context_tracking, rcu: Rename ct_dynticks_cpu_acquire() into ct_rcu_watching_cpu_acquire()

The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst

@@ -149,7 +149,7 @@ This case is handled by calls to the strongly ordered
 ``atomic_add_return()`` read-modify-write atomic operation that
 is invoked within ``rcu_dynticks_eqs_enter()`` at idle-entry
 time and within ``rcu_dynticks_eqs_exit()`` at idle-exit time.
-The grace-period kthread invokes first ``ct_dynticks_cpu_acquire()``
+The grace-period kthread invokes first ``ct_rcu_watching_cpu_acquire()``
 (preceded by a full memory barrier) and ``rcu_dynticks_in_eqs_since()``
 (both of which rely on acquire semantics) to detect idle CPUs.
 

include/linux/context_tracking_state.h

@@ -68,7 +68,7 @@ static __always_inline int ct_rcu_watching_cpu(int cpu)
 	return atomic_read(&ct->state) & CT_RCU_WATCHING_MASK;
 }
 
-static __always_inline int ct_dynticks_cpu_acquire(int cpu)
+static __always_inline int ct_rcu_watching_cpu_acquire(int cpu)
 {
 	struct context_tracking *ct = per_cpu_ptr(&context_tracking, cpu);
 

kernel/rcu/tree.c

@@ -323,7 +323,7 @@ static bool rcu_dynticks_in_eqs_since(struct rcu_data *rdp, int snap)
 	 * performed by the remote CPU prior to entering idle and therefore can
 	 * rely solely on acquire semantics.
 	 */
-	return snap != ct_dynticks_cpu_acquire(rdp->cpu);
+	return snap != ct_rcu_watching_cpu_acquire(rdp->cpu);
 }
 
 /*
@@ -782,7 +782,7 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp)
 	 * Ordering between remote CPU's pre idle accesses and post grace period
 	 * updater's accesses is enforced by the below acquire semantic.
 	 */
-	rdp->dynticks_snap = ct_dynticks_cpu_acquire(rdp->cpu);
+	rdp->dynticks_snap = ct_rcu_watching_cpu_acquire(rdp->cpu);
 	if (rcu_dynticks_in_eqs(rdp->dynticks_snap)) {
 		trace_rcu_fqs(rcu_state.name, rdp->gp_seq, rdp->cpu, TPS("dti"));
 		rcu_gpnum_ovf(rdp->mynode, rdp);

kernel/rcu/tree_exp.h

@@ -376,7 +376,7 @@ static void __sync_rcu_exp_select_node_cpus(struct rcu_exp_work *rewp)
 			 * post grace period updater's accesses is enforced by the
 			 * below acquire semantic.
 			 */
-			snap = ct_dynticks_cpu_acquire(cpu);
+			snap = ct_rcu_watching_cpu_acquire(cpu);
 			if (rcu_dynticks_in_eqs(snap))
 				mask_ofl_test |= mask;
 			else