LU-9121 lnet: Preferred gateway selection

[fs/lustre-release.git] / lnet / lnet / peer.c

diff --git a/lnet/lnet/peer.c b/lnet/lnet/peer.c
index 826589f..5f6b3ad 100644 (file)
--- a/lnet/lnet/peer.c
+++ b/lnet/lnet/peer.c
@@ -898,6 +898,94 @@ lnet_push_update_to_peers(int force)
        wake_up(&the_lnet.ln_dc_waitq);
 }
 
+/* find the NID in the preferred gateways for the remote peer
+ * return:
+ *     false: list is not empty and NID is not preferred
+ *     false: list is empty
+ *     true: nid is found in the list
+ */
+bool
+lnet_peer_is_pref_rtr_locked(struct lnet_peer_ni *lpni,
+                            lnet_nid_t gw_nid)
+{
+       struct lnet_nid_list *ne;
+
+       CDEBUG(D_NET, "%s: rtr pref emtpy: %d\n",
+              libcfs_nid2str(lpni->lpni_nid),
+              list_empty(&lpni->lpni_rtr_pref_nids));
+
+       if (list_empty(&lpni->lpni_rtr_pref_nids))
+               return false;
+
+       /* iterate through all the preferred NIDs and see if any of them
+        * matches the provided gw_nid
+        */
+       list_for_each_entry(ne, &lpni->lpni_rtr_pref_nids, nl_list) {
+               CDEBUG(D_NET, "Comparing pref %s with gw %s\n",
+                      libcfs_nid2str(ne->nl_nid),
+                      libcfs_nid2str(gw_nid));
+               if (ne->nl_nid == gw_nid)
+                       return true;
+       }
+
+       return false;
+}
+
+void
+lnet_peer_clr_pref_rtrs(struct lnet_peer_ni *lpni)
+{
+       struct list_head zombies;
+       struct lnet_nid_list *ne;
+       struct lnet_nid_list *tmp;
+       int cpt = lpni->lpni_cpt;
+
+       INIT_LIST_HEAD(&zombies);
+
+       lnet_net_lock(cpt);
+       list_splice_init(&lpni->lpni_rtr_pref_nids, &zombies);
+       lnet_net_unlock(cpt);
+
+       list_for_each_entry_safe(ne, tmp, &zombies, nl_list) {
+               list_del(&ne->nl_list);
+               LIBCFS_FREE(ne, sizeof(*ne));
+       }
+}
+
+int
+lnet_peer_add_pref_rtr(struct lnet_peer_ni *lpni,
+                      lnet_nid_t gw_nid)
+{
+       int cpt = lpni->lpni_cpt;
+       struct lnet_nid_list *ne = NULL;
+
+       /* This function is called with api_mutex held. When the api_mutex
+        * is held the list can not be modified, as it is only modified as
+        * a result of applying a UDSP and that happens under api_mutex
+        * lock.
+        */
+       __must_hold(&the_lnet.ln_api_mutex);
+
+       list_for_each_entry(ne, &lpni->lpni_rtr_pref_nids, nl_list) {
+               if (ne->nl_nid == gw_nid)
+                       return -EEXIST;
+       }
+
+       LIBCFS_CPT_ALLOC(ne, lnet_cpt_table(), cpt, sizeof(*ne));
+       if (!ne)
+               return -ENOMEM;
+
+       ne->nl_nid = gw_nid;
+
+       /* Lock the cpt to protect against addition and checks in the
+        * selection algorithm
+        */
+       lnet_net_lock(cpt);
+       list_add(&ne->nl_list, &lpni->lpni_rtr_pref_nids);
+       lnet_net_unlock(cpt);
+
+       return 0;
+}
+
 /*
  * Test whether a ni is a preferred ni for this peer_ni, e.g, whether
  * this is a preferred point-to-point path. Call with lnet_net_lock in
@@ -1129,6 +1217,29 @@ out:
        return rc;
 }
 
+void
+lnet_peer_clr_pref_nids(struct lnet_peer_ni *lpni)
+{
+       struct list_head zombies;
+       struct lnet_nid_list *ne;
+       struct lnet_nid_list *tmp;
+
+       INIT_LIST_HEAD(&zombies);
+
+       lnet_net_lock(LNET_LOCK_EX);
+       if (lpni->lpni_pref_nnids == 1)
+               lpni->lpni_pref.nid = LNET_NID_ANY;
+       else if (lpni->lpni_pref_nnids > 1)
+               list_splice_init(&lpni->lpni_pref.nids, &zombies);
+       lpni->lpni_pref_nnids = 0;
+       lnet_net_unlock(LNET_LOCK_EX);
+
+       list_for_each_entry_safe(ne, tmp, &zombies, nl_list) {
+               list_del_init(&ne->nl_list);
+               LIBCFS_FREE(ne, sizeof(*ne));
+       }
+}
+
 lnet_nid_t
 lnet_peer_primary_nid_locked(lnet_nid_t nid)
 {