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Date: Tue, 12 Dec 2000 12:11:03 -0800 (PST)
From: John Baldwin <jhb@FreeBSD.org>
To: Alfred Perlstein <bright@wintelcom.net>
Subject: Re: MEXT_IS_REF broken.
Cc: Bosko Milekic <bmilekic@technokratis.com>, net@FreeBSD.org,
	jasone@FreeBSD.org
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On 12-Dec-00 Alfred Perlstein wrote:
> * John Baldwin <jhb@FreeBSD.org> [001212 08:39] wrote:
>> 
>> On 12-Dec-00 Alfred Perlstein wrote:
>> > grr...
>> > 
>> > considering this:
>> > 
>> >#define MEXT_IS_REF(m) ((m)->m_ext.ref_cnt->refcnt > 1)
>> > 
>> >#define MEXT_REM_REF(m) do {                        \
>> >     KASSERT((m)->m_ext.ref_cnt->refcnt > 0, ("m_ext refcnt < 0"));  \
>> >     atomic_subtract_long(&((m)->m_ext.ref_cnt->refcnt), 1);     \
>> > } while(0)
>> > 
>> > this:
>> > 
>> >#define MEXTFREE(m) do {                        \
>> >     struct mbuf *_mmm = (m);                    \
>> >                                     \
>> >     if (MEXT_IS_REF(_mmm))                      \
>> >         MEXT_REM_REF(_mmm);                 \
>> > 
>> >  
>> > is not mpsafe.  we _NEED_ some type that allows atomic dec and test
>> > for 0.
>> 
>> http://www.FreeBSD.org/~jhb/patches/refcount.patch
> 
> You do have a commit bit if I'm not mistaken. :)

I would like some feedback on it. :)  I guess I should really send it off to
-arch for a bikeshed slugfest.

-- 

John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/
PGP Key: http://www.baldwin.cx/~john/pgpkey.asc
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/


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