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    Subject[PATCH 06/25] mm: factor out a devm_request_free_mem_region helper
    Date
    Keep the physical address allocation that hmm_add_device does with the
    rest of the resource code, and allow future reuse of it without the hmm
    wrapper.

    Signed-off-by: Christoph Hellwig <hch@lst.de>
    Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
    Reviewed-by: John Hubbard <jhubbard@nvidia.com>
    ---
    include/linux/ioport.h | 2 ++
    kernel/resource.c | 39 +++++++++++++++++++++++++++++++++++++++
    mm/hmm.c | 33 ++++-----------------------------
    3 files changed, 45 insertions(+), 29 deletions(-)

    diff --git a/include/linux/ioport.h b/include/linux/ioport.h
    index da0ebaec25f0..76a33ae3bf6c 100644
    --- a/include/linux/ioport.h
    +++ b/include/linux/ioport.h
    @@ -286,6 +286,8 @@ static inline bool resource_overlaps(struct resource *r1, struct resource *r2)
    return (r1->start <= r2->end && r1->end >= r2->start);
    }

    +struct resource *devm_request_free_mem_region(struct device *dev,
    + struct resource *base, unsigned long size);

    #endif /* __ASSEMBLY__ */
    #endif /* _LINUX_IOPORT_H */
    diff --git a/kernel/resource.c b/kernel/resource.c
    index 158f04ec1d4f..d22423e85cf8 100644
    --- a/kernel/resource.c
    +++ b/kernel/resource.c
    @@ -1628,6 +1628,45 @@ void resource_list_free(struct list_head *head)
    }
    EXPORT_SYMBOL(resource_list_free);

    +#ifdef CONFIG_DEVICE_PRIVATE
    +/**
    + * devm_request_free_mem_region - find free region for device private memory
    + *
    + * @dev: device struct to bind the resource to
    + * @size: size in bytes of the device memory to add
    + * @base: resource tree to look in
    + *
    + * This function tries to find an empty range of physical address big enough to
    + * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
    + * memory, which in turn allocates struct pages.
    + */
    +struct resource *devm_request_free_mem_region(struct device *dev,
    + struct resource *base, unsigned long size)
    +{
    + resource_size_t end, addr;
    + struct resource *res;
    +
    + size = ALIGN(size, 1UL << PA_SECTION_SHIFT);
    + end = min_t(unsigned long, base->end, (1UL << MAX_PHYSMEM_BITS) - 1);
    + addr = end - size + 1UL;
    +
    + for (; addr > size && addr >= base->start; addr -= size) {
    + if (region_intersects(addr, size, 0, IORES_DESC_NONE) !=
    + REGION_DISJOINT)
    + continue;
    +
    + res = devm_request_mem_region(dev, addr, size, dev_name(dev));
    + if (!res)
    + return ERR_PTR(-ENOMEM);
    + res->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
    + return res;
    + }
    +
    + return ERR_PTR(-ERANGE);
    +}
    +EXPORT_SYMBOL_GPL(devm_request_free_mem_region);
    +#endif /* CONFIG_DEVICE_PRIVATE */
    +
    static int __init strict_iomem(char *str)
    {
    if (strstr(str, "relaxed"))
    diff --git a/mm/hmm.c b/mm/hmm.c
    index 64e788bb1211..172d695dcb8b 100644
    --- a/mm/hmm.c
    +++ b/mm/hmm.c
    @@ -25,8 +25,6 @@
    #include <linux/mmu_notifier.h>
    #include <linux/memory_hotplug.h>

    -#define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT)
    -
    #if IS_ENABLED(CONFIG_HMM_MIRROR)
    static const struct mmu_notifier_ops hmm_mmu_notifier_ops;

    @@ -1405,7 +1403,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
    unsigned long size)
    {
    struct hmm_devmem *devmem;
    - resource_size_t addr;
    void *result;
    int ret;

    @@ -1427,32 +1424,10 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
    if (ret)
    return ERR_PTR(ret);

    - size = ALIGN(size, PA_SECTION_SIZE);
    - addr = min((unsigned long)iomem_resource.end,
    - (1UL << MAX_PHYSMEM_BITS) - 1);
    - addr = addr - size + 1UL;
    -
    - /*
    - * FIXME add a new helper to quickly walk resource tree and find free
    - * range
    - *
    - * FIXME what about ioport_resource resource ?
    - */
    - for (; addr > size && addr >= iomem_resource.start; addr -= size) {
    - ret = region_intersects(addr, size, 0, IORES_DESC_NONE);
    - if (ret != REGION_DISJOINT)
    - continue;
    -
    - devmem->resource = devm_request_mem_region(device, addr, size,
    - dev_name(device));
    - if (!devmem->resource)
    - return ERR_PTR(-ENOMEM);
    - break;
    - }
    - if (!devmem->resource)
    - return ERR_PTR(-ERANGE);
    -
    - devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
    + devmem->resource = devm_request_free_mem_region(device, &iomem_resource,
    + size);
    + if (IS_ERR(devmem->resource))
    + return ERR_CAST(devmem->resource);
    devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
    devmem->pfn_last = devmem->pfn_first +
    (resource_size(devmem->resource) >> PAGE_SHIFT);
    --
    2.20.1
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