Re: [v2 1/2] soc: fsl: dpio: Use scope-based resource management in dpaa2_io_store_create()

Ioana Ciornei <[email protected]>
Newsgroups org.ozlabs.lists.linuxppc-dev,org.infradead.lists.linux-arm-kernel,org.kernel.vger.kernel-janitors,org.kernel.vger.linux-kernel
Message-ID <55dkpjlibtfurmrrzxzznq6e3dhxvo76rsrjnokkaquwktl74r@omft73n4kp52>
On Mon, Jul 27, 2026 at 02:24:55PM +0200, Markus Elfring wrote:
> >> Scope-based resource management became supported for some
> >> programming interfaces by contributions of Peter Zijlstra on 2023-05-26.
> >> See also the commit 54da6a0924311c7cf5015533991e44fb8eb12773 ("locking:
> >> Introduce __cleanup() based infrastructure").
> >>
> >> * Thus use the attribute “__free(kfree)”.
> >>
> >> * Reduce the scope for the local variable “ret”.
> > 
> > Please don't. Let all the variables be defined at the start of each function.
> 
> Do we stumble on another coding style preferences conflict here?

Yes, especially when moving the variable definition is unnecessary.

> https://elixir.bootlin.com/linux/v7.2-rc4/source/include/linux/cleanup.h#L142-L146

The context for the recommendation linked by you is (also from
cleanup.h):

	 * "When multiple variables in the same scope have cleanup attributes,
	 * at exit from the scope their associated cleanup functions are run in
	 * reverse order of definition (last defined, first cleanup)."
	 *
	 * When the unwind order matters it requires that variables be defined
	 * mid-function scope rather than at the top of the file.  Take the
	 * following example and notice the bug highlighted by "!!"::

Which is not the case of these simple functions which only need a kfree.

> 
> 
> >> * Omit two kfree() calls accordingly.
> >>
> >> * Omit the local variable “size” (for another memory allocation).
> > 
> > Please remove this change, not related to the intention of the patch.
> What does hinder to perform the required size determination as a direct parameter
> for a kzalloc() call?

Nothing, but it's a different change. On top of this, it's just churning
the code without an added benefit.

Ioana
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