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* [PATCH] arm64: avoid clang warning about self-assignment
@ 2019-02-22 14:42 Arnd Bergmann
  2019-02-22 15:50 ` Andrey Konovalov
  0 siblings, 1 reply; 2+ messages in thread
From: Arnd Bergmann @ 2019-02-22 14:42 UTC (permalink / raw)
  To: Catalin Marinas, Will Deacon
  Cc: natechancellor, ndesaulniers, Arnd Bergmann, Andrey Konovalov,
	Andrey Ryabinin, Dmitry Vyukov, linux-arm-kernel, linux-kernel

Building a preprocessed source file for arm64 now always produces
a warning with clang because of the page_to_virt() macro assigning
a variable to itself.

Adding a new temporary variable avoids this issue.

Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm64/include/asm/memory.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index b01ef0180a03..290195168bb3 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -312,8 +312,9 @@ static inline void *phys_to_virt(phys_addr_t x)
 #define page_to_virt(page)	({					\
 	unsigned long __addr =						\
 		((__page_to_voff(page)) | PAGE_OFFSET);			\
-	__addr = __tag_set(__addr, page_kasan_tag(page));		\
-	((void *)__addr);						\
+	unsigned long __addr_tag =					\
+		 __tag_set(__addr, page_kasan_tag(page));		\
+	((void *)__addr_tag);						\
 })
 
 #define virt_to_page(vaddr)	((struct page *)((__virt_to_pgoff(vaddr)) | VMEMMAP_START))
-- 
2.20.0


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] arm64: avoid clang warning about self-assignment
  2019-02-22 14:42 [PATCH] arm64: avoid clang warning about self-assignment Arnd Bergmann
@ 2019-02-22 15:50 ` Andrey Konovalov
  0 siblings, 0 replies; 2+ messages in thread
From: Andrey Konovalov @ 2019-02-22 15:50 UTC (permalink / raw)
  To: Arnd Bergmann
  Cc: Catalin Marinas, Will Deacon, natechancellor, Nick Desaulniers,
	Andrey Ryabinin, Dmitry Vyukov, Linux ARM, LKML

On Fri, Feb 22, 2019 at 3:43 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> Building a preprocessed source file for arm64 now always produces
> a warning with clang because of the page_to_virt() macro assigning
> a variable to itself.
>
> Adding a new temporary variable avoids this issue.
>
> Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Andrey Konovalov <andreyknvl@google.com>

Thanks!

> ---
>  arch/arm64/include/asm/memory.h | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index b01ef0180a03..290195168bb3 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -312,8 +312,9 @@ static inline void *phys_to_virt(phys_addr_t x)
>  #define page_to_virt(page)     ({                                      \
>         unsigned long __addr =                                          \
>                 ((__page_to_voff(page)) | PAGE_OFFSET);                 \
> -       __addr = __tag_set(__addr, page_kasan_tag(page));               \
> -       ((void *)__addr);                                               \
> +       unsigned long __addr_tag =                                      \
> +                __tag_set(__addr, page_kasan_tag(page));               \
> +       ((void *)__addr_tag);                                           \
>  })
>
>  #define virt_to_page(vaddr)    ((struct page *)((__virt_to_pgoff(vaddr)) | VMEMMAP_START))
> --
> 2.20.0
>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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