LU-13028 lnet: advertise discovery when toggled

[fs/lustre-release.git] / lnet / lnet / api-ni.c

diff --git a/lnet/lnet/api-ni.c b/lnet/lnet/api-ni.c
index 388e7eb..7534a1e 100644 (file)
--- a/lnet/lnet/api-ni.c
+++ b/lnet/lnet/api-ni.c
@@ -349,9 +349,15 @@ discovery_set(const char *val, cfs_kernel_param_arg_t *kp)
                return 0;
        }
 
-       *discovery = value;
-
+       /*
+        * We still want to set the discovery value even when LNet is not
+        * running. This is the case when LNet is being loaded and we want
+        * the module parameters to take effect. Otherwise if we're
+        * changing the value dynamically, we want to set it after
+        * updating the peers
+        */
        if (the_lnet.ln_state != LNET_STATE_RUNNING) {
+               *discovery = value;
                mutex_unlock(&the_lnet.ln_api_mutex);
                return 0;
        }
@@ -365,7 +371,23 @@ discovery_set(const char *val, cfs_kernel_param_arg_t *kp)
                pbuf->pb_info.pi_features |= LNET_PING_FEAT_DISCOVERY;
        lnet_net_unlock(LNET_LOCK_EX);
 
+       /*
+        * Always update the peers. This will result in a push to the
+        * peers with the updated capabilities feature mask. The peer can
+        * then take appropriate action to update its representation of
+        * the node.
+        *
+        * If discovery is already off, turn it on first before pushing
+        * the update. The discovery flag must be on before pushing.
+        * otherwise if the flag is on and we're turning it off then push
+        * first before turning the flag off. In the former case the flag
+        * is being set twice, but I find it's better to do that rather
+        * than have duplicate code in an if/else statement.
+        */
+       if (*discovery > 0 && value == 0)
+               *discovery = value;
        lnet_push_update_to_peers(1);
+       *discovery = value;
 
        mutex_unlock(&the_lnet.ln_api_mutex);