[Intel-gfx] [PATCH 07/15] drm/i915: Move object close under its own lock

[Matthew Auld]

On Mon, 3 Jun 2019 at 15:00, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>
> Use i915_gem_object_lock() to guard the LUT and active reference to
> allow us to break free of struct_mutex for handling GEM_CLOSE.
>
> Testcase: igt/gem_close_race
> Testcase: igt/gem_exec_parallel
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_context.c   | 75 ++++++++++---------
>  .../gpu/drm/i915/gem/i915_gem_context_types.h | 12 +--
>  .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 25 +++++--
>  drivers/gpu/drm/i915/gem/i915_gem_object.c    | 38 ++++++----
>  .../gpu/drm/i915/gem/i915_gem_object_types.h  |  1 -
>  .../gpu/drm/i915/gem/selftests/mock_context.c |  1 -
>  drivers/gpu/drm/i915/i915_drv.h               |  4 +-
>  drivers/gpu/drm/i915/i915_gem.c               |  1 +
>  drivers/gpu/drm/i915/i915_gem_gtt.c           |  1 +
>  drivers/gpu/drm/i915/i915_timeline.c          | 13 ++--
>  drivers/gpu/drm/i915/i915_vma.c               | 42 +++++++----
>  drivers/gpu/drm/i915/i915_vma.h               | 17 ++---
>  .../gpu/drm/i915/selftests/mock_gem_device.c  |  1 +
>  13 files changed, 131 insertions(+), 100 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index 08721ef62e4e..fb03a19932cf 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -95,24 +95,40 @@ void i915_lut_handle_free(struct i915_lut_handle *lut)
>
>  static void lut_close(struct i915_gem_context *ctx)
>  {
> -       struct i915_lut_handle *lut, *ln;
>         struct radix_tree_iter iter;
>         void __rcu **slot;
>
> -       list_for_each_entry_safe(lut, ln, &ctx->handles_list, ctx_link) {
> -               list_del(&lut->obj_link);
> -               i915_lut_handle_free(lut);
> -       }
> -       INIT_LIST_HEAD(&ctx->handles_list);
> +       lockdep_assert_held(&ctx->mutex);
>
>         rcu_read_lock();
>         radix_tree_for_each_slot(slot, &ctx->handles_vma, &iter, 0) {
>                 struct i915_vma *vma = rcu_dereference_raw(*slot);
> +               struct drm_i915_gem_object *obj = vma->obj;
> +               struct i915_lut_handle *lut;
> +
> +               rcu_read_unlock();
> +               i915_gem_object_lock(obj);
> +               list_for_each_entry(lut, &obj->lut_list, obj_link) {
> +                       if (lut->ctx != ctx)
> +                               continue;
>
> -               radix_tree_iter_delete(&ctx->handles_vma, &iter, slot);
> +                       if (lut->handle != iter.index)
> +                               continue;
>
> -               vma->open_count--;
> -               i915_vma_put(vma);
> +                       list_del(&lut->obj_link);
> +                       break;
> +               }
> +               i915_gem_object_unlock(obj);
> +               rcu_read_lock();
> +
> +               if (&lut->obj_link != &obj->lut_list) {

So mean.

Fwiw,
Reviewed-by: Matthew Auld <matthew.auld at intel.com>