add missing comment to wfstack.c

[urcu.git] / urcu-bp-static.h

diff --git a/urcu-bp-static.h b/urcu-bp-static.h
index ff16fd4712ff3e669fbb9420c4f5364087c9c701..515be288d6b75011a1428994343d641e2cf9f330 100644 (file)
--- a/urcu-bp-static.h
+++ b/urcu-bp-static.h
@@ -9,7 +9,7 @@
  * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See urcu.h for linking
  * dynamically with the userspace rcu library.
  *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
  *
  * This library is free software; you can redistribute it and/or
@@ -48,6 +48,10 @@
  * This is required to permit relinking with newer versions of the library.
  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*
  * Active attempts to check for reader Q.S. before calling sleep().
  */
@@ -69,7 +73,7 @@
 #define YIELD_WRITE    (1 << 1)
 
 /*
- * Updates without URCU_MB are much slower. Account this in
+ * Updates without RCU_MB are much slower. Account this in
  * the delay.
  */
 /* maximum sleep delay, in us */
@@ -112,13 +116,13 @@ static inline void debug_yield_init(void)
 #endif
 
 /*
- * The trick here is that RCU_GP_CTR_BIT must be a multiple of 8 so we can use a
+ * The trick here is that RCU_GP_CTR_PHASE must be a multiple of 8 so we can use a
  * full 8-bits, 16-bits or 32-bits bitmask for the lower order bits.
  */
 #define RCU_GP_COUNT           (1UL << 0)
 /* Use the amount of bits equal to half of the architecture long size */
-#define RCU_GP_CTR_BIT         (1UL << (sizeof(long) << 2))
-#define RCU_GP_CTR_NEST_MASK   (RCU_GP_CTR_BIT - 1)
+#define RCU_GP_CTR_PHASE               (1UL << (sizeof(long) << 2))
+#define RCU_GP_CTR_NEST_MASK   (RCU_GP_CTR_PHASE - 1)
 
 /*
  * Used internally by _rcu_read_lock.
@@ -130,13 +134,13 @@ extern void rcu_bp_register(void);
  * Using a int rather than a char to eliminate false register dependencies
  * causing stalls on some architectures.
  */
-extern long urcu_gp_ctr;
+extern long rcu_gp_ctr;
 
-struct urcu_reader {
+struct rcu_reader {
        /* Data used by both reader and synchronize_rcu() */
        long ctr;
        /* Data used for registry */
-       struct list_head head __attribute__((aligned(CACHE_LINE_SIZE)));
+       struct list_head node __attribute__((aligned(CACHE_LINE_SIZE)));
        pthread_t tid;
        int alloc;      /* registry entry allocated */
 };
@@ -146,7 +150,7 @@ struct urcu_reader {
  * Adds a pointer dereference on the read-side, but won't require to unregister
  * the reader thread.
  */
-extern struct urcu_reader __thread *urcu_reader;
+extern struct rcu_reader __thread *rcu_reader;
 
 static inline int rcu_old_gp_ongoing(long *value)
 {
@@ -160,7 +164,7 @@ static inline int rcu_old_gp_ongoing(long *value)
         */
        v = LOAD_SHARED(*value);
        return (v & RCU_GP_CTR_NEST_MASK) &&
-                ((v ^ urcu_gp_ctr) & RCU_GP_CTR_BIT);
+                ((v ^ rcu_gp_ctr) & RCU_GP_CTR_PHASE);
 }
 
 static inline void _rcu_read_lock(void)
@@ -168,20 +172,23 @@ static inline void _rcu_read_lock(void)
        long tmp;
 
        /* Check if registered */
-       if (unlikely(!urcu_reader))
+       if (unlikely(!rcu_reader))
                rcu_bp_register();
 
-       tmp = urcu_reader->ctr;
-       /* urcu_gp_ctr = RCU_GP_COUNT | (~RCU_GP_CTR_BIT or RCU_GP_CTR_BIT) */
+       tmp = rcu_reader->ctr;
+       /*
+        * rcu_gp_ctr is
+        *   RCU_GP_COUNT | (~RCU_GP_CTR_PHASE or RCU_GP_CTR_PHASE)
+        */
        if (likely(!(tmp & RCU_GP_CTR_NEST_MASK))) {
-               _STORE_SHARED(urcu_reader->ctr, _LOAD_SHARED(urcu_gp_ctr));
+               _STORE_SHARED(rcu_reader->ctr, _LOAD_SHARED(rcu_gp_ctr));
                /*
                 * Set active readers count for outermost nesting level before
                 * accessing the pointer.
                 */
                smp_mb();
        } else {
-               _STORE_SHARED(urcu_reader->ctr, tmp + RCU_GP_COUNT);
+               _STORE_SHARED(rcu_reader->ctr, tmp + RCU_GP_COUNT);
        }
 }
 
@@ -191,7 +198,11 @@ static inline void _rcu_read_unlock(void)
         * Finish using rcu before decrementing the pointer.
         */
        smp_mb();
-       _STORE_SHARED(urcu_reader->ctr, urcu_reader->ctr - RCU_GP_COUNT);
+       _STORE_SHARED(rcu_reader->ctr, rcu_reader->ctr - RCU_GP_COUNT);
 }
 
+#ifdef __cplusplus 
+}
+#endif
+
 #endif /* _URCU_BP_STATIC_H */