xref: /openbmc/linux/drivers/gpu/drm/i915/gvt/dmabuf.c (revision 0c6dfa75)
1 /*
2  * Copyright 2017 Intel Corporation. All rights reserved.
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
21  * DEALINGS IN THE SOFTWARE.
22  *
23  * Authors:
24  *    Zhiyuan Lv <zhiyuan.lv@intel.com>
25  *
26  * Contributors:
27  *    Xiaoguang Chen
28  *    Tina Zhang <tina.zhang@intel.com>
29  */
30 
31 #include <linux/dma-buf.h>
32 #include <linux/mdev.h>
33 
34 #include <drm/drm_fourcc.h>
35 #include <drm/drm_plane.h>
36 
37 #include "gem/i915_gem_dmabuf.h"
38 
39 #include "i915_drv.h"
40 #include "i915_reg.h"
41 #include "gvt.h"
42 
43 #define GEN8_DECODE_PTE(pte) (pte & GENMASK_ULL(63, 12))
44 
45 static int vgpu_gem_get_pages(struct drm_i915_gem_object *obj)
46 {
47 	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
48 	struct intel_vgpu *vgpu;
49 	struct sg_table *st;
50 	struct scatterlist *sg;
51 	int i, j, ret;
52 	gen8_pte_t __iomem *gtt_entries;
53 	struct intel_vgpu_fb_info *fb_info;
54 	unsigned int page_num; /* limited by sg_alloc_table */
55 
56 	if (overflows_type(obj->base.size >> PAGE_SHIFT, page_num))
57 		return -E2BIG;
58 
59 	page_num = obj->base.size >> PAGE_SHIFT;
60 	fb_info = (struct intel_vgpu_fb_info *)obj->gvt_info;
61 	if (drm_WARN_ON(&dev_priv->drm, !fb_info))
62 		return -ENODEV;
63 
64 	vgpu = fb_info->obj->vgpu;
65 	if (drm_WARN_ON(&dev_priv->drm, !vgpu))
66 		return -ENODEV;
67 
68 	st = kmalloc(sizeof(*st), GFP_KERNEL);
69 	if (unlikely(!st))
70 		return -ENOMEM;
71 
72 	ret = sg_alloc_table(st, page_num, GFP_KERNEL);
73 	if (ret) {
74 		kfree(st);
75 		return ret;
76 	}
77 	gtt_entries = (gen8_pte_t __iomem *)to_gt(dev_priv)->ggtt->gsm +
78 		(fb_info->start >> PAGE_SHIFT);
79 	for_each_sg(st->sgl, sg, page_num, i) {
80 		dma_addr_t dma_addr =
81 			GEN8_DECODE_PTE(readq(&gtt_entries[i]));
82 		if (intel_gvt_dma_pin_guest_page(vgpu, dma_addr)) {
83 			ret = -EINVAL;
84 			goto out;
85 		}
86 
87 		sg->offset = 0;
88 		sg->length = PAGE_SIZE;
89 		sg_dma_len(sg) = PAGE_SIZE;
90 		sg_dma_address(sg) = dma_addr;
91 	}
92 
93 	__i915_gem_object_set_pages(obj, st);
94 out:
95 	if (ret) {
96 		dma_addr_t dma_addr;
97 
98 		for_each_sg(st->sgl, sg, i, j) {
99 			dma_addr = sg_dma_address(sg);
100 			if (dma_addr)
101 				intel_gvt_dma_unmap_guest_page(vgpu, dma_addr);
102 		}
103 		sg_free_table(st);
104 		kfree(st);
105 	}
106 
107 	return ret;
108 
109 }
110 
111 static void vgpu_gem_put_pages(struct drm_i915_gem_object *obj,
112 		struct sg_table *pages)
113 {
114 	struct scatterlist *sg;
115 
116 	if (obj->base.dma_buf) {
117 		struct intel_vgpu_fb_info *fb_info = obj->gvt_info;
118 		struct intel_vgpu_dmabuf_obj *obj = fb_info->obj;
119 		struct intel_vgpu *vgpu = obj->vgpu;
120 		int i;
121 
122 		for_each_sg(pages->sgl, sg, fb_info->size, i)
123 			intel_gvt_dma_unmap_guest_page(vgpu,
124 					       sg_dma_address(sg));
125 	}
126 
127 	sg_free_table(pages);
128 	kfree(pages);
129 }
130 
131 static void dmabuf_gem_object_free(struct kref *kref)
132 {
133 	struct intel_vgpu_dmabuf_obj *obj =
134 		container_of(kref, struct intel_vgpu_dmabuf_obj, kref);
135 	struct intel_vgpu *vgpu = obj->vgpu;
136 	struct list_head *pos;
137 	struct intel_vgpu_dmabuf_obj *dmabuf_obj;
138 
139 	if (vgpu && test_bit(INTEL_VGPU_STATUS_ACTIVE, vgpu->status) &&
140 	    !list_empty(&vgpu->dmabuf_obj_list_head)) {
141 		list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
142 			dmabuf_obj = list_entry(pos, struct intel_vgpu_dmabuf_obj, list);
143 			if (dmabuf_obj == obj) {
144 				list_del(pos);
145 				idr_remove(&vgpu->object_idr,
146 					   dmabuf_obj->dmabuf_id);
147 				kfree(dmabuf_obj->info);
148 				kfree(dmabuf_obj);
149 				break;
150 			}
151 		}
152 	} else {
153 		/* Free the orphan dmabuf_objs here */
154 		kfree(obj->info);
155 		kfree(obj);
156 	}
157 }
158 
159 
160 static inline void dmabuf_obj_get(struct intel_vgpu_dmabuf_obj *obj)
161 {
162 	kref_get(&obj->kref);
163 }
164 
165 static inline void dmabuf_obj_put(struct intel_vgpu_dmabuf_obj *obj)
166 {
167 	kref_put(&obj->kref, dmabuf_gem_object_free);
168 }
169 
170 static void vgpu_gem_release(struct drm_i915_gem_object *gem_obj)
171 {
172 
173 	struct intel_vgpu_fb_info *fb_info = gem_obj->gvt_info;
174 	struct intel_vgpu_dmabuf_obj *obj = fb_info->obj;
175 	struct intel_vgpu *vgpu = obj->vgpu;
176 
177 	if (vgpu) {
178 		mutex_lock(&vgpu->dmabuf_lock);
179 		gem_obj->base.dma_buf = NULL;
180 		dmabuf_obj_put(obj);
181 		mutex_unlock(&vgpu->dmabuf_lock);
182 	} else {
183 		/* vgpu is NULL, as it has been removed already */
184 		gem_obj->base.dma_buf = NULL;
185 		dmabuf_obj_put(obj);
186 	}
187 }
188 
189 static const struct drm_i915_gem_object_ops intel_vgpu_gem_ops = {
190 	.name = "i915_gem_object_vgpu",
191 	.flags = I915_GEM_OBJECT_IS_PROXY,
192 	.get_pages = vgpu_gem_get_pages,
193 	.put_pages = vgpu_gem_put_pages,
194 	.release = vgpu_gem_release,
195 };
196 
197 static struct drm_i915_gem_object *vgpu_create_gem(struct drm_device *dev,
198 		struct intel_vgpu_fb_info *info)
199 {
200 	static struct lock_class_key lock_class;
201 	struct drm_i915_private *dev_priv = to_i915(dev);
202 	struct drm_i915_gem_object *obj;
203 
204 	obj = i915_gem_object_alloc();
205 	if (obj == NULL)
206 		return NULL;
207 
208 	drm_gem_private_object_init(dev, &obj->base,
209 		roundup(info->size, PAGE_SIZE));
210 	i915_gem_object_init(obj, &intel_vgpu_gem_ops, &lock_class, 0);
211 	i915_gem_object_set_readonly(obj);
212 
213 	obj->read_domains = I915_GEM_DOMAIN_GTT;
214 	obj->write_domain = 0;
215 	if (GRAPHICS_VER(dev_priv) >= 9) {
216 		unsigned int tiling_mode = 0;
217 		unsigned int stride = 0;
218 
219 		switch (info->drm_format_mod) {
220 		case DRM_FORMAT_MOD_LINEAR:
221 			tiling_mode = I915_TILING_NONE;
222 			break;
223 		case I915_FORMAT_MOD_X_TILED:
224 			tiling_mode = I915_TILING_X;
225 			stride = info->stride;
226 			break;
227 		case I915_FORMAT_MOD_Y_TILED:
228 		case I915_FORMAT_MOD_Yf_TILED:
229 			tiling_mode = I915_TILING_Y;
230 			stride = info->stride;
231 			break;
232 		default:
233 			gvt_dbg_core("invalid drm_format_mod %llx for tiling\n",
234 				     info->drm_format_mod);
235 		}
236 		obj->tiling_and_stride = tiling_mode | stride;
237 	} else {
238 		obj->tiling_and_stride = info->drm_format_mod ?
239 					I915_TILING_X : 0;
240 	}
241 
242 	return obj;
243 }
244 
245 static bool validate_hotspot(struct intel_vgpu_cursor_plane_format *c)
246 {
247 	if (c && c->x_hot <= c->width && c->y_hot <= c->height)
248 		return true;
249 	else
250 		return false;
251 }
252 
253 static int vgpu_get_plane_info(struct drm_device *dev,
254 		struct intel_vgpu *vgpu,
255 		struct intel_vgpu_fb_info *info,
256 		int plane_id)
257 {
258 	struct intel_vgpu_primary_plane_format p;
259 	struct intel_vgpu_cursor_plane_format c;
260 	int ret, tile_height = 1;
261 
262 	memset(info, 0, sizeof(*info));
263 
264 	if (plane_id == DRM_PLANE_TYPE_PRIMARY) {
265 		ret = intel_vgpu_decode_primary_plane(vgpu, &p);
266 		if (ret)
267 			return ret;
268 		info->start = p.base;
269 		info->start_gpa = p.base_gpa;
270 		info->width = p.width;
271 		info->height = p.height;
272 		info->stride = p.stride;
273 		info->drm_format = p.drm_format;
274 
275 		switch (p.tiled) {
276 		case PLANE_CTL_TILED_LINEAR:
277 			info->drm_format_mod = DRM_FORMAT_MOD_LINEAR;
278 			break;
279 		case PLANE_CTL_TILED_X:
280 			info->drm_format_mod = I915_FORMAT_MOD_X_TILED;
281 			tile_height = 8;
282 			break;
283 		case PLANE_CTL_TILED_Y:
284 			info->drm_format_mod = I915_FORMAT_MOD_Y_TILED;
285 			tile_height = 32;
286 			break;
287 		case PLANE_CTL_TILED_YF:
288 			info->drm_format_mod = I915_FORMAT_MOD_Yf_TILED;
289 			tile_height = 32;
290 			break;
291 		default:
292 			gvt_vgpu_err("invalid tiling mode: %x\n", p.tiled);
293 		}
294 	} else if (plane_id == DRM_PLANE_TYPE_CURSOR) {
295 		ret = intel_vgpu_decode_cursor_plane(vgpu, &c);
296 		if (ret)
297 			return ret;
298 		info->start = c.base;
299 		info->start_gpa = c.base_gpa;
300 		info->width = c.width;
301 		info->height = c.height;
302 		info->stride = c.width * (c.bpp / 8);
303 		info->drm_format = c.drm_format;
304 		info->drm_format_mod = 0;
305 		info->x_pos = c.x_pos;
306 		info->y_pos = c.y_pos;
307 
308 		if (validate_hotspot(&c)) {
309 			info->x_hot = c.x_hot;
310 			info->y_hot = c.y_hot;
311 		} else {
312 			info->x_hot = UINT_MAX;
313 			info->y_hot = UINT_MAX;
314 		}
315 	} else {
316 		gvt_vgpu_err("invalid plane id:%d\n", plane_id);
317 		return -EINVAL;
318 	}
319 
320 	info->size = info->stride * roundup(info->height, tile_height);
321 	if (info->size == 0) {
322 		gvt_vgpu_err("fb size is zero\n");
323 		return -EINVAL;
324 	}
325 
326 	if (info->start & (PAGE_SIZE - 1)) {
327 		gvt_vgpu_err("Not aligned fb address:0x%llx\n", info->start);
328 		return -EFAULT;
329 	}
330 
331 	if (!intel_gvt_ggtt_validate_range(vgpu, info->start, info->size)) {
332 		gvt_vgpu_err("invalid gma addr\n");
333 		return -EFAULT;
334 	}
335 
336 	return 0;
337 }
338 
339 static struct intel_vgpu_dmabuf_obj *
340 pick_dmabuf_by_info(struct intel_vgpu *vgpu,
341 		    struct intel_vgpu_fb_info *latest_info)
342 {
343 	struct list_head *pos;
344 	struct intel_vgpu_fb_info *fb_info;
345 	struct intel_vgpu_dmabuf_obj *dmabuf_obj = NULL;
346 	struct intel_vgpu_dmabuf_obj *ret = NULL;
347 
348 	list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
349 		dmabuf_obj = list_entry(pos, struct intel_vgpu_dmabuf_obj, list);
350 		if (!dmabuf_obj->info)
351 			continue;
352 
353 		fb_info = (struct intel_vgpu_fb_info *)dmabuf_obj->info;
354 		if ((fb_info->start == latest_info->start) &&
355 		    (fb_info->start_gpa == latest_info->start_gpa) &&
356 		    (fb_info->size == latest_info->size) &&
357 		    (fb_info->drm_format_mod == latest_info->drm_format_mod) &&
358 		    (fb_info->drm_format == latest_info->drm_format) &&
359 		    (fb_info->width == latest_info->width) &&
360 		    (fb_info->height == latest_info->height)) {
361 			ret = dmabuf_obj;
362 			break;
363 		}
364 	}
365 
366 	return ret;
367 }
368 
369 static struct intel_vgpu_dmabuf_obj *
370 pick_dmabuf_by_num(struct intel_vgpu *vgpu, u32 id)
371 {
372 	struct list_head *pos;
373 	struct intel_vgpu_dmabuf_obj *dmabuf_obj = NULL;
374 	struct intel_vgpu_dmabuf_obj *ret = NULL;
375 
376 	list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
377 		dmabuf_obj = list_entry(pos, struct intel_vgpu_dmabuf_obj, list);
378 		if (dmabuf_obj->dmabuf_id == id) {
379 			ret = dmabuf_obj;
380 			break;
381 		}
382 	}
383 
384 	return ret;
385 }
386 
387 static void update_fb_info(struct vfio_device_gfx_plane_info *gvt_dmabuf,
388 		      struct intel_vgpu_fb_info *fb_info)
389 {
390 	gvt_dmabuf->drm_format = fb_info->drm_format;
391 	gvt_dmabuf->drm_format_mod = fb_info->drm_format_mod;
392 	gvt_dmabuf->width = fb_info->width;
393 	gvt_dmabuf->height = fb_info->height;
394 	gvt_dmabuf->stride = fb_info->stride;
395 	gvt_dmabuf->size = fb_info->size;
396 	gvt_dmabuf->x_pos = fb_info->x_pos;
397 	gvt_dmabuf->y_pos = fb_info->y_pos;
398 	gvt_dmabuf->x_hot = fb_info->x_hot;
399 	gvt_dmabuf->y_hot = fb_info->y_hot;
400 }
401 
402 int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args)
403 {
404 	struct drm_device *dev = &vgpu->gvt->gt->i915->drm;
405 	struct vfio_device_gfx_plane_info *gfx_plane_info = args;
406 	struct intel_vgpu_dmabuf_obj *dmabuf_obj;
407 	struct intel_vgpu_fb_info fb_info;
408 	int ret = 0;
409 
410 	if (gfx_plane_info->flags == (VFIO_GFX_PLANE_TYPE_DMABUF |
411 				       VFIO_GFX_PLANE_TYPE_PROBE))
412 		return ret;
413 	else if ((gfx_plane_info->flags & ~VFIO_GFX_PLANE_TYPE_DMABUF) ||
414 			(!gfx_plane_info->flags))
415 		return -EINVAL;
416 
417 	ret = vgpu_get_plane_info(dev, vgpu, &fb_info,
418 					gfx_plane_info->drm_plane_type);
419 	if (ret != 0)
420 		goto out;
421 
422 	mutex_lock(&vgpu->dmabuf_lock);
423 	/* If exists, pick up the exposed dmabuf_obj */
424 	dmabuf_obj = pick_dmabuf_by_info(vgpu, &fb_info);
425 	if (dmabuf_obj) {
426 		update_fb_info(gfx_plane_info, &fb_info);
427 		gfx_plane_info->dmabuf_id = dmabuf_obj->dmabuf_id;
428 
429 		/* This buffer may be released between query_plane ioctl and
430 		 * get_dmabuf ioctl. Add the refcount to make sure it won't
431 		 * be released between the two ioctls.
432 		 */
433 		if (!dmabuf_obj->initref) {
434 			dmabuf_obj->initref = true;
435 			dmabuf_obj_get(dmabuf_obj);
436 		}
437 		ret = 0;
438 		gvt_dbg_dpy("vgpu%d: re-use dmabuf_obj ref %d, id %d\n",
439 			    vgpu->id, kref_read(&dmabuf_obj->kref),
440 			    gfx_plane_info->dmabuf_id);
441 		mutex_unlock(&vgpu->dmabuf_lock);
442 		goto out;
443 	}
444 
445 	mutex_unlock(&vgpu->dmabuf_lock);
446 
447 	/* Need to allocate a new one*/
448 	dmabuf_obj = kmalloc(sizeof(struct intel_vgpu_dmabuf_obj), GFP_KERNEL);
449 	if (unlikely(!dmabuf_obj)) {
450 		gvt_vgpu_err("alloc dmabuf_obj failed\n");
451 		ret = -ENOMEM;
452 		goto out;
453 	}
454 
455 	dmabuf_obj->info = kmalloc(sizeof(struct intel_vgpu_fb_info),
456 				   GFP_KERNEL);
457 	if (unlikely(!dmabuf_obj->info)) {
458 		gvt_vgpu_err("allocate intel vgpu fb info failed\n");
459 		ret = -ENOMEM;
460 		goto out_free_dmabuf;
461 	}
462 	memcpy(dmabuf_obj->info, &fb_info, sizeof(struct intel_vgpu_fb_info));
463 
464 	((struct intel_vgpu_fb_info *)dmabuf_obj->info)->obj = dmabuf_obj;
465 
466 	dmabuf_obj->vgpu = vgpu;
467 
468 	ret = idr_alloc(&vgpu->object_idr, dmabuf_obj, 1, 0, GFP_NOWAIT);
469 	if (ret < 0)
470 		goto out_free_info;
471 	gfx_plane_info->dmabuf_id = ret;
472 	dmabuf_obj->dmabuf_id = ret;
473 
474 	dmabuf_obj->initref = true;
475 
476 	kref_init(&dmabuf_obj->kref);
477 
478 	update_fb_info(gfx_plane_info, &fb_info);
479 
480 	INIT_LIST_HEAD(&dmabuf_obj->list);
481 	mutex_lock(&vgpu->dmabuf_lock);
482 	list_add_tail(&dmabuf_obj->list, &vgpu->dmabuf_obj_list_head);
483 	mutex_unlock(&vgpu->dmabuf_lock);
484 
485 	gvt_dbg_dpy("vgpu%d: %s new dmabuf_obj ref %d, id %d\n", vgpu->id,
486 		    __func__, kref_read(&dmabuf_obj->kref), ret);
487 
488 	return 0;
489 
490 out_free_info:
491 	kfree(dmabuf_obj->info);
492 out_free_dmabuf:
493 	kfree(dmabuf_obj);
494 out:
495 	/* ENODEV means plane isn't ready, which might be a normal case. */
496 	return (ret == -ENODEV) ? 0 : ret;
497 }
498 
499 /* To associate an exposed dmabuf with the dmabuf_obj */
500 int intel_vgpu_get_dmabuf(struct intel_vgpu *vgpu, unsigned int dmabuf_id)
501 {
502 	struct drm_device *dev = &vgpu->gvt->gt->i915->drm;
503 	struct intel_vgpu_dmabuf_obj *dmabuf_obj;
504 	struct drm_i915_gem_object *obj;
505 	struct dma_buf *dmabuf;
506 	int dmabuf_fd;
507 	int ret = 0;
508 
509 	mutex_lock(&vgpu->dmabuf_lock);
510 
511 	dmabuf_obj = pick_dmabuf_by_num(vgpu, dmabuf_id);
512 	if (dmabuf_obj == NULL) {
513 		gvt_vgpu_err("invalid dmabuf id:%d\n", dmabuf_id);
514 		ret = -EINVAL;
515 		goto out;
516 	}
517 
518 	obj = vgpu_create_gem(dev, dmabuf_obj->info);
519 	if (obj == NULL) {
520 		gvt_vgpu_err("create gvt gem obj failed\n");
521 		ret = -ENOMEM;
522 		goto out;
523 	}
524 
525 	obj->gvt_info = dmabuf_obj->info;
526 
527 	dmabuf = i915_gem_prime_export(&obj->base, DRM_CLOEXEC | DRM_RDWR);
528 	if (IS_ERR(dmabuf)) {
529 		gvt_vgpu_err("export dma-buf failed\n");
530 		ret = PTR_ERR(dmabuf);
531 		goto out_free_gem;
532 	}
533 
534 	ret = dma_buf_fd(dmabuf, DRM_CLOEXEC | DRM_RDWR);
535 	if (ret < 0) {
536 		gvt_vgpu_err("create dma-buf fd failed ret:%d\n", ret);
537 		goto out_free_dmabuf;
538 	}
539 	dmabuf_fd = ret;
540 
541 	dmabuf_obj_get(dmabuf_obj);
542 
543 	if (dmabuf_obj->initref) {
544 		dmabuf_obj->initref = false;
545 		dmabuf_obj_put(dmabuf_obj);
546 	}
547 
548 	mutex_unlock(&vgpu->dmabuf_lock);
549 
550 	gvt_dbg_dpy("vgpu%d: dmabuf:%d, dmabuf ref %d, fd:%d\n"
551 		    "        file count: %ld, GEM ref: %d\n",
552 		    vgpu->id, dmabuf_obj->dmabuf_id,
553 		    kref_read(&dmabuf_obj->kref),
554 		    dmabuf_fd,
555 		    file_count(dmabuf->file),
556 		    kref_read(&obj->base.refcount));
557 
558 	i915_gem_object_put(obj);
559 
560 	return dmabuf_fd;
561 
562 out_free_dmabuf:
563 	dma_buf_put(dmabuf);
564 out_free_gem:
565 	i915_gem_object_put(obj);
566 out:
567 	mutex_unlock(&vgpu->dmabuf_lock);
568 	return ret;
569 }
570 
571 void intel_vgpu_dmabuf_cleanup(struct intel_vgpu *vgpu)
572 {
573 	struct list_head *pos, *n;
574 	struct intel_vgpu_dmabuf_obj *dmabuf_obj;
575 
576 	mutex_lock(&vgpu->dmabuf_lock);
577 	list_for_each_safe(pos, n, &vgpu->dmabuf_obj_list_head) {
578 		dmabuf_obj = list_entry(pos, struct intel_vgpu_dmabuf_obj, list);
579 		dmabuf_obj->vgpu = NULL;
580 
581 		idr_remove(&vgpu->object_idr, dmabuf_obj->dmabuf_id);
582 		list_del(pos);
583 
584 		/* dmabuf_obj might be freed in dmabuf_obj_put */
585 		if (dmabuf_obj->initref) {
586 			dmabuf_obj->initref = false;
587 			dmabuf_obj_put(dmabuf_obj);
588 		}
589 
590 	}
591 	mutex_unlock(&vgpu->dmabuf_lock);
592 }
593