1// SPDX-License-Identifier: MIT
2/*
3 * Copyright �� 2020 Intel Corporation
4 */
5#include <linux/dma-resv.h>
6#include "i915_gem_ww.h"
7#include "gem/i915_gem_object.h"
8
9void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ww, bool intr)
10{
11	ww_acquire_init(&ww->ctx, &reservation_ww_class);
12	INIT_LIST_HEAD(&ww->obj_list);
13	ww->intr = intr;
14	ww->contended = NULL;
15}
16
17static void i915_gem_ww_ctx_unlock_all(struct i915_gem_ww_ctx *ww)
18{
19	struct drm_i915_gem_object *obj;
20
21	while ((obj = list_first_entry_or_null(&ww->obj_list, struct drm_i915_gem_object, obj_link))) {
22		list_del(&obj->obj_link);
23		i915_gem_object_unlock(obj);
24		i915_gem_object_put(obj);
25	}
26}
27
28void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj)
29{
30	list_del(&obj->obj_link);
31	i915_gem_object_unlock(obj);
32	i915_gem_object_put(obj);
33}
34
35void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ww)
36{
37	i915_gem_ww_ctx_unlock_all(ww);
38	WARN_ON(ww->contended);
39	ww_acquire_fini(&ww->ctx);
40}
41
42int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ww)
43{
44	int ret = 0;
45
46	if (WARN_ON(!ww->contended))
47		return -EINVAL;
48
49	i915_gem_ww_ctx_unlock_all(ww);
50	if (ww->intr)
51		ret = dma_resv_lock_slow_interruptible(ww->contended->base.resv, &ww->ctx);
52	else
53		dma_resv_lock_slow(ww->contended->base.resv, &ww->ctx);
54
55	if (!ret)
56		list_add_tail(&ww->contended->obj_link, &ww->obj_list);
57	else
58		i915_gem_object_put(ww->contended);
59
60	ww->contended = NULL;
61
62	return ret;
63}
64