On 08/09/18 17:28, Borislav Petkov wrote:
> When CONFIG_PARAVIRT_SPINLOCKS=n, it fires
> 
>   arch/x86/kernel/paravirt_patch_64.c: In function ‘native_patch’:
>   arch/x86/kernel/paravirt_patch_64.c:89:1: warning: label ‘patch_site’ 
> defined but not used [-Wunused-label]
>    patch_site:
> 
> but those labels can simply be removed by directly calling the
> respective functions there.
> 
> Get rid of local variables too, while at it.
> 
> Signed-off-by: Borislav Petkov <[email protected]>
> Cc: Juergen Gross <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> ---
> 
> It looks even more cleaner now. :)

And there is still some more clean up possible:

> 
>  arch/x86/kernel/paravirt_patch_32.c | 48 +++++++++++-----------------
>  arch/x86/kernel/paravirt_patch_64.c | 49 ++++++++++++-----------------
>  2 files changed, 39 insertions(+), 58 deletions(-)
> 
> diff --git a/arch/x86/kernel/paravirt_patch_32.c 
> b/arch/x86/kernel/paravirt_patch_32.c
> index d460cbcabcfe..0865323c2716 100644
> --- a/arch/x86/kernel/paravirt_patch_32.c
> +++ b/arch/x86/kernel/paravirt_patch_32.c
> @@ -34,14 +34,10 @@ extern bool pv_is_native_vcpu_is_preempted(void);
>  
>  unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len)
>  {
> -     const unsigned char *start, *end;
> -     unsigned ret;
> -
>  #define PATCH_SITE(ops, x)                                   \
> -             case PARAVIRT_PATCH(ops.x):                     \
> -                     start = start_##ops##_##x;              \
> -                     end = end_##ops##_##x;                  \
> -                     goto patch_site
> +     case PARAVIRT_PATCH(ops.x):                             \
> +             return paravirt_patch_insns(ibuf, len, start_##ops##_##x, 
> end_##ops##_##x)
> +
>       switch (type) {
>  #ifdef CONFIG_PARAVIRT_XXL
>               PATCH_SITE(irq, irq_disable);
> @@ -54,32 +50,26 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long 
> addr, unsigned len)
>               PATCH_SITE(mmu, write_cr3);
>  #endif
>  #if defined(CONFIG_PARAVIRT_SPINLOCKS)
> -             case PARAVIRT_PATCH(lock.queued_spin_unlock):
> -                     if (pv_is_native_spin_unlock()) {
> -                             start = start_lock_queued_spin_unlock;
> -                             end   = end_lock_queued_spin_unlock;
> -                             goto patch_site;
> -                     }
> -                     goto patch_default;
> +     case PARAVIRT_PATCH(lock.queued_spin_unlock):
> +             if (pv_is_native_spin_unlock())
> +                     return paravirt_patch_insns(ibuf, len,
> +                                                 
> start_lock_queued_spin_unlock,
> +                                                 
> end_lock_queued_spin_unlock);
> +             else
> +                     return paravirt_patch_default(type, ibuf, addr, len);

Why not replace the else clause by a "break;" and ...

>  
> -             case PARAVIRT_PATCH(lock.vcpu_is_preempted):
> -                     if (pv_is_native_vcpu_is_preempted()) {
> -                             start = start_lock_vcpu_is_preempted;
> -                             end   = end_lock_vcpu_is_preempted;
> -                             goto patch_site;
> -                     }
> -                     goto patch_default;
> +     case PARAVIRT_PATCH(lock.vcpu_is_preempted):
> +             if (pv_is_native_vcpu_is_preempted())
> +                     return paravirt_patch_insns(ibuf, len,
> +                                                 
> start_lock_vcpu_is_preempted,
> +                                                 end_lock_vcpu_is_preempted);
> +             else
> +                     return paravirt_patch_default(type, ibuf, addr, len);

... this as well and ...

>  #endif
>  
>       default:
> -patch_default: __maybe_unused
> -             ret = paravirt_patch_default(type, ibuf, addr, len);
> -             break;
> -
> -patch_site:
> -             ret = paravirt_patch_insns(ibuf, len, start, end);
> -             break;
> +             return paravirt_patch_default(type, ibuf, addr, len);

... remove this return and ...

>       }
>  #undef PATCH_SITE
> -     return ret;
> +     return 0;

Replace this by
        return paravirt_patch_default(type, ibuf, addr, len);


Same for paravirt_patch_64.c, of course.


Juergen
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