Date: Mon, 3 Mar 2008 17:33:40 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Alan Stern <stern@rowland.harvard.edu>, Pavel Machek <pavel@ucw.cz>,
       "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@osdl.org>,
       Zdenek Kabelac <zdenek.kabelac@gmail.com>, davem@davemloft.net,
       "Rafael J. Wysocki" <rjw@sisk.pl>, Pierre Ossman <drzeus-mmc@drzeus.cx>,
       Kernel development list <linux-kernel@vger.kernel.org>,
       pm list <linux-pm@lists.linux-foundation.org>
Subject: Re: [patch] Re: using long instead of atomic_t when only set/read
 is required
Message-ID: <20080303173340.55a38c6b@core>
In-Reply-To: <200803040416.33937.nickpiggin@yahoo.com.au>
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	<200803040416.33937.nickpiggin@yahoo.com.au>
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> Are you sure gcc doesn't? Or is it just "C"?

gcc doesn't

> Linux wouldn't work today if gcc did something non-atomic there
> (presuming you're talking about naturally aligned pointers/ints).
> It is widely used and accepted.

Yes and we've had tty layer traces in the past clearly showing it isn't
always safe, especially if any math is involved anywhere near the
assignment. That may be why pointer flipping happens to work.

Alan
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