Re: [Linux-kernel-mentees] [PATCH v3 1/4] PCI: sysfs: Define device attributes with DEVICE_ATTR*

[Ruslan Bilovol <ruslan.bilovol@gmail.com>]

On Thu, Aug 15, 2019 at 7:01 PM Kelsey Skunberg
<skunberg.kelsey@gmail.com> wrote:
>
> Defining device attributes should be done through the helper
> DEVICE_ATTR_RO(), DEVICE_ATTR_WO(), or similar. Change all instances using
> __ATTR* to now use its equivalent DEVICE_ATTR*.
>
> Example of old:
>
> static struct device_attribute dev_name_##_attr=__ATTR_RO(_name);
>
> Example of new:
>
> static DEVICE_ATTR_RO(_name);
>
> Signed-off-by: Kelsey Skunberg <skunberg.kelsey@gmail.com>
> ---
>  drivers/pci/pci-sysfs.c | 59 +++++++++++++++++++----------------------
>  1 file changed, 27 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 965c72104150..8af7944fdccb 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -464,9 +464,7 @@ static ssize_t dev_rescan_store(struct device *dev,
>         }
>         return count;
>  }
> -static struct device_attribute dev_rescan_attr = __ATTR(rescan,
> -                                                       (S_IWUSR|S_IWGRP),
> -                                                       NULL, dev_rescan_store);
> +static DEVICE_ATTR(rescan, (S_IWUSR | S_IWGRP), NULL, dev_rescan_store);
>
>  static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
>                             const char *buf, size_t count)
> @@ -480,9 +478,8 @@ static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
>                 pci_stop_and_remove_bus_device_locked(to_pci_dev(dev));
>         return count;
>  }
> -static struct device_attribute dev_remove_attr = __ATTR_IGNORE_LOCKDEP(remove,
> -                                                       (S_IWUSR|S_IWGRP),
> -                                                       NULL, remove_store);
> +static DEVICE_ATTR_IGNORE_LOCKDEP(remove, (S_IWUSR | S_IWGRP), NULL,
> +                                 remove_store);
>
>  static ssize_t dev_bus_rescan_store(struct device *dev,
>                                     struct device_attribute *attr,
> @@ -504,7 +501,7 @@ static ssize_t dev_bus_rescan_store(struct device *dev,
>         }
>         return count;
>  }
> -static DEVICE_ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, dev_bus_rescan_store);
> +static DEVICE_ATTR(bus_rescan, (S_IWUSR | S_IWGRP), NULL, dev_bus_rescan_store);

This patch renamed 'rescan' to 'bus_rescan' and broke my userspace application.
There is also mismatch now between real functionality and documentation
Documentation/ABI/testing/sysfs-bus-pci which still contains old "rescan"
descriptions.

Another patch from this patch series also renamed 'rescan' to 'dev_rescan'

Here is a comparison between two stable kernels (with and without this
patch series):

v5.4
# find /sys -name '*rescan'
/sys/devices/pci0000:00/0000:00:01.2/dev_rescan
/sys/devices/pci0000:00/0000:00:01.0/dev_rescan
/sys/devices/pci0000:00/0000:00:04.0/dev_rescan
/sys/devices/pci0000:00/0000:00:00.0/dev_rescan
/sys/devices/pci0000:00/pci_bus/0000:00/bus_rescan
/sys/devices/pci0000:00/0000:00:01.3/dev_rescan
/sys/devices/pci0000:00/0000:00:03.0/dev_rescan
/sys/devices/pci0000:00/0000:00:01.1/dev_rescan
/sys/devices/pci0000:00/0000:00:02.0/dev_rescan
/sys/devices/pci0000:00/0000:00:05.0/dev_rescan
/sys/bus/pci/rescan

v4.19
# find /sys -name '*rescan'
/sys/devices/pci0000:00/0000:00:01.2/rescan
/sys/devices/pci0000:00/0000:00:01.0/rescan
/sys/devices/pci0000:00/0000:00:04.0/rescan
/sys/devices/pci0000:00/0000:00:00.0/rescan
/sys/devices/pci0000:00/pci_bus/0000:00/rescan
/sys/devices/pci0000:00/0000:00:01.3/rescan
/sys/devices/pci0000:00/0000:00:03.0/rescan
/sys/devices/pci0000:00/0000:00:01.1/rescan
/sys/devices/pci0000:00/0000:00:02.0/rescan
/sys/devices/pci0000:00/0000:00:05.0/rescan
/sys/bus/pci/rescan

Do we maintain this kind of API as non-changeable?

Thanks,
Ruslan

>
>  #if defined(CONFIG_PM) && defined(CONFIG_ACPI)
>  static ssize_t d3cold_allowed_store(struct device *dev,
> @@ -687,16 +684,14 @@ static ssize_t sriov_drivers_autoprobe_store(struct device *dev,
>         return count;
>  }
>
> -static struct device_attribute sriov_totalvfs_attr = __ATTR_RO(sriov_totalvfs);
> -static struct device_attribute sriov_numvfs_attr =
> -               __ATTR(sriov_numvfs, (S_IRUGO|S_IWUSR|S_IWGRP),
> -                      sriov_numvfs_show, sriov_numvfs_store);
> -static struct device_attribute sriov_offset_attr = __ATTR_RO(sriov_offset);
> -static struct device_attribute sriov_stride_attr = __ATTR_RO(sriov_stride);
> -static struct device_attribute sriov_vf_device_attr = __ATTR_RO(sriov_vf_device);
> -static struct device_attribute sriov_drivers_autoprobe_attr =
> -               __ATTR(sriov_drivers_autoprobe, (S_IRUGO|S_IWUSR|S_IWGRP),
> -                      sriov_drivers_autoprobe_show, sriov_drivers_autoprobe_store);
> +static DEVICE_ATTR_RO(sriov_totalvfs);
> +static DEVICE_ATTR(sriov_numvfs, (S_IRUGO | S_IWUSR | S_IWGRP),
> +                                 sriov_numvfs_show, sriov_numvfs_store);
> +static DEVICE_ATTR_RO(sriov_offset);
> +static DEVICE_ATTR_RO(sriov_stride);
> +static DEVICE_ATTR_RO(sriov_vf_device);
> +static DEVICE_ATTR(sriov_drivers_autoprobe, (S_IRUGO | S_IWUSR | S_IWGRP),
> +                  sriov_drivers_autoprobe_show, sriov_drivers_autoprobe_store);
>  #endif /* CONFIG_PCI_IOV */
>
>  static ssize_t driver_override_store(struct device *dev,
> @@ -792,7 +787,7 @@ static struct attribute *pcie_dev_attrs[] = {
>  };
>
>  static struct attribute *pcibus_attrs[] = {
> -       &dev_attr_rescan.attr,
> +       &dev_attr_bus_rescan.attr,
>         &dev_attr_cpuaffinity.attr,
>         &dev_attr_cpulistaffinity.attr,
>         NULL,
> @@ -820,7 +815,7 @@ static ssize_t boot_vga_show(struct device *dev, struct device_attribute *attr,
>                 !!(pdev->resource[PCI_ROM_RESOURCE].flags &
>                    IORESOURCE_ROM_SHADOW));
>  }
> -static struct device_attribute vga_attr = __ATTR_RO(boot_vga);
> +static DEVICE_ATTR_RO(boot_vga);
>
>  static ssize_t pci_read_config(struct file *filp, struct kobject *kobj,
>                                struct bin_attribute *bin_attr, char *buf,
> @@ -1458,7 +1453,7 @@ static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
>         return count;
>  }
>
> -static struct device_attribute reset_attr = __ATTR(reset, 0200, NULL, reset_store);
> +static DEVICE_ATTR(reset, 0200, NULL, reset_store);
>
>  static int pci_create_capabilities_sysfs(struct pci_dev *dev)
>  {
> @@ -1468,7 +1463,7 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev)
>         pcie_aspm_create_sysfs_dev_files(dev);
>
>         if (dev->reset_fn) {
> -               retval = device_create_file(&dev->dev, &reset_attr);
> +               retval = device_create_file(&dev->dev, &dev_attr_reset);
>                 if (retval)
>                         goto error;
>         }
> @@ -1553,7 +1548,7 @@ static void pci_remove_capabilities_sysfs(struct pci_dev *dev)
>         pcie_vpd_remove_sysfs_dev_files(dev);
>         pcie_aspm_remove_sysfs_dev_files(dev);
>         if (dev->reset_fn) {
> -               device_remove_file(&dev->dev, &reset_attr);
> +               device_remove_file(&dev->dev, &dev_attr_reset);
>                 dev->reset_fn = 0;
>         }
>  }
> @@ -1606,7 +1601,7 @@ static int __init pci_sysfs_init(void)
>  late_initcall(pci_sysfs_init);
>
>  static struct attribute *pci_dev_dev_attrs[] = {
> -       &vga_attr.attr,
> +       &dev_attr_boot_vga.attr,
>         NULL,
>  };
>
> @@ -1616,7 +1611,7 @@ static umode_t pci_dev_attrs_are_visible(struct kobject *kobj,
>         struct device *dev = kobj_to_dev(kobj);
>         struct pci_dev *pdev = to_pci_dev(dev);
>
> -       if (a == &vga_attr.attr)
> +       if (a == &dev_attr_boot_vga.attr)
>                 if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
>                         return 0;
>
> @@ -1624,8 +1619,8 @@ static umode_t pci_dev_attrs_are_visible(struct kobject *kobj,
>  }
>
>  static struct attribute *pci_dev_hp_attrs[] = {
> -       &dev_remove_attr.attr,
> -       &dev_rescan_attr.attr,
> +       &dev_attr_remove.attr,
> +       &dev_attr_rescan.attr,
>         NULL,
>  };
>
> @@ -1699,12 +1694,12 @@ static const struct attribute_group pci_dev_hp_attr_group = {
>
>  #ifdef CONFIG_PCI_IOV
>  static struct attribute *sriov_dev_attrs[] = {
> -       &sriov_totalvfs_attr.attr,
> -       &sriov_numvfs_attr.attr,
> -       &sriov_offset_attr.attr,
> -       &sriov_stride_attr.attr,
> -       &sriov_vf_device_attr.attr,
> -       &sriov_drivers_autoprobe_attr.attr,
> +       &dev_attr_sriov_totalvfs.attr,
> +       &dev_attr_sriov_numvfs.attr,
> +       &dev_attr_sriov_offset.attr,
> +       &dev_attr_sriov_stride.attr,
> +       &dev_attr_sriov_vf_device.attr,
> +       &dev_attr_sriov_drivers_autoprobe.attr,
>         NULL,
>  };
>
> --
> 2.20.1
>
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