Re: [PATCH 2/4] dmi: Add a DMI firmware node and handling

[Corey Minyard]

On 02/01/2016 03:25 AM, Jean Delvare wrote:
> Hi Corey,
>
> I won't comment on the IPMI side of this as this isn't my area. However
> I have a comment on the DMI part:
>
> Le Friday 29 January 2016 Ã 16:43 -0600, minyard@xxxxxxx a Ãcrit :
> > From: Corey Minyard <cminyard@xxxxxxxxxx>
> >
> > This is so that an IPMI platform device can be created from a
> > DMI firmware entry.
> >
> > Signed-off-by: Corey Minyard <cminyard@xxxxxxxxxx>
> > Cc: Jean Delvare <jdelvare@xxxxxxx>
> > Cc: Andy Lutomirski <luto@xxxxxxxxxx>
> > ---
> >   drivers/firmware/dmi_scan.c | 34 ++++++++++++++++++++++++----------
> >   include/linux/dmi.h         | 24 ++++++++++++++++++++++++
> >   include/linux/fwnode.h      |  1 +
> >   3 files changed, 49 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
> > index da471b2..13d9bca 100644
> > --- a/drivers/firmware/dmi_scan.c
> > +++ b/drivers/firmware/dmi_scan.c
> > @@ -41,6 +41,16 @@ static struct dmi_memdev_info {
> >   } *dmi_memdev;
> >   static int dmi_memdev_nr;
> >   
> > +static void *dmi_zalloc(unsigned len)
> > +{
> > +	void *ret = dmi_alloc(len);
> > +
> > +	if (ret)
> > +		memset(ret, 0, len);
> > +
> > +	return ret;
> > +}
> > +
> >   static const char * __init dmi_string_nosave(const struct dmi_header *dm, u8 s)
> >   {
> >   	const u8 *bp = ((u8 *) dm) + dm->length;
> > @@ -242,6 +252,12 @@ static void __init dmi_save_type(const struct dmi_header *dm, int slot,
> > (...)
> > @@ -250,15 +266,14 @@ static void __init dmi_save_one_device(int type, const char *name)
> >   	if (dmi_find_device(type, name, NULL))
> >   		return;
> >   
> > -	dev = dmi_alloc(sizeof(*dev) + strlen(name) + 1);
> > +	dev = dmi_zalloc(sizeof(*dev) + strlen(name) + 1);
> >   	if (!dev)
> >   		return;
> >   
> >   	dev->type = type;
> >   	strcpy((char *)(dev + 1), name);
> >   	dev->name = (char *)(dev + 1);
> > -	dev->device_data = NULL;
> This change seems rather unrelated, and I'm not sure what purpose it
> serves. On ia64 and arm64 it is clearly redundant as dmi_alloc calls
> kzalloc directly. On x86_64, extend_brk is called instead (don't ask me
> why, I have no clue) but looking at the code I see that it does
> memset(ret, 0, size) as well so memory is also zeroed there. Which makes
> dmi_alloc the same as dmi_zalloc on all 3 architectures.
>
> So please revert this change. This will make your patch easier to
> review, too.
Ok.  I had assumed extend_break wasn't zeroing since there were all the 
NULL assignments,
I should have looked.

I was thinking about this, and the fwnode could just be added to the 
IPMI device.  I'm not
sure if you would prefer that over adding it to dmi_device.  The fwnode 
is in acpi_device,
and I was modelling these changes after that, but maybe that's not 
required here.

Thanks,

-corey