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authorYing Xue <ying.xue@windriver.com>2014-04-21 06:55:47 +0400
committerDavid S. Miller <davem@davemloft.net>2014-04-23 05:17:53 +0400
commit2231c5af451e4b7ae3cc56eaa4653af6ede51109 (patch)
tree7c7e78e9adc9f746f64290530d40ce7a9b155fb7
parent7a2f7d18e79b09c5c5a65fb1fa0e31ad046b3116 (diff)
downloadlinux-2231c5af451e4b7ae3cc56eaa4653af6ede51109.tar.xz
tipc: use RCU to protect media_ptr pointer
Now the media_ptr pointer is protected with tipc_net_lock write lock on write side; tipc_net_lock read lock is used to read side. As the part of effort of eliminating tipc_net_lock, we decide to adjust the locking policy of media_ptr pointer protection: on write side, RTNL lock is use while on read side RCU read lock is applied. Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Tested-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/tipc/bearer.c13
-rw-r--r--net/tipc/bearer.h2
2 files changed, 11 insertions, 4 deletions
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index e0625e9e2c72..c24a35114fd7 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -458,7 +458,7 @@ int tipc_enable_l2_media(struct tipc_bearer *b)
return -ENODEV;
/* Associate TIPC bearer with Ethernet bearer */
- b->media_ptr = dev;
+ rcu_assign_pointer(b->media_ptr, dev);
memset(b->bcast_addr.value, 0, sizeof(b->bcast_addr.value));
memcpy(b->bcast_addr.value, dev->broadcast, b->media->hwaddr_len);
b->bcast_addr.media_id = b->media->type_id;
@@ -477,7 +477,10 @@ int tipc_enable_l2_media(struct tipc_bearer *b)
*/
void tipc_disable_l2_media(struct tipc_bearer *b)
{
- struct net_device *dev = (struct net_device *)b->media_ptr;
+ struct net_device *dev;
+
+ dev = (struct net_device *)rtnl_dereference(b->media_ptr);
+ RCU_INIT_POINTER(b->media_ptr, NULL);
RCU_INIT_POINTER(dev->tipc_ptr, NULL);
dev_put(dev);
}
@@ -492,8 +495,12 @@ int tipc_l2_send_msg(struct sk_buff *buf, struct tipc_bearer *b,
struct tipc_media_addr *dest)
{
struct sk_buff *clone;
+ struct net_device *dev;
int delta;
- struct net_device *dev = (struct net_device *)b->media_ptr;
+
+ dev = (struct net_device *)rcu_dereference_rtnl(b->media_ptr);
+ if (!dev)
+ return 0;
clone = skb_clone(buf, GFP_ATOMIC);
if (!clone)
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 2fa86bd67c0a..a983b3005e71 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -128,7 +128,7 @@ struct tipc_media {
* care of initializing all other fields.
*/
struct tipc_bearer {
- void *media_ptr; /* initalized by media */
+ void __rcu *media_ptr; /* initalized by media */
u32 mtu; /* initalized by media */
struct tipc_media_addr addr; /* initalized by media */
char name[TIPC_MAX_BEARER_NAME];