target/linux/brcm2708/patches-4.4/0540-drm-vc4-Use-drm_gem_object_unreference_unlocked.patch

   1 From 180aed47cc2cc41b8669e9e6c61f79bf1b018fed Mon Sep 17 00:00:00 2001
   2 From: Daniel Vetter <daniel.vetter@ffwll.ch>
   3 Date: Mon, 30 May 2016 19:53:06 +0200
   4 Subject: [PATCH] drm/vc4: Use drm_gem_object_unreference_unlocked
   5
   6 Since my last struct_mutex crusade someone escaped!
   7
   8 This already has the advantage that for the common case when someone
   9 else holds a ref the unref won't even acquire dev->struct_mutex. And
  10 I'm working on code to allow drivers to completely opt-out of any and
  11 all dev->struct_mutex usage, but that only works if they use the
  12 _unlocked variants everywhere.
  13
  14 v2: Drop comment too.
  15
  16 v3: Drop the other comment too.
  17
  18 Cc: Eric Anholt <eric@anholt.net>
  19 Reviewed-by: Eric Anholt <eric@anholt.net>
  20 Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
  21 Link: http://patchwork.freedesktop.org/patch/msgid/1464630800-30786-15-git-send-email-daniel.vetter@ffwll.ch
  22 (cherry picked from commit db3697295cf4da1356e3ec86761d464d6d013b48)
  23 ---
  24  drivers/gpu/drm/vc4/vc4_bo.c  |  2 --
  25  drivers/gpu/drm/vc4/vc4_gem.c | 11 +++--------
  26  2 files changed, 3 insertions(+), 10 deletions(-)
  27
  28 --- a/drivers/gpu/drm/vc4/vc4_bo.c
  29 +++ b/drivers/gpu/drm/vc4/vc4_bo.c
  30 @@ -311,8 +311,6 @@ static void vc4_bo_cache_free_old(struct
  31
  32  /* Called on the last userspace/kernel unreference of the BO.  Returns
  33   * it to the BO cache if possible, otherwise frees it.
  34 - *
  35 - * Note that this is called with the struct_mutex held.
  36   */
  37  void vc4_free_object(struct drm_gem_object *gem_bo)
  38  {
  39 --- a/drivers/gpu/drm/vc4/vc4_gem.c
  40 +++ b/drivers/gpu/drm/vc4/vc4_gem.c
  41 @@ -67,10 +67,8 @@ vc4_free_hang_state(struct drm_device *d
  42  {
  43         unsigned int i;
  44
  45 -       mutex_lock(&dev->struct_mutex);
  46         for (i = 0; i < state->user_state.bo_count; i++)
  47 -               drm_gem_object_unreference(state->bo[i]);
  48 -       mutex_unlock(&dev->struct_mutex);
  49 +               drm_gem_object_unreference_unlocked(state->bo[i]);
  50
  51         kfree(state);
  52  }
  53 @@ -711,11 +709,9 @@ vc4_complete_exec(struct drm_device *dev
  54         struct vc4_dev *vc4 = to_vc4_dev(dev);
  55         unsigned i;
  56
  57 -       /* Need the struct lock for drm_gem_object_unreference(). */
  58 -       mutex_lock(&dev->struct_mutex);
  59         if (exec->bo) {
  60                 for (i = 0; i < exec->bo_count; i++)
  61 -                       drm_gem_object_unreference(&exec->bo[i]->base);
  62 +                       drm_gem_object_unreference_unlocked(&exec->bo[i]->base);
  63                 kfree(exec->bo);
  64         }
  65
  66 @@ -723,9 +719,8 @@ vc4_complete_exec(struct drm_device *dev
  67                 struct vc4_bo *bo = list_first_entry(&exec->unref_list,
  68                                                      struct vc4_bo, unref_head);
  69                 list_del(&bo->unref_head);
  70 -               drm_gem_object_unreference(&bo->base.base);
  71 +               drm_gem_object_unreference_unlocked(&bo->base.base);
  72         }
  73 -       mutex_unlock(&dev->struct_mutex);
  74
  75         mutex_lock(&vc4->power_lock);
  76         if (--vc4->power_refcount == 0) {