Date: Tue, 15 Aug 2006 17:49:56 +0200 From: Divacky Roman <xdivac02@stud.fit.vutbr.cz> To: John Baldwin <jhb@freebsd.org> Cc: Roman Divacky <rdivacky@freebsd.org>, Perforce Change Reviews <perforce@freebsd.org> Subject: Re: PERFORCE change 104029 for review Message-ID: <20060815154956.GB60482@stud.fit.vutbr.cz> In-Reply-To: <200608151127.54902.jhb@freebsd.org> References: <200608151407.k7FE7Lj5095567@repoman.freebsd.org> <200608151127.54902.jhb@freebsd.org>
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On Tue, Aug 15, 2006 at 11:27:54AM -0400, John Baldwin wrote: > On Tuesday 15 August 2006 10:07, Roman Divacky wrote: > > http://perforce.freebsd.org/chv.cgi?CH=104029 > > > > Change 104029 by rdivacky@rdivacky_witten on 2006/08/15 14:06:41 > > > > Protect against racing concurent creation in futex_get() > > > > Pointed out by: jhb > > > > Affected files ... > > > > .. //depot/projects/soc2006/rdivacky_linuxolator/compat/linux/linux_futex.c#24 > edit > > > > Differences ... > > > > > ==== //depot/projects/soc2006/rdivacky_linuxolator/compat/linux/linux_futex.c#24 > (text+ko) ==== > > > > @@ -342,13 +342,13 @@ > > if (locked == FUTEX_UNLOCKED) > > FUTEX_UNLOCK; > > > > + if (locked == FUTEX_UNLOCKED) > > + FUTEX_LOCK; > > Looks like you should collapse the lock/unlock. However, it's probably best > to use mutexes instead of sx locks, and to instead do something like this: the lock here IS a mutex... > lock(); > if (item in list) { > item->ref++; > unlock(); > return (item); > } > unlock(); > > new_item = new_item(); > > lock(); > if (item in list) { > item->ref++; > unlock(); > free(new_item); > return (item); > } > insert new_item > new_item->ref++; > unlock(); > return (new_item) isnt this exactly what I am doing in later revision?
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