linux-kernel - RE: [PATCH v3] efivars,efi-pstore: Hold off deletion of sysfs entry until, the scan is completed

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Date:	Wed, 30 Oct 2013 19:19:11 +0000
From:	Seiji Aguchi <seiji.aguchi@....com>
To:	Matt Fleming <matt@...sole-pimps.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"matt.fleming@...el.com" <matt.fleming@...el.com>,
	"tony.luck@...el.com" <tony.luck@...el.com>,
	Tomoki Sekiyama <tomoki.sekiyama@....com>,
	"dle-develop@...ts.sourceforge.net" 
	<dle-develop@...ts.sourceforge.net>
Subject: RE: [PATCH v3] efivars,efi-pstore: Hold off deletion of sysfs entry
 until, the scan is completed

> On Fri, 18 Oct, at 10:30:58PM, Seiji Aguchi wrote:
> > The scanning and deleting logic is still needed.  In case an entry(A)
> > is found, the pointer is saved to psi->data.  And efi_pstore_read()
> > passes the entry(A) to a pstore filesystem by releasing
> > __efivars->lock.
> >
> > And then, the pstore filesystem calls efi_pstore_read() again and the
> > same entry(A), which is saved to psi->data, is used for re-scanning a
> > sysfs-list.  (That is why list_for_each_entry_safe_from () is used in
> > efi_pstore_sysfs_entry_iter().)
> >
> > So, to protect the entry(A), the logic is needed because, in pstore
> > filesystem,  __efivars->lock Is released.
> 
> Very good point.

Thanks,

I will add the description in the next patch.

Seiji
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