Make `populate_device` infallible

kernel/src/vm/vmar/vm_mapping.rs

@@ -188,22 +188,15 @@ impl VmMapping {
     ///
     /// In debug builds, this method panics if the mapping is not a device
     /// memory mapping.
-    pub(super) fn populate_device(
-        &self,
-        vm_space: &VmSpace,
-        io_mem: IoMem,
-        vmo_offset: usize,
-    ) -> Result<()> {
+    pub(super) fn populate_device(&self, vm_space: &VmSpace, io_mem: IoMem, vmo_offset: usize) {
         debug_assert!(matches!(self.mapped_mem, MappedMemory::Device));
 
         let preempt_guard = disable_preempt();
         let map_range = self.map_to_addr..self.map_to_addr + self.map_size.get();
-        let mut cursor = vm_space.cursor_mut(&preempt_guard, &map_range)?;
+        let mut cursor = vm_space.cursor_mut(&preempt_guard, &map_range).unwrap();
         let io_page_prop =
             PageProperty::new_user(PageFlags::from(self.perms), io_mem.cache_policy());
         cursor.map_iomem(io_mem, io_page_prop, self.map_size.get(), vmo_offset);
-
-        Ok(())
     }
 
     /// Prints the mapping information in the format of `/proc/[pid]/maps`.

kernel/src/vm/vmar/vmar_impls/map.rs

@@ -350,7 +350,7 @@ impl<'a> VmarMapOptions<'a> {
         // Exchange the operation is ok since we hold the write lock on the
         // VMAR.
         if let Some(io_mem) = io_mem {
-            vm_mapping.populate_device(parent.vm_space(), io_mem, vmo_offset)?;
+            vm_mapping.populate_device(parent.vm_space(), io_mem, vmo_offset);
         }
 
         // Add the mapping to the VMAR.