[PATCH] tuntap: synchronize through tfiles instead of numqueues

[Jason Wang]

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
 drivers/net/tun.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 80bff1b4ec17..03715f605fb5 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -698,6 +698,7 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
 
 		rcu_assign_pointer(tun->tfiles[index],
 				   tun->tfiles[tun->numqueues - 1]);
+		rcu_assign_pointer(tun->tfiles[tun->numqueues], NULL);
 		ntfile = rtnl_dereference(tun->tfiles[index]);
 		ntfile->queue_index = index;
 
@@ -1082,7 +1083,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	tfile = rcu_dereference(tun->tfiles[txq]);
 
 	/* Drop packet if interface is not attached */
-	if (txq >= tun->numqueues)
+	if (!tfile)
 		goto drop;
 
 	if (!rcu_dereference(tun->steering_prog))
@@ -1305,15 +1306,13 @@ static int tun_xdp_xmit(struct net_device *dev, int n,
 
 	rcu_read_lock();
 
-	numqueues = READ_ONCE(tun->numqueues);
-	if (!numqueues) {
+	tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
+					    tun->numqueues]);
+	if (!tfile) {
 		rcu_read_unlock();
 		return -ENXIO; /* Caller will free/return all frames */
 	}
 
-	tfile = rcu_dereference(tun->tfiles[smp_processor_id() %
-					    numqueues]);
-
 	spin_lock(&tfile->tx_ring.producer_lock);
 	for (i = 0; i < n; i++) {
 		struct xdp_frame *xdp = frames[i];
-- 
2.19.1