[PATCH tip/core/rcu 5/5] rcu: Update __call_rcu() comments

From: paulmck
Date: Fri Feb 14 2020 - 19:19:11 EST


From: "Paul E. McKenney" <paulmck@xxxxxxxxxx>

The __call_rcu() function's header comment refers to a cpu argument
that no longer exists, and the comment of the return path from
rcu_nocb_try_bypass() ignores the non-no-CBs CPU case. This comit
therefore update both comments.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/rcu/tree.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 48fba22..0a9de9f 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2642,12 +2642,7 @@ static void check_cb_ovld(struct rcu_data *rdp)
raw_spin_unlock_rcu_node(rnp);
}

-/*
- * Helper function for call_rcu() and friends. The cpu argument will
- * normally be -1, indicating "currently running CPU". It may specify
- * a CPU only if that CPU is a no-CBs CPU. Currently, only rcu_barrier()
- * is expected to specify a CPU.
- */
+/* Helper function for call_rcu() and friends. */
static void
__call_rcu(struct rcu_head *head, rcu_callback_t func)
{
@@ -2688,7 +2683,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func)
check_cb_ovld(rdp);
if (rcu_nocb_try_bypass(rdp, head, &was_alldone, flags))
return; // Enqueued onto ->nocb_bypass, so just leave.
- /* If we get here, rcu_nocb_try_bypass() acquired ->nocb_lock. */
+ // If no-CBs CPU gets here, rcu_nocb_try_bypass() acquired ->nocb_lock.
rcu_segcblist_enqueue(&rdp->cblist, head);
if (__is_kfree_rcu_offset((unsigned long)func))
trace_rcu_kfree_callback(rcu_state.name, head,
--
2.9.5