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Subject: RE: [PATCH v4 1/8] drivers: base: Add hardware prefetch control core
 driver
Thread-Topic: [PATCH v4 1/8] drivers: base: Add hardware prefetch control core
 driver
Thread-Index: AQHYaoDl8CSHsFy4xEexv5ItLZ1gVa0kN1gAgABT8sA=
Date:   Wed, 18 May 2022 12:38:02 +0000
Message-ID: <OSBPR01MB203742A3195333D0E8785E5A80D19@OSBPR01MB2037.jpnprd01.prod.outlook.com>
References: <20220518063032.2377351-1-tarumizu.kohei@fujitsu.com>
 <20220518063032.2377351-2-tarumizu.kohei@fujitsu.com>
 <YoSbmA+5m1Le0XGe@kroah.com>
In-Reply-To: <YoSbmA+5m1Le0XGe@kroah.com>
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Thanks for the comment.

> This feels wrong, attributes should be groups and be automatically added =
and
> removed by the driver core that way.  Not as lists of attributes like thi=
s, as that
> will race and be wrong.
>=20
> Use a list of attribute groups please.

> You just raced with userspace and lost :(
>=20
> Please use attribute groups instead of manually adding files after the de=
vice is
> created and userspace is notified that it was present.
>=20
> That also makes your clean up logic much simpler (i.e. none as the drive =
core did it
> for you already.)

> Attribute groups please.

I modify to use attribute groups in the next version.

> Why do you think this needs to be in the driver core?  Why isn't this jus=
t a normal
> cpu driver?
>=20
> thanks,

Does this mean that creating only dedicated driver for a CPU (e.g.
arch/x86/kernel/cpu/x86-pfctl.c) without creating core driver?
If so, there is no problem. I remove the core driver and create only
the dedicated drivers for each CPU in the next version.

As a reference, I previously wanted to define it as a common sysfs I/F
for A64FX and x86, so I create a core driver to provide it. However,
as I proceed with the consideration, it became clear that these were
independent I/F specifications. Therefore, the core driver is not
currently needed.