NFS Client Changes Bring Some Optimizations For Linux 4.20~5.0

For those of you using the Network File-System System (NFS), the client code has queued some optimizations that may be worthwhile when upgrading your kernel that will be christened as either Linux 4.20 or Linux 5.0.

Most significant appears to be an overhaul to the RPC client socket code to eliminate a locking bottleneck and reducing latency when handling lots of requests in parallel. Additionally there is parallelization support within the RPCSEC_GSS encoding of an RPC request, improved efficiency within the RPC client socket receive code, and several look-up operations were converted to use RCUs rather than global locks.

There are also clean-ups around NFS v4.2 copy-completion code, various fixes, RPC/RDMA connection work, and other code improvements. The complete list of details can be found via this pull request.