From: Arnd Bergmann arnd@arndb.de
[ Upstream commit 9c106119f6538f65bdddb7948a157d90625effa7 ]
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 sstabellini@kernel.org Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/xen/swiotlb-xen.c | 2 +- kernel/dma/swiotlb.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index d53f3493a6b9..cfbe46785a3b 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -402,7 +402,7 @@ 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); diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 13f0cb080a4d..5f4e1b78babb 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -546,7 +546,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, 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); @@ -664,7 +664,7 @@ 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 */