[ovs-dev] [netdev 25/27] netdev-vport: Make netdev_vport_patch_peer() return a malloc()'d string.
Ben Pfaff
blp at nicira.com
Thu Aug 1 21:29:48 UTC 2013
When threading comes into the picture there arises the possibility of a
race between netdev_vport_patch_peer()'s caller using the returned string
and another caller changing the peer. It is safer to return a copy.
Signed-off-by: Ben Pfaff <blp at nicira.com>
---
lib/netdev-vport.c | 21 ++++++++++++++++-----
lib/netdev-vport.h | 2 +-
ofproto/ofproto-dpif.c | 8 +++++---
3 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/lib/netdev-vport.c b/lib/netdev-vport.c
index ac3da63..287edae 100644
--- a/lib/netdev-vport.c
+++ b/lib/netdev-vport.c
@@ -553,12 +553,23 @@ get_tunnel_config(const struct netdev *dev, struct smap *args)
/* Code specific to patch ports. */
-const char *
-netdev_vport_patch_peer(const struct netdev *netdev)
+/* If 'netdev' is a patch port, returns the name of its peer as a malloc()'d
+ * string that the caller must free.
+ *
+ * If 'netdev' is not a patch port, returns NULL. */
+char *
+netdev_vport_patch_peer(const struct netdev *netdev_)
{
- return (netdev_vport_is_patch(netdev)
- ? netdev_vport_cast(netdev)->peer
- : NULL);
+ char *peer = NULL;
+
+ if (netdev_vport_is_patch(netdev_)) {
+ struct netdev_vport *netdev = netdev_vport_cast(netdev_);
+ if (netdev->peer) {
+ peer = xstrdup(netdev->peer);
+ }
+ }
+
+ return peer;
}
void
diff --git a/lib/netdev-vport.h b/lib/netdev-vport.h
index 5394966..dc49097 100644
--- a/lib/netdev-vport.h
+++ b/lib/netdev-vport.h
@@ -31,7 +31,7 @@ void netdev_vport_patch_register(void);
bool netdev_vport_is_patch(const struct netdev *);
-const char *netdev_vport_patch_peer(const struct netdev *netdev);
+char *netdev_vport_patch_peer(const struct netdev *netdev);
void netdev_vport_inc_rx(const struct netdev *,
const struct dpif_flow_stats *);
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 839de69..9d53ccf 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -2890,7 +2890,7 @@ ofport_update_peer(struct ofport_dpif *ofport)
{
const struct ofproto_dpif *ofproto;
struct dpif_backer *backer;
- const char *peer_name;
+ char *peer_name;
if (!netdev_vport_is_patch(ofport->up.netdev)) {
return;
@@ -2912,7 +2912,7 @@ ofport_update_peer(struct ofport_dpif *ofport)
HMAP_FOR_EACH (ofproto, all_ofproto_dpifs_node, &all_ofproto_dpifs) {
struct ofport *peer_ofport;
struct ofport_dpif *peer;
- const char *peer_peer;
+ char *peer_peer;
if (ofproto->backer != backer) {
continue;
@@ -2930,9 +2930,11 @@ ofport_update_peer(struct ofport_dpif *ofport)
ofport->peer = peer;
ofport->peer->peer = ofport;
}
+ free(peer_peer);
- return;
+ break;
}
+ free(peer_name);
}
static void
--
1.7.10.4
More information about the dev
mailing list