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[v8,03/63] arm64: Turn flush_dcache_mmap_lock into a no-op

Message ID 20180306192413.5499-4-willy@infradead.org (mailing list archive)
State New, archived
Headers show

Commit Message

Matthew Wilcox (Oracle) March 6, 2018, 7:23 p.m. UTC 
From: Matthew Wilcox <mawilcox@microsoft.com>

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(-)
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Patch

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index bef9f418f089..550b0abea953 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -137,10 +137,8 @@  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