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

From: Corey Minyard
Date: Tue Feb 02 2016 - 08:37:34 EST


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