ERR_PTR(-ENOMEM);
552
553 mapping_set_unevictable(mapping);
554
555 for (i = 0; i < npages; i++) {
556 p = shmem_read_mapping_page(mapping, i);
557 if (IS_ERR(p))
558 goto fail;
559 pages[i] = p;
560
561 /* Make sure shmem keeps __GFP_DMA32 allocated pages in the
562 * correct region during swapin. Note that this requires
563 * __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
564 * so shmem can relocate pages during swapin if required.
565 */
566 BUG_ON(mapping_gfp_constraint(mapping, __GFP_DMA32) &&
567 (page_to_pfn(p) >= 0x00100000UL));
568 }
569
570 return pages;
571
572 fail:
573 mapping_clear_unevictable(mapping);
574 pagevec_init(&pvec);
575 while (i--) {
576 if (!pagevec_add(&pvec, pages[i]))
577 drm_gem_check_release_pagevec(&pvec);
578 }
579 if (pagevec_count(&pvec))
580 drm_gem_check_release_pagevec(&pvec);
581
582 kvfree(pages);
583 return ERR_CAST(p);
584 }
585 EXPORT_SYMBOL(drm_gem_get_pages);
586
587 /**
588 * drm_gem_put_pages - helper to free backing pages for a GEM object
589 * @obj: obj in question
590 * @pages: pages to free
591 * @dirty: if true, pages will be marked as dirty
592 * @accessed: if true, the pages will be marked as accessed
593 */
drm_gem_put_pages(struct drm_gem_object * obj,struct page ** pages,bool dirty,bool accessed)594 void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
595 bool dirty, bool accessed)
596 {
597 int i, npages;
598 struct address_space *mapping;
599 struct pagevec pvec;
600
601 mapping = file_inode(obj->filp)->i_mapping;
602 mapping_clear_unevictable(mapping);
603
604 /* We already BUG_ON() for non-page-aligned sizes in
605 * drm_gem_object_init(), so we should never hit this unless
606 * driver author is doing something really wrong:
607 */
608 WARN_ON((obj->size & (PAGE_SIZE - 1)) != 0);
609
610 npages = obj->size >> PAGE_SHIFT;
611
612 pagevec_init(&pvec);
613 for (i = 0; i < npages; i++) {
614 if (!pages[i])
615 continue;
616
617 if (dirty)
618 set_page_dirty(pages[i]);
619
620 if (accessed)
621 mark_page_accessed(pages[i]);
622
623 /* Undo the reference we took when populating the table */
624 if (!pagevec_add(&pvec, pages[i]))
625 drm_gem_check_release_pagevec(&pvec);
626 }
627 if (pagevec_count(&pvec))
628 drm_gem_check_release_pagevec(&pvec);
629
630 kvfree(pages);
631 }
632 EXPORT_SYMBOL(drm_gem_put_pages);
633
objects_lookup(struct drm_file * filp,u32 * handle,int count,struct drm_gem_object ** objs)634 static int objects_lookup(struct drm_file *filp, u32 *handle, int count,
635 struct drm_gem_object **objs)
636 {
637 int i, ret = 0;
638 struct drm_gem_object *obj;
639
640 spin_lock(&filp->table_lock);
641
642 for (i = 0; i < count; i++) {
643 /* Check if we currently have a reference on the object */
644 obj = idr_find(&filp->object_idr, handle[i]);
645 if (!obj) {
646 ret = -ENOENT;
647 break;
648 }
649 drm_gem_object_get(obj);
650 objs[i] = obj;
651 }
652 spin_unlock(&filp->table_lock);
653
654 return ret;
655 }
656
657 /**
658 * drm_gem_objects_lookup - look up GEM objects from an array of handles
659 * @filp: DRM file private date
660 * @bo_handles: user pointer to array of userspace handle
661 * @count: size of handle array
662 * @objs_out: returned pointer to array of drm_gem_object pointers
663 *
664 * Takes an array of userspace handles and returns a newly allocated array of
665 * GEM objects.
666 *
667 * For a single handle lookup, use drm_gem_object_lookup().
668 *
669 * Returns:
670 *
671 * @objs filled in with GEM object pointers. Returned GEM objects need to be
672 * released with drm_gem_object_put(). -ENOENT is returned on a lookup
673 * failure. 0 is returned on success.
674 *
675 */
drm_gem_objects_lookup(struct drm_file * filp,void __user * bo_handles,int count,struct drm_gem_object *** objs_out)676 int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles,
677 int count, struct drm_gem_object ***objs_out)
678 {
679 int ret;
680 u32 *handles;
681 struct drm_gem_object **objs;
682
683 if (!count)
684 return 0;
685
686 objs = kvmalloc_array(count, sizeof(struct drm_gem_object *),
687 GFP_KERNEL | __GFP_ZERO);
688 if (!objs)
689 return -ENOMEM;
690
691 *objs_out = objs;
692
693 handles = kvmalloc_array(count, sizeof(u32), GFP_KERNEL);
694 if (!handles) {
695 ret = -ENOMEM;
696 goto out;
697 }
698
699 if (copy_from_user(handles, bo_handles, count * sizeof(u32))) {
700 ret = -EFAULT;
701 DRM_DEBUG("Failed to copy in GEM handles\n");
702 goto out;
703 }
704
705 ret = objects_lookup(filp, handles, count, objs);
706 out:
707 kvfree(handles);
708 return ret;
709
710 }
711 EXPORT_SYMBOL(drm_gem_objects_lookup);
712
713 /**
714 * drm_gem_object_lookup - look up a GEM object from its handle
715 * @filp: DRM file private date
716 * @handle: userspace handle
717 *
718 * Returns:
719 *
720 * A reference to the object named by the handle if such exists on @filp, NULL
721 * otherwise.
722 *
723 * If looking up an array of handles, use drm_gem_objects_lookup().
724 */
725 struct drm_gem_object *
drm_gem_object_lookup(struct drm_file * filp,u32 handle)726 drm_gem_object_lookup(struct drm_file *filp, u32 handle)
727 {
728 struct drm_gem_object *obj = NULL;
729
730 objects_lookup(filp, &handle, 1, &obj);
731 return obj;
732 }
733 EXPORT_SYMBOL(drm_gem_object_lookup);
734
735 /**
736 * drm_gem_dma_resv_wait - Wait on GEM object's reservation's objects
737 * shared and/or exclusive fences.
738 * @filep: DRM file private date
739 * @handle: userspace handle
740 * @wait_all: if true, wait on all fences, else wait on just exclusive fence
741 * @timeout: timeout value in jiffies or zero to return immediately
742 *
743 * Returns:
744 *
745 * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
746 * greater than 0 on success.
747 */
drm_gem_dma_resv_wait(struct drm_file * filep,u32 handle,bool wait_all,unsigned long timeout)748 long drm_gem_dma_resv_wait(struct drm_file *filep, u32 handle,
749 bool wait_all, unsigned long timeout)
750 {
751 long ret;
752 struct drm_gem_object *obj;
753
754 obj = drm_gem_object_lookup(filep, handle);
755 if (!obj) {
756 DRM_DEBUG("Failed to look up GEM BO %d\n", handle);
757 return -EINVAL;
758 }
759
760 ret = dma_resv_wait_timeout(obj->resv, dma_resv_usage_rw(wait_all),
761 true, timeout);
762 if (ret == 0)
763 ret = -ETIME;
764 else if (ret > 0)
765 ret = 0;
766
767 drm_gem_object_put(obj);
768
769 return ret;
770 }
771 EXPORT_SYMBOL(drm_gem_dma_resv_wait);
772
773 /**
774 * drm_gem_close_ioctl - implementation of the GEM_CLOSE ioctl
775 * @dev: drm_device
776 * @data: ioctl data
777 * @file_priv: drm file-private structure
778 *
779 * Releases the handle to an mm object.
780 */
781 int
drm_gem_close_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)782 drm_gem_close_ioctl(struct drm_device *dev, void *data,
783 struct drm_file *file_priv)
784 {
785 struct drm_gem_close *args = data;
786 int ret;
787
788 if (!drm_core_check_feature(dev, DRIVER_GEM))
789 return -EOPNOTSUPP;
790
791 ret = drm_gem_handle_delete(file_priv, args->handle);
792
793 return ret;
794 }
795
796 /**
797 * drm_gem_flink_ioctl - implementation of the GEM_FLINK ioctl
798 * @dev: drm_device
799 * @data: ioctl data
800 * @file_priv: drm file-private structure
801 *
802 * Create a global name for an object, returning the name.
803 *
804 * Note that the name does not hold a reference; when the object
805 * is freed, the name goes away.
806 */
807 int
drm_gem_flink_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)808 drm_gem_flink_ioctl(struct drm_device *dev, void *data,
809 struct drm_file *file_priv)
810 {
811 struct drm_gem_flink *args = data;
812 struct drm_gem_object *obj;
813 int ret;
814
815 if (!drm_core_check_feature(dev, DRIVER_GEM))
816 return -EOPNOTSUPP;
817
818 obj = drm_gem_object_lookup(file_priv, args->handle);
819 if (obj == NULL)
820 return -ENOENT;
821
822 mutex_lock(&dev->object_name_lock);
823 /* prevent races with concurrent gem_close. */
824 if (obj->handle_count == 0) {
825 ret = -ENOENT;
826 goto err;
827 }
828
829 if (!obj->name) {
830 ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_KERNEL);
831 if (ret < 0)
832 goto err;
833
834 obj->name = ret;
835 }
836
837 args->name = (uint64_t) obj->name;
838 ret = 0;
839
840 err:
841 mutex_unlock(&dev->object_name_lock);
842 drm_gem_object_put(obj);
843 return ret;
844 }
845
846 /**
847 * drm_gem_open_ioctl - implementation of the GEM_OPEN ioctl
848 * @dev: drm_device
849 * @data: ioctl data
850 * @file_priv: drm file-private structure
851 *
852 * Open an object using the global name, returning a handle and the size.
853 *
854 * This handle (of course) holds a reference to the object, so the object
855 * will not go away until the handle is deleted.
856 */
857 int
drm_gem_open_ioctl(struct drm_device * dev,void * data,struct drm_file * file_priv)858 drm_gem_open_ioctl(struct drm_device *dev, void *data,
859 struct drm_file *file_priv)
860 {
861 struct drm_gem_open *args = data;
862 struct drm_gem_object *obj;
863 int ret;
864 u32 handle;
865
866 if (!drm_core_check_feature(dev, DRIVER_GEM))
867 return -EOPNOTSUPP;
868
869 mutex_lock(&dev->object_name_lock);
870 obj = idr_find(&dev->object_name_idr, (int) args->name);
871 if (obj) {
872 drm_gem_object_get(obj);
873 } else {
874 mutex_unlock(&dev->object_name_lock);
875 return -ENOENT;
876 }
877
878 /* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
879 ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
880 if (ret)
881 goto err;
882
883 args->handle = handle;
884 args->size = obj->size;
885
886 err:
887 drm_gem_object_put(obj);
888 return ret;
889 }
890
891 /**
892 * drm_gem_open - initializes GEM file-private structures at devnode open time
893 * @dev: drm_device which is being opened by userspace
894 * @file_private: drm file-private structure to set up
895 *
896 * Called at device open time, sets up the structure for handling refcounting
897 * of mm objects.
898 */
899 void
drm_gem_open(struct drm_device * dev,struct drm_file * file_private)900 drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
901 {
902 idr_init_base(&file_private->object_idr, 1);
903 spin_lock_init(&file_private->table_lock);
904 }
905
906 /**
907 * drm_gem_release - release file-private GEM resources
908 * @dev: drm_device which is being closed by userspace
909 * @file_private: drm file-private structure to clean up
910 *
911 * Called at close time when the filp is going away.
912 *
913 * Releases any remaining references on objects by this filp.
914 */
915 void
drm_gem_release(struct drm_device * dev,struct drm_file * file_private)916 drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
917 {
918 idr_for_each(&file_private->object_idr,
919 &drm_gem_object_release_handle, file_private);
920 idr_destroy(&file_private->object_idr);
921 }
922
923 /**
924 * drm_gem_object_release - release GEM buffer object resources
925 * @obj: GEM buffer object
926 *
927 * This releases any structures and resources used by @obj and is the inverse of
928 * drm_gem_object_init().
929 */
930 void
drm_gem_object_release(struct drm_gem_object * obj)931 drm_gem_object_release(struct drm_gem_object *obj)
932 {
933 WARN_ON(obj->dma_buf);
934
935 if (obj->filp)
936 fput(obj->filp);
937
938 dma_resv_fini(&obj->_resv);
939 drm_gem_free_mmap_offset(obj);
940 drm_gem_lru_remove(obj);
941 }
942 EXPORT_SYMBOL(drm_gem_object_release);
943
944 /**
945 * drm_gem_object_free - free a GEM object
946 * @kref: kref of the object to free
947 *
948 * Called after the last reference to the object has been lost.
949 *
950 * Frees the object
951 */
952 void
drm_gem_object_free(struct kref * kref)953 drm_gem_object_free(struct kref *kref)
954 {
955 struct drm_gem_object *obj =
956 container_of(kref, struct drm_gem_object, refcount);
957
958 if (WARN_ON(!obj->funcs->free))
959 return;
960
961 obj->funcs->free(obj);
962 }
963 EXPORT_SYMBOL(drm_gem_object_free);
964
965 /**
966 * drm_gem_vm_open - vma->ops->open implementation for GEM
967 * @vma: VM area structure
968 *
969 * This function implements the #vm_operations_struct open() callback for GEM
970 * drivers. This must be used together with drm_gem_vm_close().
971 */
drm_gem_vm_open(struct vm_area_struct * vma)972 void drm_gem_vm_open(struct vm_area_struct *vma)
973 {
974 struct drm_gem_object *obj = vma->vm_private_data;
975
976 drm_gem_object_get(obj);
977 }
978 EXPORT_SYMBOL(drm_gem_vm_open);
979
980 /**
981 * drm_gem_vm_close - vma->ops->close implementation for GEM
982 * @vma: VM area structure
983 *
984 * This function implements the #vm_operations_struct close() callback for GEM
985 * drivers. This must be used together with drm_gem_vm_open().
986 */
drm_gem_vm_close(struct vm_area_struct * vma)987 void drm_gem_vm_close(struct vm_area_struct *vma)
988 {
989 struct drm_gem_object *obj = vma->vm_private_data;
990
991 drm_gem_object_put(obj);
992 }
993 EXPORT_SYMBOL(drm_gem_vm_close);
994
995 /**
996 * drm_gem_mmap_obj - memory map a GEM object
997 * @obj: the GEM object to map
998 * @obj_size: the object size to be mapped, in bytes
999 * @vma: VMA for the area to be mapped
1000 *
1001 * Set up the VMA to prepare mapping of the GEM object using the GEM object's
1002 * vm_ops. Depending on their requirements, GEM objects can either
1003 * provide a fault handler in their vm_ops (in which case any accesses to
1004 * the object will be trapped, to perform migration, GTT binding, surface
1005 * register allocation, or performance monitoring), or mmap the buffer memory
1006 * synchronously after calling drm_gem_mmap_obj.
1007 *
1008 * This function is mainly intended to implement the DMABUF mmap operation, when
1009 * the GEM object is not looked up based on its fake offset. To implement the
1010 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
1011 *
1012 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
1013 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
1014 * callers must verify access restrictions before calling this helper.
1015 *
1016 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
1017 * size, or if no vm_ops are provided.
1018 */
drm_gem_mmap_obj(struct drm_gem_object * obj,unsigned long obj_size,struct vm_area_struct * vma)1019 int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
1020 struct vm_area_struct *vma)
1021 {
1022 int ret;
1023
1024 /* Check for valid size. */
1025 if (obj_size < vma->vm_end - vma->vm_start)
1026 return -EINVAL;
1027
1028 /* Take a ref for this mapping of the object, so that the fault
1029 * handler can dereference the mmap offset's pointer to the object.
1030 * This reference is cleaned up by the corresponding vm_close
1031 * (which should happen whether the vma was created by this call, or
1032 * by a vm_open due to mremap or partial unmap or whatever).
1033 */
1034 drm_gem_object_get(obj);
1035
1036 vma->vm_private_data = obj;
1037 vma->vm_ops = obj->funcs->vm_ops;
1038
1039 if (obj->funcs->mmap) {
1040 ret = obj->funcs->mmap(obj, vma);
1041 if (ret)
1042 goto err_drm_gem_object_put;
1043 WARN_ON(!(vma->vm_flags & VM_DONTEXPAND));
1044 } else {
1045 if (!vma->vm_ops) {
1046 ret = -EINVAL;
1047 goto err_drm_gem_object_put;
1048 }
1049
1050 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
1051 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
1052 vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
1053 }
1054
1055 return 0;
1056
1057 err_drm_gem_object_put:
1058 drm_gem_object_put(obj);
1059 return ret;
1060 }
1061 EXPORT_SYMBOL(drm_gem_mmap_obj);
1062
1063 /**
1064 * drm_gem_mmap - memory map routine for GEM objects
1065 * @filp: DRM file pointer
1066 * @vma: VMA for the area to be mapped
1067 *
1068 * If a driver supports GEM object mapping, mmap calls on the DRM file
1069 * descriptor will end up here.
1070 *
1071 * Look up the GEM object based on the offset passed in (vma->vm_pgoff will
1072 * contain the fake offset we created when the GTT map ioctl was called on
1073 * the object) and map it with a call to drm_gem_mmap_obj().
1074 *
1075 * If the caller is not granted access to the buffer object, the mmap will fail
1076 * with EACCES. Please see the vma manager for more information.
1077 */
drm_gem_mmap(struct file * filp,struct vm_area_struct * vma)1078 int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
1079 {
1080 struct drm_file *priv = filp->private_data;
1081 struct drm_device *dev = priv->minor->dev;
1082 struct drm_gem_object *obj = NULL;
1083 struct drm_vma_offset_node *node;
1084 int ret;
1085
1086 if (drm_dev_is_unplugged(dev))
1087 return -ENODEV;
1088
1089 drm_vma_offset_lock_lookup(dev->vma_offset_manager);
1090 node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
1091 vma->vm_pgoff,
1092 vma_pages(vma));
1093 if (likely(node)) {
1094 obj = container_of(node, struct drm_gem_object, vma_node);
1095 /*
1096 * When the object is being freed, after it hits 0-refcnt it
1097 * proceeds to tear down the object. In the process it will
1098 * attempt to remove the VMA offset and so acquire this
1099 * mgr->vm_lock. Therefore if we find an object with a 0-refcnt
1100 * that matches our range, we know it is in the process of being
1101 * destroyed and will be freed as soon as we release the lock -
1102 * so we have to check for the 0-refcnted object and treat it as
1103 * invalid.
1104 */
1105 if (!kref_get_unless_zero(&obj->refcount))
1106 obj = NULL;
1107 }
1108 drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
1109
1110 if (!obj)
1111 return -EINVAL;
1112
1113 if (!drm_vma_node_is_allowed(node, priv)) {
1114 drm_gem_object_put(obj);
1115 return -EACCES;
1116 }
1117
1118 ret = drm_gem_mmap_obj(obj, drm_vma_node_size(node) << PAGE_SHIFT,
1119 vma);
1120
1121 drm_gem_object_put(obj);
1122
1123 return ret;
1124 }
1125 EXPORT_SYMBOL(drm_gem_mmap);
1126
drm_gem_print_info(struct drm_printer * p,unsigned int indent,const struct drm_gem_object * obj)1127 void drm_gem_print_info(struct drm_printer *p, unsigned int indent,
1128 const struct drm_gem_object *obj)
1129 {
1130 drm_printf_indent(p, indent, "name=%d\n", obj->name);
1131 drm_printf_indent(p, indent, "refcount=%u\n",
1132 kref_read(&obj->refcount));
1133 drm_printf_indent(p, indent, "start=%08lx\n",
1134 drm_vma_node_start(&obj->vma_node));
1135 drm_printf_indent(p, indent, "size=%zu\n", obj->size);
1136 drm_printf_indent(p, indent, "imported=%s\n",
1137 str_yes_no(obj->import_attach));
1138
1139 if (obj->funcs->print_info)
1140 obj->funcs->print_info(p, indent, obj);
1141 }
1142
drm_gem_pin(struct drm_gem_object * obj)1143 int drm_gem_pin(struct drm_gem_object *obj)
1144 {
1145 if (obj->funcs->pin)
1146 return obj->funcs->pin(obj);
1147 else
1148 return 0;
1149 }
1150
drm_gem_unpin(struct drm_gem_object * obj)1151 void drm_gem_unpin(struct drm_gem_object *obj)
1152 {
1153 if (obj->funcs->unpin)
1154 obj->funcs->unpin(obj);
1155 }
1156
drm_gem_vmap(struct drm_gem_object * obj,struct iosys_map * map)1157 int drm_gem_vmap(struct drm_gem_object *obj, struct iosys_map *map)
1158 {
1159 int ret;
1160
1161 if (!obj->funcs->vmap)
1162 return -EOPNOTSUPP;
1163
1164 ret = obj->funcs->vmap(obj, map);
1165 if (ret)
1166 return ret;
1167 else if (iosys_map_is_null(map))
1168 return -ENOMEM;
1169
1170 return 0;
1171 }
1172 EXPORT_SYMBOL(drm_gem_vmap);
1173
drm_gem_vunmap(struct drm_gem_object * obj,struct iosys_map * map)1174 void drm_gem_vunmap(struct drm_gem_object *obj, struct iosys_map *map)
1175 {
1176 if (iosys_map_is_null(map))
1177 return;
1178
1179 if (obj->funcs->vunmap)
1180 obj->funcs->vunmap(obj, map);
1181
1182 /* Always set the mapping to NULL. Callers may rely on this. */
1183 iosys_map_clear(map);
1184 }
1185 EXPORT_SYMBOL(drm_gem_vunmap);
1186
1187 /**
1188 * drm_gem_lock_reservations - Sets up the ww context and acquires
1189 * the lock on an array of GEM objects.
1190 *
1191 * Once you've locked your reservations, you'll want to set up space
1192 * for your shared fences (if applicable), submit your job, then
1193 * drm_gem_unlock_reservations().
1194 *
1195 * @objs: drm_gem_objects to lock
1196 * @count: Number of objects in @objs
1197 * @acquire_ctx: struct ww_acquire_ctx that will be initialized as
1198 * part of tracking this set of locked reservations.
1199 */
1200 int
drm_gem_lock_reservations(struct drm_gem_object ** objs,int count,struct ww_acquire_ctx * acquire_ctx)1201 drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
1202 struct ww_acquire_ctx *acquire_ctx)
1203 {
1204 int contended = -1;
1205 int i, ret;
1206
1207 ww_acquire_init(acquire_ctx, &reservation_ww_class);
1208
1209 retry:
1210 if (contended != -1) {
1211 struct drm_gem_object *obj = objs[contended];
1212
1213 ret = dma_resv_lock_slow_interruptible(obj->resv,
1214 acquire_ctx);
1215 if (ret) {
1216 ww_acquire_fini(acquire_ctx);
1217 return ret;
1218 }
1219 }
1220
1221 for (i = 0; i < count; i++) {
1222 if (i == contended)
1223 continue;
1224
1225 ret = dma_resv_lock_interruptible(objs[i]->resv,
1226 acquire_ctx);
1227 if (ret) {
1228 int j;
1229
1230 for (j = 0; j < i; j++)
1231 dma_resv_unlock(objs[j]->resv);
1232
1233 if (contended != -1 && contended >= i)
1234 dma_resv_unlock(objs[contended]->resv);
1235
1236 if (ret == -EDEADLK) {
1237 contended = i;
1238 goto retry;
1239 }
1240
1241 ww_acquire_fini(acquire_ctx);
1242 return ret;
1243 }
1244 }
1245
1246 ww_acquire_done(acquire_ctx);
1247
1248 return 0;
1249 }
1250 EXPORT_SYMBOL(drm_gem_lock_reservations);
1251
1252 void
drm_gem_unlock_reservations(struct drm_gem_object ** objs,int count,struct ww_acquire_ctx * acquire_ctx)1253 drm_gem_unlock_reservations(struct drm_gem_object **objs, int count,
1254 struct ww_acquire_ctx *acquire_ctx)
1255 {
1256 int i;
1257
1258 for (i = 0; i < count; i++)
1259 dma_resv_unlock(objs[i]->resv);
1260
1261 ww_acquire_fini(acquire_ctx);
1262 }
1263 EXPORT_SYMBOL(drm_gem_unlock_reservations);
1264
1265 /**
1266 * drm_gem_lru_init - initialize a LRU
1267 *
1268 * @lru: The LRU to initialize
1269 * @lock: The lock protecting the LRU
1270 */
1271 void
drm_gem_lru_init(struct drm_gem_lru * lru,struct mutex * lock)1272 drm_gem_lru_init(struct drm_gem_lru *lru, struct mutex *lock)
1273 {
1274 lru->lock = lock;
1275 lru->count = 0;
1276 INIT_LIST_HEAD(&lru->list);
1277 }
1278 EXPORT_SYMBOL(drm_gem_lru_init);
1279
1280 static void
drm_gem_lru_remove_locked(struct drm_gem_object * obj)1281 drm_gem_lru_remove_locked(struct drm_gem_object *obj)
1282 {
1283 obj->lru->count -= obj->size >> PAGE_SHIFT;
1284 WARN_ON(obj->lru->count < 0);
1285 list_del(&obj->lru_node);
1286 obj->lru = NULL;
1287 }
1288
1289 /**
1290 * drm_gem_lru_remove - remove object from whatever LRU it is in
1291 *
1292 * If the object is currently in any LRU, remove it.
1293 *
1294 * @obj: The GEM object to remove from current LRU
1295 */
1296 void
drm_gem_lru_remove(struct drm_gem_object * obj)1297 drm_gem_lru_remove(struct drm_gem_object *obj)
1298 {
1299 struct drm_gem_lru *lru = obj->lru;
1300
1301 if (!lru)
1302 return;
1303
1304 mutex_lock(lru->lock);
1305 drm_gem_lru_remove_locked(obj);
1306 mutex_unlock(lru->lock);
1307 }
1308 EXPORT_SYMBOL(drm_gem_lru_remove);
1309
1310 static void
drm_gem_lru_move_tail_locked(struct drm_gem_lru * lru,struct drm_gem_object * obj)1311 drm_gem_lru_move_tail_locked(struct drm_gem_lru *lru, struct drm_gem_object *obj)
1312 {
1313 lockdep_assert_held_once(lru->lock);
1314
1315 if (obj->lru)
1316 drm_gem_lru_remove_locked(obj);
1317
1318 lru->count += obj->size >> PAGE_SHIFT;
1319 list_add_tail(&obj->lru_node, &lru->list);
1320 obj->lru = lru;
1321 }
1322
1323 /**
1324 * drm_gem_lru_move_tail - move the object to the tail of the LRU
1325 *
1326 * If the object is already in this LRU it will be moved to the
1327 * tail. Otherwise it will be removed from whichever other LRU
1328 * it is in (if any) and moved into this LRU.
1329 *
1330 * @lru: The LRU to move the object into.
1331 * @obj: The GEM object to move into this LRU
1332 */
1333 void
drm_gem_lru_move_tail(struct drm_gem_lru * lru,struct drm_gem_object * obj)1334 drm_gem_lru_move_tail(struct drm_gem_lru *lru, struct drm_gem_object *obj)
1335 {
1336 mutex_lock(lru->lock);
1337 drm_gem_lru_move_tail_locked(lru, obj);
1338 mutex_unlock(lru->lock);
1339 }
1340 EXPORT_SYMBOL(drm_gem_lru_move_tail);
1341
1342 /**
1343 * drm_gem_lru_scan - helper to implement shrinker.scan_objects
1344 *
1345 * If the shrink callback succeeds, it is expected that the driver
1346 * move the object out of this LRU.
1347 *
1348 * If the LRU possibly contain active buffers, it is the responsibility
1349 * of the shrink callback to check for this (ie. dma_resv_test_signaled())
1350 * or if necessary block until the buffer becomes idle.
1351 *
1352 * @lru: The LRU to scan
1353 * @nr_to_scan: The number of pages to try to reclaim
1354 * @shrink: Callback to try to shrink/reclaim the object.
1355 */
1356 unsigned long
drm_gem_lru_scan(struct drm_gem_lru * lru,unsigned nr_to_scan,bool (* shrink)(struct drm_gem_object * obj))1357 drm_gem_lru_scan(struct drm_gem_lru *lru, unsigned nr_to_scan,
1358 bool (*shrink)(struct drm_gem_object *obj))
1359 {
1360 struct drm_gem_lru still_in_lru;
1361 struct drm_gem_object *obj;
1362 unsigned freed = 0;
1363
1364 drm_gem_lru_init(&still_in_lru, lru->lock);
1365
1366 mutex_lock(lru->lock);
1367
1368 while (freed < nr_to_scan) {
1369 obj = list_first_entry_or_null(&lru->list, typeof(*obj), lru_node);
1370
1371 if (!obj)
1372 break;
1373
1374 drm_gem_lru_move_tail_locked(&still_in_lru, obj);
1375
1376 /*
1377 * If it's in the process of being freed, gem_object->free()
1378 * may be blocked on lock waiting to remove it. So just
1379 * skip it.
1380 */
1381 if (!kref_get_unless_zero(&obj->refcount))
1382 continue;
1383
1384 /*
1385 * Now that we own a reference, we can drop the lock for the
1386 * rest of the loop body, to reduce contention with other
1387 * code paths that need the LRU lock
1388 */
1389 mutex_unlock(lru->lock);
1390
1391 /*
1392 * Note that this still needs to be trylock, since we can
1393 * hit shrinker in response to trying to get backing pages
1394 * for this obj (ie. while it's lock is already held)
1395 */
1396 if (!dma_resv_trylock(obj->resv))
1397 goto tail;
1398
1399 if (shrink(obj)) {
1400 freed += obj->size >> PAGE_SHIFT;
1401
1402 /*
1403 * If we succeeded in releasing the object's backing
1404 * pages, we expect the driver to have moved the object
1405 * out of this LRU
1406 */
1407 WARN_ON(obj->lru == &still_in_lru);
1408 WARN_ON(obj->lru == lru);
1409 }
1410
1411 dma_resv_unlock(obj->resv);
1412
1413 tail:
1414 drm_gem_object_put(obj);
1415 mutex_lock(lru->lock);
1416 }
1417
1418 /*
1419 * Move objects we've skipped over out of the temporary still_in_lru
1420 * back into this LRU
1421 */
1422 list_for_each_entry (obj, &still_in_lru.list, lru_node)
1423 obj->lru = lru;
1424 list_splice_tail(&still_in_lru.list, &lru->list);
1425 lru->count += still_in_lru.count;
1426
1427 mutex_unlock(lru->lock);
1428
1429 return freed;
1430 }
1431 EXPORT_SYMBOL(drm_gem_lru_scan);
1432