From: Dan Williams dan.j.williams@intel.com Subject: mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support

In preparation for consolidating all ZONE_DEVICE enabling via devm_memremap_pages(), teach it how to handle the constraints of MEMORY_DEVICE_PRIVATE ranges.

[jglisse@redhat.com: call move_pfn_range_to_zone for MEMORY_DEVICE_PRIVATE] Link: http://lkml.kernel.org/r/154275559036.76910.12434636179931292607.stgit@dwill... Signed-off-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Jérôme Glisse jglisse@redhat.com Acked-by: Christoph Hellwig hch@lst.de Reported-by: Logan Gunthorpe logang@deltatee.com Reviewed-by: Logan Gunthorpe logang@deltatee.com Cc: Balbir Singh bsingharora@gmail.com Cc: Michal Hocko mhocko@suse.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

--- a/kernel/memremap.c~mm-devm_memremap_pages-add-memory_device_private-support +++ a/kernel/memremap.c @@ -98,9 +98,15 @@ static void devm_memremap_pages_release( - align_start;

mem_hotplug_begin(); - arch_remove_memory(align_start, align_size, pgmap->altmap_valid ? - &pgmap->altmap : NULL); - kasan_remove_zero_shadow(__va(align_start), align_size); + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { + pfn = align_start >> PAGE_SHIFT; + __remove_pages(page_zone(pfn_to_page(pfn)), pfn, + align_size >> PAGE_SHIFT, NULL); + } else { + arch_remove_memory(align_start, align_size, + pgmap->altmap_valid ? &pgmap->altmap : NULL); + kasan_remove_zero_shadow(__va(align_start), align_size); + } mem_hotplug_done();

untrack_pfn(NULL, PHYS_PFN(align_start), align_size); @@ -187,17 +193,40 @@ void *devm_memremap_pages(struct device goto err_pfn_remap;

mem_hotplug_begin(); - error = kasan_add_zero_shadow(__va(align_start), align_size); - if (error) { - mem_hotplug_done(); - goto err_kasan; + + /* + * For device private memory we call add_pages() as we only need to + * allocate and initialize struct page for the device memory. More- + * over the device memory is un-accessible thus we do not want to + * create a linear mapping for the memory like arch_add_memory() + * would do. + * + * For all other device memory types, which are accessible by + * the CPU, we do want the linear mapping and thus use + * arch_add_memory(). + */ + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { + error = add_pages(nid, align_start >> PAGE_SHIFT, + align_size >> PAGE_SHIFT, NULL, false); + } else { + error = kasan_add_zero_shadow(__va(align_start), align_size); + if (error) { + mem_hotplug_done(); + goto err_kasan; + } + + error = arch_add_memory(nid, align_start, align_size, altmap, + false); + } + + if (!error) { + struct zone *zone; + + zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; + move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT, + align_size >> PAGE_SHIFT, altmap); }

- error = arch_add_memory(nid, align_start, align_size, altmap, false); - if (!error) - move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], - align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, altmap); mem_hotplug_done(); if (error) goto err_add_memory; _