Date: Sun, 17 Aug 2008 00:52:55 -0700 (PDT)
Message-Id: <20080817.005255.28108612.davem@davemloft.net>
To: torvalds@linux-foundation.org
Cc: adobriyan@gmail.com, jirislaby@gmail.com, akpm@linuxfoundation.org,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] De-macro spin_trylock_irq, spin_trylock_irqsave,
 write_trylock_irqsave
From: David Miller <davem@davemloft.net>
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References: <48A6D694.4070302@gmail.com>
	<20080816204855.GA5151@martell.zuzino.mipt.ru>
	<alpine.LFD.1.10.0808161417400.3324@nehalem.linux-foundation.org>
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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 16 Aug 2008 14:21:41 -0700 (PDT)

> 
> 
> On Sun, 17 Aug 2008, Alexey Dobriyan wrote:
> 
> > On Sat, Aug 16, 2008 at 03:31:00PM +0200, Jiri Slaby wrote:
> > >
> > > Doesn't this break on sparc -- is it tested there?
> > 
> > What's so special about sparc?
> 
> Sparc _used_ to save/restore the whole processor flags word with the irq 
> flags. That includes, iirc, things like the register window crap, so if 
> you did a save/restore flags in a function, it would get all that wrong 
> and things would blow up.
> 
> However, I don't think sparc has actually done that for a _loong_ time 
> now, due to it always being problematic.

We fixed it.

Although I still sometimes consider saving and restoring cpu IRQ flags
in different function contexts to be on the ugly side :)
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