diff --git a/homeassistant/components/synology_dsm/__init__.py b/homeassistant/components/synology_dsm/__init__.py
index b3b40d975ce..e568ce5a6d1 100644
--- a/homeassistant/components/synology_dsm/__init__.py
+++ b/homeassistant/components/synology_dsm/__init__.py
@@ -45,7 +45,7 @@ CONFIG_SCHEMA = cv.config_entry_only_config_schema(DOMAIN)
 async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     """Set up the Synology DSM component."""
 
-    await async_setup_services(hass)
+    async_setup_services(hass)
 
     return True
 
diff --git a/homeassistant/components/synology_dsm/services.py b/homeassistant/components/synology_dsm/services.py
index 40b6fd4bc30..9522361d500 100644
--- a/homeassistant/components/synology_dsm/services.py
+++ b/homeassistant/components/synology_dsm/services.py
@@ -7,7 +7,7 @@ from typing import cast
 
 from synology_dsm.exceptions import SynologyDSMException
 
-from homeassistant.core import HomeAssistant, ServiceCall
+from homeassistant.core import HomeAssistant, ServiceCall, callback
 
 from .const import CONF_SERIAL, DOMAIN, SERVICE_REBOOT, SERVICE_SHUTDOWN, SERVICES
 from .coordinator import SynologyDSMConfigEntry
@@ -15,63 +15,63 @@ from .coordinator import SynologyDSMConfigEntry
 LOGGER = logging.getLogger(__name__)
 
 
-async def async_setup_services(hass: HomeAssistant) -> None:
-    """Service handler setup."""
+async def _service_handler(call: ServiceCall) -> None:
+    """Handle service call."""
+    serial: str | None = call.data.get(CONF_SERIAL)
+    entries: list[SynologyDSMConfigEntry] = (
+        call.hass.config_entries.async_loaded_entries(DOMAIN)
+    )
+    dsm_devices = {cast(str, entry.unique_id): entry.runtime_data for entry in entries}
 
-    async def service_handler(call: ServiceCall) -> None:
-        """Handle service call."""
-        serial: str | None = call.data.get(CONF_SERIAL)
-        entries: list[SynologyDSMConfigEntry] = (
-            hass.config_entries.async_loaded_entries(DOMAIN)
+    if serial:
+        entry: SynologyDSMConfigEntry | None = (
+            call.hass.config_entries.async_entry_for_domain_unique_id(DOMAIN, serial)
         )
-        dsm_devices = {
-            cast(str, entry.unique_id): entry.runtime_data for entry in entries
-        }
+        assert entry
+        dsm_device = entry.runtime_data
+    elif len(dsm_devices) == 1:
+        dsm_device = next(iter(dsm_devices.values()))
+        serial = next(iter(dsm_devices))
+    else:
+        LOGGER.error(
+            "More than one DSM configured, must specify one of serials %s",
+            sorted(dsm_devices),
+        )
+        return
 
-        if serial:
-            entry: SynologyDSMConfigEntry | None = (
-                hass.config_entries.async_entry_for_domain_unique_id(DOMAIN, serial)
-            )
-            assert entry
-            dsm_device = entry.runtime_data
-        elif len(dsm_devices) == 1:
-            dsm_device = next(iter(dsm_devices.values()))
-            serial = next(iter(dsm_devices))
-        else:
-            LOGGER.error(
-                "More than one DSM configured, must specify one of serials %s",
-                sorted(dsm_devices),
-            )
-            return
+    if not dsm_device:
+        LOGGER.error("DSM with specified serial %s not found", serial)
+        return
 
-        if not dsm_device:
+    if call.service in [SERVICE_REBOOT, SERVICE_SHUTDOWN]:
+        if serial not in dsm_devices:
             LOGGER.error("DSM with specified serial %s not found", serial)
             return
-
-        if call.service in [SERVICE_REBOOT, SERVICE_SHUTDOWN]:
-            if serial not in dsm_devices:
-                LOGGER.error("DSM with specified serial %s not found", serial)
-                return
-            LOGGER.debug("%s DSM with serial %s", call.service, serial)
-            LOGGER.warning(
-                (
-                    "The %s service is deprecated and will be removed in future"
-                    " release. Please use the corresponding button entity"
-                ),
+        LOGGER.debug("%s DSM with serial %s", call.service, serial)
+        LOGGER.warning(
+            (
+                "The %s service is deprecated and will be removed in future"
+                " release. Please use the corresponding button entity"
+            ),
+            call.service,
+        )
+        dsm_device = dsm_devices[serial]
+        dsm_api = dsm_device.api
+        try:
+            await getattr(dsm_api, f"async_{call.service}")()
+        except SynologyDSMException as ex:
+            LOGGER.error(
+                "%s of DSM with serial %s not possible, because of %s",
                 call.service,
+                serial,
+                ex,
             )
-            dsm_device = dsm_devices[serial]
-            dsm_api = dsm_device.api
-            try:
-                await getattr(dsm_api, f"async_{call.service}")()
-            except SynologyDSMException as ex:
-                LOGGER.error(
-                    "%s of DSM with serial %s not possible, because of %s",
-                    call.service,
-                    serial,
-                    ex,
-                )
-                return
+            return
+
+
+@callback
+def async_setup_services(hass: HomeAssistant) -> None:
+    """Service handler setup."""
 
     for service in SERVICES:
-        hass.services.async_register(DOMAIN, service, service_handler)
+        hass.services.async_register(DOMAIN, service, _service_handler)