Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 14 Mar 2022 16:10:39 -0700
From:   "Luck, Tony" <tony.luck@intel.com>
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     Jithu Joseph <jithu.joseph@intel.com>, hdegoede@redhat.com,
        markgross@kernel.org, tglx@linutronix.de, mingo@redhat.com,
        bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org,
        hpa@zytor.com, corbet@lwn.net, andriy.shevchenko@linux.intel.com,
        ashok.raj@intel.com, rostedt@goodmis.org,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
        platform-driver-x86@vger.kernel.org, patches@lists.linux.dev,
        ravi.v.shankar@intel.com, Dan Williams <dan.j.williams@intel.com>
Subject: Re: [RFC 00/10] Introduce In Field Scan driver
Message-ID: <Yi/Lb5laEki0JHft@agluck-desk3.sc.intel.com>
References: <20220301195457.21152-1-jithu.joseph@intel.com>
 <Yh59rOIH24X+6GyI@kroah.com>
 <Yh5+om/Nr06V0+Qj@kroah.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <Yh5+om/Nr06V0+Qj@kroah.com>
Precedence: bulk

On Tue, Mar 01, 2022 at 09:14:26PM +0100, Greg KH wrote:
> On Tue, Mar 01, 2022 at 09:10:20PM +0100, Greg KH wrote:
> > On Tue, Mar 01, 2022 at 11:54:47AM -0800, Jithu Joseph wrote:
> > > Note to Maintainers:
> > > Requesting x86 Maintainers to take a look at patch01 as it
> > > touches arch/x86 portion of the kernel. Also would like to guide them
> > > to patch07 which sets up hotplug notifiers and creates kthreads.
> > > 
> > > Patch 2/10 - Adds Documentation. Requesting Documentation maintainer to review it.
> > > 
> > > Requesting Greg KH to review the sysfs changes added by patch08.
> > 
> > "RFC" means you are not comfortable submitting the changes yet, so you
> > don't need my review at this point in time.  Become confident in your
> > changes before asking for others to review the code please.
> 
> Hint, it needs work, sysfs_emit() for one thing, lack of reference
> counting on your cpu objects is another...

Greg,

Thanks for the comments. They triggered a bunch of internal
re-thinking of the interface.  One idea that has some traction
(Credit/Blame: Dan Williams) is to:

1) Don't put anything in /sys/devices/system/cpu/*
2) Driver creates some info/control files in its own
   corner of /sys/devices/.../ifs
3) No per-cpu files ... run a test with:
   # echo ${cpu} > /sys/devices/.../ifs/run_test
4) No test result files.
   When tests complete they report using uevents

Using uevent to report means that we can easily have
mutiple parts to the result (pass/fail/incomplete status, as well
as diagnostic details about the reason for the failure,
or why the test was not completed).

This seems a novel use of uevent ... is it OK, or is is abuse?

Thanks

-Tony