Date: Thu, 25 Apr 2002 17:19:00 +0900 From: Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp> To: John Baldwin <jhb@FreeBSD.org> Cc: Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp>, smp@FreeBSD.org, current@FreeBSD.org Subject: Re: Locking down a socket, milestone 1 Message-ID: <200204250819.g3P8J00o013784@rina.r.dl.itc.u-tokyo.ac.jp> In-Reply-To: <XFMail.20020424101801.jhb@FreeBSD.org> References: <200204241110.g3OB8u8t006194@bunko> <XFMail.20020424101801.jhb@FreeBSD.org>
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On Wed, 24 Apr 2002 10:18:01 -0400 (EDT), John Baldwin <jhb@FreeBSD.org> said: jhb> On 24-Apr-2002 Seigo Tanimura wrote: >> I am now working on locking down a socket. (I have heard that Jeffrey >> Hsu is also doing that, but I have never seen his patch. Has anyone >> seen that?) My first milestone patch is now available at: >> >> >> http://people.FreeBSD.org/~tanimura/patches/socket_milestone1.diff.gz >> >> >> The works I have done so far are: >> >> >> - Determine the lock required to protect each of the members in struct >> socket. >> >> - Add mutexes to each of the sockbufs in a socket as BSD/OS does. >> >> - Lock down so_count, so_options, so_linger and so_state. >> >> - Add a global mutex socq_lock to protect the connection queues of a >> listening socket. Lock socq_lock to lock two sockets at once, >> followed by enqueuing or dequeuing a socket, or moving a socket across >> queues. socq_lock is not an sx lock because we usually have to lock >> two sockets to modify them. jhb> Do you actually lock two sockets at once or do you lock one at a time while jhb> holding socq_lock. If you do lock two at once, what is the defined locking jhb> order? At the moment, I lock two sockets at once. This is required, eg in soisconnected() to move an accepting socket across the connection queues of a listening socket. The lock order is: 1. socq_lock 2. an accepting socket 3. a listening socket (in so_head of the accepting socket) -- Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp> <tanimura@FreeBSD.org> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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