netdev - [bpf PATCH v2 2/2] bpf: sockmap, hash table is RCU so readers do not need locks

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Date:   Thu, 05 Jul 2018 08:06:01 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     ast@...nel.org, daniel@...earbox.net
Cc:     netdev@...r.kernel.org, john.fastabend@...il.com
Subject: [bpf PATCH v2 2/2] 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@...il.com>
---
 kernel/bpf/sockmap.c |    2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 3847a7c..00fb2e3 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;
 }