Date: Wed, 8 Oct 2008 20:48:43 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: John Baldwin <jhb@freebsd.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/kern uipc_socket.c Message-ID: <alpine.BSF.1.10.0810082047220.60960@fledge.watson.org> In-Reply-To: <200810081114.40433.jhb@freebsd.org> References: <200810072058.m97Kw3q0073534@repoman.freebsd.org> <200810071736.50999.jhb@freebsd.org> <alpine.BSF.1.10.0810080714290.91071@fledge.watson.org> <200810081114.40433.jhb@freebsd.org>
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On Wed, 8 Oct 2008, John Baldwin wrote: >>>> In soreceive_dgram, when a 0-length buffer is passed into recv(2) and >>>> no data is ready, return 0 rather than blocking or returning EAGAIN. >>>> This is consistent with the behavior of soreceive_generic (soreceive) >>>> in earlier versions of FreeBSD, and restores this behavior for UDP. .. >> >> Yes, I agree it's odd, and I'm not sure I like it. I discovered the >> problem while writing edge-case regression tests for socket receive to >> better exercise soreceive_dgram, at first concluding it was a bug in >> soreceive_generic! My feeling, though, is that I should leave behavior >> "compatible" for 7.1, and perhaps we should change it for 7.2. > > Ok, so I guess you will revert this from HEAD after the MFC? That and modify soreceive_generic() to do the same thing in the same circumstances -- soreceive_dgram() falls back on soreceive_generic() for any non-fast path (complicated) cases, so consistency of semantics is quite important. Robert N M Watson Computer Laboratory University of Cambridge
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