swiotlb: fix phys_addr_t overflow warning (9c106119) · Commits · 戴 / test

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: ("swiotlb: remove SWIOTLB_MAP_ERROR") Acked-by:

Stefano Stabellini <sstabellini@kernel.org> Signed-off-by:

Arnd Bergmann <arnd@arndb.de> Signed-off-by:

Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/swiotlb-xen.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);

kernel/dma/swiotlb.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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 */

Admin message