[Intel-gfx] [PATCH 1/4] drm/i915: Translate ENOSPC from shmem_get_page() to ENOMEM

[Barbalho, Rafael]

> -----Original Message-----
> From: Intel-gfx [mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf
> Of Chris Wilson
> Sent: Tuesday, March 25, 2014 1:23 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Hugh Dickins
> Subject: [Intel-gfx] [PATCH 1/4] drm/i915: Translate ENOSPC from
> shmem_get_page() to ENOMEM
> 
> shmemfs first checks if there is enough memory to allocate the page and
> reports ENOSPC should there be insufficient, along with the usual ENOMEM
> for a genuine allocation failure.
> 
> We use ENOSPC in our driver to mean that we have run out of aperture
> space and so want to translate the error from shmemfs back to our usual
> understanding of ENOMEM. None of the the other GEM users appear to
> distinguish between ENOMEM and ENOSPC in their error handling, hence it is
> easiest to do the fixup in i915.ko
> 
> Cc: Hugh Dickins <hughd at google.com>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Reviewed-by: Rafael Barbalho <rafael.barbalho at intel.com>

> ---
>  drivers/gpu/drm/i915/i915_gem.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> b/drivers/gpu/drm/i915/i915_gem.c index 33bbaa0d4412..c23034021753
> 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1976,7 +1976,19 @@ err_pages:
>  		page_cache_release(sg_page_iter_page(&sg_iter));
>  	sg_free_table(st);
>  	kfree(st);
> -	return PTR_ERR(page);
> +
> +	/* shmemfs first checks if there is enough memory to allocate the
> page
> +	 * and reports ENOSPC should there be insufficient, along with the
> usual
> +	 * ENOMEM for a genuine allocation failure.
> +	 *
> +	 * We use ENOSPC in our driver to mean that we have run out of
> aperture
> +	 * space and so want to translate the error from shmemfs back to our
> +	 * usual understanding of ENOMEM.
> +	 */
> +	if (PTR_ERR(page) == -ENOSPC)
> +		return -ENOMEM;
> +	else
> +		return PTR_ERR(page);
>  }
> 
>  /* Ensure that the associated pages are gathered from the backing storage
> --
> 1.9.1
> 
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