drbd: get_one_status(): Iterate over resource->devices instead of connection->peer_devices

Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>

1 files changed, 46 insertions, 26 deletions

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 81e07e2664b3..6f11d8579263 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -2752,23 +2752,28 @@ int drbd_adm_outdate(struct sk_buff *skb, struct genl_info *info)
         return drbd_adm_simple_request_state(skb, info, NS(disk, D_OUTDATED));
 }
 
-static int nla_put_drbd_cfg_context(struct sk_buff *skb, struct drbd_connection *connection, unsigned vnr)
+static int nla_put_drbd_cfg_context(struct sk_buff *skb,
+                                    struct drbd_resource *resource,
+                                    struct drbd_connection *connection,
+                                    struct drbd_device *device)
 {
         struct nlattr *nla;
         nla = nla_nest_start(skb, DRBD_NLA_CFG_CONTEXT);
         if (!nla)
                 goto nla_put_failure;
-        if (vnr != VOLUME_UNSPECIFIED &&
-            nla_put_u32(skb, T_ctx_volume, vnr))
+        if (device &&
+            nla_put_u32(skb, T_ctx_volume, device->vnr))
                 goto nla_put_failure;
         if (nla_put_string(skb, T_ctx_resource_name, connection->resource->name))
                 goto nla_put_failure;
-        if (connection->my_addr_len &&
-            nla_put(skb, T_ctx_my_addr, connection->my_addr_len, &connection->my_addr))
-                goto nla_put_failure;
-        if (connection->peer_addr_len &&
-            nla_put(skb, T_ctx_peer_addr, connection->peer_addr_len, &connection->peer_addr))
-                goto nla_put_failure;
+        if (connection) {
+                if (connection->my_addr_len &&
+                    nla_put(skb, T_ctx_my_addr, connection->my_addr_len, &connection->my_addr))
+                        goto nla_put_failure;
+                if (connection->peer_addr_len &&
+                    nla_put(skb, T_ctx_peer_addr, connection->peer_addr_len, &connection->peer_addr))
+                        goto nla_put_failure;
+        }
         nla_nest_end(skb, nla);
         return 0;
 
@@ -2778,9 +2783,22 @@ nla_put_failure:
         return -EMSGSIZE;
 }
 
-static int nla_put_status_info(struct sk_buff *skb, struct drbd_device *device,
+/*
+ * Return the connection of @resource if @resource has exactly one connection.
+ */
+static struct drbd_connection *the_only_connection(struct drbd_resource *resource)
+{
+        struct list_head *connections = &resource->connections;
+
+        if (list_empty(connections) || connections->next->next != connections)
+                return NULL;
+        return list_first_entry(&resource->connections, struct drbd_connection, connections);
+}
+
+int nla_put_status_info(struct sk_buff *skb, struct drbd_device *device,
                 const struct sib_info *sib)
 {
+        struct drbd_resource *resource = device->resource;
         struct state_info *si = NULL; /* for sizeof(si->member); */
         struct nlattr *nla;
         int got_ldev;
@@ -2804,7 +2822,7 @@ static int nla_put_status_info(struct sk_buff *skb, struct drbd_device *device,
 
         /* We need to add connection name and volume number information still.
          * Minor number is in drbd_genlmsghdr. */
-        if (nla_put_drbd_cfg_context(skb, first_peer_device(device)->connection, device->vnr))
+        if (nla_put_drbd_cfg_context(skb, resource, the_only_connection(resource), device))
                 goto nla_put_failure;
 
         if (res_opts_to_skb(skb, &device->resource->res_opts, exclude_sensitive))
@@ -2922,19 +2940,17 @@ out:
 
 static int get_one_status(struct sk_buff *skb, struct netlink_callback *cb)
 {
-        struct drbd_peer_device *peer_device;
         struct drbd_device *device;
         struct drbd_genlmsghdr *dh;
         struct drbd_resource *pos = (struct drbd_resource *)cb->args[0];
         struct drbd_resource *resource = NULL;
-        struct drbd_connection *connection;
         struct drbd_resource *tmp;
         unsigned volume = cb->args[1];
 
         /* Open coded, deferred, iteration:
          * for_each_resource_safe(resource, tmp, &drbd_resources) {
-         *      connection = "first connection of resource";
-         *      idr_for_each_entry(&connection->peer_devices, peer_device, i) {
+         *      connection = "first connection of resource or undefined";
+         *      idr_for_each_entry(&resource->devices, device, i) {
          *        ...
          *      }
          * }
@@ -2969,9 +2985,8 @@ static int get_one_status(struct sk_buff *skb, struct netlink_callback *cb)
         }
         if (resource) {
 next_resource:
-                connection = first_connection(resource);
-                peer_device = idr_get_next(&connection->peer_devices, &volume);
-                if (!peer_device) {
+                device = idr_get_next(&resource->devices, &volume);
+                if (!device) {
                         /* No more volumes to dump on this resource.
                          * Advance resource iterator. */
                         pos = list_entry_rcu(resource->resources.next,
@@ -2995,24 +3010,29 @@ next_resource:
                 if (!dh)
                         goto out;
 
-                if (!peer_device) {
+                if (!device) {
                         /* This is a connection without a single volume.
                          * Suprisingly enough, it may have a network
                          * configuration. */
-                        struct net_conf *nc;
+                        struct drbd_connection *connection;
+
                         dh->minor = -1U;
                         dh->ret_code = NO_ERROR;
-                        if (nla_put_drbd_cfg_context(skb, connection, VOLUME_UNSPECIFIED))
-                                goto cancel;
-                        nc = rcu_dereference(connection->net_conf);
-                        if (nc && net_conf_to_skb(skb, nc, 1) != 0)
+                        connection = the_only_connection(resource);
+                        if (nla_put_drbd_cfg_context(skb, resource, connection, NULL))
                                 goto cancel;
+                        if (connection) {
+                                struct net_conf *nc;
+
+                                nc = rcu_dereference(connection->net_conf);
+                                if (nc && net_conf_to_skb(skb, nc, 1) != 0)
+                                        goto cancel;
+                        }
                         goto done;
                 }
 
-                device = peer_device->device;
                 D_ASSERT(device, device->vnr == volume);
-                D_ASSERT(device, first_peer_device(device)->connection == connection);
+                D_ASSERT(device, device->resource == resource);
 
                 dh->minor = device_to_minor(device);
                 dh->ret_code = NO_ERROR;