Disable drain_filter feature

This replaces drain_filter with retain

Author: mkroening

src/drivers/virtio/virtqueue/packed.rs

@@ -1025,7 +1025,7 @@ impl PackedVq {
 		if !self.dropped.borrow().is_empty() {
 			self.dropped
 				.borrow_mut()
-				.drain_filter(|tkn| tkn.state == TransferState::Finished);
+				.retain(|tkn| tkn.state != TransferState::Finished);
 		}
 	}
 

src/drivers/virtio/virtqueue/split.rs

@@ -271,7 +271,7 @@ impl SplitVq {
 		if !self.dropped.borrow().is_empty() {
 			self.dropped
 				.borrow_mut()
-				.drain_filter(|tkn| tkn.state == TransferState::Finished);
+				.retain(|tkn| tkn.state != TransferState::Finished);
 		}
 	}
 

src/lib.rs

@@ -19,7 +19,6 @@
 #![feature(core_intrinsics)]
 #![feature(alloc_error_handler)]
 #![feature(vec_into_raw_parts)]
-#![feature(drain_filter)]
 #![feature(strict_provenance)]
 #![feature(is_some_and)]
 #![cfg_attr(target_os = "none", no_std)]