[Intel-gfx] [PATCH] drm/i915: Assert that the context pin_counts do not overflow

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> This should be impossible, but let's assert that we do not pin a context
> 4 billion times before retiring!
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_lrc.c        | 1 +
>  drivers/gpu/drm/i915/intel_ringbuffer.c | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 32ec06245281..77574dfc48ef 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -747,6 +747,7 @@ static int execlists_context_pin(struct intel_engine_cs *engine,
>  
>  	if (ce->pin_count++)
>  		return 0;
> +	GEM_BUG_ON(ce->pin_count); /* no overflow please! */
>

!ce->pin_count?
-Mika

>  	if (!ce->state) {
>  		ret = execlists_context_deferred_alloc(ctx, engine);
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index e895c99f5dd9..758191e69403 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -1445,6 +1445,7 @@ static int intel_ring_context_pin(struct intel_engine_cs *engine,
>  
>  	if (ce->pin_count++)
>  		return 0;
> +	GEM_BUG_ON(ce->pin_count); /* no overflow please! */
>  
>  	if (ce->state) {
>  		ret = context_pin(ctx);
> -- 
> 2.11.0
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx