[CC += linuux-api]@vger.kernel.org Hi David, Could you please CC linux-api@ on all future iterations of this patch! Cheers, Michael On Wed, Oct 26, 2016 at 9:17 PM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote: > Hi > > This proposal introduces bus1.ko, a kernel messaging bus. This is not a request > for inclusion, yet. It is rather an initial draft and a Request For Comments. > > While bus1 emerged out of the kdbus project, bus1 was started from scratch and > the concepts have little in common. In a nutshell, bus1 provides a > capability-based IPC system, similar in nature to Android Binder, Cap'n Proto, > and seL4. The module is completely generic and does neither require nor mandate > a user-space counter-part. > > o Description > > Bus1 is a local IPC system, which provides a decentralized infrastructure to > share objects between local peers. The main building blocks are nodes and > handles. Nodes represent objects of a local peer, while handles represent > descriptors that point to a node. Nodes can be created and destroyed by any > peer, and they will always remain owned by their respective creator. Handles > on the other hand, are used to refer to nodes and can be passed around with > messages as auxiliary data. Whenever a handle is transferred, the receiver > will get its own handle allocated, pointing to the same node as the original > handle. > > Any peer can send messages directed at one of their handles. This will > transfer the message to the owner of the node the handle points to. If a > peer does not posess a handle to a given node, it will not be able to send a > message to that node. That is, handles provide exclusive access management. > Anyone that somehow acquired a handle to a node is privileged to further > send this handle to other peers. As such, access management is transitive. > Once a peer acquired a handle, it cannot be revoked again. However, a node > owner can, at anytime, destroy a node. This will effectively unbind all > existing handles to that node on any peer, notifying each one of the > destruction. > > Unlike nodes and handles, peers cannot be addressed directly. In fact, peers > are completely disconnected entities. A peer is merely an anchor of a set of > nodes and handles, including an incoming message queue for any of those. > Whether multiple nodes are all part of the same peer, or part of different > peers does not affect the remote view of those. Peers solely exist as > management entity and command dispatcher to local processes. > > The set of actors on a system is completely decentralized. There is no > global component involved that provides a central registry or discovery > mechanism. Furthermore, communication between peers only involves those > peers, and does not affect any other peer in any way. No global > communication lock is taken. However, any communication is still globally > ordered, including unicasts, multicasts, and notifications. > > o Prior Art > > The concepts behind bus1 are almost identical to capability systems like > Android Binder, Google Mojo, Cap'n Proto, seL4, and more. Bus1 differs from > them by supporting Global Ordering, Multicasts, Resource Accounting, No > Global Locking, No Global Context. > > While the bus1 UAPI does not expose all features (like soft-references as > supported by Binder), the in-kernel code includes support for it. Multiple > UAPIs can be supported on top of the in-kernel bus1 code, including support > for the Binder UAPI. Efforts on this are still on-going. > > o Documentation > > The first patch in this series provides the bus1(7) man-page. It explains > all concepts in bus1 in more detail. Furthermore, it describes the API that > is available on bus1 file descriptors. The pre-compiled man-page is > available at: > > http://www.bus1.org/bus1.html > > There is also a great bunch of in-source documentation available. All > cross-source-file APIs have KernelDoc annotations. Furthermore, we have an > introduction for each subsystem, to be found in the header files. The total > number in lines of code for bus1 is roughly ~4.5k. The remaining ~5k LOC > are comments and documentation. > > o Upstream > > The upstream development repository is available on github: > > http://github.com/bus1/bus1 > > It is an out-of-tree repository that allows easy and fast development of > new bus1 features. The in-tree integration repository is available at: > > http://github.com/bus1/linux > > o Conferences > > Tom and I will be attending Linux Plumbers Conf next week. Please do not > hesitate to contact us there in person. There will also be a presentation > [1] of bus1 on the last day of the conference. > > Thanks > Tom & David > > [1] https://www.linuxplumbersconf.org/2016/ocw/proposals/3819 > > Tom Gundersen (14): > bus1: add bus1(7) man-page > bus1: provide stub cdev /dev/bus1 > bus1: util - active reference utility library > bus1: util - fixed list utility library > bus1: util - pool utility library > bus1: util - queue utility library > bus1: tracking user contexts > bus1: implement peer management context > bus1: provide transaction context for multicasts > bus1: add handle management > bus1: implement message transmission > bus1: hook up file-operations > bus1: limit and protect resources > bus1: basic user-space kselftests > > Documentation/bus1/.gitignore | 2 + > Documentation/bus1/Makefile | 41 + > Documentation/bus1/bus1.xml | 833 +++++++++++++++++++++ > Documentation/bus1/stylesheet.xsl | 16 + > include/uapi/linux/bus1.h | 138 ++++ > init/Kconfig | 17 + > ipc/Makefile | 1 + > ipc/bus1/Makefile | 16 + > ipc/bus1/handle.c | 823 ++++++++++++++++++++ > ipc/bus1/handle.h | 312 ++++++++ > ipc/bus1/main.c | 146 ++++ > ipc/bus1/main.h | 88 +++ > ipc/bus1/message.c | 656 ++++++++++++++++ > ipc/bus1/message.h | 171 +++++ > ipc/bus1/peer.c | 1163 +++++++++++++++++++++++++++++ > ipc/bus1/peer.h | 163 ++++ > ipc/bus1/security.h | 45 ++ > ipc/bus1/tests.c | 19 + > ipc/bus1/tests.h | 32 + > ipc/bus1/tx.c | 360 +++++++++ > ipc/bus1/tx.h | 102 +++ > ipc/bus1/user.c | 628 ++++++++++++++++ > ipc/bus1/user.h | 140 ++++ > ipc/bus1/util.c | 214 ++++++ > ipc/bus1/util.h | 141 ++++ > ipc/bus1/util/active.c | 419 +++++++++++ > ipc/bus1/util/active.h | 154 ++++ > ipc/bus1/util/flist.c | 116 +++ > ipc/bus1/util/flist.h | 202 +++++ > ipc/bus1/util/pool.c | 572 ++++++++++++++ > ipc/bus1/util/pool.h | 164 ++++ > ipc/bus1/util/queue.c | 445 +++++++++++ > ipc/bus1/util/queue.h | 351 +++++++++ > tools/testing/selftests/bus1/.gitignore | 2 + > tools/testing/selftests/bus1/Makefile | 19 + > tools/testing/selftests/bus1/bus1-ioctl.h | 111 +++ > tools/testing/selftests/bus1/test-api.c | 532 +++++++++++++ > tools/testing/selftests/bus1/test-io.c | 198 +++++ > tools/testing/selftests/bus1/test.h | 114 +++ > 39 files changed, 9666 insertions(+) > create mode 100644 Documentation/bus1/.gitignore > create mode 100644 Documentation/bus1/Makefile > create mode 100644 Documentation/bus1/bus1.xml > create mode 100644 Documentation/bus1/stylesheet.xsl > create mode 100644 include/uapi/linux/bus1.h > create mode 100644 ipc/bus1/Makefile > create mode 100644 ipc/bus1/handle.c > create mode 100644 ipc/bus1/handle.h > create mode 100644 ipc/bus1/main.c > create mode 100644 ipc/bus1/main.h > create mode 100644 ipc/bus1/message.c > create mode 100644 ipc/bus1/message.h > create mode 100644 ipc/bus1/peer.c > create mode 100644 ipc/bus1/peer.h > create mode 100644 ipc/bus1/security.h > create mode 100644 ipc/bus1/tests.c > create mode 100644 ipc/bus1/tests.h > create mode 100644 ipc/bus1/tx.c > create mode 100644 ipc/bus1/tx.h > create mode 100644 ipc/bus1/user.c > create mode 100644 ipc/bus1/user.h > create mode 100644 ipc/bus1/util.c > create mode 100644 ipc/bus1/util.h > create mode 100644 ipc/bus1/util/active.c > create mode 100644 ipc/bus1/util/active.h > create mode 100644 ipc/bus1/util/flist.c > create mode 100644 ipc/bus1/util/flist.h > create mode 100644 ipc/bus1/util/pool.c > create mode 100644 ipc/bus1/util/pool.h > create mode 100644 ipc/bus1/util/queue.c > create mode 100644 ipc/bus1/util/queue.h > create mode 100644 tools/testing/selftests/bus1/.gitignore > create mode 100644 tools/testing/selftests/bus1/Makefile > create mode 100644 tools/testing/selftests/bus1/bus1-ioctl.h > create mode 100644 tools/testing/selftests/bus1/test-api.c > create mode 100644 tools/testing/selftests/bus1/test-io.c > create mode 100644 tools/testing/selftests/bus1/test.h > > -- > 2.10.1 > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface", http://blog.man7.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
