Because the rcu_cblist_n_cbs() just samples the ->len counter, and
because the rcu_cblist structure is quite straightforward, it makes
sense to open-code rcu_cblist_n_cbs(p) as p->len, cutting out a level
of indirection.  This commit makes this change.

Reported-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Linus Torvalds <torva...@linux-foundation.org>
---
 kernel/rcu/rcu_segcblist.h | 6 ------
 kernel/rcu/tree.c          | 9 ++++-----
 kernel/rcu/tree_plugin.h   | 2 +-
 kernel/rcu/tree_trace.c    | 2 +-
 4 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h
index 7d18d41f0116..424a6b230921 100644
--- a/kernel/rcu/rcu_segcblist.h
+++ b/kernel/rcu/rcu_segcblist.h
@@ -22,12 +22,6 @@
 
 #include <linux/rcu_segcblist.h>
 
-/* Return number of callbacks in simple callback list. */
-static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
-{
-       return rclp->len;
-}
-
 /* Return number of lazy callbacks in simple callback list. */
 static inline long rcu_cblist_n_lazy_cbs(struct rcu_cblist *rclp)
 {
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 35152414760d..942d529fccbc 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2633,9 +2633,8 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, 
unsigned long flags)
                return;
 
        /* Do the accounting first. */
-       rdp->n_cbs_adopted += rcu_cblist_n_cbs(&rsp->orphan_done);
-       if (rcu_cblist_n_lazy_cbs(&rsp->orphan_done) !=
-           rcu_cblist_n_cbs(&rsp->orphan_done))
+       rdp->n_cbs_adopted += rsp->orphan_done.len;
+       if (rcu_cblist_n_lazy_cbs(&rsp->orphan_done) != rsp->orphan_done.len)
                rcu_idle_count_callbacks_posted();
        rcu_segcblist_insert_count(&rdp->cblist, &rsp->orphan_done);
 
@@ -2792,14 +2791,14 @@ static void rcu_do_batch(struct rcu_state *rsp, struct 
rcu_data *rdp)
                 * Stop only if limit reached and CPU has something to do.
                 * Note: The rcl structure counts down from zero.
                 */
-               if (-rcu_cblist_n_cbs(&rcl) >= bl &&
+               if (-rcl.len >= bl &&
                    (need_resched() ||
                     (!is_idle_task(current) && !rcu_is_callbacks_kthread())))
                        break;
        }
 
        local_irq_save(flags);
-       count = -rcu_cblist_n_cbs(&rcl);
+       count = -rcl.len;
        trace_rcu_batch_end(rsp->name, count, !!rcl.head, need_resched(),
                            is_idle_task(current), rcu_is_callbacks_kthread());
 
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6b4b1f8a272d..7ebe357df155 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1934,7 +1934,7 @@ static bool __maybe_unused 
rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp,
                                                     struct rcu_data *rdp,
                                                     unsigned long flags)
 {
-       long ql = rcu_cblist_n_cbs(&rsp->orphan_done);
+       long ql = rsp->orphan_done.len;
        long qll = rcu_cblist_n_lazy_cbs(&rsp->orphan_done);
 
        /* If this is not a no-CBs CPU, tell the caller to do it the old way. */
diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c
index 30c5bf89ee58..b7743aa2965f 100644
--- a/kernel/rcu/tree_trace.c
+++ b/kernel/rcu/tree_trace.c
@@ -278,7 +278,7 @@ static void print_one_rcu_state(struct seq_file *m, struct 
rcu_state *rsp)
                   rsp->n_force_qs - rsp->n_force_qs_ngp,
                   READ_ONCE(rsp->n_force_qs_lh),
                   rcu_cblist_n_lazy_cbs(&rsp->orphan_done),
-                  rcu_cblist_n_cbs(&rsp->orphan_done));
+                  rsp->orphan_done.len);
        for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
                if (rnp->level != level) {
                        seq_puts(m, "\n");
-- 
2.5.2

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