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authorRussell King <rmk+kernel@arm.linux.org.uk>2012-10-11 10:55:04 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-10-11 10:55:04 +0100
commita0f0dd57f4a85310d9936f1770a0424b49fef876 (patch)
tree2f85b8b67dda13d19b02ca39e0fbef921cb1cf8b /arch/arm/include/asm/mutex.h
parent2a552d5e63d7fa602c9a9a0717008737f55625a6 (diff)
parent846a136881b8f73c1f74250bf6acfaa309cab1f2 (diff)
downloadblackbird-op-linux-a0f0dd57f4a85310d9936f1770a0424b49fef876.tar.gz
blackbird-op-linux-a0f0dd57f4a85310d9936f1770a0424b49fef876.zip
Merge branch 'fixes' into for-linus
Conflicts: arch/arm/kernel/smp.c
Diffstat (limited to 'arch/arm/include/asm/mutex.h')
-rw-r--r--arch/arm/include/asm/mutex.h9
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/arm/include/asm/mutex.h b/arch/arm/include/asm/mutex.h
index b1479fd04a95..87c044910fe0 100644
--- a/arch/arm/include/asm/mutex.h
+++ b/arch/arm/include/asm/mutex.h
@@ -9,8 +9,13 @@
#define _ASM_MUTEX_H
/*
* On pre-ARMv6 hardware this results in a swp-based implementation,
- * which is the most efficient. For ARMv6+, we emit a pair of exclusive
- * accesses instead.
+ * which is the most efficient. For ARMv6+, we have exclusive memory
+ * accessors and use atomic_dec to avoid the extra xchg operations
+ * on the locking slowpaths.
*/
+#if __LINUX_ARM_ARCH__ < 6
#include <asm-generic/mutex-xchg.h>
+#else
+#include <asm-generic/mutex-dec.h>
#endif
+#endif /* _ASM_MUTEX_H */
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