Recently, nommu iounmap() was converted from a static inline function to
a macro again, basically reverting commit 4580ba4ad2e6b8dd ("sh: Convert
iounmap() macros to inline functions").  With -Werror, this leads to
build failures like:

    drivers/iio/adc/xilinx-ams.c: In function ‘ams_iounmap_ps’:
    drivers/iio/adc/xilinx-ams.c:1195:14: error: unused variable ‘ams’ [-Werror=unused-variable]
     1195 |  struct ams *ams = data;
	  |              ^~~

Fix this by replacing the macros for ioremap() and iounmap() by static
inline functions, based on <asm-generic/io.h>.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Fixes: 13f1fc870dd74713 ("sh: move the ioremap implementation out of line")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
This is actually the third time this change was made, as Christoph
converted iounmap() to a macro before in commit 98c90e5ea34e98bd ("sh:
remove __iounmap"), reverting commit 733f0025f0fb43e3 ("sh: prevent
warnings when using iounmap").

Probably sh-nommu should include <asm-generic/io.h>, but that would
require a lot more changes.
---
 arch/sh/include/asm/io.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h
index cf9a3ec32406f856..fba90e670ed41d48 100644
--- a/arch/sh/include/asm/io.h
+++ b/arch/sh/include/asm/io.h
@@ -271,8 +271,12 @@ static inline void __iomem *ioremap_prot(phys_addr_t offset, unsigned long size,
 #endif /* CONFIG_HAVE_IOREMAP_PROT */
 
 #else /* CONFIG_MMU */
-#define iounmap(addr)		do { } while (0)
-#define ioremap(offset, size)	((void __iomem *)(unsigned long)(offset))
+static inline void __iomem *ioremap(phys_addr_t offset, size_t size)
+{
+	return (void __iomem *)(unsigned long)offset;
+}
+
+static inline void iounmap(volatile void __iomem *addr) { }
 #endif /* CONFIG_MMU */
 
 #define ioremap_uc	ioremap
-- 
2.25.1

On Tue, 15 Feb 2022 09:51:05 +0100
Geert Uytterhoeven <geert+renesas@glider.be> wrote:

> Recently, nommu iounmap() was converted from a static inline function to
> a macro again, basically reverting commit 4580ba4ad2e6b8dd ("sh: Convert
> iounmap() macros to inline functions").  With -Werror, this leads to
> build failures like:
> 
>     drivers/iio/adc/xilinx-ams.c: In function ‘ams_iounmap_ps’:
>     drivers/iio/adc/xilinx-ams.c:1195:14: error: unused variable ‘ams’ [-Werror=unused-variable]
>      1195 |  struct ams *ams = data;
> 	  |              ^~~
> 
> Fix this by replacing the macros for ioremap() and iounmap() by static
> inline functions, based on <asm-generic/io.h>.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Fixes: 13f1fc870dd74713 ("sh: move the ioremap implementation out of line")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Looks good.

Thanks for the quick response.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
> This is actually the third time this change was made, as Christoph
> converted iounmap() to a macro before in commit 98c90e5ea34e98bd ("sh:
> remove __iounmap"), reverting commit 733f0025f0fb43e3 ("sh: prevent
> warnings when using iounmap").
> 
> Probably sh-nommu should include <asm-generic/io.h>, but that would
> require a lot more changes.
> ---
>  arch/sh/include/asm/io.h | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h
> index cf9a3ec32406f856..fba90e670ed41d48 100644
> --- a/arch/sh/include/asm/io.h
> +++ b/arch/sh/include/asm/io.h
> @@ -271,8 +271,12 @@ static inline void __iomem *ioremap_prot(phys_addr_t offset, unsigned long size,
>  #endif /* CONFIG_HAVE_IOREMAP_PROT */
>  
>  #else /* CONFIG_MMU */
> -#define iounmap(addr)		do { } while (0)
> -#define ioremap(offset, size)	((void __iomem *)(unsigned long)(offset))
> +static inline void __iomem *ioremap(phys_addr_t offset, size_t size)
> +{
> +	return (void __iomem *)(unsigned long)offset;
> +}
> +
> +static inline void iounmap(volatile void __iomem *addr) { }
>  #endif /* CONFIG_MMU */
>  
>  #define ioremap_uc	ioremap

On Tue, Feb 15, 2022 at 09:51:05AM +0100, Geert Uytterhoeven wrote:
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Fixes: 13f1fc870dd74713 ("sh: move the ioremap implementation out of line")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

> ---
> This is actually the third time this change was made, as Christoph
> converted iounmap() to a macro before in commit 98c90e5ea34e98bd ("sh:
> remove __iounmap"), reverting commit 733f0025f0fb43e3 ("sh: prevent
> warnings when using iounmap").
> 
> Probably sh-nommu should include <asm-generic/io.h>, but that would
> require a lot more changes.

I don't think it would be all that bad.  But between the breakage and
the fact that sh is almost unmaintained let's get the quick fix in if
we can..