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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260430232202.GA3577346@rocinante> On Fri, May 01, 2026 at 08:32:30AM +0900, Krzysztof Wilczyński wrote: > Hello, > > > The alternative would be separate llseek callbacks for both the legacy > > and resource attributes, which we can add if this would be the preference > > here. > > If we were to do this, then it would be as follows: > > static loff_t pci_llseek_resource(struct file *filep, > struct kobject *kobj, > const struct bin_attribute *attr, > loff_t offset, int whence) > { > struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj)); > int bar = (unsigned long)attr->private; > > return fixed_size_llseek(filep, offset, whence, > pci_resource_len(pdev, bar)); > } > > static loff_t pci_llseek_resource_legacy(struct file *filep, > struct kobject *kobj __always_unused, > const struct bin_attribute *attr, > loff_t offset, int whence) > { > return fixed_size_llseek(filep, offset, whence, attr->size); > } > > Each callback would be placed within the corresponding #ifdef block, so one > for HAVE_PCI_MMAP or ARCH_GENERIC_PCI_MMAP_RESOURCE, and the other for the > legacy attributes, so behind the HAVE_PCI_LEGACY guard. > > Note, the names need to be different, as some architectures offer both > type of resource files, like PowerPC, which defines both the HAVE_PCI_LEGACY > and HAVE_PCI_MMAP. > > With this split, we can also drop the __maybe_unused annotation. > > While I wanted to keep the changes to only what was needed for the > pci_llseek_resource() to cover both type of resources, it would be > also fine to have two distinct callbacks, too. Yes, I think this is much more readable than the "if (attr->size)" check.