On Wed, 12 Jun 2024 11:56:27 +0300
Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote:
> Setting the end address for a resource with a given size lacks a helper
> and is therefore open coded unlike the getter side which has a helper
> for resource size calculation. Also, almost all callsites that
> calculate end address for a resource also set the start address right
> before it like this:
>
> res->start = start_addr;
> res->end = res->start + size - 1;
>
> Thus, add resource_set_range(res, start_addr, size) that sets the start
> address and calculates the end address to simplify this often repeated
> fragment. In addition, introduce resource_set_size() for the cases
> where setting the start address of the resource is not necessary but
> note resource_set_range() is preferred.
>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
We have a bunch of cases of this in CXL. Adding this helper seems like
a good idea to me.
I'm not sure the odd semantics of resource_set_size() are a good idea.
Maybe it could by naming hint that it's relying internally on
size already being set.
resource_update_size() for instance might make people think or perhaps
that's just more obscure. Meh, I've argued myself around to there
not being a better name.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>`
> ---
> include/linux/ioport.h | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/include/linux/ioport.h b/include/linux/ioport.h
> index db7fe25f3370..2a1d33ad151c 100644
> --- a/include/linux/ioport.h
> +++ b/include/linux/ioport.h
> @@ -216,6 +216,38 @@ struct resource *lookup_resource(struct resource *root, resource_size_t start);
> int adjust_resource(struct resource *res, resource_size_t start,
> resource_size_t size);
> resource_size_t resource_alignment(struct resource *res);
> +
> +/**
> + * resource_set_size - Calculates resource end address from size and start address
> + * @res: The resource descriptor
> + * @size: The size of the resource
> + *
> + * Calculates the end address for @res based on @size.
> + *
> + * Note: The start address of @res must be set when calling this function.
> + * Use resource_set_range() if setting both the start address and @size.
> + */
> +static inline void resource_set_size(struct resource *res, resource_size_t size)
> +{
> + res->end = res->start + size - 1;
> +}
> +
> +/**
> + * resource_set_range - Sets resource start and end addresses
> + * @res: The resource descriptor
> + * @start: The start address for the resource
> + * @size: The size of the resource
> + *
> + * Sets @res start address and calculates the end address based on @size.
> + */
> +static inline void resource_set_range(struct resource *res,
> + resource_size_t start,
> + resource_size_t size)
> +{
> + res->start = start;
> + resource_set_size(res, size);
> +}
> +
> static inline resource_size_t resource_size(const struct resource *res)
> {
> return res->end - res->start + 1;
