Re: [PATCH] Export tiny shmem_file_setup for DRM-GEM

[Dave Airlie <airlied@redhat.com>]

On Sun, 2008-10-19 at 12:52 +0100, Hugh Dickins wrote:
> We're trying to keep the !CONFIG_SHMEM tiny-shmem.c (using ramfs without
> swap) in synch with CONFIG_SHMEM shmem.c (and mpm is preparing patches
> to combine them).  I was glad to see EXPORT_SYMBOL_GPL(shmem_file_setup)
> go into shmem.c, but why not support DRM-GEM when !CONFIG_SHMEM too?
> But caution says still depend on MMU, since !CONFIG_MMU is.. different.
> 
> Signed-off-by: Hugh Dickins <hugh@veritas.com>

Acked-by: Dave Airlie <airlied@redhat.com>


> ---
> I should admit that I've not actually tested this patch,
> but can't imagine why it would be a problem: if you gobble
> up too much RAM, well, that's just life with tiny-shmem.
> 
> I did promise a patch to make read_mapping_page() return -EINVAL instead
> of oopsing when the underlying filesystem doesn't support it.  But that
> was when people were trying to persuade GEM to map files on whatever fs:
> I can't now see the point of such a patch while you're known to be on
> tmpfs or ramfs, and intending later to use a new interface from Nick.
> 
>  drivers/gpu/drm/Kconfig |    2 +-
>  mm/tiny-shmem.c         |    1 +
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -6,7 +6,7 @@
>  #
>  menuconfig DRM
>  	tristate "Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)"
> -	depends on (AGP || AGP=n) && PCI && !EMULATED_CMPXCHG && SHMEM
> +	depends on (AGP || AGP=n) && PCI && !EMULATED_CMPXCHG && MMU
>  	help
>  	  Kernel-level support for the Direct Rendering Infrastructure (DRI)
>  	  introduced in XFree86 4.0. If you say Y here, you need to select
> --- a/mm/tiny-shmem.c
> +++ b/mm/tiny-shmem.c
> @@ -95,6 +95,7 @@ put_dentry:
>  put_memory:
>  	return ERR_PTR(error);
>  }
> +EXPORT_SYMBOL_GPL(shmem_file_setup);
>  
>  /**
>   * shmem_zero_setup - setup a shared anonymous mapping