From 7a4452275ea73fd6c07529a745b8946b75a7243a Mon Sep 17 00:00:00 2001
From: Paul Hauner <paul@paulhauner.com>
Date: Thu, 16 Jun 2022 18:22:32 +1000
Subject: [PATCH] Use fast head in notifier

---
 beacon_node/client/src/notifier.rs | 14 ++++----------
 beacon_node/http_api/src/lib.rs    |  4 ++--
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/beacon_node/client/src/notifier.rs b/beacon_node/client/src/notifier.rs
index b2ea17103c5..0892a016d5f 100644
--- a/beacon_node/client/src/notifier.rs
+++ b/beacon_node/client/src/notifier.rs
@@ -100,16 +100,10 @@ pub fn spawn_notifier<T: BeaconChainTypes>(
                 current_sync_state = sync_state;
             }
 
-            // Atomically collect info about the head, avoiding holding the `canonical_head` lock
-            // any longer than necessary.
-            let (head_slot, head_root, finalized_checkpoint) = {
-                let head_lock = beacon_chain.canonical_head.read();
-                (
-                    head_lock.head_slot(),
-                    head_lock.head_block_root(),
-                    head_lock.finalized_checkpoint(),
-                )
-            };
+            let fast_head = beacon_chain.fast_canonical_head();
+            let head_slot = fast_head.head_block_slot;
+            let head_root = fast_head.head_block_root;
+            let finalized_checkpoint = fast_head.finalized_checkpoint;
 
             metrics::set_gauge(&metrics::NOTIFIER_HEAD_SLOT, head_slot.as_u64() as i64);
 
diff --git a/beacon_node/http_api/src/lib.rs b/beacon_node/http_api/src/lib.rs
index e2b989c0aa3..cf686d59fa6 100644
--- a/beacon_node/http_api/src/lib.rs
+++ b/beacon_node/http_api/src/lib.rs
@@ -369,7 +369,7 @@ pub fn serve<T: BeaconChainTypes>(
                       chain: Arc<BeaconChain<T>>| async move {
                     match *network_globals.sync_state.read() {
                         SyncState::SyncingFinalized { .. } => {
-                            let head_slot = chain.fast_canonical_head().head_slot;
+                            let head_slot = chain.fast_canonical_head().head_block_slot;
 
                             let current_slot =
                                 chain.slot_clock.now_or_genesis().ok_or_else(|| {
@@ -1691,7 +1691,7 @@ pub fn serve<T: BeaconChainTypes>(
         .and_then(
             |network_globals: Arc<NetworkGlobals<T::EthSpec>>, chain: Arc<BeaconChain<T>>| {
                 blocking_json_task(move || {
-                    let head_slot = chain.fast_canonical_head().head_slot;
+                    let head_slot = chain.fast_canonical_head().head_block_slot;
                     let current_slot = chain.slot_clock.now_or_genesis().ok_or_else(|| {
                         warp_utils::reject::custom_server_error("Unable to read slot clock".into())
                     })?;