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Date: Thu, 27 Oct 2016 20:25:57 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Fenghua Yu <fenghua.yu@intel.com>
cc: "H. Peter Anvin" <h.peter.anvin@intel.com>,
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Subject: Re: [PATCH v5 12/18] x86/intel_rdt: Add "info" files to resctrl file
 system
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On Thu, 27 Oct 2016, Fenghua Yu wrote:

> On Wed, Oct 26, 2016 at 04:45:50PM +0200, Thomas Gleixner wrote:
> > On Sat, 22 Oct 2016, Fenghua Yu wrote:
> > > +/*
> > > + * Forcibly remove all of subdirectories under root.
> > > + */
> > > +static void rmdir_all_sub(void)
> > > +{
> > > +	kernfs_remove(kn_info);
> > 
> > What clears kn_info?
> 
> Is the question "Why clears kn_info?"
> 
> kn_info is created during mount time and has different contents
> under "info" directory with CDP enabled or disabled by mount parameter "cdp".
> 
> umount needs to remove kn_info so that it's ready to be created next time
> during mount time. So user can do CAT mount, check "info", umount, and then
> CDP mount, check "info". The user will see different contents in two "info"
> checks.

Lemme rephrase. What does: kn_info = NULL; ?

We should clear static variables for correctness sake. The current code has
no problem with that, but 5 month down the road something is going to trip
over the stale reference.

Thanks,

	tglx