When bypassing SWIOTLB on small-memory systems, we need to avoid calling into swiotlb_dma_mapping_error() in exactly the same way as we avoid swiotlb_dma_supported(), because the former also relies on SWIOTLB state being initialised. Under the assumptions for which we skip SWIOTLB, dma_map_{single,page}() will only ever return the DMA-offset-adjusted physical address of the page passed in, thus we can report success unconditionally. Fixes: b67a8b29df7e ("arm64: mm: only initialize swiotlb when necessary") CC: stable@xxxxxxxxxxxxxxx CC: Jisheng Zhang <jszhang@xxxxxxxxxxx> Reported-by: Aaro Koskinen <aaro.koskinen@xxxxxx> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx> --- v2: Get the return value the right way round this time... After some careful reasoning it really is that simple. arch/arm64/mm/dma-mapping.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index e04082700bb1..1ffb7d5d299a 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -352,6 +352,13 @@ static int __swiotlb_dma_supported(struct device *hwdev, u64 mask) return 1; } +static int __swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t addr) +{ + if (swiotlb) + return swiotlb_dma_mapping_error(hwdev, addr); + return 0; +} + static struct dma_map_ops swiotlb_dma_ops = { .alloc = __dma_alloc, .free = __dma_free, @@ -366,7 +373,7 @@ static struct dma_map_ops swiotlb_dma_ops = { .sync_sg_for_cpu = __swiotlb_sync_sg_for_cpu, .sync_sg_for_device = __swiotlb_sync_sg_for_device, .dma_supported = __swiotlb_dma_supported, - .mapping_error = swiotlb_dma_mapping_error, + .mapping_error = __swiotlb_dma_mapping_error, }; static int __init atomic_pool_init(void) -- 2.11.0.dirty -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html