Merge branch 'linus' into timers/clocksource

... to bring it up to date for new changes.

1 files changed, 10 insertions, 23 deletions

diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index 682a9f34214b..e9662db7198f 100644
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -284,17 +284,6 @@ static void __free_rcu(struct rcu_head *head)
 	atomic_set(&c->call_rcu_ttrace_in_progress, 0);
 }
 
-static void __free_rcu_tasks_trace(struct rcu_head *head)
-{
-	/* If RCU Tasks Trace grace period implies RCU grace period,
-	 * there is no need to invoke call_rcu().
-	 */
-	if (rcu_trace_implies_rcu_gp())
-		__free_rcu(head);
-	else
-		call_rcu(head, __free_rcu);
-}
-
 static void enque_to_free(struct bpf_mem_cache *c, void *obj)
 {
 	struct llist_node *llnode = obj;
@@ -326,12 +315,12 @@ static void do_call_rcu_ttrace(struct bpf_mem_cache *c)
 		return;
 	}
 
-	/* Use call_rcu_tasks_trace() to wait for sleepable progs to finish.
-	 * If RCU Tasks Trace grace period implies RCU grace period, free
-	 * these elements directly, else use call_rcu() to wait for normal
-	 * progs to finish and finally do free_one() on each element.
+	/*
+	 * Use call_rcu_tasks_trace() to wait for sleepable progs to finish.
+	 * RCU Tasks Trace grace period implies RCU grace period, so pass
+	 * __free_rcu directly as the callback.
 	 */
-	call_rcu_tasks_trace(&c->rcu_ttrace, __free_rcu_tasks_trace);
+	call_rcu_tasks_trace(&c->rcu_ttrace, __free_rcu);
 }
 
 static void free_bulk(struct bpf_mem_cache *c)
@@ -696,20 +685,18 @@ static void free_mem_alloc_no_barrier(struct bpf_mem_alloc *ma)
 
 static void free_mem_alloc(struct bpf_mem_alloc *ma)
 {
-	/* waiting_for_gp[_ttrace] lists were drained, but RCU callbacks
+	/*
+	 * waiting_for_gp[_ttrace] lists were drained, but RCU callbacks
 	 * might still execute. Wait for them.
 	 *
 	 * rcu_barrier_tasks_trace() doesn't imply synchronize_rcu_tasks_trace(),
 	 * but rcu_barrier_tasks_trace() and rcu_barrier() below are only used
-	 * to wait for the pending __free_rcu_tasks_trace() and __free_rcu(),
-	 * so if call_rcu(head, __free_rcu) is skipped due to
-	 * rcu_trace_implies_rcu_gp(), it will be OK to skip rcu_barrier() by
-	 * using rcu_trace_implies_rcu_gp() as well.
+	 * to wait for the pending __free_by_rcu(), and __free_rcu(). RCU Tasks
+	 * Trace grace period implies RCU grace period, so all __free_rcu don't
+	 * need extra call_rcu() (and thus extra rcu_barrier() here).
 	 */
 	rcu_barrier(); /* wait for __free_by_rcu */
 	rcu_barrier_tasks_trace(); /* wait for __free_rcu */
-	if (!rcu_trace_implies_rcu_gp())
-		rcu_barrier();
 	free_mem_alloc_no_barrier(ma);
 }