The tap_queue and the 'tap_dev' are loosely coupled, not 'macvlan_dev'.
Taking rcu_read_lock a little later seems can slightly reduce rcu read critical
section.
Signed-off-by: Wang Jian <jianjian.wa...@gmail.com>
---
drivers/net/tap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index f0f7cd977667..e5e5a8e4a60d 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -125,7 +125,7 @@ static struct tap_dev *tap_dev_get_rcu(const struct
net_device *dev)
/*
* RCU usage:
- * The tap_queue and the macvlan_dev are loosely coupled, the
+ * The tap_queue and the tap_dev are loosely coupled, the
* pointers from one to the other can only be read while rcu_read_lock
* or rtnl is held.
*
@@ -720,8 +720,6 @@ static ssize_t tap_get_user(struct tap_queue *q, struct
msghdr *m,
__vlan_get_protocol(skb, skb->protocol, &depth) != 0)
skb_set_network_header(skb, depth);
- rcu_read_lock();
- tap = rcu_dereference(q->tap);
/* copy skb_ubuf_info for callback when skb has no error */
if (zerocopy) {
skb_shinfo(skb)->destructor_arg = m->msg_control;
@@ -732,6 +730,8 @@ static ssize_t tap_get_user(struct tap_queue *q, struct
msghdr *m,
uarg->callback(uarg, false);
}
+ rcu_read_lock();
+ tap = rcu_dereference(q->tap);
if (tap) {
skb->dev = tap->dev;
dev_queue_xmit(skb);
--
2.17.1
