diff --git a/mm/shmem.c b/mm/shmem.c
index 9382528467a97866c4e66bc4078f5dc256891590..5b93877c20f183ca0b9f42bfc4327a1c2394a332 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2720,7 +2720,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
 		}
 
 		shmem_falloc.waitq = &shmem_falloc_waitq;
-		shmem_falloc.start = unmap_start >> PAGE_SHIFT;
+		shmem_falloc.start = (u64)unmap_start >> PAGE_SHIFT;
 		shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT;
 		spin_lock(&inode->i_lock);
 		inode->i_private = &shmem_falloc;