linux-kernel - Re: [PATCH 2/2] nvmem: core: append offset to cell name in sysfs

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Message-ID: <20230731174506.00368411@xps-13>
Date:   Mon, 31 Jul 2023 17:45:06 +0200
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Daniel Golle <daniel@...rotopia.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] nvmem: core: append offset to cell name in sysfs

Hi Daniel,

daniel@...rotopia.org wrote on Tue, 18 Jul 2023 14:55:57 +0100:

> The device tree node names are not required to be unique. Append the
> offset to the name to make cell nodes with identical names become
> accessible via sysfs and avoid kernel stackdump caused by
> sysfs: cannot create duplicate filename '...'
> 
> Fixes: 757f8b3835c9 ("nvmem: core: Expose cells through sysfs")
> Signed-off-by: Daniel Golle <daniel@...rotopia.org>
> ---
>  drivers/nvmem/core.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 70e951088826d..90fe9dc30f8ba 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -480,7 +480,9 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem)
>  	/* Initialize each attribute to take the name and size of the cell */
>  	list_for_each_entry(entry, &nvmem->cells, node) {
>  		sysfs_bin_attr_init(&attrs[i]);
> -		attrs[i].attr.name = devm_kstrdup(&nvmem->dev, entry->name, GFP_KERNEL);
> +		attrs[i].attr.name = devm_kasprintf(&nvmem->dev, GFP_KERNEL,
> +						    "%s@%d", entry->name,
> +						    entry->offset);

Shouldn't we use %s@%x instead to match the DT descriptions?

>  		attrs[i].attr.mode = 0444;
>  		attrs[i].size = entry->bytes;
>  		attrs[i].read = &nvmem_cell_attr_read;

I plan another version of the series which triggered these patches, if
you don't mind I will squash patch 1 into my patches and pick this one
as a preparation change (likely with the above fix if you agree and
without the Fixes tag).

Thanks,
Miquèl