408f2c9c15
On s390 each PCI device has a user-defined ID (UID) exposed under
/sys/bus/pci/devices/<dev>/uid. This ID was designed to serve as the PCI
device's primary index and to match the device within Linux to the
device configured in the hypervisor. To serve as a primary identifier
the UID must be unique within the Linux instance, this is guaranteed by
the platform if and only if the UID Uniqueness Checking flag is set
within the CLP List PCI Functions response.
While the UID has been exposed to userspace since commit ac4995b9d570
("s390/pci: add some new arch specific pci attributes") whether or not
the platform guarantees its uniqueness for the lifetime of the Linux
instance while defined is not visible from userspace. Remedy this by
exposing this as a per device attribute at
/sys/bus/pci/devices/<dev>/uid_is_unique
Keeping this a per device attribute allows for maximum flexibility if we
ever end up with some devices not having a UID or not enjoying the
guaranteed uniqueness.
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Viktor Mihajlovski <mihajlov@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.