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 --- kernel/dma/swiotlb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/dma') diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 38d57218809c..48e7488e3482 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -538,7 +538,7 @@ not_found: if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit()) dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n", size, io_tlb_nslabs, tmp_io_tlb_used); - return DMA_MAPPING_ERROR; + return (phys_addr_t)DMA_MAPPING_ERROR; found: io_tlb_used += nslots; spin_unlock_irqrestore(&io_tlb_lock, flags); @@ -656,7 +656,7 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr, /* Oh well, have to allocate and map a bounce buffer. */ *phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start), *phys, size, dir, attrs); - if (*phys == DMA_MAPPING_ERROR) + if (*phys == (phys_addr_t)DMA_MAPPING_ERROR) return false; /* Ensure that the address returned is DMA'ble */ -- cgit v1.2.3