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From: Thomas Gleixner <tglx@linutronix.de>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: Maciej Szmigiero <mhej@o2.pl>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	Anton Vorontsov <avorontsov@ru.mvista.com>,
	Greg Kroah-Hartman <gregkh@suse.de>,
	Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Arnd Bergmann <arnd@arndb.de>, Jonathan Cameron <jic23@cam.ac.uk>,
	Ben Nizette <bn@niasdigital.com>
Subject: Re: [GPIO]implement sleeping GPIO chip removal
Date: Wed, 10 Nov 2010 10:49:44 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.2.00.1011101045230.2900@localhost6.localdomain6> (raw)
In-Reply-To: <20101110050947.GC4110@angua.secretlab.ca>

On Tue, 9 Nov 2010, Grant Likely wrote:

> On Sun, Nov 07, 2010 at 07:30:33PM +0100, Maciej Szmigiero wrote:
> > [GPIO]implement sleeping GPIO chip removal
> > 
> > Existing GPIO chip removal code is only of "non-blocking" type: if the chip is currently
> > requested it just returns -EBUSY.
> > This is bad for devices which disappear and reappear, like those on hot pluggable buses,
> > because it forces the driver to call gpiochip_remove() in loop until it returns 0.
> > 
> > This patch implements a new function which sleeps until device is free instead of
> > returning -EBUSY like gpiochip_remove().
> > 
> > Signed-off-by: Maciej Szmigiero <mhej@o2.pl>
> 
> This patch makes me uncomfortable, but I'm not entirely sure why.  Is

Maybe because it open codes a sloppy refcounting with a loop and magic
sleeps instead of converting the code to kobjects and proper
refcounting ?

Thanks,

	tglx

  reply	other threads:[~2010-11-10  9:50 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-07 18:30 Maciej Szmigiero
2010-11-10  5:09 ` Grant Likely
2010-11-10  9:49   ` Thomas Gleixner [this message]
2010-11-10 15:28   ` Maciej Szmigiero
2010-11-10 20:42     ` Thomas Gleixner
2010-11-10 21:01       ` Maciej Szmigiero
2010-11-10 21:07         ` Thomas Gleixner
2010-11-10 21:15           ` Grant Likely
2010-11-10 22:45             ` Greg KH
2010-11-10 22:47               ` Thomas Gleixner
2010-11-10 23:15               ` Paul Mundt
2010-11-10 22:14         ` Grant Likely
2010-11-12 20:46           ` Maciej Szmigiero

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