Re: [PATCH v8 04/25] PCI/sysfs: Split pci_llseek_resource() for device and legacy attributes

[sashiko-bot@kernel.org]

> Both legacy and resource attributes set .f_mapping = iomem_get_mapping,
> so the default generic_file_llseek() would consult iomem_inode for the
> file size, which knows nothing about the attribute.  That is why custom
> llseek callbacks exist.
> 
> Currently, the legacy and resource attributes have .size set at creation
> time, as such, using the attr->size is sufficient.  However, the upcoming
> static resource attributes will have .size == 0 set, since they are const,
> and the .bin_size callback will be used to provide the real size to kernfs
> instead.
> 
> The legacy attributes operate on a struct pci_bus, not struct pci_dev,
> so calling to_pci_dev() on them would be invalid.
> 
> Thus, split pci_llseek_resource() into two functions:
> 
>   - pci_llseek_resource(), which derives the file size from the BAR
>     using pci_resource_len().
> 
>   - pci_llseek_resource_legacy(), which uses attr->size directly.
> 
> Update the dynamic legacy attribute creation to use the new
> pci_llseek_resource_legacy() callback.
> 
> The original pci_llseek_resource() was added in commit 24de09c16f97
> ("PCI: Implement custom llseek for sysfs resource entries").
> 
> Tested-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
> Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260619085200.3729431-1-kwilczynski@kernel.org?part=4