This patch set was originally posted to linux-raid, Neil suggested that
I send to linux-kernel as well:
Per the discussion in this thread (http://marc.theaimsgroup.com/?
t=112603120100004&r=1&w=2) these patches implement the first phase of MD
acceleration, pre-emptible xor. To date these patches only cover raid5
calls to compute_parity for read/modify and reconstruct writes. The
plan is to expand this to cover raid5 check parity, raid5 compute block,
as well as the raid6 equivalents.
The ADMA (Asynchronous / Application Specific DMA) interface is proposed
as a cross platform mechanism for supporting system CPU offload engines.
The goal is to provide a unified asynchronous interface to support
memory copies, block xor, block pattern setting, block compare, CRC
calculation, cryptography etc. The ADMA interface should support a PIO
fallback mode allowing a given ADMA engine implementation to use the
system CPU for operations without a hardware accelerated backend. In
other words a client coded to the ADMA interface transparently receives
hardware acceleration for its operations depending on the features of
the underlying platform.