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Date:   Thu, 13 Apr 2023 11:02:44 +0100
From:   Conor Dooley <conor.dooley@microchip.com>
To:     Pierre Gondois <pierre.gondois@arm.com>
CC:     <linux-kernel@vger.kernel.org>, Radu Rendec <rrendec@redhat.com>,
        Alexandre Ghiti <alexghiti@rivosinc.com>,
        Will Deacon <will@kernel.org>, Conor Dooley <conor@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Palmer Dabbelt <palmer@rivosinc.com>,
        Gavin Shan <gshan@redhat.com>
Subject: Re: [PATCH v3 3/4] arch_topology: Remove early cacheinfo error
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Message-ID: <20230413-prudishly-unruly-090f5297fd54@wendy>
References: <20230413091436.230134-1-pierre.gondois@arm.com>
 <20230413091436.230134-4-pierre.gondois@arm.com>
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On Thu, Apr 13, 2023 at 11:14:33AM +0200, Pierre Gondois wrote:
> fetch_cache_info() tries to get the number of cache leaves/levels
> for each CPU in order to pre-allocate memory for cacheinfo struct.
> Allocating this memory later triggers a:
>   'BUG: sleeping function called from invalid context'
> in PREEMPT_RT kernels.
>=20
> If there is no cache related information available in DT or ACPI,
> fetch_cache_info() fails and an error message is printed:
>   'Early cacheinfo failed, ret =3D ...'
>=20
> Not having cache information should be a valid configuration.
> Remove the error message if fetch_cache_info() fails.
>=20
> Suggested-by: Conor Dooley <conor@kernel.org>

Not that it really matters for suggested-by, and there's no way really
for you to know, but the corporate overlords prefer:
s/conor@kernel.org/conor.dooley@microchip.com/

> Link: https://lore.kernel.org/all/20230404-hatred-swimmer-6fecdf33b57a@sp=
ud/
> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
> ---
>  drivers/base/arch_topology.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>=20
> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index b1c1dd38ab01..1f071eaede5b 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c
> @@ -843,10 +843,8 @@ void __init init_cpu_topology(void)
> =20
>  	for_each_possible_cpu(cpu) {
>  		ret =3D fetch_cache_info(cpu);
> -		if (ret) {
> -			pr_err("Early cacheinfo failed, ret =3D %d\n", ret);

Hmm do you really want to remove the print altogether? This can fail
with -EINVAL and -ENOMEM too, so should we just check for
| if (ret && ret !=3D -ENOENT)
instead, since in the other cases it really did fail?

Cheers,
Conor.

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