rcu: Make cpu_needs_another_gp() be bool

The cpu_needs_another_gp() function is currently of type int, but only
returns zero or one.  Bow to reality and make it be of type bool.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcu/tree.c

@@ -597,25 +597,25 @@ static int rcu_future_needs_gp(struct rcu_state *rsp)
  * The caller must have disabled interrupts to prevent races with
  * normal callback registry.
  */
-static int
+static bool
 cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp)
 {
 	int i;
 
 	if (rcu_gp_in_progress(rsp))
-		return 0;  /* No, a grace period is already in progress. */
+		return false;  /* No, a grace period is already in progress. */
 	if (rcu_future_needs_gp(rsp))
-		return 1;  /* Yes, a no-CBs CPU needs one. */
+		return true;  /* Yes, a no-CBs CPU needs one. */
 	if (!rdp->nxttail[RCU_NEXT_TAIL])
-		return 0;  /* No, this is a no-CBs (or offline) CPU. */
+		return false;  /* No, this is a no-CBs (or offline) CPU. */
 	if (*rdp->nxttail[RCU_NEXT_READY_TAIL])
-		return 1;  /* Yes, this CPU has newly registered callbacks. */
+		return true;  /* Yes, CPU has newly registered callbacks. */
 	for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++)
 		if (rdp->nxttail[i - 1] != rdp->nxttail[i] &&
 		    ULONG_CMP_LT(READ_ONCE(rsp->completed),
 				 rdp->nxtcompleted[i]))
-			return 1;  /* Yes, CBs for future grace period. */
-	return 0; /* No grace period needed. */
+			return true;  /* Yes, CBs for future grace period. */
+	return false; /* No grace period needed. */
 }
 
 /*