From patchwork Wed Jan 25 18:31:31 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [v2] arm64: dma-mapping: Fix dma_mapping_error() when bypassing SWIOTLB From: Robin Murphy X-Patchwork-Id: 9537723 Message-Id: <840027acb4750542003dff17b4a8902ba8972754.1485368348.git.robin.murphy@arm.com> To: will.deacon@arm.com, catalin.marinas@arm.com Cc: Jisheng Zhang , arnd@arndb.de, konrad.wilk@oracle.com, aaro.koskinen@iki.fi, stable@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Date: Wed, 25 Jan 2017 18:31:31 +0000 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@vger.kernel.org CC: Jisheng Zhang Reported-by: Aaro Koskinen Signed-off-by: Robin Murphy Tested-by: Aaro Koskinen --- 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)