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Date: Thu, 25 Sep 2025 16:30:46 -0400
From: Nathan Chancellor <nathan@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
	Patrisious Haddad <phaddad@nvidia.com>,
	Tariq Toukan <tariqt@nvidia.com>,
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Subject: Re: [PATCH net-next V5] net/mlx5: Improve write-combining test
 reliability for ARM64 Grace CPUs
Message-ID: <20250925203046.GA491548@ax162>
References: <1758800913-830383-1-git-send-email-tariqt@nvidia.com>
 <20250925115433.GU2617119@nvidia.com>
 <d548b14e-ae28-4807-9b29-9961543ea549@nvidia.com>
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On Thu, Sep 25, 2025 at 03:05:52PM +0200, Arnd Bergmann wrote:
> On the other hand, I would in general strongly prefer
> 
>      if (IS_ENABLED(CONFIG_FOO)) {
>             ...
>      }
> 
> over any of the preprocessor conditionals, both for readability
> and for improving compile-time coverage of the conditional code.
> 
> Unfortunately that does not work here because kernel_neon_begin()
> etc are only defined on Arm.

Even if the neon macros/functions were to be dummy defined, I suspect
clang may complain about the vector register clobbers on architectures
other than arm64, since it will validate some inline assembly even in
dead code.