[Intel-gfx] [PATCH] drm/shmem-helper: Fix obj->filp derefence

[Thomas Zimmermann]

Hi,

as discussed on IRC, we still need this patch.

Am 15.06.20 um 17:10 schrieb Daniel Vetter:
> I broke that in my refactoring:
> 
> commit 7d2cd72a9aa3df3604cafd169a2d4a525afb68ca
> Author: Daniel Vetter <daniel.vetter at ffwll.ch>
> Date:   Fri May 29 16:05:42 2020 +0200
> 
>     drm/shmem-helpers: Simplify dma-buf importing
> 
> Reported-by: Thomas Zimmermann <tzimmermann at suse.de>
> Fixes: 7d2cd72a9aa3 ("drm/shmem-helpers: Simplify dma-buf importing")
> Cc: Boris Brezillon <boris.brezillon at collabora.com>
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: Gerd Hoffmann <kraxel at redhat.com>
> Cc: Rob Herring <robh at kernel.org>
> Cc: Noralf Trønnes <noralf at tronnes.org>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  drivers/gpu/drm/drm_gem_shmem_helper.c | 20 +++++++++++---------
>  1 file changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> index 0a7e3b664bc2..3e7ee407a17c 100644
> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> @@ -70,15 +70,17 @@ __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private)
>  	mutex_init(&shmem->vmap_lock);
>  	INIT_LIST_HEAD(&shmem->madv_list);
>  
> -	/*
> -	 * Our buffers are kept pinned, so allocating them
> -	 * from the MOVABLE zone is a really bad idea, and
> -	 * conflicts with CMA. See comments above new_inode()
> -	 * why this is required _and_ expected if you're
> -	 * going to pin these pages.
> -	 */
> -	mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
> -			     __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
> +	if (!private) {

I would test for (obj->filp) here, because it's what the branch depends
on. Your choice. In any case

Tested-by: Thomas Zimmermann <tzimmermann at suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann at suse.de>


> +		/*
> +		 * Our buffers are kept pinned, so allocating them
> +		 * from the MOVABLE zone is a really bad idea, and
> +		 * conflicts with CMA. See comments above new_inode()
> +		 * why this is required _and_ expected if you're
> +		 * going to pin these pages.
> +		 */
> +		mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
> +				     __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
> +	}
>  
>  	return shmem;
>  
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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