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(ctx: &ww->ctx, ww_class: &reservation_ww_class);
12 INIT_LIST_HEAD(list: &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(entry: &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(entry: &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(ctx: &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(obj: ww->contended->base.resv, ctx: &ww->ctx);
52 else
53 dma_resv_lock_slow(obj: ww->contended->base.resv, ctx: &ww->ctx);
54
55 if (!ret)
56 list_add_tail(new: &ww->contended->obj_link, head: &ww->obj_list);
57 else
58 i915_gem_object_put(obj: ww->contended);
59
60 ww->contended = NULL;
61
62 return ret;
63}
64