Re: [PATCH] drm/i915/execlists: Check for ce->state before destroy

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 22/06/2018 11:57, Chris Wilson wrote:
> As we may cancel the ce->state allocation during context pinning (but
> crucially after we mark ce as operational), that means we may be asked
> to destroy a nonexistent ce->state. Given the choice in handing a
> complex error path on pinning, and just ignoring the lack of state in
> destroy, choice the latter for simplicity.
> 
> Reported-by: Zhao Yakui <yakui.zhao@intel.com>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
>   drivers/gpu/drm/i915/intel_lrc.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 33bc914c2ef5..02ee3b12507f 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -1337,11 +1337,15 @@ static void execlists_schedule(struct i915_request *request,
>   
>   static void execlists_context_destroy(struct intel_context *ce)
>   {
> -	GEM_BUG_ON(!ce->state);
>   	GEM_BUG_ON(ce->pin_count);
>   
> +	if (!ce->state)
> +		return;

Or set ce->ops only after success in execlists_context_pin? Sounds 
simpler and more logical unless I am missing something.

> +
> +	GEM_BUG_ON(i915_gem_object_is_active(ce->state->obj));
> +
>   	intel_ring_free(ce->ring);
> -	__i915_gem_object_release_unless_active(ce->state->obj);
> +	i915_gem_object_put(ce->state->obj);

Hm this bit is unexpected. I don't see an immediate intersect with the 
commit message and previous change. Intuitively it makes sense that 
ce->state->obj can/must never be active once here - but then doesn't 
this second part belong in a separate patch?

Regards,

Tvrtko

>   }
>   
>   static void execlists_context_unpin(struct intel_context *ce)
> 
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