[PATCH -next] arm64: mm: Fix unused variable warning in zone_sizes_init

[PATCH -next] arm64: mm: Fix unused variable warning in zone_sizes_init

[Nathan Chancellor]

When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
get disabled so there is a warning about max_dma being unused.

../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
[-Wunused-variable]
        unsigned long max_dma = min;
                      ^
1 warning generated.

Add an ifdef around the variable to fix this.

Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 arch/arm64/mm/init.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 44f07fdf7a59..c3d6657b9942 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -212,7 +212,9 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
 	struct memblock_region *reg;
 	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
 	unsigned long max_dma32 = min;
+#if defined(CONFIG_ZONE_DMA) || defined(CONFIG_ZONE_DMA)
 	unsigned long max_dma = min;
+#endif
 
 	memset(zone_size, 0, sizeof(zone_size));
 
-- 
2.23.0

Re: [PATCH -next] arm64: mm: Fix unused variable warning in zone_sizes_init

[Will Deacon]

On Tue, Oct 15, 2019 at 03:43:04PM -0700, Nathan Chancellor wrote:
> When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
> get disabled so there is a warning about max_dma being unused.
> 
> ../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
> [-Wunused-variable]
>         unsigned long max_dma = min;
>                       ^
> 1 warning generated.
> 
> Add an ifdef around the variable to fix this.
> 
> Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  arch/arm64/mm/init.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 44f07fdf7a59..c3d6657b9942 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -212,7 +212,9 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
>  	struct memblock_region *reg;
>  	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
>  	unsigned long max_dma32 = min;
> +#if defined(CONFIG_ZONE_DMA) || defined(CONFIG_ZONE_DMA)
>  	unsigned long max_dma = min;
> +#endif

This looks bogus to me :/ You're referring to CONFIG_ZONE_DMA twice, and I
can't see how that symbol even exists on arm64.

Will

Re: [PATCH -next] arm64: mm: Fix unused variable warning in zone_sizes_init

[Nathan Chancellor]

On Wed, Oct 16, 2019 at 04:00:52AM +0100, Will Deacon wrote:
> On Tue, Oct 15, 2019 at 03:43:04PM -0700, Nathan Chancellor wrote:
> > When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
> > get disabled so there is a warning about max_dma being unused.
> > 
> > ../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
> > [-Wunused-variable]
> >         unsigned long max_dma = min;
> >                       ^
> > 1 warning generated.
> > 
> > Add an ifdef around the variable to fix this.
> > 
> > Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > ---
> >  arch/arm64/mm/init.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index 44f07fdf7a59..c3d6657b9942 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -212,7 +212,9 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
> >  	struct memblock_region *reg;
> >  	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
> >  	unsigned long max_dma32 = min;
> > +#if defined(CONFIG_ZONE_DMA) || defined(CONFIG_ZONE_DMA)
> >  	unsigned long max_dma = min;
> > +#endif
> 
> This looks bogus to me :/ You're referring to CONFIG_ZONE_DMA twice, and I
> can't see how that symbol even exists on arm64.
> 
> Will

Gah, sorry, one of those CONFIGs should be CONFIG_ZONE_DMA32. I will
send a v2 to fix that shortly.

Note, this patch is targetting for-next/zone-dma, which reintroduces
CONFIG_ZONE_DMA. Sorry if the patch tag and Fixes tag didn't make that
clear, let me know how I can better convey that in the future!

Cheers,
Nathan

[PATCH -next v2] arm64: mm: Fix unused variable warning in zone_sizes_init

[Nathan Chancellor]

When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
get disabled so there is a warning about max_dma being unused.

../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
[-Wunused-variable]
        unsigned long max_dma = min;
                      ^
1 warning generated.

Add an ifdef around the variable to fix this.

Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

v1 -> v2:

* Fix check for CONFIG_ZONE_DMA32 as pointed out by Will.

 arch/arm64/mm/init.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 44f07fdf7a59..359c3b08b968 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -212,7 +212,9 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
 	struct memblock_region *reg;
 	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
 	unsigned long max_dma32 = min;
+#if defined(CONFIG_ZONE_DMA) || defined(CONFIG_ZONE_DMA32)
 	unsigned long max_dma = min;
+#endif
 
 	memset(zone_size, 0, sizeof(zone_size));
 
-- 
2.23.0

Re: [PATCH -next v2] arm64: mm: Fix unused variable warning in zone_sizes_init

[Nicolas Saenz Julienne]

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On Tue, 2019-10-15 at 20:11 -0700, Nathan Chancellor wrote:
> When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
> get disabled so there is a warning about max_dma being unused.
> 
> ../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
> [-Wunused-variable]
>         unsigned long max_dma = min;
>                       ^
> 1 warning generated.
> 
> Add an ifdef around the variable to fix this.
> 
> Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> 
> v1 -> v2:
> 
> * Fix check for CONFIG_ZONE_DMA32 as pointed out by Will.
> 
>  arch/arm64/mm/init.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 44f07fdf7a59..359c3b08b968 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -212,7 +212,9 @@ static void __init zone_sizes_init(unsigned long min,
> unsigned long max)
>  	struct memblock_region *reg;
>  	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
>  	unsigned long max_dma32 = min;
> +#if defined(CONFIG_ZONE_DMA) || defined(CONFIG_ZONE_DMA32)
>  	unsigned long max_dma = min;
> +#endif
>  
>  	memset(zone_size, 0, sizeof(zone_size));
>  

Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

Thanks!


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Re: [PATCH -next v2] arm64: mm: Fix unused variable warning in zone_sizes_init

[Catalin Marinas]

On Tue, Oct 15, 2019 at 08:11:08PM -0700, Nathan Chancellor wrote:
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 44f07fdf7a59..359c3b08b968 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -212,7 +212,9 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
>  	struct memblock_region *reg;
>  	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
>  	unsigned long max_dma32 = min;
> +#if defined(CONFIG_ZONE_DMA) || defined(CONFIG_ZONE_DMA32)
>  	unsigned long max_dma = min;
> +#endif

Nitpick: the coding style recommends __maybe_unused instead of #ifdef.

-- 
Catalin

[PATCH -next v3] arm64: mm: Fix unused variable warning in zone_sizes_init

[Nathan Chancellor]

When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
get disabled so there is a warning about max_dma being unused.

../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
[-Wunused-variable]
        unsigned long max_dma = min;
                      ^
1 warning generated.

Add __maybe_unused to make this clear to the compiler.

Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

v1 -> v2:

* Fix check for CONFIG_ZONE_DMA32 as pointed out by Will.

v2 -> v3:

* Use __maybe_unused attribute instead of preprocessor ifdefs
  to conform to section 21 of the coding style as pointed out by
  Catalin.

 arch/arm64/mm/init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 44f07fdf7a59..71b45c58218b 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -212,7 +212,7 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
 	struct memblock_region *reg;
 	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
 	unsigned long max_dma32 = min;
-	unsigned long max_dma = min;
+	unsigned long __maybe_unused max_dma = min;
 
 	memset(zone_size, 0, sizeof(zone_size));
 
-- 
2.23.0

Re: [PATCH -next v3] arm64: mm: Fix unused variable warning in zone_sizes_init

[Catalin Marinas]

On Wed, Oct 16, 2019 at 07:47:14AM -0700, Nathan Chancellor wrote:
> When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
> get disabled so there is a warning about max_dma being unused.
> 
> ../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
> [-Wunused-variable]
>         unsigned long max_dma = min;
>                       ^
> 1 warning generated.
> 
> Add __maybe_unused to make this clear to the compiler.
> 
> Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Thanks. Queued on top of Nicolas' patches for 5.5. I also added Nicolas'
reviewed-by from v2 as I suspect it still stands.

-- 
Catalin

Re: [PATCH -next v3] arm64: mm: Fix unused variable warning in zone_sizes_init

[Nicolas Saenz Julienne]

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On Wed, 2019-10-16 at 16:08 +0100, Catalin Marinas wrote:
> On Wed, Oct 16, 2019 at 07:47:14AM -0700, Nathan Chancellor wrote:
> > When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
> > get disabled so there is a warning about max_dma being unused.
> > 
> > ../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
> > [-Wunused-variable]
> >         unsigned long max_dma = min;
> >                       ^
> > 1 warning generated.
> > 
> > Add __maybe_unused to make this clear to the compiler.
> > 
> > Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> 
> Thanks. Queued on top of Nicolas' patches for 5.5. I also added Nicolas'
> reviewed-by from v2 as I suspect it still stands.

Yes, thanks!


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Re: [PATCH -next v3] arm64: mm: Fix unused variable warning in zone_sizes_init

[Nathan Chancellor]

On Wed, Oct 16, 2019 at 05:09:30PM +0200, Nicolas Saenz Julienne wrote:
> On Wed, 2019-10-16 at 16:08 +0100, Catalin Marinas wrote:
> > On Wed, Oct 16, 2019 at 07:47:14AM -0700, Nathan Chancellor wrote:
> > > When building arm64 allnoconfig, CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32
> > > get disabled so there is a warning about max_dma being unused.
> > > 
> > > ../arch/arm64/mm/init.c:215:16: warning: unused variable 'max_dma'
> > > [-Wunused-variable]
> > >         unsigned long max_dma = min;
> > >                       ^
> > > 1 warning generated.
> > > 
> > > Add __maybe_unused to make this clear to the compiler.
> > > 
> > > Fixes: 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32")
> > > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > 
> > Thanks. Queued on top of Nicolas' patches for 5.5. I also added Nicolas'
> > reviewed-by from v2 as I suspect it still stands.
> 
> Yes, thanks!
> 

Thank you both for reviewing the patch and picking it up!

Cheers,
Nathan