linux-kernel - Re: [PATCH v2 2/2] misc: sram: Generate unique names for subpools

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Message-ID: <e41ff013-8224-1b96-5cd3-f0632d27191d@gmail.com>
Date:   Mon, 19 Jun 2023 00:33:56 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Rob Herring <robh@...nel.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] misc: sram: Generate unique names for subpools

21.04.2023 00:17, Linus Walleij пишет:
> The current code will, if we do not specify unique labels
> for the SRAM subnodes, fail to register several nodes named
> the same.
> 
> Example:
> 
> sram@...20000 {
>   (...)
>   sram@0 {
>     (...)
>   };
>   sram@...0 {
>     (...)
>   };
> };
> 
> Since the child->name in both cases will be "sram" the
> gen_pool_create() will fail because the name is not unique.
> 
> Use dev_name() for the device as this will have bus ID
> set to the fully translated address for the node, and that
> will always be unique.
> 
> Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
> ---
> ChangeLog v1->v2:
> - Stop complicating things and just use dev_name()
> ---
>  drivers/misc/sram.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
> index f0e7f02605eb..f80c3adddf0b 100644
> --- a/drivers/misc/sram.c
> +++ b/drivers/misc/sram.c
> @@ -240,10 +240,11 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res)
>  				goto err_chunks;
>  			}
>  			if (!label)
> -				label = child->name;
> -
> -			block->label = devm_kstrdup(sram->dev,
> -						    label, GFP_KERNEL);
> +				block->label = devm_kasprintf(sram->dev, GFP_KERNEL,
> +							      "%s", dev_name(sram->dev));

This broke device-trees that have no label property. The SRAM DT binding
says:

"
label:
description:
	The name for the reserved partition, if omitted, the label is taken
	from the node name excluding the unit address.
"

Not sure whether breakage was on purpose, otherwise doc needs to be
updated or there should be explicit check for the duplicated node names.

Secondly, AFAICS, the dev_name(sram->dev) is the name of the parent SRAM
device and not of the children sub-nodes, hence it's now always the same
dev_name(sram->dev) for all sub-nodes.