diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 80250e63bd07..db0c83af44de 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -433,7 +433,8 @@ static u8 * __init alloc_command_buffer(struct amd_iommu *iommu)
 
 static void __init free_command_buffer(struct amd_iommu *iommu)
 {
-	free_pages((unsigned long)iommu->cmd_buf, get_order(CMD_BUFFER_SIZE));
+	free_pages((unsigned long)iommu->cmd_buf,
+		   get_order(iommu->cmd_buf_size));
 }
 
 /* allocates the memory where the IOMMU will log its events to */