On Mon, 29 Nov 2021 at 13:57, Maarten Lankhorst
<maarten.lankhorst@xxxxxxxxxxxxxxx> wrote:
>
> Big delta, but boils down to moving set_pages to i915_vma.c, and removing
> the special handling, all callers use the defaults anyway. We only remap
> in ggtt, so default case will fall through.
>
> Because we still don't require locking in i915_vma_unpin(), handle this by
> using xchg in get_pages(), as it's locked with obj->mutex, and cmpxchg in
> unpin, which only fails if we race a against a new pin.
>
> Changes since v1:
> - aliasing gtt sets ZERO_SIZE_PTR, not -ENODEV, remove special case
> from __i915_vma_get_pages(). (Matt)
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
<snip>
> +static int
> +__i915_vma_get_pages(struct i915_vma *vma)
> +{
> + struct sg_table *pages;
> + int ret;
> +
> + /*
> + * The vma->pages are only valid within the lifespan of the borrowed
> + * obj->mm.pages. When the obj->mm.pages sg_table is regenerated, so
> + * must be the vma->pages. A simple rule is that vma->pages must only
> + * be accessed when the obj->mm.pages are pinned.
> + */
> + GEM_BUG_ON(!i915_gem_object_has_pinned_pages(vma->obj));
> +
> + switch (vma->ggtt_view.type) {
> + default:
> + GEM_BUG_ON(vma->ggtt_view.type);
> + fallthrough;
> + case I915_GGTT_VIEW_NORMAL:
> + pages = vma->obj->mm.pages;
> + break;
> +
> + case I915_GGTT_VIEW_ROTATED:
> + pages =
> + intel_rotate_pages(&vma->ggtt_view.rotated, vma->obj);
> + break;
> +
> + case I915_GGTT_VIEW_REMAPPED:
> + pages =
> + intel_remap_pages(&vma->ggtt_view.remapped, vma->obj);
> + break;
> +
> + case I915_GGTT_VIEW_PARTIAL:
> + pages = intel_partial_pages(&vma->ggtt_view, vma->obj);
> + break;
> + }
> +
> + ret = 0;
> + if (IS_ERR(pages)) {
> + ret = PTR_ERR(pages);
> + pages = NULL;
> + drm_err(&vma->vm->i915->drm,
> + "Failed to get pages for VMA view type %u (%d)!\n",
> + vma->ggtt_view.type, ret);
> + }
> +
> + pages = xchg(&vma->pages, pages);
> +
> + /* did we race against a put_pages? */
> + if (pages && pages != vma->obj->mm.pages) {
> + sg_free_table(vma->pages);
> + kfree(vma->pages);
So should this one rather be:
sg_free_table(pages);
kfree(pages);
Or am I missing something?
