search for: unlocked_

...nt for > kicking the state machine into action when there is no previous > command being worked on, but otherwise, the state machine itself can > recognize when the command queue needs draining. I have a queued series which adds some new calls that may make this patch simpler: int nbd_[unlocked_]aio_is_created (conn) Returns true if the connection is in the START state int nbd_[unlocked_]aio_is_connecting (conn) Returns true if the connection is connecting or handshaking int nbd_[unlocked_]aio_is_processing (conn) Returns true if the connection is issuing or replying t...

...ers in the call stack can modify the > incoming pointer rather than their own copy. > > This patch is just preparatory, with no semantic change. The public > API still passes closures by copy, but the generator then operates on > the address of that closure through all internal nbd_unlocked_* > functions, rather than making further copies through each additional > function call. > --- > generator/C.ml | 35 ++++++++++++----------- > generator/C.mli | 1 + > lib/debug.c | 6 ++-- > lib/opt.c | 26 ++++++++--------- > lib/rw.c | 76 +++++++++++...

As promised in my earlier thread on libnbd completion callback question. Eric Blake (2): generator: Refactor handling of closures in unlocked functions generator: Free closures on failure docs/libnbd.pod | 2 +- generator/C.ml | 48 +++++++++++------ generator/C.mli | 1 + lib/debug.c | 7 +-- lib/opt.c | 31 ++++++-----

...l functions, so that helpers in the call stack can modify the incoming pointer rather than their own copy. This patch is just preparatory, with no semantic change. The public API still passes closures by copy, but the generator then operates on the address of that closure through all internal nbd_unlocked_* functions, rather than making further copies through each additional function call. --- generator/C.ml | 35 ++++++++++++----------- generator/C.mli | 1 + lib/debug.c | 6 ++-- lib/opt.c | 26 ++++++++--------- lib/rw.c | 76 ++++++++++++++++++++++++-------------------------...

On 6/5/19 6:15 AM, Richard W.M. Jones wrote: > For each nbd_(unlocked_)?aio_is_* function, split it into an internal > function that tests the state and a public visible API function. > > For calls within the library, use the internal function. > > This is simple refactoring. > > As a side effect this fixes a race condition identified by Eric B...

On v1, we discussed whether cmds_to_issue needed to be a list, since it never had more than one element. I played with the idea of making it a list, and allowing the client to queue up new commands regardless of whether the state machine is currently in READY. I also polished up the tmp demo into a bit more full-fledged example file, worth including since it also let me discover a hard-to-hit race

For each nbd_(unlocked_)?aio_is_* function, split it into an internal function that tests the state and a public visible API function. For calls within the library, use the internal function. This is simple refactoring. As a side effect this fixes a race condition identified by Eric Blake: Thread A...

...an of attack is to document that ALL functions that take a closure argument promise to eventually free the closure, even if the API fails, and to declare our memory leak as a bug to be fixed in libnbd proper. To do that, the generator will now blindly free anything that has not been cleared by the unlocked_* helper, which in turn are now careful to clear any callback once it has successfully been copied into somewhere that will guarantee subsequent cleanup (whether as part of the state machine, or by the fact that nbd_internal_command_common now cleans up on all error paths). Yes, our change means th...

...utable (Int "error")] } ]; + optargs = [ OFlags "flags" ]; ret = RInt64; permitted_states = [ Connected ]; shortdesc = "send block status command to the NBD server, with callback on completion"; @@ -3149,7 +3160,8 @@ module C : sig val generate_lib_unlocked_h : unit -> unit val generate_lib_api_c : unit -> unit val generate_docs_libnbd_api_pod : unit -> unit - val print_arg_list : ?handle:bool -> ?types:bool -> arg list -> unit + val print_arg_list : ?handle:bool -> ?types:bool -> + arg list -> o...

I need to think about this patch series a bit more, but it does at least pass the tests. Rich.

These are some simplifications to the generator. They don't probably make much sense on their own, but they are preparatory to better handling of enums, and or'd lists of flags. Rich.

This isn't quite finished because not all of the tests or examples have been updated, but it demonstrates an idea: Should we forget about the concept of having multiple connections managed under a single handle? In this patch there is a single ‘struct nbd_handle *’ which manages a single state machine and connection (and therefore no nbd_connection). To connect to a multi-conn server you must