Messages in this thread | | | Date | Tue, 13 Jun 2017 10:03:28 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH] arm64/dma-mapping: Fix null-pointer check |
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On Mon, Jun 12, 2017 at 01:50:28PM -0700, Olav Haugan wrote: > On 17-06-12 13:29:04, Catalin Marinas wrote: > > On Sat, Jun 10, 2017 at 12:41:10PM -0700, Olav Haugan wrote: > > > @@ -149,6 +140,11 @@ static void *__dma_alloc(struct device *dev, size_t size, > > > bool coherent = is_device_dma_coherent(dev); > > > pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, false); > > > > > > + if (!dev) { > > > + WARN_ONCE(1, "Use an actual device structure for DMA allocation\n"); > > > + return NULL; > > > + } > > > + > > > size = PAGE_ALIGN(size); > > > > > > if (!coherent && !gfpflags_allow_blocking(flags)) { > > > @@ -192,8 +188,13 @@ static void __dma_free(struct device *dev, size_t size, > > > void *vaddr, dma_addr_t dma_handle, > > > unsigned long attrs) > > > { > > > - void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle)); > > > + void *swiotlb_addr; > > > > > > + if (!dev) { > > > + WARN_ONCE(1, "Use an actual device structure for DMA free\n"); > > > + return; > > > + } > > > + swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle)); > > > > I don't think we need the checks anymore. With commit 1dccb598df54 > > ("arm64: simplify dma_get_ops") __generic_dma_ops() returns > > dummy_dma_ops when dev == NULL, so the above __dma_alloc/__dma_free > > functions would not be called. > > We don't need the check in is_device_dma_coherent() either then right?
Right. The only user of this function outside arch/arm64/mm/dma-mapping.c is Xen (shared with arm32 under arch/arm/xen/) but since arm32 doesn't do this NULL check either, we should be fine.
-- Catalin
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