From 2f980d741737fd3296d8063d800753a2d77bd730 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@nicira.com>
Date: Thu, 25 Jul 2013 16:27:39 -0700
Subject: [PATCH] netdev: Make netdev_get_devices() take a reference to each
 netdev.

This API change is necessary for thread safety, to be added in an upcoming
commit.  Otherwise, the client would not be able to actually use any of
the returned netdevs because they could already have been destroyed.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
---
 lib/netdev-bsd.c   | 32 ++++++++++----------------------
 lib/netdev-linux.c |  4 ++++
 lib/netdev.c       |  5 +++--
 3 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/lib/netdev-bsd.c b/lib/netdev-bsd.c
index 6ff6b3e95..5c23d3810 100644
--- a/lib/netdev-bsd.c
+++ b/lib/netdev-bsd.c
@@ -255,6 +255,7 @@ netdev_bsd_cache_cb(const struct rtbsd_change *change,
                 dev->cache_valid = 0;
                 netdev_bsd_changed(dev);
             }
+            netdev_close(base_dev);
         }
     } else {
         /*
@@ -271,6 +272,7 @@ netdev_bsd_cache_cb(const struct rtbsd_change *change,
             dev = netdev_bsd_cast(netdev);
             dev->cache_valid = 0;
             netdev_bsd_changed(dev);
+            netdev_close(netdev);
         }
         shash_destroy(&device_shash);
     }
@@ -1200,9 +1202,10 @@ netdev_bsd_get_in6(const struct netdev *netdev_, struct in6_addr *in6)
 }
 
 #if defined(__NetBSD__)
-static struct netdev *
-find_netdev_by_kernel_name(const char *kernel_name)
+static char *
+netdev_bsd_kernel_name_to_ovs_name(const char *kernel_name)
 {
+    char *ovs_name = NULL;
     struct shash device_shash;
     struct shash_node *node;
 
@@ -1213,24 +1216,14 @@ find_netdev_by_kernel_name(const char *kernel_name)
         struct netdev_bsd * const dev = netdev_bsd_cast(netdev);
 
         if (!strcmp(dev->kernel_name, kernel_name)) {
-            shash_destroy(&device_shash);
-            return &dev->up;
+            free(ovs_name);
+            ovs_name = xstrdup(netdev_get_name(&dev->up));
         }
+        netdev_close(netdev);
     }
     shash_destroy(&device_shash);
-    return NULL;
-}
-
-static const char *
-netdev_bsd_convert_kernel_name_to_ovs_name(const char *kernel_name)
-{
-    const struct netdev * const netdev =
-      find_netdev_by_kernel_name(kernel_name);
 
-    if (netdev == NULL) {
-        return NULL;
-    }
-    return netdev_get_name(netdev);
+    return ovs_name ? ovs_name : xstrdup(kernel_name);
 }
 #endif
 
@@ -1315,12 +1308,7 @@ netdev_bsd_get_next_hop(const struct in_addr *host OVS_UNUSED,
                 char *kernel_name;
 
                 kernel_name = xmemdup0(sdl->sdl_data, sdl->sdl_nlen);
-                name = netdev_bsd_convert_kernel_name_to_ovs_name(kernel_name);
-                if (name == NULL) {
-                    ifname = xstrdup(kernel_name);
-                } else {
-                    ifname = xstrdup(name);
-                }
+                ifname = netdev_bsd_kernel_name_to_ovs_name(kernel_name);
                 free(kernel_name);
             }
             RT_ADVANCE(cp, sa);
diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index ba0d8633c..5bbaf632f 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -555,6 +555,7 @@ netdev_linux_cache_cb(const struct rtnetlink_link_change *change,
 
             get_flags(&dev->up, &flags);
             netdev_linux_changed(dev, flags, 0);
+            netdev_close(netdev);
         }
         shash_destroy(&device_shash);
     }
@@ -1180,6 +1181,7 @@ netdev_linux_miimon_run(void)
         bool miimon;
 
         if (dev->miimon_interval <= 0 || !timer_expired(&dev->miimon_timer)) {
+            netdev_close(netdev);
             continue;
         }
 
@@ -1190,6 +1192,7 @@ netdev_linux_miimon_run(void)
         }
 
         timer_set_duration(&dev->miimon_timer, dev->miimon_interval);
+        netdev_close(netdev);
     }
 
     shash_destroy(&device_shash);
@@ -1210,6 +1213,7 @@ netdev_linux_miimon_wait(void)
         if (dev->miimon_interval > 0) {
             timer_wait(&dev->miimon_timer);
         }
+        netdev_close(netdev);
     }
     shash_destroy(&device_shash);
 }
diff --git a/lib/netdev.c b/lib/netdev.c
index 0079dc209..25615380f 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -1395,8 +1395,8 @@ netdev_from_name(const char *name)
 
 /* Fills 'device_list' with devices that match 'netdev_class'.
  *
- * The caller is responsible for initializing and destroying 'device_list'
- * but the contained netdevs must not be freed. */
+ * The caller is responsible for initializing and destroying 'device_list' and
+ * must close each device on the list. */
 void
 netdev_get_devices(const struct netdev_class *netdev_class,
                    struct shash *device_list)
@@ -1406,6 +1406,7 @@ netdev_get_devices(const struct netdev_class *netdev_class,
         struct netdev *dev = node->data;
 
         if (dev->netdev_class == netdev_class) {
+            dev->ref_cnt++;
             shash_add(device_list, node->name, node->data);
         }
     }
-- 
2.43.0