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

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Message-ID: <20251118155122.59dde92f@gandalf.local.home>
Date: Tue, 18 Nov 2025 15:51:22 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: James Bottomley <James.Bottomley@...senPartnership.com>
Cc: Linus Torvalds  <torvalds@...ux-foundation.org>, Bart Van Assche
 <bvanassche@....org>, 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, 18 Nov 2025 15:21:10 -0500
James Bottomley <James.Bottomley@...senPartnership.com> wrote:

> There is one last case that hasn't been discussed, which is where you
> deliberately introduce an extra scope block for the free and
> allocation, so in your example above it would look like
> 
> 	if (ret < )
> 		return -ERROR
> 
> 	[ several more error exits ]
> 
> 	{
> 		struct foo *var __free(kfree) = kmalloc(...)
> 
> 		[...]
> 	}

I'm not too big on explicit blocks for just declarations. Especially, in my
case where the var is used until the end:

	{
		struct foo *var __free(kfree) = kmalloc(...)

		[...]

		return func(..., var);
	}

It seems a bit strange to have the final return of a function from within
an explicit scope block. Especially since the beginning is just for error
conditions, and the meat of the function is now in that explicit block.

-- Steve