Re: [PATCH] spi: spidev: Add 32 bit compat ioctl()

From: Bernhard Walle <walle@corscience.de>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>,
	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, 02 Feb 2011 11:56:56 +0100	[thread overview]
Message-ID: <4D493878.9090607@corscience.de> (raw)
In-Reply-To: <201102021037.14364.arnd@arndb.de>

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Am 02.02.2011 10:37, schrieb Arnd Bergmann:
> 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));
> }

Thanks for the input. I modified my patch and sent it again.

Regards,
Bernhard

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