[Intel-gfx] [PATCH 2/2] drm/i915: Handle vm_mmap error during I915_GEM_MMAP ioctl with WC set

[Tvrtko Ursulin]

On 07/01/2019 08:56, Joonas Lahtinen wrote:
> Add err goto label and use it when VMA can't be established or changes
> underneath.
> 
> Fixes: 1816f9236303 ("drm/i915: Support creation of unbound wc user mappings for objects")
> Reported-by: Adam Zabrocki <adamza at microsoft.com>
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: <stable at vger.kernel.org> # v4.0+
> Cc: Akash Goel <akash.goel at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Cc: Adam Zabrocki <adamza at microsoft.com>
> ---
>   drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index f1d594a53978..97cbc0e27e3e 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1738,6 +1738,9 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   	addr = vm_mmap(obj->base.filp, 0, args->size,
>   		       PROT_READ | PROT_WRITE, MAP_SHARED,
>   		       args->offset);
> +	if (IS_ERR((void *)addr))
> +		goto err;
> +
>   	if (args->flags & I915_MMAP_WC) {
>   		struct mm_struct *mm = current->mm;
>   		struct vm_area_struct *vma;
> @@ -1753,17 +1756,22 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   		else
>   			addr = -ENOMEM;
>   		up_write(&mm->mmap_sem);
> +		if (IS_ERR((void *)addr))
> +			goto err;
>   
>   		/* This may race, but that's ok, it only gets set */
>   		WRITE_ONCE(obj->frontbuffer_ggtt_origin, ORIGIN_CPU);
>   	}
>   	i915_gem_object_put(obj);
> -	if (IS_ERR((void *)addr))
> -		return addr;
>   
>   	args->addr_ptr = (uint64_t) addr;
>   
>   	return 0;
> +
> +err:
> +	i915_gem_object_put(obj);
> +
> +	return addr;
>   }
>   
>   static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
> 

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko