From: Arnd Bergmann <arnd@arndb.de>
To: Geoff Levand <geoffrey.levand@am.sony.com>
Cc: linuxppc-dev@ozlabs.org, paulus@samba.org,
Takashi Yamamoto <Takashi02_Yamamoto@hq.scei.sony.co.jp>
Subject: Re: [patch 3/3] PS3: Add logical performance monitor driver support
Date: Sun, 6 Jan 2008 22:56:17 +0100 [thread overview]
Message-ID: <200801062256.18885.arnd@arndb.de> (raw)
In-Reply-To: <47813CA4.8000203@am.sony.com>
On Sunday 06 January 2008, Geoff Levand wrote:
>
> > This mutex is documented as the 'open/close' mutex and you use it
> > to prevent concurrent execution of the open and close functions.
> > However, it's unclear what data structures are actually protected
> > by it.
> >
> > I think this is the result of unusual lifetime rules for the lpm_priv
> > object, which I already mentioned above.
>
> Yes, we really just need to use the mutex to allow only a single instance,
> and so do a mutex_trylock() in ps3_lpm_open() and return -EBUSY on fail,
> and then a mutex_unlock() in ps3_lpm_close().
A simple atomic_test_and_set in open() should do the job just as well then.
Arnd <><
prev parent reply other threads:[~2008-01-06 21:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20080105003019.595703814@am.sony.com>
2008-01-05 3:12 ` [patch 1/3] PS3: Add logical performance monitor repository routines Geoff Levand
2008-01-05 3:12 ` [patch 2/3] PS3: Add logical performance monitor device support Geoff Levand
2008-01-05 11:29 ` Arnd Bergmann
2008-01-06 20:39 ` Geoff Levand
2008-01-05 3:30 ` [patch 3/3] PS3: Add logical performance monitor driver support Geoff Levand
2008-01-05 11:56 ` Arnd Bergmann
2008-01-06 20:40 ` Geoff Levand
2008-01-06 21:56 ` Arnd Bergmann [this message]
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