rdmacg: fix kernel-doc warnings in rdmacg

Fix all kernel-doc warnings in rdmacg:

kernel/cgroup/rdma.c:209: warning: Function parameter or member 'cg'
not described in 'rdmacg_uncharge_hierarchy'
kernel/cgroup/rdma.c:230: warning: Function parameter or member 'cg'
not described in 'rdmacg_uncharge'

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

cgroup: fix spelling mistakes

Fix some spelling mistakes in comments:
hierarhcy ==> hierarchy
automtically ==> automatically
overriden ==> overridden
In absense of .. or ==> In absence of .. and
assocaited ==> associated
taget ==> target
initate ==> initiate
succeded ==> succeeded
curremt ==> current
udpated ==> updated

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 451

Based on 1 normalized pattern(s):

this file is subject to the terms and conditions of version 2 of the
gnu general public license see the file copying in the main
directory of the linux distribution for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 5 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081200.872755311@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

IB/core: Simplify rdma cgroup registration

RDMA cgroup registration routine always returns success, so simplify
function to be void and run clang formatter over whole CONFIG_CGROUP_RDMA
art of core_priv.h.

This reduces unwinding error path for regular registration and future net
namespace change functionality for rdma device.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

rdmacg: Convert to use match_string() helper

The new helper returns index of the matching string in an array.
We are going to use it here.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

rdmacg: Fixed uninitialized current resource usage

Fixed warning reported by kbuild test robot.
When reading current resource usage value, when no resources are
allocated, its possible that it can report a uninitialized value
for current resource usage.
This fix avoids it by initializing it to zero as no resource is
allocated.

Signed-off-by: Parav Pandit <pandit.parav@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

rdmacg: Added rdma cgroup controller

Added rdma cgroup controller that does accounting, limit enforcement
on rdma/IB resources.

Added rdma cgroup header file which defines its APIs to perform
charging/uncharging functionality. It also defined APIs for RDMA/IB
stack for device registration. Devices which are registered will
participate in controller functions of accounting and limit
enforcements. It define rdmacg_device structure to bind IB stack
and RDMA cgroup controller.

RDMA resources are tracked using resource pool. Resource pool is per
device, per cgroup entity which allows setting up accounting limits
on per device basis.

Currently resources are defined by the RDMA cgroup.

Resource pool is created/destroyed dynamically whenever
charging/uncharging occurs respectively and whenever user
configuration is done. Its a tradeoff of memory vs little more code
space that creates resource pool object whenever necessary, instead of
creating them during cgroup creation and device registration time.

Signed-off-by: Parav Pandit <pandit.parav@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>