bridge: add rcu_read_lock on transmit

[ Upstream commit eeaf61d8891f9c9ed12c1a667e72bf83f0857954 ]

Long ago, when bridge was converted to RCU, rcu lock was equivalent
to having preempt disabled. RCU has changed a lot since then and
bridge code was still assuming the since transmit was called with
bottom half disabled, it was RCU safe.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 90a9024e5c1eaf30713258c4d32151a89cc87c06..5752057a924ac50cb9c3fb014bdbe7990eaddb13 100644 (file)
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -19,7 +19,7 @@
 #include <asm/uaccess.h>
 #include "br_private.h"
 
-/* net device transmit always called with no BH (preempt_disabled) */
+/* net device transmit always called with BH disabled */
 netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        struct net_bridge *br = netdev_priv(dev);
@@ -35,6 +35,7 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
        skb_reset_mac_header(skb);
        skb_pull(skb, ETH_HLEN);
 
+       rcu_read_lock();
        if (dest[0] & 1) {
                if (br_multicast_rcv(br, NULL, skb))
                        goto out;
@@ -50,6 +51,7 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
                br_flood_deliver(br, skb);
 
 out:
+       rcu_read_unlock();
        return NETDEV_TX_OK;
 }
 

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 26c0cbec4ced533c0dc897c0e5ae4a8b3acfc594..5c96374b4907b1696524656eb369c4bfc9fc243c 100644 (file)
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -214,7 +214,7 @@ void br_fdb_delete_by_port(struct net_bridge *br,
        spin_unlock_bh(&br->hash_lock);
 }
 
-/* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
+/* No locking or refcounting, assumes caller has rcu_read_lock */
 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
                                          const unsigned char *addr)
 {

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index a82dde2d2ead34d32af8ecd3829ee5563d8cf710..9015a20eec5a1d3ed0922f0b6844f78b1e0f2aa3 100644 (file)
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -35,7 +35,7 @@ static int br_pass_frame_up(struct sk_buff *skb)
                       netif_receive_skb);
 }
 
-/* note: already called with rcu_read_lock (preempt_disabled) */
+/* note: already called with rcu_read_lock */
 int br_handle_frame_finish(struct sk_buff *skb)
 {
        const unsigned char *dest = eth_hdr(skb)->h_dest;
@@ -106,7 +106,7 @@ drop:
        goto out;
 }
 
-/* note: already called with rcu_read_lock (preempt_disabled) */
+/* note: already called with rcu_read_lock */
 static int br_handle_local_finish(struct sk_buff *skb)
 {
        struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
@@ -131,7 +131,7 @@ static inline int is_link_local(const unsigned char *dest)
 /*
  * Called via br_handle_frame_hook.
  * Return NULL if skb is handled
- * note: already called with rcu_read_lock (preempt_disabled)
+ * note: already called with rcu_read_lock
  */
 struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
 {

diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
index d66cce11f3bf93475b85d827dbf6b11de8897886..edc7111b3db809e79e36312475fd58a7cf29bcb1 100644 (file)
--- a/net/bridge/br_stp_bpdu.c
+++ b/net/bridge/br_stp_bpdu.c
@@ -131,7 +131,7 @@ void br_send_tcn_bpdu(struct net_bridge_port *p)
 /*
  * Called from llc.
  *
- * NO locks, but rcu_read_lock (preempt_disabled)
+ * NO locks, but rcu_read_lock
  */
 void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
                struct net_device *dev)