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Date:   Wed, 31 May 2023 10:26:14 +0100
From:   Conor Dooley <conor@kernel.org>
To:     Sudeep Holla <sudeep.holla@arm.com>
Cc:     Florian Fainelli <florian.fainelli@broadcom.com>,
        stable@vger.kernel.org, Pierre Gondois <pierre.gondois@arm.com>,
        Conor Dooley <conor.dooley@microchip.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        "open list:GENERIC ARCHITECTURE TOPOLOGY" 
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH stable 6.3 v2] arch_topology: Remove early cacheinfo
 error message if -ENOENT
Message-ID: <20230531-anatomy-rectified-6ed3555c5f16@spud>
References: <20230530201955.848176-1-florian.fainelli@broadcom.com>
 <20230530-basically-wildly-84415a94171d@spud>
 <72d84100-55cf-566d-8301-7147ce14b1e9@broadcom.com>
 <20230531085356.ru4fmtawyxo5cq5s@bogus>
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On Wed, May 31, 2023 at 09:53:56AM +0100, Sudeep Holla wrote:
> On Tue, May 30, 2023 at 03:42:45PM -0700, Florian Fainelli wrote:
> > Hi Conor,
> >=20
> > On 5/30/23 14:39, Conor Dooley wrote:
> > > Yo Florian,
> > >=20
> > > On Tue, May 30, 2023 at 01:19:55PM -0700, Florian Fainelli wrote:
> > > > From: Pierre Gondois <pierre.gondois@arm.com>
> > > >=20
> > > > commit 3522340199cc060b70f0094e3039bdb43c3f6ee1 upstream
> > > >=20
> > > > 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 with -ENOENT.
> > > >=20
> > > > Suggested-by: Conor Dooley <conor.dooley@microchip.com>
> > > > Link: https://lore.kernel.org/all/20230404-hatred-swimmer-6fecdf33b=
57a@spud/
> > > > Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
> > > > Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> > > > Link: https://lore.kernel.org/r/20230414081453.244787-4-pierre.gond=
ois@arm.com
> > > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> > > > Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
> > >=20
> > > How come this now needs a backport? Did the rest of the series get
> > > backported, but not this one since it has no fixes tag?
> >=20
> > Humm, indeed, this has been present in v6.3.2 since I requested it to be
> > included. The error that I saw this morning was not -ENOENT, but -EINVA=
L.
> >=20
> > With those patches applied, no more -EINVAL:
> >=20
> > cacheinfo: Allow early level detection when DT/ACPI info is missing/bro=
ken
> > cacheinfo: Add arm64 early level initializer implementation
> > cacheinfo: Add arch specific early level initializer
> > cacheinfo: Add use_arch[|_cache]_info field/function
> >=20
> > I will submit those shortly unless we think they better not be in 6.3, =
in
> > which case it would be nice to silence those -EINVAL errors.
>=20
> I prefer this option instead of back porting all the above 4 as there are
> some pending fixes for the issues found in those patches. I am fine if Gr=
eg
> is happy with the backport, so no strong rejection from my side :).

Just to be clear, I was not objecting, just curious!

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