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Date: Tue, 26 Mar 2024 13:06:05 +0100
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To: Dan Williams <dan.j.williams@intel.com>,
 Peter Zijlstra <peterz@infradead.org>,
 Linus Torvalds <torvalds@linux-foundation.org>,
 Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
 kernel-janitors@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>,
 Ira Weiny <ira.weiny@intel.com>,
 Jesse Brandeburg <jesse.brandeburg@intel.com>,
 Jonathan Cameron <Jonathan.Cameron@huawei.com>,
 Julia Lawall <Julia.Lawall@inria.fr>, Kevin Tian <kevin.tian@intel.com>,
 Lukas Wunner <lukas.wunner@intel.com>, Matthew Wilcox <willy@infradead.org>
References: <171140738438.1574931.15717256954707430472.stgit@dwillia2-xfh.jf.intel.com>
Subject: Re: [PATCH v2] cleanup: Add usage and style documentation
Content-Language: en-GB
From: Markus Elfring <Markus.Elfring@web.de>
In-Reply-To: <171140738438.1574931.15717256954707430472.stgit@dwillia2-xfh.jf.intel.com>
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=E2=80=A6
> +++ b/include/linux/cleanup.h
> @@ -4,6 +4,157 @@
>
>  #include <linux/compiler.h>
>
> +/**
> + * DOC: scope-based cleanup helpers
> + *
> + * The "goto error" pattern is notorious for introducing =E2=80=A6

Will any other label become more helpful for this description approach?

> + * this tedium =E2=80=A6

Would an other wording be more appropriate here?


> + *                          =E2=80=A6 maintaining FILO (first in last o=
ut)

How does this text fit to your response from yesterday?
https://lore.kernel.org/all/6601c7f7369d4_2690d29490@dwillia2-mobl3.amr.co=
rp.intel.com.notmuch/


> + *                                                       =E2=80=A6 If a=
 function
> + * wants to invoke pci_dev_put() on error, but return @dev (i.e. withou=
t
> + * freeing it) on success, it can do:
> + *
> + * ::
> + *
> + *	return no_free_ptr(dev);
> + *
> + * ...or:
> + *
> + * ::
> + *
> + *	return_ptr(dev);
=E2=80=A6

Would this macro call be preferred as a succinct specification
(so that only the shorter one should be mentioned here)?
https://elixir.bootlin.com/linux/v6.8.1/source/include/linux/cleanup.h#L78


> + * Observe the lock is held for the remainder of the "if ()" block not
> + * the remainder of "func()".

I suggest to add a word in this sentence.

* Observe the lock is held for the remainder of the "if ()" block
* (and not the remainder of "func()").


> + * the top of the function poses this potential interdependency problem

I suggest to add a comma at the end of this line.


> + * the recommendation is to always define and assign variables in one
> + * statement and not group variable definitions at the top of the
> + * function when __free() is used.

I became curious how code layout guidance will evolve further also
according to such an advice.


Would you like to increase the collaboration with the macros =E2=80=9CDEFI=
NE_CLASS=E2=80=9D and =E2=80=9CCLASS=E2=80=9D?
https://elixir.bootlin.com/linux/v6.8.1/source/include/linux/cleanup.h#L82

Regards,
Markus