diff --git a/arch/ia64/lib/swiotlb.c b/arch/ia64/lib/swiotlb.c
index ab7b3ad99a7f..dbc0b3e449c5 100644
--- a/arch/ia64/lib/swiotlb.c
+++ b/arch/ia64/lib/swiotlb.c
@@ -93,8 +93,7 @@ static int __init
 setup_io_tlb_npages(char *str)
 {
 	if (isdigit(*str)) {
-		io_tlb_nslabs = simple_strtoul(str, &str, 0) <<
-			(PAGE_SHIFT - IO_TLB_SHIFT);
+		io_tlb_nslabs = simple_strtoul(str, &str, 0);
 		/* avoid tail segment of size < IO_TLB_SEGSIZE */
 		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
 	}
@@ -117,7 +116,7 @@ swiotlb_init_with_default_size (size_t default_size)
 	unsigned long i;
 
 	if (!io_tlb_nslabs) {
-		io_tlb_nslabs = (default_size >> PAGE_SHIFT);
+		io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
 		io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
 	}