4e5cb354c8
umount_resctrlfs() directly attempts to unmount resctrl file system without checking if resctrl FS is already mounted or not. It returns 0 on success and on failure it prints an error message and returns an error status. Calling umount_resctrlfs() when resctrl FS isn't mounted will return an error status. There could be situations where-in the caller might not know if resctrl FS is already mounted or not and the caller might still want to unmount resctrl FS if it's already mounted (For example during teardown). To support above use cases, change umount_resctrlfs() such that it now first checks if resctrl FS is already mounted or not and unmounts resctrl FS only if it's already mounted. unmount resctrl FS upon exit. For example, running only mba test on a Broadwell (BDW) machine (MBA isn't supported on BDW CPU). This happens because validate_resctrl_feature_request() would mount resctrl FS to check if mba is enabled on the platform or not and finds that the H/W doesn't support mba and hence will return false to run_mba_test(). This in turn makes the main() function return without unmounting resctrl FS. Tested-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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.