From 9c106119f6538f65bdddb7948a157d90625effa7 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 17 Jun 2019 15:28:43 +0200 Subject: swiotlb: fix phys_addr_t overflow warning On architectures that have a larger dma_addr_t than phys_addr_t, the swiotlb_tbl_map_single() function truncates its return code in the failure path, making it impossible to identify the error later, as we compare to the original value: kernel/dma/swiotlb.c:551:9: error: implicit conversion from 'dma_addr_t' (aka 'unsigned long long') to 'phys_addr_t' (aka 'unsigned int') changes value from 18446744073709551615 to 4294967295 [-Werror,-Wconstant-conversion] return DMA_MAPPING_ERROR; Use an explicit typecast here to convert it to the narrower type, and use the same expression in the error handling later. Fixes: b907e20508d0 ("swiotlb: remove SWIOTLB_MAP_ERROR") Acked-by: Stefano Stabellini Signed-off-by: Arnd Bergmann Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/swiotlb-xen.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/xen') diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 342762b1aefb..f5ae8b00df3c 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -408,7 +408,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir, attrs); - if (map == DMA_MAPPING_ERROR) + if (map == (phys_addr_t)DMA_MAPPING_ERROR) return DMA_MAPPING_ERROR; dev_addr = xen_phys_to_bus(map); -- cgit v1.2.3-59-g8ed1b