Re: [RESEND][PATCH 0/7] Avoid overflow at boundary_size

From: Nicolin Chen
Date: Tue Sep 01 2020 - 03:54:39 EST

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In reply to: Christoph Hellwig: "Re: [RESEND][PATCH 0/7] Avoid overflow at boundary_size"
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Hi Christoph,

On Tue, Sep 01, 2020 at 09:36:23AM +0200, Christoph Hellwig wrote:
> I really don't like all the open coded smarts in the various drivers.
> What do you think about a helper like the one in the untested patch

A helper function will be actually better. I was thinking of
one yet not very sure about the naming and where to put it.

> below (on top of your series). Also please include the original
> segment boundary patch with the next resend so that the series has
> the full context.

I will use your change instead and resend with the ULONG_MAX
change. But in that case, should I make separate changes for
different files like this series, or just one single change
like yours?

Asking this as I was expecting that those changes would get
applied by different maintainers. But now it feels like you
will merge it to your tree at once?

Thanks
Nic

> diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
> index 1ef2c647bd3ec2..6f7de4f4e191e7 100644
> --- a/arch/alpha/kernel/pci_iommu.c
> +++ b/arch/alpha/kernel/pci_iommu.c
> @@ -141,10 +141,7 @@ iommu_arena_find_pages(struct device *dev, struct pci_iommu_arena *arena,
> unsigned long boundary_size;
>
> base = arena->dma_base >> PAGE_SHIFT;
> -
> - boundary_size = dev ? dma_get_seg_boundary(dev) : U32_MAX;
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - boundary_size = (boundary_size >> PAGE_SHIFT) + 1;
> + boundary_size = dma_get_seg_boundary_nr_pages(dev, PAGE_SHIFT);
>
> /* Search forward for the first mask-aligned sequence of N free ptes */
> ptes = arena->ptes;
> diff --git a/arch/ia64/hp/common/sba_iommu.c b/arch/ia64/hp/common/sba_iommu.c
> index 945954903bb0ba..b49b73a95067d2 100644
> --- a/arch/ia64/hp/common/sba_iommu.c
> +++ b/arch/ia64/hp/common/sba_iommu.c
> @@ -485,8 +485,7 @@ sba_search_bitmap(struct ioc *ioc, struct device *dev,
> ASSERT(((unsigned long) ioc->res_hint & (sizeof(unsigned long) - 1UL)) == 0);
> ASSERT(res_ptr < res_end);
>
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - boundary_size = (dma_get_seg_boundary(dev) >> iovp_shift) + 1;
> + boundary_size = dma_get_seg_boundary_nr_pages(dev, iovp_shift);
>
> BUG_ON(ioc->ibase & ~iovp_mask);
> shift = ioc->ibase >> iovp_shift;
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index c01ccbf8afdd42..cbc2e62db597cf 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -236,11 +236,7 @@ static unsigned long iommu_range_alloc(struct device *dev,
> }
> }
>
> - /* 4GB boundary for iseries_hv_alloc and iseries_hv_map */
> - boundary_size = dev ? dma_get_seg_boundary(dev) : U32_MAX;
> -
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - boundary_size = (boundary_size >> tbl->it_page_shift) + 1;
> + boundary_size = dma_get_seg_boundary_nr_pages(dev, tbl->it_page_shift);
>
> n = iommu_area_alloc(tbl->it_map, limit, start, npages, tbl->it_offset,
> boundary_size, align_mask);
> diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
> index ecb067acc6d532..4a37d8f4de9d9d 100644
> --- a/arch/s390/pci/pci_dma.c
> +++ b/arch/s390/pci/pci_dma.c
> @@ -261,13 +261,11 @@ static unsigned long __dma_alloc_iommu(struct device *dev,
> unsigned long start, int size)
> {
> struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
> - unsigned long boundary_size;
>
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - boundary_size = (dma_get_seg_boundary(dev) >> PAGE_SHIFT) + 1;
> return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
> start, size, zdev->start_dma >> PAGE_SHIFT,
> - boundary_size, 0);
> + dma_get_seg_boundary_nr_pages(dev, PAGE_SHIFT),
> + 0);
> }
>
> static dma_addr_t dma_alloc_address(struct device *dev, int size)
> diff --git a/arch/sparc/kernel/iommu-common.c b/arch/sparc/kernel/iommu-common.c
> index 843e71894d0482..e6139c99762e11 100644
> --- a/arch/sparc/kernel/iommu-common.c
> +++ b/arch/sparc/kernel/iommu-common.c
> @@ -166,10 +166,6 @@ unsigned long iommu_tbl_range_alloc(struct device *dev,
> }
> }
>
> - boundary_size = dev ? dma_get_seg_boundary(dev) : U32_MAX;
> -
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - boundary_size = (boundary_size >> iommu->table_shift) + 1;
> /*
> * if the skip_span_boundary_check had been set during init, we set
> * things up so that iommu_is_span_boundary() merely checks if the
> @@ -178,7 +174,11 @@ unsigned long iommu_tbl_range_alloc(struct device *dev,
> if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) {
> shift = 0;
> boundary_size = iommu->poolsize * iommu->nr_pools;
> + } else {
> + boundary_size = dma_get_seg_boundary_nr_pages(dev,
> + iommu->table_shift);
> }
> +
> n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
> boundary_size, align_mask);
> if (n == -1) {
> diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
> index d981c37305ae31..c3e4e2df26a8b8 100644
> --- a/arch/sparc/kernel/iommu.c
> +++ b/arch/sparc/kernel/iommu.c
> @@ -472,8 +472,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
> outs->dma_length = 0;
>
> max_seg_size = dma_get_max_seg_size(dev);
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - seg_boundary_size = (dma_get_seg_boundary(dev) >> IO_PAGE_SHIFT) + 1;
> + seg_boundary_size = dma_get_seg_boundary_nr_pages(dev, IO_PAGE_SHIFT);
> base_shift = iommu->tbl.table_map_base >> IO_PAGE_SHIFT;
> for_each_sg(sglist, s, nelems, i) {
> unsigned long paddr, npages, entry, out_entry = 0, slen;
> diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c
> index 233fe8a20cec33..6b92dd51c0026f 100644
> --- a/arch/sparc/kernel/pci_sun4v.c
> +++ b/arch/sparc/kernel/pci_sun4v.c
> @@ -508,8 +508,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
> iommu_batch_start(dev, prot, ~0UL);
>
> max_seg_size = dma_get_max_seg_size(dev);
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - seg_boundary_size = (dma_get_seg_boundary(dev) >> IO_PAGE_SHIFT) + 1;
> + seg_boundary_size = dma_get_seg_boundary_nr_pages(dev, IO_PAGE_SHIFT);
>
> mask = *dev->dma_mask;
> if (!iommu_use_atu(iommu, mask))
> diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
> index 7fa0bb490065a1..bccc5357bffd6c 100644
> --- a/arch/x86/kernel/amd_gart_64.c
> +++ b/arch/x86/kernel/amd_gart_64.c
> @@ -96,8 +96,7 @@ static unsigned long alloc_iommu(struct device *dev, int size,
>
> base_index = ALIGN(iommu_bus_base & dma_get_seg_boundary(dev),
> PAGE_SIZE) >> PAGE_SHIFT;
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - boundary_size = (dma_get_seg_boundary(dev) >> PAGE_SHIFT) + 1;
> + boundary_size = dma_get_seg_boundary_nr_pages(dev, PAGE_SHIFT);
>
> spin_lock_irqsave(&iommu_bitmap_lock, flags);
> offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, next_bit,
> diff --git a/drivers/parisc/ccio-dma.c b/drivers/parisc/ccio-dma.c
> index c667d6aba7646e..ba16b7f8f80612 100644
> --- a/drivers/parisc/ccio-dma.c
> +++ b/drivers/parisc/ccio-dma.c
> @@ -356,8 +356,7 @@ ccio_alloc_range(struct ioc *ioc, struct device *dev, size_t size)
> ** ggg sacrifices another 710 to the computer gods.
> */
>
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - boundary_size = (dma_get_seg_boundary(dev) >> IOVP_SHIFT) + 1;
> + boundary_size = dma_get_seg_boundary_nr_pages(dev, IOVP_SHIFT);
>
> if (pages_needed <= 8) {
> /*
> diff --git a/drivers/parisc/sba_iommu.c b/drivers/parisc/sba_iommu.c
> index 96bc2c617cbd19..959bda193b9603 100644
> --- a/drivers/parisc/sba_iommu.c
> +++ b/drivers/parisc/sba_iommu.c
> @@ -342,8 +342,7 @@ sba_search_bitmap(struct ioc *ioc, struct device *dev,
> unsigned long shift;
> int ret;
>
> - /* Overflow-free shortcut for: ALIGN(b + 1, 1 << s) >> s */
> - boundary_size = (dma_get_seg_boundary(dev) >> IOVP_SHIFT) + 1;
> + boundary_size = dma_get_seg_boundary_nr_pages(dev, IOVP_SHIFT);
>
> #if defined(ZX1_SUPPORT)
> BUG_ON(ioc->ibase & ~IOVP_MASK);
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 52635e91143b25..7477a164500adb 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -632,6 +632,25 @@ static inline unsigned long dma_get_seg_boundary(struct device *dev)
> return DMA_BIT_MASK(32);
> }
>
> +/**
> + * dma_get_seg_boundary_nr_pages - return the segment boundary in "page" units
> + * @dev: device to guery the boundary for
> + * @page_shift: ilog() of the the IOMMU page size
> + *
> + * Return the segment boundary in IOMMU page units (which may be different from
> + * the CPU page size) for the passed in device.
> + *
> + * If @dev is NULL a boundary of U32_MAX is assumed, this case is just for
> + * non-DMA API callers.
> + */
> +static inline unsigned long dma_get_seg_boundary_nr_pages(struct device *dev,
> + unsigned int page_shift)
> +{
> + if (!dev)
> + return (U32_MAX >> page_shift) + 1;
> + return (dma_get_seg_boundary(dev) >> page_shift) + 1;
> +}
> +
> static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask)
> {
> if (dev->dma_parms) {

Next message: Krzysztof Kozlowski: "[PATCH 01/13] ARM: dts: exynos: Correct compatible for Exynos5 GIC"
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In reply to: Christoph Hellwig: "Re: [RESEND][PATCH 0/7] Avoid overflow at boundary_size"
Next in thread: Christoph Hellwig: "Re: [RESEND][PATCH 0/7] Avoid overflow at boundary_size"
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