Re: [PATCH] Convert filldir[64]() from __put_user() to unsafe_put_user()

[Linus Torvalds]

On Mon, Oct 7, 2019 at 10:34 AM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> Tangentially related: copy_regster_to_user() and copy_regset_from_user().

Not a worry. It's not performance-critical code, and if it ever is, it
needs to be rewritten anyway.


> The former variant tends to lead to few calls
> of __copy_{to,from}_user(); the latter...  On x86 it ends up doing
> this:

Just replace the __put_user() with a put_user() and be done with it.
That code isn't acceptable, and if somebody ever complains about
performance it's not the lack of __put_user that is the problem.

           Linus