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From: Andrew Morton <akpm@linux-foundation.org>
To: minyard@acm.org
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
	OpenIPMI Developers <openipmi-developer@lists.sourceforge.net>,
	Konstantin Baydarov <kbaidarov@ru.mvista.com>
Subject: Re: [PATCH 3/4] IPMI: convert locked counters to atomics
Date: Thu, 14 Feb 2008 11:11:43 -0800	[thread overview]
Message-ID: <20080214111143.7e0937ea.akpm@linux-foundation.org> (raw)
In-Reply-To: <20080214183051.GC20148@minyard.local>


> +	for (i = 0; i < IPMI_NUM_STATS; i++)
> +		atomic_set(&intf->stats[i], 0);

And this is why it would be very hard for any architecture to ever
implement atomic_t as

struct atomic_t {
	int counter;
	spinlock_t lock;
};

The interface assumes that atomic_set() fully initialises the atomic_t, and
that atomic_set() can be used agaisnt both an uninitialised atomic_t and
against an already-initialised atomic_t.  IOW, we don't have atomic_init().

So would our hypothetical future architcture's atomic_set() do spin_lock(),
or would it do spin_lock_init()?  Either one is wrong in many atomic_set
callsites.

Oh well.

  reply	other threads:[~2008-02-14 19:12 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-14 18:30 Corey Minyard
2008-02-14 19:11 ` Andrew Morton [this message]
2008-02-14 19:33   ` Corey Minyard
2008-02-14 20:23     ` Andrew Morton
2008-02-15 13:57 ` Peter Zijlstra
2008-02-15 14:08   ` [Openipmi-developer] " Corey Minyard
2008-02-16 16:44 ` Matt Domsch
2008-02-20 15:20   ` Corey Minyard

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