[PATCH 2/5] lockdep: Apply bitlock to bit_spin_lock

[Byungchul Park]

Currently, bit_spin_lock does not use lockdep_map at all. Of course,
the lock correctness validator is not supported for bit_spin_lock.
This patch makes bit_spin_lock possible to use the validator using
CONFIG_BITLOCK_ALLOC.

Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
---
 include/linux/bit_spinlock.h | 57 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 51 insertions(+), 6 deletions(-)

diff --git a/include/linux/bit_spinlock.h b/include/linux/bit_spinlock.h
index 3b5bafc..3f8b013 100644
--- a/include/linux/bit_spinlock.h
+++ b/include/linux/bit_spinlock.h
@@ -6,13 +6,43 @@
 #include <linux/atomic.h>
 #include <linux/bug.h>
 
+#ifdef CONFIG_BITLOCK_ALLOC
+#include <linux/bitlock.h>
+#define bit_spin_init(b, a)			\
+do {						\
+	static struct lock_class_key __key;	\
+	bitlock_init(b, a, #b "@" #a, &__key);	\
+} while (0)
+
+static inline void bit_spin_free(int bitnum, unsigned long *addr)
+{
+	bitlock_free(bitnum, addr);
+}
+
+static inline void bit_spin_acquire(int bitnum, unsigned long *addr, int try)
+{
+	struct lockdep_map *map = bitlock_get_map(bitnum, addr, BIT_ACQUIRE);
+	if (map)
+		spin_acquire(map, 0, try, _RET_IP_);
+}
+
+static inline void bit_spin_release(int bitnum, unsigned long *addr)
+{
+	struct lockdep_map *map = bitlock_get_map(bitnum, addr, BIT_RELEASE);
+	if (map)
+		spin_release(map, 0, _RET_IP_);
+}
+#else
+static inline void bit_spin_init(int bitnum, unsigned long *addr) {}
+static inline void bit_spin_free(int bitnum, unsigned long *addr) {}
+static inline void bit_spin_acquire(int bitnum, unsigned long *addr, int try) {}
+static inline void bit_spin_release(int bitnum, unsigned long *addr) {}
+#endif
+
 /*
- *  bit-based spin_lock()
- *
- * Don't use this unless you really need to: spin_lock() and spin_unlock()
- * are significantly faster.
+ * bit-based spin_lock() without lock acquiring
  */
-static inline void bit_spin_lock(int bitnum, unsigned long *addr)
+static inline void do_raw_bit_spin_lock(int bitnum, unsigned long *addr)
 {
 	/*
 	 * Assuming the lock is uncontended, this never enters
@@ -21,7 +51,6 @@ static inline void bit_spin_lock(int bitnum, unsigned long *addr)
 	 * busywait with less bus contention for a good time to
 	 * attempt to acquire the lock bit.
 	 */
-	preempt_disable();
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 	while (unlikely(test_and_set_bit_lock(bitnum, addr))) {
 		preempt_enable();
@@ -35,6 +64,19 @@ static inline void bit_spin_lock(int bitnum, unsigned long *addr)
 }
 
 /*
+ *  bit-based spin_lock()
+ *
+ * Don't use this unless you really need to: spin_lock() and spin_unlock()
+ * are significantly faster.
+ */
+static inline void bit_spin_lock(int bitnum, unsigned long *addr)
+{
+	preempt_disable();
+	bit_spin_acquire(bitnum, addr, 0);
+	do_raw_bit_spin_lock(bitnum, addr);
+}
+
+/*
  * Return true if it was acquired
  */
 static inline int bit_spin_trylock(int bitnum, unsigned long *addr)
@@ -46,6 +88,7 @@ static inline int bit_spin_trylock(int bitnum, unsigned long *addr)
 		return 0;
 	}
 #endif
+	bit_spin_acquire(bitnum, addr, 1);
 	__acquire(bitlock);
 	return 1;
 }
@@ -55,6 +98,7 @@ static inline int bit_spin_trylock(int bitnum, unsigned long *addr)
  */
 static inline void bit_spin_unlock(int bitnum, unsigned long *addr)
 {
+	bit_spin_release(bitnum, addr);
 #ifdef CONFIG_DEBUG_SPINLOCK
 	BUG_ON(!test_bit(bitnum, addr));
 #endif
@@ -72,6 +116,7 @@ static inline void bit_spin_unlock(int bitnum, unsigned long *addr)
  */
 static inline void __bit_spin_unlock(int bitnum, unsigned long *addr)
 {
+	bit_spin_release(bitnum, addr);
 #ifdef CONFIG_DEBUG_SPINLOCK
 	BUG_ON(!test_bit(bitnum, addr));
 #endif
-- 
1.9.1