2018-06-22 19:30:10

by Mathieu Malaterre

Subject: [PATCH] powerpc/mm: remove warning about ‘type’ being set

‘type’ is only used when CONFIG_DEBUG_HIGHMEM is set. So add a possibly
unused tag to variable. Remove warning treated as error with W=1:

arch/powerpc/mm/highmem.c:59:6: error: variable ‘type’ set but not used [-Werror=unused-but-set-variable]

Signed-off-by: Mathieu Malaterre <[email protected]>
---
arch/powerpc/mm/highmem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c
index 668e87d03f9e..82a0e37557a5 100644
--- a/arch/powerpc/mm/highmem.c
+++ b/arch/powerpc/mm/highmem.c
@@ -56,7 +56,7 @@ EXPORT_SYMBOL(kmap_atomic_prot);
void __kunmap_atomic(void *kvaddr)
{
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
- int type;
+ int type __maybe_unused;

if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
pagefault_enable();
--
2.11.0

2018-06-23 17:13:39

by Christophe Leroy

Subject: Re: [PATCH] powerpc/mm: remove warning about ‘type’ being set

Le 22/06/2018 à 21:27, Mathieu Malaterre a écrit :
> ‘type’ is only used when CONFIG_DEBUG_HIGHMEM is set. So add a possibly
> unused tag to variable. Remove warning treated as error with W=1:
>
> arch/powerpc/mm/highmem.c:59:6: error: variable ‘type’ set but not used [-Werror=unused-but-set-variable]

Is type neeeded at all when CONFIG_DEBUG_HIGHMEM is not set ?

The call type = kmap_atomic_idx(); seems useless when
CONFIG_DEBUG_HIGHMEM isn't set. Couldn't we just most type definition
and setting inside the CONFIG_DEBUG_HIGHMEM {} below ?

Alternatively, maybe you could replace the #ifdef CONFIG_DEBUG_HIGHMEM
by an if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM)) ?

Christophe

>
> Signed-off-by: Mathieu Malaterre <[email protected]>
> ---
> arch/powerpc/mm/highmem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c
> index 668e87d03f9e..82a0e37557a5 100644
> --- a/arch/powerpc/mm/highmem.c
> +++ b/arch/powerpc/mm/highmem.c
> @@ -56,7 +56,7 @@ EXPORT_SYMBOL(kmap_atomic_prot);
> void __kunmap_atomic(void *kvaddr)
> {
> unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
> - int type;
> + int type __maybe_unused;
>
> if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
> pagefault_enable();
>

---
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https://www.avast.com/antivirus

2018-06-26 06:26:50

by Mathieu Malaterre

Subject: Re: [PATCH] powerpc/mm: remove warning about ‘type’ being set

On Sat, Jun 23, 2018 at 7:12 PM christophe leroy
<[email protected]> wrote:
>
>
>
> Le 22/06/2018 à 21:27, Mathieu Malaterre a écrit :
> > ‘type’ is only used when CONFIG_DEBUG_HIGHMEM is set. So add a possibly
> > unused tag to variable. Remove warning treated as error with W=1:
> >
> > arch/powerpc/mm/highmem.c:59:6: error: variable ‘type’ set but not used [-Werror=unused-but-set-variable]
>
> Is type neeeded at all when CONFIG_DEBUG_HIGHMEM is not set ?
>
> The call type = kmap_atomic_idx(); seems useless when
> CONFIG_DEBUG_HIGHMEM isn't set. Couldn't we just most type definition
> and setting inside the CONFIG_DEBUG_HIGHMEM {} below ?
>
> Alternatively, maybe you could replace the #ifdef CONFIG_DEBUG_HIGHMEM
> by an if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM)) ?

I am not familiar with this code. But starring at other arch
implementations (eg. `arch/x86/mm/highmem_32.c`), it feels like
powerpc is skipping `pte_clear(&init_mm, vaddr, kmap_pte-idx);` unless
`CONFIG_DEBUG_HIGHMEM=y`. Could someone please confirm this is the
correct behavior ?

Or else I can rewrite the code a bit like `arch/arm/mm/highmem.c`
which skips `set_fixmap_pte(idx, __pte(0));` unless
`CONFIG_DEBUG_HIGHMEM=y`.

> Christophe
>
> >
> > Signed-off-by: Mathieu Malaterre <[email protected]>
> > ---
> > arch/powerpc/mm/highmem.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c
> > index 668e87d03f9e..82a0e37557a5 100644
> > --- a/arch/powerpc/mm/highmem.c
> > +++ b/arch/powerpc/mm/highmem.c
> > @@ -56,7 +56,7 @@ EXPORT_SYMBOL(kmap_atomic_prot);
> > void __kunmap_atomic(void *kvaddr)
> > {
> > unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
> > - int type;
> > + int type __maybe_unused;
> >
> > if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
> > pagefault_enable();
> >
>
> ---
> L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
> https://www.avast.com/antivirus
>

2018-08-13 11:24:43

by Michael Ellerman

Subject: Re: powerpc/mm: remove warning about ‘type’ being set

On Fri, 2018-06-22 at 19:27:47 UTC, Mathieu Malaterre wrote:
> ‘type’ is only used when CONFIG_DEBUG_HIGHMEM is set. So add a possibly
> unused tag to variable. Remove warning treated as error with W=1:
>
> arch/powerpc/mm/highmem.c:59:6: error: variable ‘type’ set but not used [-Werror=unused-but-set-variable]
>
> Signed-off-by: Mathieu Malaterre <[email protected]>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/fce278af81daf8599f9e94883cbe43

cheers