[lttng-dev] [PATCH] Fix: revise urcu_read_lock_update() comment

[Li-Kuan Ou]

Read-side critical section nesting is tracked in lower-order bits
and grace-period phase number use a single high-order bit

Signed-off-by: Li-Kuan Ou <k777k777tw at gmail.com>
---
 include/urcu/static/urcu-bp.h     | 6 +++---
 include/urcu/static/urcu-mb.h     | 6 +++---
 include/urcu/static/urcu-memb.h   | 6 +++---
 include/urcu/static/urcu-signal.h | 6 +++---
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/urcu/static/urcu-bp.h b/include/urcu/static/urcu-bp.h
index 8ba3830..b163a90 100644
--- a/include/urcu/static/urcu-bp.h
+++ b/include/urcu/static/urcu-bp.h
@@ -137,9 +137,9 @@ static inline enum urcu_bp_state urcu_bp_reader_state(unsigned long *ctr)
 
 /*
  * Helper for _urcu_bp_read_lock().  The format of urcu_bp_gp.ctr (as well as
- * the per-thread rcu_reader.ctr) has the upper bits containing a count of
- * _urcu_bp_read_lock() nesting, and a lower-order bit that contains either zero
- * or URCU_BP_GP_CTR_PHASE.  The smp_mb_slave() ensures that the accesses in
+ * the per-thread rcu_reader.ctr) has the lower-order bits containing a count of
+ * _urcu_bp_read_lock() nesting, and a single high-order URCU_BP_GP_CTR_PHASE bit
+ * that contains either zero or one.  The smp_mb_slave() ensures that the accesses in
  * _urcu_bp_read_lock() happen before the subsequent read-side critical section.
  */
 static inline void _urcu_bp_read_lock_update(unsigned long tmp)
diff --git a/include/urcu/static/urcu-mb.h b/include/urcu/static/urcu-mb.h
index b97e42a..253d29b 100644
--- a/include/urcu/static/urcu-mb.h
+++ b/include/urcu/static/urcu-mb.h
@@ -63,9 +63,9 @@ extern DECLARE_URCU_TLS(struct urcu_reader, urcu_mb_reader);
 
 /*
  * Helper for _urcu_mb_read_lock().  The format of urcu_mb_gp.ctr (as well as
- * the per-thread rcu_reader.ctr) has the upper bits containing a count of
- * _urcu_mb_read_lock() nesting, and a lower-order bit that contains either zero
- * or URCU_GP_CTR_PHASE.  The cmm_smp_mb() ensures that the accesses in
+ * the per-thread rcu_reader.ctr) has the lower-order bits containing a count of
+ * _urcu_mb_read_lock() nesting, and a single high-order URCU_BP_GP_CTR_PHASE bit
+ * that contains either zero or one.  The cmm_smp_mb() ensures that the accesses in
  * _urcu_mb_read_lock() happen before the subsequent read-side critical section.
  */
 static inline void _urcu_mb_read_lock_update(unsigned long tmp)
diff --git a/include/urcu/static/urcu-memb.h b/include/urcu/static/urcu-memb.h
index c8d102f..f64cb57 100644
--- a/include/urcu/static/urcu-memb.h
+++ b/include/urcu/static/urcu-memb.h
@@ -86,9 +86,9 @@ extern DECLARE_URCU_TLS(struct urcu_reader, urcu_memb_reader);
 
 /*
  * Helper for _rcu_read_lock().  The format of urcu_memb_gp.ctr (as well as
- * the per-thread rcu_reader.ctr) has the upper bits containing a count of
- * _rcu_read_lock() nesting, and a lower-order bit that contains either zero
- * or URCU_GP_CTR_PHASE.  The smp_mb_slave() ensures that the accesses in
+ * the per-thread rcu_reader.ctr) has the lower-order bits containing a count of
+ * _rcu_read_lock() nesting, and a single high-order URCU_BP_GP_CTR_PHASE bit
+ * that contains either zero or one.  The smp_mb_slave() ensures that the accesses in
  * _rcu_read_lock() happen before the subsequent read-side critical section.
  */
 static inline void _urcu_memb_read_lock_update(unsigned long tmp)
diff --git a/include/urcu/static/urcu-signal.h b/include/urcu/static/urcu-signal.h
index c7577d3..707eaf8 100644
--- a/include/urcu/static/urcu-signal.h
+++ b/include/urcu/static/urcu-signal.h
@@ -64,9 +64,9 @@ extern DECLARE_URCU_TLS(struct urcu_reader, urcu_signal_reader);
 
 /*
  * Helper for _rcu_read_lock().  The format of urcu_signal_gp.ctr (as well as
- * the per-thread rcu_reader.ctr) has the upper bits containing a count of
- * _rcu_read_lock() nesting, and a lower-order bit that contains either zero
- * or URCU_GP_CTR_PHASE.  The cmm_barrier() ensures that the accesses in
+ * the per-thread rcu_reader.ctr) has the lower-order bits containing a count of
+ * _rcu_read_lock() nesting, and a single high-order URCU_BP_GP_CTR_PHASE bit
+ * that contains either zero or one.  The cmm_barrier() ensures that the accesses in
  * _rcu_read_lock() happen before the subsequent read-side critical section.
  */
 static inline void _urcu_signal_read_lock_update(unsigned long tmp)
-- 
2.34.1