Now that kfree_rcu() special casing have been removed from tree RCU,
remove kfree_call_rcu_nobatch() since it is not needed.

Signed-off-by: Joel Fernandes (Google) <j...@joelfernandes.org>
---
 .../admin-guide/kernel-parameters.txt         |  4 ---
 include/linux/rcutiny.h                       |  5 ---
 include/linux/rcutree.h                       |  1 -
 kernel/rcu/rcuperf.c                          | 10 +-----
 kernel/rcu/tree.c                             | 34 ++++++++-----------
 5 files changed, 15 insertions(+), 39 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt 
b/Documentation/admin-guide/kernel-parameters.txt
index 24fe8aefb12c..56be0e30100b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3909,10 +3909,6 @@
                        Number of loops doing rcuperf.kfree_alloc_num number
                        of allocations and frees.
 
-       rcuperf.kfree_no_batch= [KNL]
-                       Use the non-batching (less efficient) version of 
kfree_rcu().
-                       This is useful for comparing with the batched version.
-
        rcuperf.nreaders= [KNL]
                        Set number of RCU readers.  The value -1 selects
                        N, where N is the number of CPUs.  A value
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index b7607e2667ae..37b6f0c2b79d 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -39,11 +39,6 @@ static inline void kfree_call_rcu(struct rcu_head *head, 
rcu_callback_t func)
        call_rcu(head, func);
 }
 
-static inline void kfree_call_rcu_nobatch(struct rcu_head *head, 
rcu_callback_t func)
-{
-       call_rcu(head, func);
-}
-
 void rcu_qs(void);
 
 static inline void rcu_softirq_qs(void)
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 961b7e05d141..0b68aa952f8b 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -34,7 +34,6 @@ static inline void rcu_virt_note_context_switch(int cpu)
 
 void synchronize_rcu_expedited(void);
 void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
-void kfree_call_rcu_nobatch(struct rcu_head *head, rcu_callback_t func);
 
 void rcu_barrier(void);
 bool rcu_eqs_special_set(int cpu);
diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
index c1e25fd10f2a..da94b89cd531 100644
--- a/kernel/rcu/rcuperf.c
+++ b/kernel/rcu/rcuperf.c
@@ -593,7 +593,6 @@ rcu_perf_shutdown(void *arg)
 torture_param(int, kfree_nthreads, -1, "Number of threads running loops of 
kfree_rcu().");
 torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees 
done in an iteration.");
 torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num 
allocations and frees.");
-torture_param(int, kfree_no_batch, 0, "Use the non-batching (slower) version 
of kfree_rcu().");
 
 static struct task_struct **kfree_reader_tasks;
 static int kfree_nrealthreads;
@@ -632,14 +631,7 @@ kfree_perf_thread(void *arg)
                        if (!alloc_ptr)
                                return -ENOMEM;
 
-                       if (!kfree_no_batch) {
-                               kfree_rcu(alloc_ptr, rh);
-                       } else {
-                               rcu_callback_t cb;
-
-                               cb = (rcu_callback_t)(unsigned 
long)offsetof(struct kfree_obj, rh);
-                               kfree_call_rcu_nobatch(&(alloc_ptr->rh), cb);
-                       }
+                       kfree_rcu(alloc_ptr, rh);
                }
 
                cond_resched();
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index cd7bbc74ae20..72550343843f 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2770,8 +2770,10 @@ static void kfree_rcu_work(struct work_struct *work)
                rcu_lock_acquire(&rcu_callback_map);
                trace_rcu_invoke_kfree_callback(rcu_state.name, head, offset);
 
-               /* Could be possible to optimize with kfree_bulk in future */
-               kfree((void *)head - offset);
+               if (!WARN_ON_ONCE(!__is_kfree_rcu_offset(offset))) {
+                       /* Could be optimized with kfree_bulk() in future. */
+                       kfree((void *)head - offset);
+               }
 
                rcu_lock_release(&rcu_callback_map);
                cond_resched_tasks_rcu_qs();
@@ -2857,16 +2859,6 @@ static void kfree_rcu_monitor(struct work_struct *work)
        }
 }
 
-/*
- * This version of kfree_call_rcu does not do batching of kfree_rcu() requests.
- * Used only by rcuperf torture test for comparison with kfree_rcu_batch().
- */
-void kfree_call_rcu_nobatch(struct rcu_head *head, rcu_callback_t func)
-{
-       __call_rcu(head, func);
-}
-EXPORT_SYMBOL_GPL(kfree_call_rcu_nobatch);
-
 /*
  * Queue a request for lazy invocation of kfree() after a grace period.
  *
@@ -2886,12 +2878,6 @@ void kfree_call_rcu(struct rcu_head *head, 
rcu_callback_t func)
        unsigned long flags;
        struct kfree_rcu_cpu *krcp;
 
-       /* kfree_call_rcu() batching requires timers to be up. If the scheduler
-        * is not yet up, just skip batching and do the non-batched version.
-        */
-       if (rcu_scheduler_active != RCU_SCHEDULER_RUNNING)
-               return kfree_call_rcu_nobatch(head, func);
-
        if (debug_rcu_head_queue(head)) {
                /* Probable double kfree_rcu() */
                WARN_ONCE(1, "kfree_call_rcu(): Double-freed call. rcu_head 
%p\n",
@@ -2910,8 +2896,16 @@ void kfree_call_rcu(struct rcu_head *head, 
rcu_callback_t func)
        krcp->head = head;
 
        /* Schedule monitor for timely drain after KFREE_DRAIN_JIFFIES. */
-       if (!xchg(&krcp->monitor_todo, true))
-               schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
+       if (!krcp->monitor_todo) {
+               krcp->monitor_todo = true;
+               /* Scheduling the monitor requires scheduler/timers to be up,
+                * if it is not, just skip it. An eventual kfree_rcu() will
+                * kick it again.
+                */
+               if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING) {
+                       schedule_delayed_work(&krcp->monitor_work, 
KFREE_DRAIN_JIFFIES);
+               }
+       }
 
        spin_unlock(&krcp->lock);
        local_irq_restore(flags);
-- 
2.23.0.187.g17f5b7556c-goog

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