linux-kernel - Re: Clarifying confusion of our variable placement rules caused by cleanup.h

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Message-ID: <20251118204313.GI2441659@ZenIV>
Date: Tue, 18 Nov 2025 20:43:13 +0000
From: Al Viro <viro@...iv.linux.org.uk>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Bart Van Assche <bvanassche@....org>,
	James Bottomley <James.Bottomley@...senpartnership.com>,
	ksummit@...ts.linux.dev, Dan Williams <dan.j.williams@...el.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Dan Carpenter <dan.carpenter@...aro.org>
Subject: Re: Clarifying confusion of our variable placement rules caused by
 cleanup.h

On Tue, Nov 18, 2025 at 11:14:21AM -0800, Linus Torvalds wrote:

> It's not exactly uncommon to have code like this:
> 
>     struct xyz *abc = kzalloc(sizeof(struct xyz), GPF_KERNEL);
> 
> and I don't think there's any actual *value* in stating that "struct
> xyz" twice (or in stating the sizeof()).

Depends...  "Need to find all places where we have struct xyz instances
allocated" does happen on code audit; making it harder to find...

Pet peeve: I really wish we had a decent way to say that pointers to
this particular type are _not_ to be converted without an explicit
(and searchable) cast...   Tricks like wrapping pointer into a struct
do work to an extent, but not when you need to dereference it in a lot
of places ;-/