rcu: Open-code the rcu_cblist_n_cbs() function

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 <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>

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");