Re: [PATCH RFC v2] m68k: remove get_fs()/set_fs()

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Geert,

Am 09.07.2021 um 19:29 schrieb Geert Uytterhoeven:
> Hi Christoph,
>
> On Fri, Jul 9, 2021 at 6:22 AM Christoph Hellwig <hch@lst.de> wrote:
>> On Fri, Jul 09, 2021 at 12:31:45PM +1200, Michael Schmitz wrote:
>>> That patch works fine on a casual test. What you did to
>>> __constant_copy_to_user() does not appear to matter - but I haven't put the
>>> system under any kind of stress yet. I'm a little reluctant to do that
>>> (recovering from a trashed boot disk is a little dicey), I'll probably only
>>> try that with your changes to __constant_copy_to_user() from commit
>>> d36105c942e0 backed out.
>>
>> As Linus pointed out, small copy_to_user basically doesn't happen as
>> we have switched all the suspect call sites to just use put_user.
>>
>> Geert: do you care about __constant_copy_to_user at all, or can we just
>> kill it (as well as the copy_from_user side)?
>
> If it blocks you, feel free to remove it.
> BTW, do you have an idea of how many calls use small sizes?

Just booting to a login prompt: Quite a few with 8 bytes, some with 4 
bytes (those from the keyboard driver), the rest is 16, 24, 36 and 92 
bytes (a lot of those). Used ratelimiting so probably missed a few.

I'll repeat that again logging only the small sizes, but I think we can 
live with using the generic version for those few 4 and 8 byte cases.

Cheers,

	Michael

>
> Gr{oetje,eeting}s,
>
>                         Geert
>