From 1d033484ee1a2ec26d3eead073e7bc0f889ffdf4 Mon Sep 17 00:00:00 2001 From: Garrett D'Amore Date: Tue, 15 May 2018 01:47:12 -0700 Subject: fixes #419 want to nni_aio_stop without blocking (#428) * fixes #419 want to nni_aio_stop without blocking This actually introduces an nni_aio_close() API that causes nni_aio_begin to return NNG_ECLOSED, while scheduling a callback on the AIO to do an NNG_ECLOSED as well. This should be called in non-blocking close() contexts instead of nni_aio_stop(), and the cases where we call nni_aio_fini() multiple times are updated updated to add nni_aio_stop() calls on all "interlinked" aios before finalizing them. Furthermore, we call nni_aio_close() as soon as practical in the close path. This closes an annoying race condition where the callback from a lower subsystem could wind up rescheduling an operation that we wanted to abort. --- src/core/protocol.h | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'src/core/protocol.h') diff --git a/src/core/protocol.h b/src/core/protocol.h index 964aee1a..9c3b4d33 100644 --- a/src/core/protocol.h +++ b/src/core/protocol.h @@ -34,16 +34,19 @@ struct nni_proto_pipe_ops { // pipe_start is called to register a pipe with the protocol. The // protocol can reject this, for example if another pipe is already - // active on a 1:1 protocol. The protocol may not block during this, - // as the socket lock is held. + // active on a 1:1 protocol. The protocol may not block during this. int (*pipe_start)(void *); - // pipe_stop is called to unregister a pipe from the protocol. - // Threads may still acccess data structures, so the protocol - // should not free anything yet. This is called with the socket - // lock held, so the protocol may not call back into the socket, and - // must not block. This operation must be idempotent, and may - // be called even if pipe_start was not. + // pipe_close is an idempotent, non-blocking, operation, called + // when the pipe is being closed. Any operations pending on the + // pipe should be canceled with NNG_ECLOSED. (Best option is to + // use nng_aio_close() on them) + void (*pipe_close)(void *); + + // pipe_stop is called during finalization, to ensure that + // the protocol is absolutely finished with the pipe. It should + // wait if necessary to ensure that the pipe is not referenced + // anymore by the protocol. It should not destroy resources. void (*pipe_stop)(void *); }; -- cgit v1.2.3-70-g09d2