linux-kernel - Re: [PATCH v2 09/16] PM / hibernate: Reserve hibernation key and erase footprints

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Message-ID: <20150813032500.GG5518@linux-rxt1.site>
Date:	Thu, 13 Aug 2015 11:25:00 +0800
From:	joeyli <jlee@...e.com>
To:	"Chen, Yu C" <yu.c.chen@...el.com>
Cc:	"joeyli.kernel@...il.com" <joeyli.kernel@...il.com>,
	"matthew.garrett@...ula.com" <matthew.garrett@...ula.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"vojtech@...e.cz" <vojtech@...e.cz>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"pavel@....cz" <pavel@....cz>,
	"rjw@...ysocki.net" <rjw@...ysocki.net>,
	"jkosina@...e.cz" <jkosina@...e.cz>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"hpa@...or.com" <hpa@...or.com>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"Brown, Len" <len.brown@...el.com>,
	"jwboyer@...hat.com" <jwboyer@...hat.com>,
	"Fleming, Matt" <matt.fleming@...el.com>
Subject: Re: [PATCH v2 09/16] PM / hibernate: Reserve hibernation key and
 erase footprints

Hi Yu, 

Thanks for your reviewing.

On Thu, Aug 13, 2015 at 02:45:32AM +0000, Chen, Yu C wrote:
> Hi Chun-yi,
> On Tue, 2015-08-11 at 14:16 +0800, Lee, Chun-Yi wrote:
> 
> > +/* A page used to keep hibernation keys */
> > +static struct hibernation_keys *hibernation_keys;
> > +
> > +void __init parse_hibernation_keys(u64 phys_addr, u32 data_len)
> > +{
> > +	struct setup_data *hibernation_setup_data;
> > +
> > +	/* Reserve keys memory, will copy and erase in init_hibernation_keys() */
> > +	keys_phys_addr = phys_addr + sizeof(struct setup_data);
> > +	memblock_reserve(keys_phys_addr, sizeof(struct hibernation_keys));
> > +
> > +	/* clear hibernation_data */
> > +	hibernation_setup_data = early_memremap(phys_addr, data_len);
> > +	if (!hibernation_setup_data)
> > +		return;
> > +
> should we invoke memblock_free if early_memremap failed?
> 
> Best Regards,
> Yu
> 
> 

Should not free memblock reservation of key data.

Using memblock_reserve is for reserve hibernation key until
init_hibernation_keys() copy key data to arbitrary allocated page.
Using early_memremap is for cleaning the setup_data header that's
used to carry key. That above 2 actions are different purposes.

So, even the action of cleaning setup_data failed, it doesn't
affect to the action for reserve hibernation key by memblock until
copy it.


Thanks a lot!
Joey Lee
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