linux-kernel - Re: [PATCH v3 4/7] iio: core: Add cleanup.h support for iio_device_claim

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Message-ID: <c73935a2-1c71-493e-9504-5ea205169eb7@baylibre.com>
Date: Sun, 18 Jan 2026 13:30:10 -0600
From: David Lechner <dlechner@...libre.com>
To: Kurt Borja <kuurtb@...il.com>,
 Andy Shevchenko <andriy.shevchenko@...el.com>,
 Lars-Peter Clausen <lars@...afoo.de>,
 Michael Hennerich <Michael.Hennerich@...log.com>,
 Jonathan Cameron <jic23@...nel.org>, Benson Leung <bleung@...omium.org>,
 Antoniu Miclaus <antoniu.miclaus@...log.com>,
 Gwendal Grignou <gwendal@...omium.org>,
 Shrikant Raskar <raskar.shree97@...il.com>,
 Per-Daniel Olsson <perdaniel.olsson@...s.com>
Cc: Nuno Sá <nuno.sa@...log.com>,
 Andy Shevchenko <andy@...nel.org>, Guenter Roeck <groeck@...omium.org>,
 Jonathan Cameron <Jonathan.Cameron@...wei.com>, linux-iio@...r.kernel.org,
 linux-kernel@...r.kernel.org, chrome-platform@...ts.linux.dev
Subject: Re: [PATCH v3 4/7] iio: core: Add cleanup.h support for
 iio_device_claim_*()

On 1/18/26 9:23 AM, Kurt Borja wrote:
> On Fri Jan 16, 2026 at 5:03 PM -05, David Lechner wrote:
>> On 1/6/26 2:06 AM, Kurt Borja wrote:
>>> Add guard classes for iio_device_claim_*() conditional locks. This will
>>> aid drivers write safer and cleaner code when dealing with some common
>>> patterns.
>>>
>>> These classes are not meant to be used directly by drivers (hence the
>>> __priv__ prefix). Instead, documented wrapper macros are provided to
>>> enforce the use of ACQUIRE() or guard() semantics and avoid the
>>> problematic scoped guard.
>>>
>>> Suggested-by: Andy Shevchenko <andriy.shevchenko@...el.com>
>>> Signed-off-by: Kurt Borja <kuurtb@...il.com>
>>> ---
>>>  include/linux/iio/iio.h | 71 +++++++++++++++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 71 insertions(+)
>>>
>>> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
>>> index d8af0456f966..c795f731f2d8 100644
>>> --- a/include/linux/iio/iio.h
>>> +++ b/include/linux/iio/iio.h
>>> @@ -10,6 +10,7 @@
>>>  #include <linux/align.h>
>>>  #include <linux/device.h>
>>>  #include <linux/cdev.h>
>>> +#include <linux/cleanup.h>
>>>  #include <linux/compiler_types.h>
>>>  #include <linux/minmax.h>
>>>  #include <linux/slab.h>
>>> @@ -740,6 +741,76 @@ static inline bool iio_device_try_claim_buffer_mode(struct iio_dev *indio_dev)
>>>   */
>>>  #define iio_device_release_buffer_mode(indio_dev) __iio_dev_mode_unlock(indio_dev)
>>>  
>>> +/*
>>> + * These classes are not meant to be used directly by drivers (hence the
>>> + * __priv__ prefix). Instead, documented wrapper macros are provided bellow to
>>> + * enforce the use of ACQUIRE() or guard() semantics and avoid the problematic
>>> + * scoped guard variants.
>>> + */
>>> +DEFINE_GUARD(__priv__iio_dev_mode_lock, struct iio_dev *,
>>> +	     __iio_dev_mode_lock(_T), __iio_dev_mode_unlock(_T));
>>> +DEFINE_GUARD_COND(__priv__iio_dev_mode_lock, _try_direct,
>>> +		  iio_device_claim_direct(_T));
>>> +
>>> +/**
>>> + * IIO_DEV_ACQUIRE_DIRECT_MODE(_dev, _var) - Tries to acquire the direct mode
>>> + *                                           lock with automatic release
>>
>> I don't think it is usual to put the function parameters in the
>> doc comment like this. They don't match the actual names anyway.
> 
> Hi David,
> 
> This format of kernel-doc applies to function-like macros too [1]. I'll
> match the name of the variables though.

Right. And it has no parameters between the () on the first line
in that documentation.

/*
 * function_name() - Brief description of function.


So it should be just `IIO_DEV_ACQUIRE_DIRECT_MODE() - ...

>
>> + * @dev: IIO device instance
>> + * @claim: Variable identifier to store acquire result
>> + *

The parameters go below like this, which is already correct.