linux-kernel - [PATCH] arm64: avoid clang warning about self-assignment

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Date:   Fri, 22 Feb 2019 15:42:23 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>
Cc:     natechancellor@...il.com, ndesaulniers@...gle.com,
        Arnd Bergmann <arnd@...db.de>,
        Andrey Konovalov <andreyknvl@...gle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] arm64: avoid clang warning about self-assignment

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@...db.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