The routines hmm_devmem_add(), and hmm_devmem_add_resource() duplicated devm_memremap_pages() and are now simple now wrappers around the core facility to inject a dev_pagemap instance into the global pgmap_radix and hook page-idle events. The devm_memremap_pages() interface is base infrastructure for HMM. HMM has more and deeper ties into the kernel memory management implementation than base ZONE_DEVICE which is itself a EXPORT_SYMBOL_GPL facility. Originally, the HMM page structure creation routines copied the devm_memremap_pages() code and reused ZONE_DEVICE. A cleanup to unify the implementations was discussed during the initial review: http://lkml.iu.edu/hypermail/linux/kernel/1701.2/00812.html Recent work to extend devm_memremap_pages() for the peer-to-peer-DMA facility enabled this cleanup to move forward. In addition to the integration with devm_memremap_pages() HMM depends on other GPL-only symbols: mmu_notifier_unregister_no_release percpu_ref region_intersects __class_create It goes further to consume / indirectly expose functionality that is not exported to any other driver: alloc_pages_vma walk_page_range HMM is derived from devm_memremap_pages(), and extends deep core-kernel fundamentals. Similar to devm_memremap_pages(), mark its entry points EXPORT_SYMBOL_GPL(). Cc: "Jérôme Glisse" <jglisse@xxxxxxxxxx> Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> --- mm/hmm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/hmm.c b/mm/hmm.c index 2e72cb4188ca..90d1383c7e24 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -1062,7 +1062,7 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, return result; return devmem; } -EXPORT_SYMBOL(hmm_devmem_add); +EXPORT_SYMBOL_GPL(hmm_devmem_add); struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, struct device *device, @@ -1116,7 +1116,7 @@ struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, return result; return devmem; } -EXPORT_SYMBOL(hmm_devmem_add_resource); +EXPORT_SYMBOL_GPL(hmm_devmem_add_resource); /* * A device driver that wants to handle multiple devices memory through a
