Re: [PATCH v3 05/10] x86/fpu/xstate: Define new functions for clearing fpregs and xstates

[Yu-cheng Yu]

On Wed, 2020-04-29 at 11:27 +0200, Borislav Petkov wrote:
> On Sat, Mar 28, 2020 at 09:43:02AM -0700, Yu-cheng Yu wrote:
> > @@ -318,18 +313,40 @@ static inline void copy_init_fpstate_to_fpregs(void)
> >   * Called by sys_execve(), by the signal handler code and by various
> >   * error paths.
> >   */
> > -void fpu__clear(struct fpu *fpu)
> > +static void fpu__clear(struct fpu *fpu, int clear_user_only)
> 
> I said:
> 
> "fpu__clear(struct fpu *fpu, bool user_only)"
>                            ^^^^^^^^^^^^^^
> 
> you made it
> 
>                    ..., int clear_user_only)
> 
> Why?
> 
> If you agree with the review comment, then please do it as suggested. If
> you don't, then say why you don't.
> 
> Why would you do something in-between?
> 
> >  {
> > -   WARN_ON_FPU(fpu != &current->thread.fpu); /* Almost certainly an 
> > anomaly */
> 
> Why are you moving this into the callers when *both* do it?
> 
> > +   if (static_cpu_has(X86_FEATURE_FPU)) {
> 
> Flip this logic:
> 
>       if (!static_cpu_has(X86_FEATURE_FPU)) {
>                 fpu__drop(fpu);
>                 fpu__initialize(fpu);
>               return;
>       }
> 
>       fpregs_lock();
>       ...
> 
> to save an indentation level and make the important case more readable
> and locking more prominent.

All fixed.

Thanks,
Yu-cheng