swiotlb: avoid potential left shift overflow

The second operand passed to slot_addr() is declared as int or unsigned int
in all call sites. The left-shift to get the offset of a slot can overflow
if swiotlb size is larger than 4G.

Convert the macro to an inline function and declare the second argument as
phys_addr_t to avoid the potential overflow.

Fixes: 26a7e094783d ("swiotlb: refactor swiotlb_tbl_map_single")
Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index dd88639..1ce8977 100644 (file)
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -575,7 +575,10 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
        }
 }
 
-#define slot_addr(start, idx)  ((start) + ((idx) << IO_TLB_SHIFT))
+static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx)
+{
+       return start + (idx << IO_TLB_SHIFT);
+}
 
 /*
  * Carefully handle integer overflow which can occur when boundary_mask == ~0UL.