Re: [Xen-devel] [PATCH] cleancache: constify cleancache_ops structure

[David Vrabel]

On 23/12/15 21:06, Julia Lawall wrote:
> The cleancache_ops structure is never modified, so declare it as const.
> 
> This also removes the __read_mostly declaration on the cleancache_ops
> variable declaration, since it seems redundant with const.
> 
> Done with the help of Coccinelle.
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>
> 
> ---
> 
> Not sure that the __read_mostly change is correct.  Does it apply to the
> variable, or to what the variable points to?

The variable, so...

> --- a/mm/cleancache.c
> +++ b/mm/cleancache.c
> @@ -22,7 +22,7 @@
>   * cleancache_ops is set by cleancache_register_ops to contain the pointers
>   * to the cleancache "backend" implementation functions.
>   */
> -static struct cleancache_ops *cleancache_ops __read_mostly;
> +static const struct cleancache_ops *cleancache_ops;

...you want to retain the __read_mostly here.

David