Date: Fri, 6 Jun 2003 10:57:53 -0300
From: Werner Almesberger <wa@almesberger.net>
To: "David S. Miller" <davem@redhat.com>
Cc: chas@cmf.nrl.navy.mil, linux-kernel@vger.kernel.org
Subject: Re: [PATCH][ATM] use rtnl_{lock,unlock} during device operations (take 2)
Message-ID: <20030606105753.A3275@almesberger.net>
References: <20030606.023618.13768006.davem@redhat.com> <200306061100.h56B08sG024506@ginger.cmf.nrl.navy.mil> <20030606.040410.54190551.davem@redhat.com>
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David S. Miller wrote:
> This is very different from how you are using the lock+rtnl scheme
> for your ATM stuff.

What should help in the ATM code is that it pushes synchronization
"down", i.e. "close" functions usually can't return until they are
truly done (or at least have made sure there is nothing externally
visible left).

In the case of devices, delayed removal is possible, but is then
initiated when closing a VCC (VCCs act as an implicit reference
count for devices), which is another synchronous operation.

VCC creation/removal in response to other asynchronous activity,
e.g. after ARP, is relayed through user-space demons, which then
make normal system calls to implement the change.

- Werner

-- 
  _________________________________________________________________________
 / Werner Almesberger, Buenos Aires, Argentina         wa@almesberger.net /
/_http://www.almesberger.net/____________________________________________/
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