Common Library

* crc16.h and crc16.c were copied from the linux kernel(https://elixir.bootlin.com/linux/v5.10.232/source/lib/crc16.c).
* defs.h is a bunch of definitions to smooth things over.
* hashtable/* was downloaded from http://www.cl.cam.ac.uk/~cwc22/hashtable/
* atomic.h was downloaded from https://the-linux-channel.the-toffee-project.org/index.php?page=6-tutorials-linux-user-space-atomic-operations
* bitops.h and bitops.c were copied from the linux kernel(https://elixir.bootlin.com/linux/v5.10.232/source/lib/find_bit.c).
* compiler_attributes.h was copied from the linux kernel(https://elixir.bootlin.com/linux/v5.10.232/source/include/linux/compiler_attributes.h).
* linux_types.h was copied from the linux kernel(https://elixir.bootlin.com/linux/v5.10.232/source/include/linux/types.h overflow.h fscrypt.h).
* linux_err.h was copied from the linux kernel(https://elixir.bootlin.com/linux/v5.10.232/source/include/linux/err.h).
* hexdump.c was copied from the linux kernel(https://elixir.bootlin.com/linux/v5.10.232/source/lib/hexdump.c).
* kmem.h and kmem.c were partial copied from xfsprogs-dev(https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git/).
* sort.h and sort.c were copied from the linux kernel(https://elixir.bootlin.com/linux/v5.10.232/source/lib/sort.c).
