From: John Fastabend <john.fastabend@gmail.com>
Date: Thu, 5 Jul 2018 15:06:01 +0000 (-0700)
Subject: bpf: sockmap, hash table is RCU so readers do not need locks
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=1d1ef005dbc6de673c62cbd2562290ada3090463;p=openwrt%2Fstaging%2Fblogic.git

bpf: sockmap, hash table is RCU so readers do not need locks

This removes locking from readers of RCU hash table. Its not
necessary.

Fixes: 81110384441a ("bpf: sockmap, add hash map support")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---

diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 3847a7ce7dae..00fb2e328d1b 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -2467,10 +2467,8 @@ struct sock  *__sock_hash_lookup_elem(struct bpf_map *map, void *key)
 	b = __select_bucket(htab, hash);
 	head = &b->head;
 
-	raw_spin_lock_bh(&b->lock);
 	l = lookup_elem_raw(head, hash, key, key_size);
 	sk = l ? l->sk : NULL;
-	raw_spin_unlock_bh(&b->lock);
 	return sk;
 }