staging: ramster: ramster-specific new files

RAMster implements peer-to-peer transcendent memory, allowing a "cluster"
of kernels to dynamically pool their RAM.

This patch adds new files necessary for ramster support:  The file
ramster.h declares externs and some pampd bitfield manipulation.  The
file zcache.h declares some zcache functions that now must be accessed
from the ramster glue code.  The file r2net.c is the glue between zcache
and the messaging layer, providing routines called from zcache that
initiate messages, and routines that handle messages by calling zcache.
TODO explains future plans for merging.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/ramster/TODO

@@ -0,0 +1,13 @@
+For this staging driver, RAMster duplicates code from drivers/staging/zcache
+then incorporates changes to the local copy of the code.  For V5, it also
+directly incorporates the soon-to-be-removed drivers/staging/zram/xvmalloc.[ch]
+as all testing has been done with xvmalloc rather than the new zsmalloc.
+Before RAMster can be promoted from staging, the zcache and RAMster drivers
+should be either merged or reorganized to separate out common code.
+
+Until V4, RAMster duplicated code from fs/ocfs2/cluster, but this made
+RAMster incompatible with ocfs2 running in the same kernel and included
+lots of code that could be removed.  As of V5, the ocfs2 code has been
+mined and made RAMster-specific, made to communicate with a userland
+ramster-tools package rather than ocfs2-tools, and can co-exist with ocfs2
+both in the same kernel and in userland on the same machine.