dmaengine: idxd: add configuration for concurrent batch descriptor processing

mainline inclusion
from mainline-v6.1
commit 7ca68fa3
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I596WO


CVE: NA

Intel-SIG: commit 7ca68fa3 dmaengine: idxd: add configuration for concurrent batch descriptor processing.
Incremental backporting patches for DSA/IAA on Intel Xeon platform.

--------------------------------

Add sysfs knob to allow control of the number of batch descriptors that can
be concurrently processed by an engine in the group as a fraction of the
Maximum Work Descriptors in Progress value specfied in ENGCAP register.
This control knob is part of toggle for QoS control.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20220917161222.2835172-6-fenghua.yu@intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>