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1 /**************************************************************************
2  *
3  * Copyright (c) 2009-2013 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  * While no substantial code is shared, the prime code is inspired by
31  * drm_prime.c, with
32  * Authors:
33  *      Dave Airlie <airlied@redhat.com>
34  *      Rob Clark <rob.clark@linaro.org>
35  */
36 /** @file ttm_ref_object.c
37  *
38  * Base- and reference object implementation for the various
39  * ttm objects. Implements reference counting, minimal security checks
40  * and release on file close.
41  */
42 
43 
44 /**
45  * struct ttm_object_file
46  *
47  * @tdev: Pointer to the ttm_object_device.
48  *
49  * @lock: Lock that protects the ref_list list and the
50  * ref_hash hash tables.
51  *
52  * @ref_list: List of ttm_ref_objects to be destroyed at
53  * file release.
54  *
55  * @ref_hash: Hash tables of ref objects, one per ttm_ref_type,
56  * for fast lookup of ref objects given a base object.
57  */
58 
59 #define pr_fmt(fmt) "[TTM] " fmt
60 
61 #include <drm/ttm/ttm_object.h>
62 #include <drm/ttm/ttm_module.h>
63 #include <linux/list.h>
64 #include <linux/spinlock.h>
65 #include <linux/slab.h>
66 #include <linux/module.h>
67 #include <linux/atomic.h>
68 
69 struct ttm_object_file {
70 	struct ttm_object_device *tdev;
71 	spinlock_t lock;
72 	struct list_head ref_list;
73 	struct drm_open_hash ref_hash[TTM_REF_NUM];
74 	struct kref refcount;
75 };
76 
77 /**
78  * struct ttm_object_device
79  *
80  * @object_lock: lock that protects the object_hash hash table.
81  *
82  * @object_hash: hash table for fast lookup of object global names.
83  *
84  * @object_count: Per device object count.
85  *
86  * This is the per-device data structure needed for ttm object management.
87  */
88 
89 struct ttm_object_device {
90 	spinlock_t object_lock;
91 	struct drm_open_hash object_hash;
92 	atomic_t object_count;
93 	struct ttm_mem_global *mem_glob;
94 	struct dma_buf_ops ops;
95 	void (*dmabuf_release)(struct dma_buf *dma_buf);
96 	size_t dma_buf_size;
97 };
98 
99 /**
100  * struct ttm_ref_object
101  *
102  * @hash: Hash entry for the per-file object reference hash.
103  *
104  * @head: List entry for the per-file list of ref-objects.
105  *
106  * @kref: Ref count.
107  *
108  * @obj: Base object this ref object is referencing.
109  *
110  * @ref_type: Type of ref object.
111  *
112  * This is similar to an idr object, but it also has a hash table entry
113  * that allows lookup with a pointer to the referenced object as a key. In
114  * that way, one can easily detect whether a base object is referenced by
115  * a particular ttm_object_file. It also carries a ref count to avoid creating
116  * multiple ref objects if a ttm_object_file references the same base
117  * object more than once.
118  */
119 
120 struct ttm_ref_object {
121 	struct rcu_head rcu_head;
122 	struct drm_hash_item hash;
123 	struct list_head head;
124 	struct kref kref;
125 	enum ttm_ref_type ref_type;
126 	struct ttm_base_object *obj;
127 	struct ttm_object_file *tfile;
128 };
129 
130 static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf);
131 
132 static inline struct ttm_object_file *
ttm_object_file_ref(struct ttm_object_file * tfile)133 ttm_object_file_ref(struct ttm_object_file *tfile)
134 {
135 	kref_get(&tfile->refcount);
136 	return tfile;
137 }
138 
ttm_object_file_destroy(struct kref * kref)139 static void ttm_object_file_destroy(struct kref *kref)
140 {
141 	struct ttm_object_file *tfile =
142 		container_of(kref, struct ttm_object_file, refcount);
143 
144 	kfree(tfile);
145 }
146 
147 
ttm_object_file_unref(struct ttm_object_file ** p_tfile)148 static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile)
149 {
150 	struct ttm_object_file *tfile = *p_tfile;
151 
152 	*p_tfile = NULL;
153 	kref_put(&tfile->refcount, ttm_object_file_destroy);
154 }
155 
156 
ttm_base_object_init(struct ttm_object_file * tfile,struct ttm_base_object * base,bool shareable,enum ttm_object_type object_type,void (* refcount_release)(struct ttm_base_object **),void (* ref_obj_release)(struct ttm_base_object *,enum ttm_ref_type ref_type))157 int ttm_base_object_init(struct ttm_object_file *tfile,
158 			 struct ttm_base_object *base,
159 			 bool shareable,
160 			 enum ttm_object_type object_type,
161 			 void (*refcount_release) (struct ttm_base_object **),
162 			 void (*ref_obj_release) (struct ttm_base_object *,
163 						  enum ttm_ref_type ref_type))
164 {
165 	struct ttm_object_device *tdev = tfile->tdev;
166 	int ret;
167 
168 	base->shareable = shareable;
169 	base->tfile = ttm_object_file_ref(tfile);
170 	base->refcount_release = refcount_release;
171 	base->ref_obj_release = ref_obj_release;
172 	base->object_type = object_type;
173 	kref_init(&base->refcount);
174 	spin_lock(&tdev->object_lock);
175 	ret = drm_ht_just_insert_please_rcu(&tdev->object_hash,
176 					    &base->hash,
177 					    (unsigned long)base, 31, 0, 0);
178 	spin_unlock(&tdev->object_lock);
179 	if (unlikely(ret != 0))
180 		goto out_err0;
181 
182 	ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
183 	if (unlikely(ret != 0))
184 		goto out_err1;
185 
186 	ttm_base_object_unref(&base);
187 
188 	return 0;
189 out_err1:
190 	spin_lock(&tdev->object_lock);
191 	(void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
192 	spin_unlock(&tdev->object_lock);
193 out_err0:
194 	return ret;
195 }
196 EXPORT_SYMBOL(ttm_base_object_init);
197 
ttm_release_base(struct kref * kref)198 static void ttm_release_base(struct kref *kref)
199 {
200 	struct ttm_base_object *base =
201 	    container_of(kref, struct ttm_base_object, refcount);
202 	struct ttm_object_device *tdev = base->tfile->tdev;
203 
204 	spin_lock(&tdev->object_lock);
205 	(void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
206 	spin_unlock(&tdev->object_lock);
207 
208 	/*
209 	 * Note: We don't use synchronize_rcu() here because it's far
210 	 * too slow. It's up to the user to free the object using
211 	 * call_rcu() or ttm_base_object_kfree().
212 	 */
213 
214 	ttm_object_file_unref(&base->tfile);
215 	if (base->refcount_release)
216 		base->refcount_release(&base);
217 }
218 
ttm_base_object_unref(struct ttm_base_object ** p_base)219 void ttm_base_object_unref(struct ttm_base_object **p_base)
220 {
221 	struct ttm_base_object *base = *p_base;
222 
223 	*p_base = NULL;
224 
225 	kref_put(&base->refcount, ttm_release_base);
226 }
227 EXPORT_SYMBOL(ttm_base_object_unref);
228 
ttm_base_object_lookup(struct ttm_object_file * tfile,uint32_t key)229 struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
230 					       uint32_t key)
231 {
232 	struct ttm_base_object *base = NULL;
233 	struct drm_hash_item *hash;
234 	struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
235 	int ret;
236 
237 	rcu_read_lock();
238 	ret = drm_ht_find_item_rcu(ht, key, &hash);
239 
240 	if (likely(ret == 0)) {
241 		base = drm_hash_entry(hash, struct ttm_ref_object, hash)->obj;
242 		if (!kref_get_unless_zero(&base->refcount))
243 			base = NULL;
244 	}
245 	rcu_read_unlock();
246 
247 	return base;
248 }
249 EXPORT_SYMBOL(ttm_base_object_lookup);
250 
251 struct ttm_base_object *
ttm_base_object_lookup_for_ref(struct ttm_object_device * tdev,uint32_t key)252 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key)
253 {
254 	struct ttm_base_object *base = NULL;
255 	struct drm_hash_item *hash;
256 	struct drm_open_hash *ht = &tdev->object_hash;
257 	int ret;
258 
259 	rcu_read_lock();
260 	ret = drm_ht_find_item_rcu(ht, key, &hash);
261 
262 	if (likely(ret == 0)) {
263 		base = drm_hash_entry(hash, struct ttm_base_object, hash);
264 		if (!kref_get_unless_zero(&base->refcount))
265 			base = NULL;
266 	}
267 	rcu_read_unlock();
268 
269 	return base;
270 }
271 EXPORT_SYMBOL(ttm_base_object_lookup_for_ref);
272 
273 /**
274  * ttm_ref_object_exists - Check whether a caller has a valid ref object
275  * (has opened) a base object.
276  *
277  * @tfile: Pointer to a struct ttm_object_file identifying the caller.
278  * @base: Pointer to a struct base object.
279  *
280  * Checks wether the caller identified by @tfile has put a valid USAGE
281  * reference object on the base object identified by @base.
282  */
ttm_ref_object_exists(struct ttm_object_file * tfile,struct ttm_base_object * base)283 bool ttm_ref_object_exists(struct ttm_object_file *tfile,
284 			   struct ttm_base_object *base)
285 {
286 	struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
287 	struct drm_hash_item *hash;
288 	struct ttm_ref_object *ref;
289 
290 	rcu_read_lock();
291 	if (unlikely(drm_ht_find_item_rcu(ht, base->hash.key, &hash) != 0))
292 		goto out_false;
293 
294 	/*
295 	 * Verify that the ref object is really pointing to our base object.
296 	 * Our base object could actually be dead, and the ref object pointing
297 	 * to another base object with the same handle.
298 	 */
299 	ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
300 	if (unlikely(base != ref->obj))
301 		goto out_false;
302 
303 	/*
304 	 * Verify that the ref->obj pointer was actually valid!
305 	 */
306 	rmb();
307 	if (unlikely(atomic_read(&ref->kref.refcount) == 0))
308 		goto out_false;
309 
310 	rcu_read_unlock();
311 	return true;
312 
313  out_false:
314 	rcu_read_unlock();
315 	return false;
316 }
317 EXPORT_SYMBOL(ttm_ref_object_exists);
318 
ttm_ref_object_add(struct ttm_object_file * tfile,struct ttm_base_object * base,enum ttm_ref_type ref_type,bool * existed,bool require_existed)319 int ttm_ref_object_add(struct ttm_object_file *tfile,
320 		       struct ttm_base_object *base,
321 		       enum ttm_ref_type ref_type, bool *existed,
322 		       bool require_existed)
323 {
324 	struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
325 	struct ttm_ref_object *ref;
326 	struct drm_hash_item *hash;
327 	struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
328 	int ret = -EINVAL;
329 
330 	if (base->tfile != tfile && !base->shareable)
331 		return -EPERM;
332 
333 	if (existed != NULL)
334 		*existed = true;
335 
336 	while (ret == -EINVAL) {
337 		rcu_read_lock();
338 		ret = drm_ht_find_item_rcu(ht, base->hash.key, &hash);
339 
340 		if (ret == 0) {
341 			ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
342 			if (kref_get_unless_zero(&ref->kref)) {
343 				rcu_read_unlock();
344 				break;
345 			}
346 		}
347 
348 		rcu_read_unlock();
349 		if (require_existed)
350 			return -EPERM;
351 
352 		ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
353 					   false, false);
354 		if (unlikely(ret != 0))
355 			return ret;
356 		ref = kmalloc(sizeof(*ref), GFP_KERNEL);
357 		if (unlikely(ref == NULL)) {
358 			ttm_mem_global_free(mem_glob, sizeof(*ref));
359 			return -ENOMEM;
360 		}
361 
362 		ref->hash.key = base->hash.key;
363 		ref->obj = base;
364 		ref->tfile = tfile;
365 		ref->ref_type = ref_type;
366 		kref_init(&ref->kref);
367 
368 		spin_lock(&tfile->lock);
369 		ret = drm_ht_insert_item_rcu(ht, &ref->hash);
370 
371 		if (likely(ret == 0)) {
372 			list_add_tail(&ref->head, &tfile->ref_list);
373 			kref_get(&base->refcount);
374 			spin_unlock(&tfile->lock);
375 			if (existed != NULL)
376 				*existed = false;
377 			break;
378 		}
379 
380 		spin_unlock(&tfile->lock);
381 		BUG_ON(ret != -EINVAL);
382 
383 		ttm_mem_global_free(mem_glob, sizeof(*ref));
384 		kfree(ref);
385 	}
386 
387 	return ret;
388 }
389 EXPORT_SYMBOL(ttm_ref_object_add);
390 
ttm_ref_object_release(struct kref * kref)391 static void ttm_ref_object_release(struct kref *kref)
392 {
393 	struct ttm_ref_object *ref =
394 	    container_of(kref, struct ttm_ref_object, kref);
395 	struct ttm_base_object *base = ref->obj;
396 	struct ttm_object_file *tfile = ref->tfile;
397 	struct drm_open_hash *ht;
398 	struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
399 
400 	ht = &tfile->ref_hash[ref->ref_type];
401 	(void)drm_ht_remove_item_rcu(ht, &ref->hash);
402 	list_del(&ref->head);
403 	spin_unlock(&tfile->lock);
404 
405 	if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
406 		base->ref_obj_release(base, ref->ref_type);
407 
408 	ttm_base_object_unref(&ref->obj);
409 	ttm_mem_global_free(mem_glob, sizeof(*ref));
410 	kfree_rcu(ref, rcu_head);
411 	spin_lock(&tfile->lock);
412 }
413 
ttm_ref_object_base_unref(struct ttm_object_file * tfile,unsigned long key,enum ttm_ref_type ref_type)414 int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
415 			      unsigned long key, enum ttm_ref_type ref_type)
416 {
417 	struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
418 	struct ttm_ref_object *ref;
419 	struct drm_hash_item *hash;
420 	int ret;
421 
422 	spin_lock(&tfile->lock);
423 	ret = drm_ht_find_item(ht, key, &hash);
424 	if (unlikely(ret != 0)) {
425 		spin_unlock(&tfile->lock);
426 		return -EINVAL;
427 	}
428 	ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
429 	kref_put(&ref->kref, ttm_ref_object_release);
430 	spin_unlock(&tfile->lock);
431 	return 0;
432 }
433 EXPORT_SYMBOL(ttm_ref_object_base_unref);
434 
ttm_object_file_release(struct ttm_object_file ** p_tfile)435 void ttm_object_file_release(struct ttm_object_file **p_tfile)
436 {
437 	struct ttm_ref_object *ref;
438 	struct list_head *list;
439 	unsigned int i;
440 	struct ttm_object_file *tfile = *p_tfile;
441 
442 	*p_tfile = NULL;
443 	spin_lock(&tfile->lock);
444 
445 	/*
446 	 * Since we release the lock within the loop, we have to
447 	 * restart it from the beginning each time.
448 	 */
449 
450 	while (!list_empty(&tfile->ref_list)) {
451 		list = tfile->ref_list.next;
452 		ref = list_entry(list, struct ttm_ref_object, head);
453 		ttm_ref_object_release(&ref->kref);
454 	}
455 
456 	for (i = 0; i < TTM_REF_NUM; ++i)
457 		drm_ht_remove(&tfile->ref_hash[i]);
458 
459 	spin_unlock(&tfile->lock);
460 	ttm_object_file_unref(&tfile);
461 }
462 EXPORT_SYMBOL(ttm_object_file_release);
463 
ttm_object_file_init(struct ttm_object_device * tdev,unsigned int hash_order)464 struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
465 					     unsigned int hash_order)
466 {
467 	struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
468 	unsigned int i;
469 	unsigned int j = 0;
470 	int ret;
471 
472 	if (unlikely(tfile == NULL))
473 		return NULL;
474 
475 	spin_lock_init(&tfile->lock);
476 	tfile->tdev = tdev;
477 	kref_init(&tfile->refcount);
478 	INIT_LIST_HEAD(&tfile->ref_list);
479 
480 	for (i = 0; i < TTM_REF_NUM; ++i) {
481 		ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
482 		if (ret) {
483 			j = i;
484 			goto out_err;
485 		}
486 	}
487 
488 	return tfile;
489 out_err:
490 	for (i = 0; i < j; ++i)
491 		drm_ht_remove(&tfile->ref_hash[i]);
492 
493 	kfree(tfile);
494 
495 	return NULL;
496 }
497 EXPORT_SYMBOL(ttm_object_file_init);
498 
499 struct ttm_object_device *
ttm_object_device_init(struct ttm_mem_global * mem_glob,unsigned int hash_order,const struct dma_buf_ops * ops)500 ttm_object_device_init(struct ttm_mem_global *mem_glob,
501 		       unsigned int hash_order,
502 		       const struct dma_buf_ops *ops)
503 {
504 	struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
505 	int ret;
506 
507 	if (unlikely(tdev == NULL))
508 		return NULL;
509 
510 	tdev->mem_glob = mem_glob;
511 	spin_lock_init(&tdev->object_lock);
512 	atomic_set(&tdev->object_count, 0);
513 	ret = drm_ht_create(&tdev->object_hash, hash_order);
514 	if (ret != 0)
515 		goto out_no_object_hash;
516 
517 	tdev->ops = *ops;
518 	tdev->dmabuf_release = tdev->ops.release;
519 	tdev->ops.release = ttm_prime_dmabuf_release;
520 	tdev->dma_buf_size = ttm_round_pot(sizeof(struct dma_buf)) +
521 		ttm_round_pot(sizeof(struct file));
522 	return tdev;
523 
524 out_no_object_hash:
525 	kfree(tdev);
526 	return NULL;
527 }
528 EXPORT_SYMBOL(ttm_object_device_init);
529 
ttm_object_device_release(struct ttm_object_device ** p_tdev)530 void ttm_object_device_release(struct ttm_object_device **p_tdev)
531 {
532 	struct ttm_object_device *tdev = *p_tdev;
533 
534 	*p_tdev = NULL;
535 
536 	spin_lock(&tdev->object_lock);
537 	drm_ht_remove(&tdev->object_hash);
538 	spin_unlock(&tdev->object_lock);
539 
540 	kfree(tdev);
541 }
542 EXPORT_SYMBOL(ttm_object_device_release);
543 
544 /**
545  * get_dma_buf_unless_doomed - get a dma_buf reference if possible.
546  *
547  * @dma_buf: Non-refcounted pointer to a struct dma-buf.
548  *
549  * Obtain a file reference from a lookup structure that doesn't refcount
550  * the file, but synchronizes with its release method to make sure it has
551  * not been freed yet. See for example kref_get_unless_zero documentation.
552  * Returns true if refcounting succeeds, false otherwise.
553  *
554  * Nobody really wants this as a public API yet, so let it mature here
555  * for some time...
556  */
get_dma_buf_unless_doomed(struct dma_buf * dmabuf)557 static bool __must_check get_dma_buf_unless_doomed(struct dma_buf *dmabuf)
558 {
559 	return atomic_long_inc_not_zero(&dmabuf->file->f_count) != 0L;
560 }
561 
562 /**
563  * ttm_prime_refcount_release - refcount release method for a prime object.
564  *
565  * @p_base: Pointer to ttm_base_object pointer.
566  *
567  * This is a wrapper that calls the refcount_release founction of the
568  * underlying object. At the same time it cleans up the prime object.
569  * This function is called when all references to the base object we
570  * derive from are gone.
571  */
ttm_prime_refcount_release(struct ttm_base_object ** p_base)572 static void ttm_prime_refcount_release(struct ttm_base_object **p_base)
573 {
574 	struct ttm_base_object *base = *p_base;
575 	struct ttm_prime_object *prime;
576 
577 	*p_base = NULL;
578 	prime = container_of(base, struct ttm_prime_object, base);
579 	BUG_ON(prime->dma_buf != NULL);
580 	mutex_destroy(&prime->mutex);
581 	if (prime->refcount_release)
582 		prime->refcount_release(&base);
583 }
584 
585 /**
586  * ttm_prime_dmabuf_release - Release method for the dma-bufs we export
587  *
588  * @dma_buf:
589  *
590  * This function first calls the dma_buf release method the driver
591  * provides. Then it cleans up our dma_buf pointer used for lookup,
592  * and finally releases the reference the dma_buf has on our base
593  * object.
594  */
ttm_prime_dmabuf_release(struct dma_buf * dma_buf)595 static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf)
596 {
597 	struct ttm_prime_object *prime =
598 		(struct ttm_prime_object *) dma_buf->priv;
599 	struct ttm_base_object *base = &prime->base;
600 	struct ttm_object_device *tdev = base->tfile->tdev;
601 
602 	if (tdev->dmabuf_release)
603 		tdev->dmabuf_release(dma_buf);
604 	mutex_lock(&prime->mutex);
605 	if (prime->dma_buf == dma_buf)
606 		prime->dma_buf = NULL;
607 	mutex_unlock(&prime->mutex);
608 	ttm_mem_global_free(tdev->mem_glob, tdev->dma_buf_size);
609 	ttm_base_object_unref(&base);
610 }
611 
612 /**
613  * ttm_prime_fd_to_handle - Get a base object handle from a prime fd
614  *
615  * @tfile: A struct ttm_object_file identifying the caller.
616  * @fd: The prime / dmabuf fd.
617  * @handle: The returned handle.
618  *
619  * This function returns a handle to an object that previously exported
620  * a dma-buf. Note that we don't handle imports yet, because we simply
621  * have no consumers of that implementation.
622  */
ttm_prime_fd_to_handle(struct ttm_object_file * tfile,int fd,u32 * handle)623 int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
624 			   int fd, u32 *handle)
625 {
626 	struct ttm_object_device *tdev = tfile->tdev;
627 	struct dma_buf *dma_buf;
628 	struct ttm_prime_object *prime;
629 	struct ttm_base_object *base;
630 	int ret;
631 
632 	dma_buf = dma_buf_get(fd);
633 	if (IS_ERR(dma_buf))
634 		return PTR_ERR(dma_buf);
635 
636 	if (dma_buf->ops != &tdev->ops)
637 		return -ENOSYS;
638 
639 	prime = (struct ttm_prime_object *) dma_buf->priv;
640 	base = &prime->base;
641 	*handle = base->hash.key;
642 	ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
643 
644 	dma_buf_put(dma_buf);
645 
646 	return ret;
647 }
648 EXPORT_SYMBOL_GPL(ttm_prime_fd_to_handle);
649 
650 /**
651  * ttm_prime_handle_to_fd - Return a dma_buf fd from a ttm prime object
652  *
653  * @tfile: Struct ttm_object_file identifying the caller.
654  * @handle: Handle to the object we're exporting from.
655  * @flags: flags for dma-buf creation. We just pass them on.
656  * @prime_fd: The returned file descriptor.
657  *
658  */
ttm_prime_handle_to_fd(struct ttm_object_file * tfile,uint32_t handle,uint32_t flags,int * prime_fd)659 int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
660 			   uint32_t handle, uint32_t flags,
661 			   int *prime_fd)
662 {
663 	struct ttm_object_device *tdev = tfile->tdev;
664 	struct ttm_base_object *base;
665 	struct dma_buf *dma_buf;
666 	struct ttm_prime_object *prime;
667 	int ret;
668 
669 	base = ttm_base_object_lookup(tfile, handle);
670 	if (unlikely(base == NULL ||
671 		     base->object_type != ttm_prime_type)) {
672 		ret = -ENOENT;
673 		goto out_unref;
674 	}
675 
676 	prime = container_of(base, struct ttm_prime_object, base);
677 	if (unlikely(!base->shareable)) {
678 		ret = -EPERM;
679 		goto out_unref;
680 	}
681 
682 	ret = mutex_lock_interruptible(&prime->mutex);
683 	if (unlikely(ret != 0)) {
684 		ret = -ERESTARTSYS;
685 		goto out_unref;
686 	}
687 
688 	dma_buf = prime->dma_buf;
689 	if (!dma_buf || !get_dma_buf_unless_doomed(dma_buf)) {
690 		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
691 
692 		exp_info.ops = &tdev->ops;
693 		exp_info.size = prime->size;
694 		exp_info.flags = flags;
695 		exp_info.priv = prime;
696 
697 		/*
698 		 * Need to create a new dma_buf, with memory accounting.
699 		 */
700 		ret = ttm_mem_global_alloc(tdev->mem_glob, tdev->dma_buf_size,
701 					   false, true);
702 		if (unlikely(ret != 0)) {
703 			mutex_unlock(&prime->mutex);
704 			goto out_unref;
705 		}
706 
707 		dma_buf = dma_buf_export(&exp_info);
708 		if (IS_ERR(dma_buf)) {
709 			ret = PTR_ERR(dma_buf);
710 			ttm_mem_global_free(tdev->mem_glob,
711 					    tdev->dma_buf_size);
712 			mutex_unlock(&prime->mutex);
713 			goto out_unref;
714 		}
715 
716 		/*
717 		 * dma_buf has taken the base object reference
718 		 */
719 		base = NULL;
720 		prime->dma_buf = dma_buf;
721 	}
722 	mutex_unlock(&prime->mutex);
723 
724 	ret = dma_buf_fd(dma_buf, flags);
725 	if (ret >= 0) {
726 		*prime_fd = ret;
727 		ret = 0;
728 	} else
729 		dma_buf_put(dma_buf);
730 
731 out_unref:
732 	if (base)
733 		ttm_base_object_unref(&base);
734 	return ret;
735 }
736 EXPORT_SYMBOL_GPL(ttm_prime_handle_to_fd);
737 
738 /**
739  * ttm_prime_object_init - Initialize a ttm_prime_object
740  *
741  * @tfile: struct ttm_object_file identifying the caller
742  * @size: The size of the dma_bufs we export.
743  * @prime: The object to be initialized.
744  * @shareable: See ttm_base_object_init
745  * @type: See ttm_base_object_init
746  * @refcount_release: See ttm_base_object_init
747  * @ref_obj_release: See ttm_base_object_init
748  *
749  * Initializes an object which is compatible with the drm_prime model
750  * for data sharing between processes and devices.
751  */
ttm_prime_object_init(struct ttm_object_file * tfile,size_t size,struct ttm_prime_object * prime,bool shareable,enum ttm_object_type type,void (* refcount_release)(struct ttm_base_object **),void (* ref_obj_release)(struct ttm_base_object *,enum ttm_ref_type ref_type))752 int ttm_prime_object_init(struct ttm_object_file *tfile, size_t size,
753 			  struct ttm_prime_object *prime, bool shareable,
754 			  enum ttm_object_type type,
755 			  void (*refcount_release) (struct ttm_base_object **),
756 			  void (*ref_obj_release) (struct ttm_base_object *,
757 						   enum ttm_ref_type ref_type))
758 {
759 	mutex_init(&prime->mutex);
760 	prime->size = PAGE_ALIGN(size);
761 	prime->real_type = type;
762 	prime->dma_buf = NULL;
763 	prime->refcount_release = refcount_release;
764 	return ttm_base_object_init(tfile, &prime->base, shareable,
765 				    ttm_prime_type,
766 				    ttm_prime_refcount_release,
767 				    ref_obj_release);
768 }
769 EXPORT_SYMBOL(ttm_prime_object_init);
770