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-rw-r--r--include/asm-generic/qspinlock_types.h34
1 files changed, 32 insertions, 2 deletions
diff --git a/include/asm-generic/qspinlock_types.h b/include/asm-generic/qspinlock_types.h
index 034acd0c4956..6503e96710fa 100644
--- a/include/asm-generic/qspinlock_types.h
+++ b/include/asm-generic/qspinlock_types.h
@@ -18,6 +18,8 @@
#ifndef __ASM_GENERIC_QSPINLOCK_TYPES_H
#define __ASM_GENERIC_QSPINLOCK_TYPES_H
+#include <asm/byteorder.h>
+
/*
* Including atomic.h with PARAVIRT on will cause compilation errors because
* of recursive header file incluson via paravirt_types.h. So don't include
@@ -29,13 +31,41 @@
#endif
typedef struct qspinlock {
- atomic_t val;
+ union {
+ atomic_t val;
+
+ /*
+ * By using the whole 2nd least significant byte for the
+ * pending bit, we can allow better optimization of the lock
+ * acquisition for the pending bit holder.
+ */
+#ifdef __LITTLE_ENDIAN
+ struct {
+ u8 locked;
+ u8 pending;
+ };
+ struct {
+ u16 locked_pending;
+ u16 tail;
+ };
+#else
+ struct {
+ u16 tail;
+ u16 locked_pending;
+ };
+ struct {
+ u8 reserved[2];
+ u8 pending;
+ u8 locked;
+ };
+#endif
+ };
} arch_spinlock_t;
/*
* Initializier
*/
-#define __ARCH_SPIN_LOCK_UNLOCKED { ATOMIC_INIT(0) }
+#define __ARCH_SPIN_LOCK_UNLOCKED { { .val = ATOMIC_INIT(0) } }
/*
* Bitfields in the atomic value: