Date: Wed, 13 Dec 2000 13:06:28 -0800 (PST) From: Matt Dillon <dillon@earth.backplane.com> To: Kirk McKusick <mckusick@mckusick.com> Cc: Alfred Perlstein <bright@wintelcom.net>, arch@FreeBSD.ORG, net@FreeBSD.ORG Subject: Re: patch to cleanup inflight desciptor handling. Message-ID: <200012132106.eBDL6Sg86570@earth.backplane.com> References: <200012131852.KAA17423@beastie.mckusick.com>
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:I believe that your changes have been sorely needed for many
:years. While I would like to see regular mbufs given a callback
:mechanism, your present approach of using an mbuf cluster
:solves 90% of the problem.
:
: Kirk McKusick
... Aflred, be careful that you don't break things we only just fixed
last year. The descriptor passing code has been broken for many years.
I think the reason we have to scan the descriptor list is related to
locating isolated self-referential 'loops' with descriptor passing and
unix domain sockets and closing them. e.g. when you pass a descriptor
for a unix-domain socket through a unix-domain socket, it is possible
for the socket descriptors to reference each other and thus never have
their ref count drop to 0 even when all associated processes have
close()'d. This happens all the time. Be sure you don't break the
fix that solves that particular problem.
-Matt
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