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From: John Baldwin <jhb@FreeBSD.org>
To: freebsd-current@FreeBSD.org
Date: Thu, 30 Sep 2004 14:09:25 -0400
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cc: Poul-Henning Kamp <phk@critter.freebsd.dk>
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Subject: Re: Unit number allocation API
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On Thursday 30 September 2004 03:06 am, Poul-Henning Kamp wrote:
> I had this one out on arch@ previously.  I'm very interested in informed
> feedback on how we deal with locking for service api's like this.

I would suggest that the caller should ask for a unit before it needs a lock 
and if it finds that it doesn't need the unit after all it can give it back 
in the error handling.  That is, this is similar to malloc'ing a structure up 
front, then grabbing locks and making changes, then after releasing the lock 
free'ing the structure if it turned out we didn't need it.

-- 
John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org