Re: [PATCH v3] drm/i915: Implement dma-buf mmap() for userspace access

From: Daniel Vetter <daniel@ffwll.ch>
To: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Cc: Ander Conselvan de Oliveira
	<ander.conselvan.de.oliveira@intel.com>,
	intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH v3] drm/i915: Implement dma-buf mmap() for userspace access
Date: Thu, 19 Jun 2014 14:37:01 +0200	[thread overview]
Message-ID: <20140619123701.GT5821@phenom.ffwll.local> (raw)
In-Reply-To: <1403181274-7167-1-git-send-email-conselvan2@gmail.com>

On Thu, Jun 19, 2014 at 03:34:34PM +0300, Ander Conselvan de Oliveira wrote:
> From: Rob Bradford <rob@linux.intel.com>
> 
> The aim is that this is functionally equivalent to using the
> I915_GEM_MMAP ioctl.
> 
> v2: Add aperture check limit, limit to SNB+ and improve error handling.
> 
> v3 (anderco): Map without using the GTT.

Why that? This means you'll have a non-coherent mapping and atm dma-buf
doesn't expose and invalidate/flushing ioctls. Which really you want for
this.
-Daniel

> 
> Signed-off-by: Rob Bradford <rob@linux.intel.com>
> Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_dmabuf.c | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> index 580aa42..2d31fca 100644
> --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> @@ -193,7 +193,24 @@ static void i915_gem_dmabuf_kunmap(struct dma_buf *dma_buf, unsigned long page_n
>  
>  static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
>  {
> -	return -EINVAL;
> +	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
> +	struct drm_device *dev = obj->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	int ret;
> +
> +	if (INTEL_INFO(dev)->gen < 6)
> +		return -EINVAL;
> +
> +	ret = i915_mutex_lock_interruptible(dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = obj->base.filp->f_op->mmap(obj->base.filp, vma);
> +	fput(vma->vm_file);
> +	vma->vm_file = get_file(obj->base.filp);
> +
> +	mutex_unlock(&dev->struct_mutex);
> +	return ret;
>  }
>  
>  static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t length, enum dma_data_direction direction)
> -- 
> 1.8.3.2
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch