Re: [PATCH] nvdimm: constify device_type structures

From: Dan Williams
Date: Tue Jan 24 2017 - 21:40:29 EST

On Tue, Jan 24, 2017 at 6:37 PM, Joe Perches <joe@xxxxxxxxxxx> wrote:
> On Wed, 2017-01-25 at 00:54 +0530, Bhumika Goyal wrote:
>> Declare device_type structure as const as it is only stored in the
>> type field of a device structure. This field is of type const, so add
>> const to declaration of device_type structure.
>> File size before:
>> text data bss dec hex filename
>> 19278 3199 16 22493 57dd nvdimm/namespace_devs.o
>> File size after:
>> text data bss dec hex filename
>> 19929 3160 16 23105 5a41 nvdimm/namespace_devs.o
> Fine, but are you sure about the sizes?
> It seems odd the text went up 651 bytes
> while the data went down just 39 bytes.

Right, the size data wasn't why I applied it. It was the general rule
of "make function pointer data read-only whenever possible to
eliminate a kernel attack vector". Bhumika, you might want to mention
this as the motivating reason to apply the patch if you do more of
these changes.