Replace request-response incoming requests queue with async-channel (#14199)

substrate/client/network/sync/src/warp_request_handler.rs

@@ -17,10 +17,7 @@
 //! Helper for handling (i.e. answering) grandpa warp sync requests from a remote peer.
 
 use codec::Decode;
-use futures::{
-	channel::{mpsc, oneshot},
-	stream::StreamExt,
-};
+use futures::{channel::oneshot, stream::StreamExt};
 use log::debug;
 
 use sc_network::{
@@ -36,6 +33,9 @@ use std::{sync::Arc, time::Duration};
 
 const MAX_RESPONSE_SIZE: u64 = 16 * 1024 * 1024;
 
+/// Incoming warp requests bounded queue size.
+const MAX_WARP_REQUEST_QUEUE: usize = 20;
+
 /// Generates a [`RequestResponseConfig`] for the grandpa warp sync request protocol, refusing
 /// incoming requests.
 pub fn generate_request_response_config<Hash: AsRef<[u8]>>(
@@ -72,7 +72,7 @@ fn generate_legacy_protocol_name(protocol_id: ProtocolId) -> String {
 /// Handler for incoming grandpa warp sync requests from a remote peer.
 pub struct RequestHandler<TBlock: BlockT> {
 	backend: Arc<dyn WarpSyncProvider<TBlock>>,
-	request_receiver: mpsc::Receiver<IncomingRequest>,
+	request_receiver: async_channel::Receiver<IncomingRequest>,
 }
 
 impl<TBlock: BlockT> RequestHandler<TBlock> {
@@ -83,7 +83,7 @@ impl<TBlock: BlockT> RequestHandler<TBlock> {
 		fork_id: Option<&str>,
 		backend: Arc<dyn WarpSyncProvider<TBlock>>,
 	) -> (Self, RequestResponseConfig) {
-		let (tx, request_receiver) = mpsc::channel(20);
+		let (tx, request_receiver) = async_channel::bounded(MAX_WARP_REQUEST_QUEUE);
 
 		let mut request_response_config =
 			generate_request_response_config(protocol_id, genesis_hash, fork_id);