linux-kernel - Re: [PATCH v4 06/11] drm/ttm: factor out ttm_bo_mmap_vma

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Message-ID: <c08921f8-8ae9-55aa-c472-6b660b96576b@amd.com>
Date:   Wed, 16 Oct 2019 12:18:15 +0000
From:   "Koenig, Christian" <Christian.Koenig@....com>
To:     Gerd Hoffmann <kraxel@...hat.com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>
CC:     Thomas Zimmermann <tzimmermann@...e.de>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        "Huang, Ray" <Ray.Huang@....com>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 06/11] drm/ttm: factor out ttm_bo_mmap_vma_setup

Am 16.10.19 um 13:51 schrieb Gerd Hoffmann:
> Factor out ttm vma setup to a new function.
> Reduces code duplication a bit.
>
> v2: don't change vm_flags (moved to separate patch).
> v4: make ttm_bo_mmap_vma_setup static.
>
> Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>

Reviewed-by: Christian König <christian.koenig@....com> for this one and 
#7 in the series.

> ---
>   drivers/gpu/drm/ttm/ttm_bo_vm.c | 46 +++++++++++++++++----------------
>   1 file changed, 24 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> index 4aa007edffb0..53345c0854d5 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> @@ -426,6 +426,28 @@ static struct ttm_buffer_object *ttm_bo_vm_lookup(struct ttm_bo_device *bdev,
>   	return bo;
>   }
>   
> +static void ttm_bo_mmap_vma_setup(struct ttm_buffer_object *bo, struct vm_area_struct *vma)
> +{
> +	vma->vm_ops = &ttm_bo_vm_ops;
> +
> +	/*
> +	 * Note: We're transferring the bo reference to
> +	 * vma->vm_private_data here.
> +	 */
> +
> +	vma->vm_private_data = bo;
> +
> +	/*
> +	 * We'd like to use VM_PFNMAP on shared mappings, where
> +	 * (vma->vm_flags & VM_SHARED) != 0, for performance reasons,
> +	 * but for some reason VM_PFNMAP + x86 PAT + write-combine is very
> +	 * bad for performance. Until that has been sorted out, use
> +	 * VM_MIXEDMAP on all mappings. See freedesktop.org bug #75719
> +	 */
> +	vma->vm_flags |= VM_MIXEDMAP;
> +	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
> +}
> +
>   int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
>   		struct ttm_bo_device *bdev)
>   {
> @@ -449,24 +471,7 @@ int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
>   	if (unlikely(ret != 0))
>   		goto out_unref;
>   
> -	vma->vm_ops = &ttm_bo_vm_ops;
> -
> -	/*
> -	 * Note: We're transferring the bo reference to
> -	 * vma->vm_private_data here.
> -	 */
> -
> -	vma->vm_private_data = bo;
> -
> -	/*
> -	 * We'd like to use VM_PFNMAP on shared mappings, where
> -	 * (vma->vm_flags & VM_SHARED) != 0, for performance reasons,
> -	 * but for some reason VM_PFNMAP + x86 PAT + write-combine is very
> -	 * bad for performance. Until that has been sorted out, use
> -	 * VM_MIXEDMAP on all mappings. See freedesktop.org bug #75719
> -	 */
> -	vma->vm_flags |= VM_MIXEDMAP;
> -	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
> +	ttm_bo_mmap_vma_setup(bo, vma);
>   	return 0;
>   out_unref:
>   	ttm_bo_put(bo);
> @@ -481,10 +486,7 @@ int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
>   
>   	ttm_bo_get(bo);
>   
> -	vma->vm_ops = &ttm_bo_vm_ops;
> -	vma->vm_private_data = bo;
> -	vma->vm_flags |= VM_MIXEDMAP;
> -	vma->vm_flags |= VM_IO | VM_DONTEXPAND;
> +	ttm_bo_mmap_vma_setup(bo, vma);
>   	return 0;
>   }
>   EXPORT_SYMBOL(ttm_fbdev_mmap);