Add comment in rcu_add_lock

[urcu.git] / urcu.h

diff --git a/urcu.h b/urcu.h
index 424980650474953be7c7e081ec0fe07f5e14d034..277b7d2f45ae565610e4db9ee89457174fafa667 100644 (file)
--- a/urcu.h
+++ b/urcu.h
@@ -165,9 +165,9 @@ static inline void debug_yield_init(void)
  * The trick here is that RCU_GP_CTR_BIT 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           (1U << 0)
+#define RCU_GP_COUNT           (1UL << 0)
 /* Use the amount of bits equal to half of the architecture long size */
-#define RCU_GP_CTR_BIT         (sizeof(long) << 2)
+#define RCU_GP_CTR_BIT         (1UL << (sizeof(long) << 2))
 #define RCU_GP_CTR_NEST_MASK   (RCU_GP_CTR_BIT - 1)
 
 /*
@@ -179,7 +179,7 @@ extern long urcu_gp_ctr;
 
 extern long __thread urcu_active_readers;
 
-static inline int rcu_old_gp_ongoing(int *value)
+static inline int rcu_old_gp_ongoing(long *value)
 {
        long v;
 
@@ -199,8 +199,9 @@ static inline void rcu_read_lock(void)
        debug_yield_read();
        tmp = urcu_active_readers;
        debug_yield_read();
+       /* urcu_gp_ctr = RCU_GP_COUNT | (~RCU_GP_CTR_BIT or RCU_GP_CTR_BIT) */
        if (likely(!(tmp & RCU_GP_CTR_NEST_MASK)))
-               urcu_active_readers = urcu_gp_ctr + RCU_GP_COUNT;
+               urcu_active_readers = urcu_gp_ctr;
        else
                urcu_active_readers = tmp + RCU_GP_COUNT;
        debug_yield_read();