rcu: Eliminate a few CONFIG_RCU_NOCB_CPU_ALL #ifdefs

This commit converts several CONFIG_RCU_NOCB_CPU_ALL #ifdefs to
instead use IS_ENABLED().  This change should help avoid hiding
code from compiler diagnostics.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 87bb0ee..5ec20bc 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -1153,13 +1153,13 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
 #define kfree_rcu(ptr, rcu_head)                                       \
        __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))
 
-#if defined(CONFIG_TINY_RCU) || defined(CONFIG_RCU_NOCB_CPU_ALL)
+#ifdef CONFIG_TINY_RCU
 static inline int rcu_needs_cpu(unsigned long *delta_jiffies)
 {
        *delta_jiffies = ULONG_MAX;
        return 0;
 }
-#endif /* #if defined(CONFIG_TINY_RCU) || defined(CONFIG_RCU_NOCB_CPU_ALL) */
+#endif /* #ifdef CONFIG_TINY_RCU */
 
 #if defined(CONFIG_RCU_NOCB_CPU_ALL)
 static inline bool rcu_is_nocb_cpu(int cpu) { return true; }

diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index d2e583a..0bd400b 100644 (file)
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -31,9 +31,7 @@
 #define __LINUX_RCUTREE_H
 
 void rcu_note_context_switch(void);
-#ifndef CONFIG_RCU_NOCB_CPU_ALL
 int rcu_needs_cpu(unsigned long *delta_jiffies);
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 void rcu_cpu_stall_reset(void);
 
 /*

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 5c0122f..0730bfc 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1372,13 +1372,12 @@ static void rcu_prepare_kthreads(int cpu)
  * Because we not have RCU_FAST_NO_HZ, just check whether this CPU needs
  * any flavor of RCU.
  */
-#ifndef CONFIG_RCU_NOCB_CPU_ALL
 int rcu_needs_cpu(unsigned long *delta_jiffies)
 {
        *delta_jiffies = ULONG_MAX;
-       return rcu_cpu_has_callbacks(NULL);
+       return IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL)
+              ? 0 : rcu_cpu_has_callbacks(NULL);
 }
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 
 /*
  * Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up
@@ -1485,11 +1484,15 @@ static bool __maybe_unused rcu_try_advance_all_cbs(void)
  *
  * The caller must have disabled interrupts.
  */
-#ifndef CONFIG_RCU_NOCB_CPU_ALL
 int rcu_needs_cpu(unsigned long *dj)
 {
        struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
 
+       if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL)) {
+               *dj = ULONG_MAX;
+               return 0;
+       }
+
        /* Snapshot to detect later posting of non-lazy callback. */
        rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted;
 
@@ -1516,7 +1519,6 @@ int rcu_needs_cpu(unsigned long *dj)
        }
        return 0;
 }
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 
 /*
  * Prepare a CPU for idle from an RCU perspective.  The first major task
@@ -1530,7 +1532,6 @@ int rcu_needs_cpu(unsigned long *dj)
  */
 static void rcu_prepare_for_idle(void)
 {
-#ifndef CONFIG_RCU_NOCB_CPU_ALL
        bool needwake;
        struct rcu_data *rdp;
        struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
@@ -1538,6 +1539,9 @@ static void rcu_prepare_for_idle(void)
        struct rcu_state *rsp;
        int tne;
 
+       if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL))
+               return;
+
        /* Handle nohz enablement switches conservatively. */
        tne = READ_ONCE(tick_nohz_active);
        if (tne != rdtp->tick_nohz_enabled_snap) {
@@ -1585,7 +1589,6 @@ static void rcu_prepare_for_idle(void)
                if (needwake)
                        rcu_gp_kthread_wake(rsp);
        }
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 }
 
 /*
@@ -1595,12 +1598,11 @@ static void rcu_prepare_for_idle(void)
  */
 static void rcu_cleanup_after_idle(void)
 {
-#ifndef CONFIG_RCU_NOCB_CPU_ALL
-       if (rcu_is_nocb_cpu(smp_processor_id()))
+       if (IS_ENABLED(CONFIG_RCU_NOCB_CPU_ALL) ||
+           rcu_is_nocb_cpu(smp_processor_id()))
                return;
        if (rcu_try_advance_all_cbs())
                invoke_rcu_core();
-#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
 }
 
 /*