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Date: Wed, 15 Jan 2025 10:26:51 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Costa Shulyupin <costa.shul@redhat.com>, Daniel Bristot de Oliveira
 <bristot@kernel.org>, John Kacur <jkacur@redhat.com>, "Luis Claudio R.
 Goncalves" <lgoncalv@redhat.com>, Eder Zulian <ezulian@redhat.com>, Tomas
 Glozar <tglozar@redhat.com>, Gabriele Monaco <gmonaco@redhat.com>,
 linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] Fix bug and add osnoise_trace_is_off()
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In-Reply-To: <4ee1e1a7-f0b3-4062-97d9-45a342d0ca21@stanley.mountain>
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On Wed, 15 Jan 2025 12:02:00 +0300
Dan Carpenter <dan.carpenter@linaro.org> wrote:

> You introduced a bug by changing the order.
> 
> You have to undestand that to the original authors this stuff was really
> easy and they knew the order of the struct members because they chose it
> deliberately.  In the end, they get so used to the code that
> "&record->trace" just becomes an idiom for casting "record" and they
> forget how it looks to a newcomer.
> 
> I *personally* am not a fan of code which assumes we know the order of
> the struct members so I don't have a problem with you re-writing the
> code.  But the commit message must say that it is just a cleanup and not
> a fix.
> 
> Which reminds me that I had intended to create a container_of_first()
> for code like this which assumes that container_of() is just a cast.
> There is lots of code like this:
> 
> 	struct something *member = container_of(p, struct foo, first_member);
> 
> 	if (IS_ERR(member)) {
> 
> Which relies on the face that "first_member" is the first member of
> foo struct.  It's a quite common thing.

I agree that this is not a bug, but I will happily take a clean up to make
it more robust.

-- Steve