Re: [PATCH] mod_devicetable.h: reduce sizeof(struct of_device_id) by 80 bytes

From: Rasmus Villemoes
Date: Thu May 02 2019 - 09:07:29 EST

On 02/05/2019 14.29, Jeff Mahoney wrote:
> On 5/2/19 5:41 AM, Rasmus Villemoes wrote:

>> But we cannot really know whether there is some userspace tool that
>> parses the .ko ELF objects the same way that file2alias does, doing
>> pattern matching on the symbol names etc. I cannot see why anybody would
>> _do_ that (the in-tree infrastructure already generates the
>> MODULE_ALIAS() from which modules.alias gets generated), but the only
>> way of knowing, I think, is to try to apply the patch and see if anybody
>> complains.
> The size is part of the ABI, though. module-init-tools has a copy of
> the same struct and uses that size to walk an array of of_device_id when
> a module as more than one. If you shrink it, that will certainly break.

Urgh, yes, didn't know about module-init-tools. But it seems to be
abandoned? So does anybody actually use that with a modern kernel (there
seems to be many new structs in mod_devicetable.h that the last release
of module-init-tools doesn't know about)?

Oh well. If it's not deemed worth the risk to do a release with this
patch applied, I can always just add this to the list of trivial things
to do when asked to trim a custom kernel.