Re: [PATCH 2/7] drm/i915: Check context status before looking up our obj/vma

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

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

> Since we keep the context around across the slow lookup where we may
> drop the struct_mutex, we should double check that the context is still
> valid upon reacquisition.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 359d5dc6d8df..044fb1205554 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -679,13 +679,6 @@ static int eb_select_context(struct i915_execbuffer *eb)
>  	if (unlikely(!ctx))
>  		return -ENOENT;
>  
> -	if (unlikely(i915_gem_context_is_banned(ctx))) {
> -		DRM_DEBUG("Context %u tried to submit while banned\n",
> -			  ctx->user_handle);
> -		i915_gem_context_put(ctx);
> -		return -EIO;
> -	}
> -
>  	eb->ctx = ctx;
>  	eb->vm = ctx->ppgtt ? &ctx->ppgtt->base : &eb->i915->ggtt.base;
>  
> @@ -707,6 +700,12 @@ static int eb_lookup_vmas(struct i915_execbuffer *eb)
>  	int slow_pass = -1;
>  	int err;
>  
> +	if (unlikely(i915_gem_context_is_closed(eb->ctx)))
> +		return -ENOENT;
> +
> +	if (unlikely(i915_gem_context_is_banned(eb->ctx)))
> +		return -EIO;
> +

We are referring the lut before the context has been validated.
Not that it matters but for style, please consider assigning
the lut after the context check.

Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>

>  	INIT_LIST_HEAD(&eb->relocs);
>  	INIT_LIST_HEAD(&eb->unbound);
>  
> -- 
> 2.13.3
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