drivers/gpu/drm/i915/i915_gem_ww.c

   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
   9 void 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
  17 static 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
  28 void 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
  35 void 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
  42 int __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 }