2019-02-18 13:48:26

by Yue Haibing

Subject: [PATCH -next] mm: fix set but not used warning

Fixes gcc '-Wunused-but-set-variable' warning:

lib/ioremap.c: In function 'ioremap_page_range':
lib/ioremap.c:203:16: warning:
variable 'start' set but not used [-Wunused-but-set-variable]

flush_cache_vmap may no need param, so add __maybe_unused fix this warning.

Signed-off-by: YueHaibing <[email protected]>
---
lib/ioremap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/ioremap.c b/lib/ioremap.c
index 063213685563..d1c7a488e731 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -200,7 +200,7 @@ int ioremap_page_range(unsigned long addr,
unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
{
pgd_t *pgd;
- unsigned long start;
+ unsigned long __maybe_unused start;
unsigned long next;
int err;

2019-02-19 18:29:26

by Kani, Toshimitsu

Subject: Re: [PATCH -next] mm: fix set but not used warning

On Mon, 2019-02-18 at 13:57 +0000, YueHaibing wrote:
> Fixes gcc '-Wunused-but-set-variable' warning:
>
> lib/ioremap.c: In function 'ioremap_page_range':
> lib/ioremap.c:203:16: warning:
> variable 'start' set but not used [-Wunused-but-set-variable]
>
> flush_cache_vmap may no need param, so add __maybe_unused fix this warning.

I think flush_cache_vmap should have a proper prototype with
__maybe_unused for its args. But, there are so many arch-specific
definitions at glace, and I am not sure how manageable such change is,
though...

Thanks,
-Toshi

>
> Signed-off-by: YueHaibing <[email protected]>
> ---
> lib/ioremap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/ioremap.c b/lib/ioremap.c
> index 063213685563..d1c7a488e731 100644
> --- a/lib/ioremap.c
> +++ b/lib/ioremap.c
> @@ -200,7 +200,7 @@ int ioremap_page_range(unsigned long addr,
> unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
> {
> pgd_t *pgd;
> - unsigned long start;
> + unsigned long __maybe_unused start;
> unsigned long next;
> int err;
>
>
>

2019-02-20 21:44:26

by Andrew Morton

Subject: Re: [PATCH -next] mm: fix set but not used warning

On Tue, 19 Feb 2019 18:28:30 +0000 "Kani, Toshi" <[email protected]> wrote:

> On Mon, 2019-02-18 at 13:57 +0000, YueHaibing wrote:
> > Fixes gcc '-Wunused-but-set-variable' warning:
> >
> > lib/ioremap.c: In function 'ioremap_page_range':
> > lib/ioremap.c:203:16: warning:
> > variable 'start' set but not used [-Wunused-but-set-variable]
> >
> > flush_cache_vmap may no need param, so add __maybe_unused fix this warning.
>
> I think flush_cache_vmap should have a proper prototype with
> __maybe_unused for its args. But, there are so many arch-specific
> definitions at glace, and I am not sure how manageable such change is,
> though...

This is one of the reasons why things like flush_cache_vmap() should
be implemented as static inline C functions, not as macros.