270bf4c019
This is for counting the devices that are opened via the cdev path. This count is increased and decreased by the cdev path. The group path checks it to achieve exclusion with the cdev path. With this, only one path (group path or cdev path) will claim DMA ownership. This avoids scenarios in which devices within the same group may be opened via different paths. Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Terrence Xu <terrence.xu@intel.com> Tested-by: Nicolin Chen <nicolinc@nvidia.com> Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Tested-by: Yanting Jiang <yanting.jiang@intel.com> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20230718135551.6592-9-yi.l.liu@intel.com Signed-off-by: Alex Williamson <alex.williamson@redhat.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.