linux-kernel - Re: [PATCH 1/3] resource: Add resource set range and size helpers

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Date: Wed, 12 Jun 2024 15:48:51 +0200
From: Philipp Stanner <pstanner@...hat.com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,  Bjorn
 Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org, Lorenzo Pieralisi
 <lpieralisi@...nel.org>,  Rob Herring <robh@...nel.org>, Krzysztof
 Wilczyński <kw@...ux.com>,  linux-kernel@...r.kernel.org
Cc: Jonathan Hunter <jonathanh@...dia.com>, 
	linux-arm-kernel@...ts.infradead.org, linux-tegra@...r.kernel.org, Robert
	Richter <rric@...nel.org>, Thierry Reding <thierry.reding@...il.com>
Subject: Re: [PATCH 1/3] resource: Add resource set range and size helpers

On Wed, 2024-06-12 at 11:56 +0300, Ilpo Järvinen 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. 

"open coded"? 

How about "coded manually unlike [...]"

> Also, almost all callsites that
> calculate end address for a resource also set the start address right

"an end address" or "the end address"?

> 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.

"note"? I don't fully get that sentence.


Looks like a cool little improvement otherwise :)


P.

> 
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
> ---
>  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;