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Message-ID: <99d26b0e-efd7-a32d-7be0-607c98ac2569@redhat.com>
Date: Wed, 18 Nov 2020 12:00:49 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Justin Ernst <justin.ernst@....com>,
Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
Mark Gross <mgross@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Steve Wahl <steve.wahl@....com>, x86@...nel.org
Cc: Andy Shevchenko <andy@...radead.org>,
Darren Hart <dvhart@...radead.org>,
Dimitri Sivanich <dimitri.sivanich@....com>,
"H . Peter Anvin" <hpa@...or.com>,
Russ Anderson <russ.anderson@....com>,
linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org,
Cezary Rojewski <cezary.rojewski@...el.com>,
Ilya Dryomov <idryomov@...il.com>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
Vaibhav Jain <vaibhav@...ux.ibm.com>
Subject: Re: [PATCH 0/5] Add uv_sysfs platform driver
Hi,
On 11/17/20 9:42 PM, Justin Ernst wrote:
> Introduce a new platform driver to gather topology information from UV systems
> and expose that information via a sysfs interface at /sys/firmware/sgi_uv/.
>
> Justin Ernst (5):
> x86/platform/uv: Remove existing /sys/firmware/sgi_uv/ interface
> x86/platform/uv: Add and export uv_bios_* functions
> x86/platform/uv: Add new uv_sysfs platform driver
> x86/platform/uv: Update ABI documentation of /sys/firmware/sgi_uv/
> x86/platform/uv: Update MAINTAINERS for uv_sysfs driver
So patch 1/1 drops the existing
/sys/firmware/sgi_uv/coherence_id
/sys/firmware/sgi_uv/partition_id
sysfs API, then according to patch 4/5 patch 3/5 reintroduces
the /sys/firmware/sgi_uv/partition_id API, but the /sys/firmware/sgi_uv/coherence_id
file is gone for ever ?
I'm not sure what userspace bits (may) depend on this but without more info
this looks like a clear violation of the do not break userspace APIs rule.
So, based on this, I have to nack this series in its current state.
Now if there is a strong believe there are 0 (not a few, but _zero_) users
out there who rely on the /sys/firmware/sgi_uv/coherence_id file then this
might be ok. But then there needs to be a technical analysis of why this is
ok in the commit message of the patch dropping this sysfs file.
Also the commit message of patch 1/5 should mention that
/sys/firmware/sgi_uv/partition_id will be re-introduced later through
another driver.
Regards,
Hans
>
> .../ABI/testing/sysfs-firmware-sgi_uv | 137 ++-
> MAINTAINERS | 6 +
> arch/x86/include/asm/uv/bios.h | 49 +
> arch/x86/include/asm/uv/uv_geo.h | 103 +++
> arch/x86/platform/uv/Makefile | 2 +-
> arch/x86/platform/uv/bios_uv.c | 54 ++
> arch/x86/platform/uv/uv_sysfs.c | 63 --
> drivers/platform/x86/Kconfig | 11 +
> drivers/platform/x86/Makefile | 3 +
> drivers/platform/x86/uv_sysfs.c | 853 ++++++++++++++++++
> 10 files changed, 1202 insertions(+), 79 deletions(-)
> create mode 100644 arch/x86/include/asm/uv/uv_geo.h
> delete mode 100644 arch/x86/platform/uv/uv_sysfs.c
> create mode 100644 drivers/platform/x86/uv_sysfs.c
>
>
> base-commit: 4ef8451b332662d004df269d4cdeb7d9f31419b5
>
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