linux-kernel - Re: [cocci] [PATCH v4 2/5] arm64: tlb: Convert the opencoded field modify

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Message-ID: <20250616104109.GA17500@willie-the-truck>
Date: Mon, 16 Jun 2025 11:41:09 +0100
From: Will Deacon <will@...nel.org>
To: Luo Jie <quic_luoj@...cinc.com>
Cc: Markus Elfring <Markus.Elfring@....de>, cocci@...ia.fr,
	LKML <linux-kernel@...r.kernel.org>,
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
	Andrew Lunn <andrew@...n.ch>,
	Catalin Marinas <catalin.marinas@....com>,
	Joey Gouly <joey.gouly@....com>,
	Julia Lawall <Julia.Lawall@...ia.fr>,
	"Kiran Kumar C.S.K" <quic_kkumarcs@...cinc.com>,
	Lei Wei <quic_leiwei@...cinc.com>, Marc Zyngier <maz@...nel.org>,
	Nicolas Palix <nicolas.palix@...g.fr>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Pavithra R <quic_pavir@...cinc.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Suruchi Agarwal <quic_suruchia@...cinc.com>,
	Suzuki Poulose <suzuki.poulose@....com>,
	Yury Norov <yury.norov@...il.com>,
	Zenghui Yu <yuzenghui@...wei.com>, quic_linchen@...cinc.com
Subject: Re: [cocci] [PATCH v4 2/5] arm64: tlb: Convert the opencoded field
 modify

On Mon, Jun 16, 2025 at 06:37:41PM +0800, Luo Jie wrote:
> 
> 
> On 6/13/2025 4:15 AM, Markus Elfring wrote:
> > I see further refinement possibilities for such a change description.
> > 
> > 
> > > Replace below code with the wrapper FIELD_MODIFY(MASK, &reg, val)
> > > - reg &= ~MASK;
> > > - reg |= FIELD_PREP(MASK, val);
> > 
> > * How do you think about to omit leading minus characters?
> > 
> > * Subsequent blank line?
> > 
> > 
> > > More information about semantic patching is available at
> > > http://coccinelle.lip6.fr/
> > 
> > I suggest to omit this information here (and in similar patches).
> > 
> > Regards,
> > Markus
> 
> Thank you for your suggestions. The current commit message was generated
> by the following patch mode command:
> ```
> make coccicheck MODE=patch COCCI=scripts/coccinelle/misc/field_modify.cocci
> V=1
> ```
> However, as I understand, the discussion on the ARM patches (between
> Russel/Marc/Yury) has concluded that the ARM arch changes may not be
> adding value over the current code, so I will drop the ARM patches
> in the next version.

Well, hang on a second. From what I can tell, the objections haven't
been specific to arch/arm{,64}/. You haven't really explained why this
new helper is needed and what value it brings over the existing set of
functionality.

So maybe start there, rather than dropping the parts that attracted the
comments to start with?

Will