Fix body polling and HTTP/2 request streaming

- Replace 100ms polling with event-based waiting in BodyReceiver
- Stream HTTP/2 request bodies instead of buffering entire uploads
- Add timeout handling for disconnect detection

gunicorn/asgi/protocol.py

@@ -275,18 +275,35 @@ class BodyReceiver:
             return {"type": "http.request", "body": b"", "more_body": False}
 
     async def _read_with_disconnect_check(self):
-        """Read body with periodic disconnect checks (avoids task creation)."""
-        # Use wait_for with short timeout to check disconnect periodically
+        """Read body using event-based waiting (no polling).
+
+        Uses the protocol's data event to wait for incoming data,
+        avoiding the latency and CPU overhead of periodic polling.
+        """
         while not self._closed and not self.protocol._closed:
+            # Try to read available data
             try:
-                chunk = await asyncio.wait_for(
-                    self.request.read_body(65536),
-                    timeout=0.1
-                )
+                chunk = await self.request.read_body(65536)
                 return chunk
-            except asyncio.TimeoutError:
-                # Check disconnect and retry
-                continue
+            except Exception:
+                # If read fails, check if we should continue
+                if self._closed or self.protocol._closed:
+                    return None
+                # Wait for more data using the protocol's data event
+                if self.protocol._data_event:
+                    self.protocol._data_event.clear()
+                    # Use wait_for with longer timeout for disconnect detection
+                    try:
+                        await asyncio.wait_for(
+                            self.protocol._data_event.wait(),
+                            timeout=30.0  # 30s timeout for disconnect detection
+                        )
+                    except asyncio.TimeoutError:
+                        # Check connection state and continue
+                        continue
+                else:
+                    # No event available, brief sleep as fallback
+                    await asyncio.sleep(0.001)
         return None
 
 
@@ -1423,10 +1440,12 @@ class ASGIProtocol(asyncio.Protocol):
     async def _handle_http2_request(self, request, h2_conn, sockname, peername):
         """Handle a single HTTP/2 request with streaming support.
 
-        Streams response body chunks immediately instead of buffering,
-        enabling SSE, streaming downloads, and other real-time use cases.
+        Streams both request and response body chunks immediately,
+        avoiding buffering entire uploads and enabling SSE, streaming
+        downloads, and other real-time use cases.
         """
         stream_id = request.stream.stream_id
+        stream = h2_conn.streams.get(stream_id)
         scope = self._build_http2_scope(request, sockname, peername)
 
         response_started = False
@@ -1437,13 +1456,47 @@ class ASGIProtocol(asyncio.Protocol):
         response_headers = []
         response_sent = 0
 
+        # Track if we've finished receiving body
+        body_received = False
+
         async def receive():
-            # For HTTP/2, the body is already buffered in the stream
-            body = request.body.read()
+            nonlocal body_received
+
+            # Check if stream is closed or missing
+            if stream is None or stream.state.name == "CLOSED":
+                return {"type": "http.disconnect"}
+
+            # First call: if body already complete (small requests), return it
+            if not body_received and stream.request_complete and not stream._body_chunks:
+                body_received = True
+                body = stream.get_request_body()
+                return {
+                    "type": "http.request",
+                    "body": body,
+                    "more_body": False,
+                }
+
+            # Streaming: read next chunk
+            try:
+                chunk = await asyncio.wait_for(
+                    stream.read_body_chunk(),
+                    timeout=30.0
+                )
+            except asyncio.TimeoutError:
+                return {"type": "http.disconnect"}
+
+            if chunk is None:
+                body_received = True
+                return {
+                    "type": "http.request",
+                    "body": b"",
+                    "more_body": False,
+                }
+
             return {
                 "type": "http.request",
-                "body": body,
-                "more_body": False,
+                "body": chunk,
+                "more_body": not stream._body_complete,
             }
 
         async def send(message):