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Date: Wed, 23 Apr 2008 15:51:08 +0200
From: Rene Herman <rene.herman@keyaccess.nl>
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To: Linus Torvalds <torvalds@linux-foundation.org>
CC: Adrian Bunk <bunk@kernel.org>, Jeff Garzik <jeff@garzik.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>, rmk@arm.linux.org.uk,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>
Subject: Re: [git patch] free_irq() fixes
References: <20080422221733.GA16260@havoc.gtf.org> <alpine.LFD.1.10.0804221518520.2779@woody.linux-foundation.org> <480E6DE5.6010103@garzik.org> <alpine.LFD.1.10.0804221616280.2779@woody.linux-foundation.org> <480E796E.4070001@garzik.org> <alpine.LFD.1.10.0804221651400.2779@woody.linux-foundation.org> <20080423000529.GG28933@cs181133002.pp.htv.fi> <alpine.LFD.1.10.0804221714380.2779@woody.linux-foundation.org>
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On 23-04-08 02:16, Linus Torvalds wrote:

> On Wed, 23 Apr 2008, Adrian Bunk wrote:
>> If it goes like the regs removal in one big patch around -rc1 into your 
>> tree this shouldn't be a problem.
> 
> Well, the regs removal had a real upside (it wasn't even sensible for all 
> irq types), and really nobody used it apart from "system users" (ie Sysrq 
> etc).
> 
> I'm still waiting for anybody mentioning any upside at _all_ on removing 
> "irq".

Saves another 4 bytes of stack? :-/ Seriously, Jeff can probably better 
answer himself but when this was posted before:

http://lkml.org/lkml/2007/5/19/23

Eric Biederman said it fit nicely into his "nefarious plan of making 
everything use a struct irq pointer". A later mention:

http://lkml.org/lkml/2007/10/19/66

got strong ACKs from Thomas Gleixner, Ingo Molnar and Greg KH. Remember due 
to working on a local driver at the time and deleting the "irq" argument 
usage from its handler (unneccesarily used in a debugging printk) from it in 
response.

My own view is that if it's not really overly painful this does make for a 
nice API cleanliness thing -- the IRQ level is only relevant to the lower 
level generic handler code not the "driver endpoint handler" and not passing 
it in the first place thereby is in keeping with this layering.

Rene.