Merge commit '01e3c87' into cg_merges_20131023a

miner.h

@@ -831,7 +831,7 @@ static inline void cglock_init(cglock_t *lock)
 	rwlock_init(&lock->rwlock);
 }
 
-/* Read lock variant of cglock */
+/* Read lock variant of cglock. Cannot be promoted. */
 static inline void cg_rlock(cglock_t *lock)
 {
 	mutex_lock(&lock->mutex);
@@ -839,7 +839,8 @@ static inline void cg_rlock(cglock_t *lock)
 	mutex_unlock_noyield(&lock->mutex);
 }
 
-/* Intermediate variant of cglock */
+/* Intermediate variant of cglock - behaves as a read lock but can be promoted
+ * to a write lock or demoted to read lock. */
 static inline void cg_ilock(cglock_t *lock)
 {
 	mutex_lock(&lock->mutex);
@@ -866,6 +867,12 @@ static inline void cg_dwlock(cglock_t *lock)
 	mutex_unlock_noyield(&lock->mutex);
 }
 
+/* Demote a write variant to an intermediate variant */
+static inline void cg_dwilock(cglock_t *lock)
+{
+	wr_unlock(&lock->rwlock);
+}
+
 /* Downgrade intermediate variant to a read lock */
 static inline void cg_dlock(cglock_t *lock)
 {
@@ -880,7 +887,7 @@ static inline void cg_runlock(cglock_t *lock)
 
 static inline void cg_wunlock(cglock_t *lock)
 {
-	wr_unlock(&lock->rwlock);
+	wr_unlock_noyield(&lock->rwlock);
 	mutex_unlock(&lock->mutex);
 }