From: Patrick McHardy <kaber@trash•net>
To: Richard MUSIL <richard.musil@st•com>
Cc: netdev@vger•kernel.org
Subject: Re: [GENETLINK]: Question: global lock (genl_mutex) possible refinement?
Date: Fri, 20 Jul 2007 16:00:31 +0200 [thread overview]
Message-ID: <46A0BFFF.5020000@trash.net> (raw)
In-Reply-To: <46A0BF7F.80001@st.com>
[ Please quote and break your lines appropriately ]
Richard MUSIL wrote:
> Patrick McHardy wrote:
>>
>>The usual way to do this for auto-loading of modules that register
>>things that take a mutex that is already held during netlink queue
>>processing, like qdiscs, classifiers, .. is:
>>
>>- look for <qdisc/classifier/...>, if not found:
>>- drop mutex (using the __ unlock variant to avoid reentering queue
>>processing)
>>- perform module loading (which takes the mutex and registers itself)
>>- grab mutex again
>>- look for <qdisc/classifier/...> again
>>- if not found return -ENOENT
>>- if found drop reference, return -EAGAIN
>>
>>The caller is changed to handle -EAGAIN by replaying the entire
>>request. Your problem sounds very similar, look at net/sched/sch_api.c
>>for an example.
>
>
> The aforementioned mutex is local to genetlink module, so I cannot temporarily drop it, call the stuff and grab it again (which was mine original thought too).
Export the lock/unlock/.. functions. You'll also need a new version
similar to __rtnl_unlock.
next prev parent reply other threads:[~2007-07-20 14:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-20 12:52 [GENETLINK]: Question: global lock (genl_mutex) possible refinement? Richard MUSIL
2007-07-20 13:21 ` Patrick McHardy
2007-07-20 13:58 ` Richard MUSIL
2007-07-20 14:00 ` Patrick McHardy [this message]
2007-07-20 16:15 ` Richard MUSIL
2007-07-23 10:29 ` Thomas Graf
2007-07-23 16:45 ` Richard MUSIL
2007-07-24 9:35 ` Thomas Graf
2007-07-24 11:09 ` Richard MUSIL
2007-08-10 8:52 ` Richard MUSIL
2007-08-16 15:58 ` Thomas Graf
2007-08-17 8:38 ` Richard MUSIL
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