interacts with the userspace file server:
* since the kernel-user communication is not purely request-response
anymore (hasn't been since 2006), try to rename some "request" to
"message". more similar mangling will take place in the future.
* completely rework how messages are allocated. previously most of
them were borrowed from the stack (originally *all* of them),
but now always allocate dynamically. this makes the structure
of the code much cleaner. also makes it possible to fix a
locking order violation. it enables plenty of future enhancements.
* start generalizing the transport interface to be independent of puffs
* move transport interface to read/write instead of ioctl. the
old one had legacy design problems, and besides, ioctl's suck.
implement a very generic version for now; this will be
worked on later hopefully some day reaching "highly optimized".
* implement libpuffs support behind existing library request
interfaces. this will change eventually (I hate those interfaces)
only take the bare essentials, which currently means removing
"maxreqlen" from the argument list (all current callers I'm aware
of set it as 0 anyway). Introduce puffs_init(), which provides a
context for setting various parameters and puffs_domount(), which
can be used to mount the file system. Keep puffs_mount() as a
shortcut for the above two for simple file systems.
Bump development ABI version to 13. After all, it's Friday the 13th.
Watch out! Bad things can happen on Friday the 13th. --No carrier--
accessors for interesting data in it. Namely, you can now get
pu->pu_privdata with puffs_getspecific(), pu->pu_pn_root with
puffs_set/getroot() and pu->pu_maxreqlen with puffs_getmaxreqlen().
