source: src/linux/universal/linux-4.4/drivers/gpu/drm/ttm/ttm_object.c @ 31859

Last change on this file since 31859 was 31859, checked in by brainslayer, 6 weeks ago

kernel update

File size: 20.2 KB
Line 
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
69struct 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
89struct 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
120struct 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
130static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf);
131
132static inline struct ttm_object_file *
133ttm_object_file_ref(struct ttm_object_file *tfile)
134{
135        kref_get(&tfile->refcount);
136        return tfile;
137}
138
139static 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
148static 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
157int 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;
189out_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);
193out_err0:
194        return ret;
195}
196EXPORT_SYMBOL(ttm_base_object_init);
197
198static 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
219void 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}
227EXPORT_SYMBOL(ttm_base_object_unref);
228
229struct 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}
249EXPORT_SYMBOL(ttm_base_object_lookup);
250
251struct ttm_base_object *
252ttm_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}
271EXPORT_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 */
283bool 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}
317EXPORT_SYMBOL(ttm_ref_object_exists);
318
319int 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}
389EXPORT_SYMBOL(ttm_ref_object_add);
390
391static 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
414int 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}
433EXPORT_SYMBOL(ttm_ref_object_base_unref);
434
435void 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}
462EXPORT_SYMBOL(ttm_object_file_release);
463
464struct 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;
489out_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}
497EXPORT_SYMBOL(ttm_object_file_init);
498
499struct ttm_object_device *
500ttm_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
524out_no_object_hash:
525        kfree(tdev);
526        return NULL;
527}
528EXPORT_SYMBOL(ttm_object_device_init);
529
530void 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}
542EXPORT_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 */
557static 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 */
572static 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 */
595static 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 */
623int 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}
648EXPORT_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 */
659int 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
731out_unref:
732        if (base)
733                ttm_base_object_unref(&base);
734        return ret;
735}
736EXPORT_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 */
752int 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}
769EXPORT_SYMBOL(ttm_prime_object_init);
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