Re: [PATCH stable 6.3 v2] arch_topology: Remove early cacheinfo error message if -ENOENT

[Conor Dooley <conor@kernel.org>]

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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,
> > 
> > On 5/30/23 14:39, Conor Dooley wrote:
> > > Yo Florian,
> > > 
> > > On Tue, May 30, 2023 at 01:19:55PM -0700, Florian Fainelli wrote:
> > > > From: Pierre Gondois <pierre.gondois@arm.com>
> > > > 
> > > > commit 3522340199cc060b70f0094e3039bdb43c3f6ee1 upstream
> > > > 
> > > > 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.
> > > > 
> > > > 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 = ...'
> > > > 
> > > > Not having cache information should be a valid configuration.
> > > > Remove the error message if fetch_cache_info() fails with -ENOENT.
> > > > 
> > > > Suggested-by: Conor Dooley <conor.dooley@microchip.com>
> > > > Link: https://lore.kernel.org/all/20230404-hatred-swimmer-6fecdf33b57a@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.gondois@arm.com
> > > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> > > > Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
> > > 
> > > 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?
> > 
> > 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 -EINVAL.
> > 
> > With those patches applied, no more -EINVAL:
> > 
> > cacheinfo: Allow early level detection when DT/ACPI info is missing/broken
> > cacheinfo: Add arm64 early level initializer implementation
> > cacheinfo: Add arch specific early level initializer
> > cacheinfo: Add use_arch[|_cache]_info field/function
> > 
> > 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.
> 
> 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 Greg
> 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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