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From: Jeff Garzik <jgarzik@pobox.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: "Thomas Gleixner" <tglx@linutronix.de>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Björn Steinbrink" <B.Steinbrink@gmx.de>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.24-git: kmap_atomic() WARN_ON()
Date: Tue, 26 Feb 2008 11:32:24 -0500	[thread overview]
Message-ID: <47C43F18.6060207@pobox.com> (raw)
In-Reply-To: <20080226083904.GC9857@elte.hu>

Ingo Molnar wrote:
> * Jeff Garzik <jgarzik@pobox.com> wrote:
> 
>> +	unsigned long flags;
>> +
>> +	local_irq_save(flags);
> 
> hm, couldnt we attach the irq disabling to some spinlock, in a natural 
> way? Explicit flags fiddling is a PITA once we do things like threaded 
> irq handlers, -rt, etc.

Attaching the irq disabling to some spinlock is what would be 
artificial...  See the ahci.c patch earlier in this thread.  It is taken 
without spin_lock_irqsave() in the interrupt handler, and there is no 
reason to disable interrupts for the entirety of the interrupt handler 
run -- only the part where we call kmap.

This is only being done to satisfy kmap_atomic's requirements, not libata's.

I could add a "kmap lock" but that just seems silly.

	Jeff





  reply	other threads:[~2008-02-26 16:32 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-06 23:58 Thomas Gleixner
2008-02-13 22:39 ` Rafael J. Wysocki
2008-02-14  1:13   ` Thomas Gleixner
2008-02-25 19:59 ` Björn Steinbrink
2008-02-25 20:08   ` Jeff Garzik
2008-02-25 20:35     ` Björn Steinbrink
2008-02-25 20:40     ` Andrew Morton
2008-02-25 22:01       ` Thomas Gleixner
2008-02-25 22:17         ` Andrew Morton
2008-02-25 23:19         ` Jeff Garzik
2008-02-26  8:39           ` Ingo Molnar
2008-02-26 16:32             ` Jeff Garzik [this message]
2008-02-26 18:19               ` Andrew Morton
2008-02-26 20:49                 ` Ingo Molnar
2008-02-26 21:37                   ` Andrew Morton
2008-02-26 22:59                     ` Jeff Garzik
2008-02-27  0:02                       ` Alan Cox
2008-02-26 23:49                   ` Nick Piggin
2008-02-26  8:50           ` Thomas Gleixner

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