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To: "Brian F. G. Bidulock" <bidulock@openss7.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: export of sys_call_table
References: <20021003153943.E22418@openss7.org.suse.lists.linux.kernel> <1033682560.28850.32.camel@irongate.swansea.linux.org.uk.suse.lists.linux.kernel> <20021003170608.A30759@openss7.org.suse.lists.linux.kernel> <1033722612.1853.1.camel@localhost.localdomain.suse.lists.linux.kernel> <20021004051932.A13743@openss7.org.suse.lists.linux.kernel>
From: Andi Kleen <ak@suse.de>
Date: 04 Oct 2002 15:01:25 +0200
In-Reply-To: "Brian F. G. Bidulock"'s message of "4 Oct 2002 13:23:00 +0200"
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"Brian F. G. Bidulock" <bidulock@openss7.org> writes:


> 					   void *dataptr, int band, int flags)
> 	{
> 		int ret =3D -ENOSYS;
> 		read_lock(&streams_call_lock);

I don't think you really want to use any spinlocks this way. They would
make sleeping impossible and you could never legally do a copy_from/to_user
in your system call. And how else would you access dataptr ? 

More likely you want an atomic_inc(&modulecounter) or perhaps a rw
semaphore.

-Andi
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