From: Vlad Yasevich <vyasevic@redhat.com>
Date: Tue, 25 Jun 2013 20:04:20 +0000 (-0400)
Subject: macvtap: Consistently use rcu functions
X-Git-Tag: firefly_0821_release~176^2~5751^2~127
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ac4e4af1e59e16a018527ffa58d9d3f30bb96ca9;p=firefly-linux-kernel-4.4.55.git

macvtap: Consistently use rcu functions

Currently macvtap uses rcu_bh functions in its
user facing fuction macvtap_get_user() and macvtap_put_user().
However, its packet handlers use normal rcu as the rcu_read_lock()
is taken in netif_receive_skb().  We can safely discontinue
the usage or rcu with bh disabled.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index efbf2eb6ae78..d7856a8f589a 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -754,8 +754,8 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
 
 	skb_probe_transport_header(skb, ETH_HLEN);
 
-	rcu_read_lock_bh();
-	vlan = rcu_dereference_bh(q->vlan);
+	rcu_read_lock();
+	vlan = rcu_dereference(q->vlan);
 	/* copy skb_ubuf_info for callback when skb has no error */
 	if (zerocopy) {
 		skb_shinfo(skb)->destructor_arg = m->msg_control;
@@ -766,7 +766,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
 		macvlan_start_xmit(skb, vlan->dev);
 	else
 		kfree_skb(skb);
-	rcu_read_unlock_bh();
+	rcu_read_unlock();
 
 	return total_len;
 
@@ -774,11 +774,11 @@ err_kfree:
 	kfree_skb(skb);
 
 err:
-	rcu_read_lock_bh();
-	vlan = rcu_dereference_bh(q->vlan);
+	rcu_read_lock();
+	vlan = rcu_dereference(q->vlan);
 	if (vlan)
 		vlan->dev->stats.tx_dropped++;
-	rcu_read_unlock_bh();
+	rcu_read_unlock();
 
 	return err;
 }
@@ -854,11 +854,11 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
 	copied += len;
 
 done:
-	rcu_read_lock_bh();
-	vlan = rcu_dereference_bh(q->vlan);
+	rcu_read_lock();
+	vlan = rcu_dereference(q->vlan);
 	if (vlan)
 		macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0);
-	rcu_read_unlock_bh();
+	rcu_read_unlock();
 
 	return ret ? ret : copied;
 }