[PATCH 09/62] arm64: Turn flush_dcache_mmap_lock into a no-op

Matthew Wilcox
2017-11-22T21:08:21Z

ARM64 doesn't walk the VMA tree in its flush_dcache_page()
implementation, so has no need to take the tree_lock.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft,com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
---
arch/arm64/include/asm/cacheflush.h | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index 76d1cc85d5b1..568f83533f12 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -130,10 +130,8 @@ static inline void __flush_icache_all(void)
dsb(ish);
}

-#define flush_dcache_mmap_lock(mapping) \
- spin_lock_irq(&(mapping)->tree_lock)
-#define flush_dcache_mmap_unlock(mapping) \
- spin_unlock_irq(&(mapping)->tree_lock)
+#define flush_dcache_mmap_lock(mapping) do { } while (0)
+#define flush_dcache_mmap_unlock(mapping) do { } while (0)

/*
* We don't appear to need to do anything here. In fact, if we did, we'd
--
2.15.0