From: Eric Dumazet <edumazet@google.com>
Date: Fri, 18 Feb 2022 10:18:01 -0800
Subject: bpf: Call maybe_wait_bpf_programs() only once from
 generic_map_delete_batch()
Patch-mainline: v5.18-rc1
Git-commit: 9087c6ff8dfe0a070e4e05a434399080603c29de
References: jsc#PED-1377

As stated in the comment found in maybe_wait_bpf_programs(),
the synchronize_rcu() barrier is only needed before returning
to userspace, not after each deletion in the batch.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20220218181801.2971275-1-eric.dumazet@gmail.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 kernel/bpf/syscall.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1352,7 +1352,6 @@ int generic_map_delete_batch(struct bpf_
 		err = map->ops->map_delete_elem(map, key);
 		rcu_read_unlock();
 		bpf_enable_instrumentation();
-		maybe_wait_bpf_programs(map);
 		if (err)
 			break;
 		cond_resched();
@@ -1361,6 +1360,8 @@ int generic_map_delete_batch(struct bpf_
 		err = -EFAULT;
 
 	kvfree(key);
+
+	maybe_wait_bpf_programs(map);
 	return err;
 }