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From: Arnd Bergmann <arnd@arndb.de>
To: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] irq_flags_t: intro and core annotations
Date: Mon, 22 Oct 2007 21:10:34 +0200
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On Monday 22 October 2007, Andrew Morton wrote:
> Yes, it's always been ugly that we use unsigned long for this rather than
> abstracting it properly.
> 
> However I'd prefer that we have some really good reason for introducing
> irq_flags_t now. ?Simply so that I don't needlessly spend the next two
> years wrestling with literally thousands of convert-to-irq_flags_t patches
> and having to type "please use irq_flags_t here" in hundreds of patch
> reviews. (snivel, wimper)

On a related note, should we encourage the use of spin_lock() and
spin_lock_irq() instead of spin_lock_irqsave() where possible?

On some architectures, accessing the interrupt flag is a heavyweight
operation, especially when running under a hypervisor, so a number
of drivers could benefit from being converted to not save the flags
at all instead of just changing the type of the flags variable.

	Arnd <><
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