[PATCH 1/1] tap: comment fix

From: Wang Jian
Date: Thu Aug 16 2018 - 09:01:44 EST


The tap_queue and the "tap_dev" are loosely coupled, not "macvlan_dev".

And I also change one rcu_read_lock's place, seems can reduce rcu
critical section a little.

Signed-off-by: Wang Jian <jianjian.wang1@xxxxxxxxx>
---
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 f0f7cd9..e5e5a8e 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);

--
Regards,
Wang Jian