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From: Arnd Bergmann <arnd@arndb.de>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: Bernhard Walle <walle@corscience.de>,
	dbrownell@users.sourceforge.net,
	spi-devel-general@lists.sourceforge.net,
	linux-kernel@vger.kernel.org, akpm@linux-foundation.org
Subject: Re: [PATCH] spi: spidev: Add 32 bit compat ioctl()
Date: Wed, 2 Feb 2011 10:37:14 +0100	[thread overview]
Message-ID: <201102021037.14364.arnd@arndb.de> (raw)
In-Reply-To: <20110202043944.GG29148@angua.secretlab.ca>

On Wednesday 02 February 2011, Grant Likely wrote:
> On Tue, Feb 01, 2011 at 10:02:46AM +0100, Bernhard Walle wrote:
> > Add the compat_ioctl for operations on /dev/spi* so that 32 bit
> > userspace applications can access SPI. As far as I can see all data
> > structure are already prepared for that, so no additional conversion has
> > to be done.
> > 
> > My use case is MIPS with N32 userspace ABI and toolchain, and that was
> > also the platform where I tested it successfully (Cavium Octeon).
> > 
> > Signed-off-by: Bernhard Walle <walle@corscience.de>
> 
> Arnd, can you please give your opinion on this one?  I haven't fully
> got my head around the subtleties of 32/64 bit file_operations.

The patch is correct on everything except s390, which does not have SPI.
The only thing that is missing for s390 is a pointer conversion of the ioctl
argument, like:

static long     
compat_spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
}

Some years ago, I proposed adding a common

#ifdef CONFIG_COMPAT
long generic_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	if (!file->unlocked_ioctl)
		return -ENOTTY;
	return filp->f_ops->unlocked_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
}
#else
#define generic_compat_ioctl NULL
#endif

for this purpose, but it never made it in. Maybe I should try again.

	Arnd

  reply	other threads:[~2011-02-02  9:38 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-01  9:02 Bernhard Walle
2011-02-02  4:39 ` Grant Likely
2011-02-02  9:37   ` Arnd Bergmann [this message]
2011-02-02 10:56     ` Bernhard Walle
2011-02-02 14:12     ` Grant Likely
  -- strict thread matches above, loose matches on Subject: below --
2011-02-03  8:37 Bernhard Walle
2011-02-03 16:56 ` Grant Likely
2011-02-02 11:31 Bernhard Walle
2011-02-02 12:18 ` Arnd Bergmann
2011-02-02 14:15 ` Grant Likely
2011-02-03  8:38   ` Bernhard Walle
2011-02-02 11:30 Bernhard Walle
2011-02-02 10:57 Bernhard Walle
2011-02-02 11:15 ` Arnd Bergmann
2011-02-02 11:32   ` Bernhard Walle
2011-02-02 10:56 y
2011-01-11 15:32 Bernhard Walle
2010-12-01 10:51 Bernhard Walle

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