tipc: refactor function tipc_enable_bearer()

As a preparation for the next commits we try to reduce the footprint of
the function tipc_enable_bearer(), while hopefully making is simpler to
follow.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index f3d2e83..e18cb27 100644 (file)
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -230,88 +230,90 @@ void tipc_bearer_remove_dest(struct net *net, u32 bearer_id, u32 dest)
  * tipc_enable_bearer - enable bearer with the given name
  */
 static int tipc_enable_bearer(struct net *net, const char *name,
-                             u32 disc_domain, u32 priority,
+                             u32 disc_domain, u32 prio,
                              struct nlattr *attr[])
 {
-       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_net *tn = tipc_net(net);
+       struct tipc_bearer_names b_names;
+       u32 self = tipc_own_addr(net);
+       int with_this_prio = 1;
        struct tipc_bearer *b;
        struct tipc_media *m;
-       struct tipc_bearer_names b_names;
        struct sk_buff *skb;
        char addr_string[16];
-       u32 bearer_id;
-       u32 with_this_prio;
-       u32 i;
+       int bearer_id = 0;
        int res = -EINVAL;
+       char *errstr = "";
 
-       if (!tn->own_addr) {
-               pr_warn("Bearer <%s> rejected, not supported in standalone mode\n",
-                       name);
-               return -ENOPROTOOPT;
+       if (!self) {
+               errstr = "not supported in standalone mode";
+               res = -ENOPROTOOPT;
+               goto rejected;
        }
+
        if (!bearer_name_validate(name, &b_names)) {
-               pr_warn("Bearer <%s> rejected, illegal name\n", name);
-               return -EINVAL;
+               errstr = "illegal name";
+               goto rejected;
        }
-       if (tipc_addr_domain_valid(disc_domain) &&
-           (disc_domain != tn->own_addr)) {
-               if (tipc_in_scope(disc_domain, tn->own_addr)) {
-                       disc_domain = tn->own_addr & TIPC_ZONE_CLUSTER_MASK;
-                       res = 0;   /* accept any node in own cluster */
-               } else if (in_own_cluster_exact(net, disc_domain))
-                       res = 0;   /* accept specified node in own cluster */
+
+       if (tipc_addr_domain_valid(disc_domain) && disc_domain != self) {
+               if (tipc_in_scope(disc_domain, self)) {
+                       /* Accept any node in own cluster */
+                       disc_domain = self & TIPC_ZONE_CLUSTER_MASK;
+                       res = 0;
+               } else if (in_own_cluster_exact(net, disc_domain)) {
+                       /* Accept specified node in own cluster */
+                       res = 0;
+               }
        }
        if (res) {
-               pr_warn("Bearer <%s> rejected, illegal discovery domain\n",
-                       name);
-               return -EINVAL;
+               errstr = "illegal discovery domain";
+               goto rejected;
        }
-       if ((priority > TIPC_MAX_LINK_PRI) &&
-           (priority != TIPC_MEDIA_LINK_PRI)) {
-               pr_warn("Bearer <%s> rejected, illegal priority\n", name);
-               return -EINVAL;
+
+       if (prio > TIPC_MAX_LINK_PRI && prio != TIPC_MEDIA_LINK_PRI) {
+               errstr = "illegal priority";
+               goto rejected;
        }
 
        m = tipc_media_find(b_names.media_name);
        if (!m) {
-               pr_warn("Bearer <%s> rejected, media <%s> not registered\n",
-                       name, b_names.media_name);
-               return -EINVAL;
+               errstr = "media not registered";
+               goto rejected;
        }
 
-       if (priority == TIPC_MEDIA_LINK_PRI)
-               priority = m->priority;
+       if (prio == TIPC_MEDIA_LINK_PRI)
+               prio = m->priority;
 
-restart:
-       bearer_id = MAX_BEARERS;
-       with_this_prio = 1;
-       for (i = MAX_BEARERS; i-- != 0; ) {
-               b = rtnl_dereference(tn->bearer_list[i]);
-               if (!b) {
-                       bearer_id = i;
-                       continue;
-               }
+       /* Check new bearer vs existing ones and find free bearer id if any */
+       while (bearer_id < MAX_BEARERS) {
+               b = rtnl_dereference(tn->bearer_list[bearer_id]);
+               if (!b)
+                       break;
                if (!strcmp(name, b->name)) {
-                       pr_warn("Bearer <%s> rejected, already enabled\n",
-                               name);
-                       return -EINVAL;
+                       errstr = "already enabled";
+                       goto rejected;
                }
-               if ((b->priority == priority) &&
-                   (++with_this_prio > 2)) {
-                       if (priority-- == 0) {
-                               pr_warn("Bearer <%s> rejected, duplicate priority\n",
-                                       name);
-                               return -EINVAL;
-                       }
-                       pr_warn("Bearer <%s> priority adjustment required %u->%u\n",
-                               name, priority + 1, priority);
-                       goto restart;
+               bearer_id++;
+               if (b->priority != prio)
+                       continue;
+               if (++with_this_prio <= 2)
+                       continue;
+               pr_warn("Bearer <%s>: already 2 bearers with priority %u\n",
+                       name, prio);
+               if (prio == TIPC_MIN_LINK_PRI) {
+                       errstr = "cannot adjust to lower";
+                       goto rejected;
                }
+               pr_warn("Bearer <%s>: trying with adjusted priority\n", name);
+               prio--;
+               bearer_id = 0;
+               with_this_prio = 1;
        }
+
        if (bearer_id >= MAX_BEARERS) {
-               pr_warn("Bearer <%s> rejected, bearer limit reached (%u)\n",
-                       name, MAX_BEARERS);
-               return -EINVAL;
+               errstr = "max 3 bearers permitted";
+               goto rejected;
        }
 
        b = kzalloc(sizeof(*b), GFP_ATOMIC);
@@ -322,10 +324,9 @@ restart:
        b->media = m;
        res = m->enable_media(net, b, attr);
        if (res) {
-               pr_warn("Bearer <%s> rejected, enable failure (%d)\n",
-                       name, -res);
                kfree(b);
-               return -EINVAL;
+               errstr = "failed to enable media";
+               goto rejected;
        }
 
        b->identity = bearer_id;
@@ -333,15 +334,15 @@ restart:
        b->window = m->window;
        b->domain = disc_domain;
        b->net_plane = bearer_id + 'A';
-       b->priority = priority;
+       b->priority = prio;
        test_and_set_bit_lock(0, &b->up);
 
        res = tipc_disc_create(net, b, &b->bcast_addr, &skb);
        if (res) {
                bearer_disable(net, b);
-               pr_warn("Bearer <%s> rejected, discovery object creation failed\n",
-                       name);
-               return -EINVAL;
+               kfree(b);
+               errstr = "failed to create discoverer";
+               goto rejected;
        }
 
        rcu_assign_pointer(tn->bearer_list[bearer_id], b);
@@ -353,9 +354,12 @@ restart:
                return -ENOMEM;
        }
 
-       pr_info("Enabled bearer <%s>, discovery domain %s, priority %u\n",
-               name,
-               tipc_addr_string_fill(addr_string, disc_domain), priority);
+       tipc_addr_string_fill(addr_string, disc_domain);
+       pr_info("Enabled bearer <%s>, discovery scope %s, priority %u\n",
+               name, addr_string, prio);
+       return res;
+rejected:
+       pr_warn("Bearer <%s> rejected, %s\n", name, errstr);
        return res;
 }