Hi Nirmoy,
On Tue, Apr 23, 2024 at 11:02:06AM +0200, Nirmoy Das wrote:
> On 4/17/2024 12:49 AM, Andi Shyti wrote:
...
> void intel_engines_driver_register(struct drm_i915_private *i915)
> {
> - u16 name_instance, other_instance = 0;
> + u16 class_instance[I915_LAST_UABI_ENGINE_CLASS + 2] = { };
>
> +2 is confusing here. I think we need a better macro.
This is to avoid buffer overflow, otherwise we will always hit
the GEM_BUG_ON below.
> struct legacy_ring ring = {};
> struct list_head *it, *next;
> struct rb_node **p, *prev;
...
> + GEM_BUG_ON(uabi_class >=
> + ARRAY_SIZE(i915->engine_uabi_class_count));
> + i915->engine_uabi_class_count[uabi_class]++;
>
> Shouldn't this be i915->engine_uabi_class_count[uabi_class] = class_instance
> [uabi_class]; ?
that's mostly a counter, we don't really need to be on sync with
the real instance of the engines.
> What I see is that this patch mainly adding this class_instance array and rest
> looks the same.
> May be it make sense to add other upcoming patches to better understand why we
> need this patch.
yes, this patch simplifies the coming patches and the logic
inside, as well.
I just wanted to anticipate some of the refactorings so that we
could speed up the reviews. There is no functional change in
here, that's why I thought it was harmless.
Thanks for taking a look into it.
Andi
