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

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sat, Mar 14, 2020 at 12:51:47PM +0200, Ruslan Bilovol wrote:
> 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?

Yeah, that's a bug and should be fixed, sorry for missing that on
review.

Kelsey, can you fix this up?

thanks,

greg k-h
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