diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 708125dce96a..798c4ae0bded 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -45,7 +45,7 @@ impl GenDiskBuilder {
 
     /// Validate block size by verifying that it is between 512 and `PAGE_SIZE`,
     /// and that it is a power of two.
-    fn validate_block_size(size: u32) -> Result<()> {
+    fn validate_block_size(size: u32) -> Result {
         if !(512..=bindings::PAGE_SIZE as u32).contains(&size) || !size.is_power_of_two() {
             Err(error::code::EINVAL)
         } else {