This is a simple kernel module written to demonstrate the speed of the PRNG
currently in OpenZFS's Linux SPL.

This module was written on Gentoo Linux against Linux 5.16.14-gentoo-x86_64,
but should build against any recent kernel (Linux 5.0 and later) on any
distribution with the kernel toolchain, headers and build system installed.
Here is a sample session:

	$ cd /path/to/poc_dev
	$ make
	make -C /lib/modules/5.16.14-gentoo-x86_64/build M=/home/richard/poc-urandom modules
	make[1]: Entering directory '/usr/src/linux-5.16.14-gentoo'
	warning: the compiler differs from the one used to build the kernel
	  The kernel was built by: x86_64-pc-linux-gnu-gcc (Gentoo 11.3.0 p4) 11.3.0
	  You are using:           gcc (Gentoo 11.3.0 p4) 11.3.0
	make[1]: Leaving directory '/usr/src/linux-5.16.14-gentoo'
	$ sudo insmod poc_char.ko
	$ time dd if=/dev/urandom-fast bs=1M count=1000 of=/dev/null
	1000+0 records in
	1000+0 records out
	1048576000 bytes (1.0 GB, 1000 MiB) copied, 0.333377 s, 3.1 GB/s

	real    0m0.334s
	user    0m0.000s
	sys     0m0.332s
	$ make clean
	make -C /lib/modules/5.16.14-gentoo-x86_64/build M=/home/richard/poc-urandom clean
	make[1]: Entering directory '/usr/src/linux-5.16.14-gentoo'
	  CLEAN   /home/richard/poc-urandom/Module.symvers
	make[1]: Leaving directory '/usr/src/linux-5.16.14-gentoo'
	$ sudo rmmod poc_char.ko