Merge branch 'hmm-devmem-cleanup.4' into rdma.git hmm

Christoph Hellwig says:

====================
Below is a series that cleans up the dev_pagemap interface so that it is
more easily usable, which removes the need to wrap it in hmm and thus
allowing to kill a lot of code

Changes since v3:
 - pull in "mm/swap: Fix release_pages() when releasing devmap pages" and
   rebase the other patches on top of that
 - fold the hmm_devmem_add_resource into the DEVICE_PUBLIC memory removal
   patch
 - remove _vm_normal_page as it isn't needed without DEVICE_PUBLIC memory
 - pick up various ACKs

Changes since v2:
 - fix nvdimm kunit build
 - add a new memory type for device dax
 - fix a few issues in intermediate patches that didn't show up in the end
   result
 - incorporate feedback from Michal Hocko, including killing of
   the DEVICE_PUBLIC memory type entirely

Changes since v1:
 - rebase
 - also switch p2pdma to the internal refcount
 - add type checking for pgmap->type
 - rename the migrate method to migrate_to_ram
 - cleanup the altmap_valid flag
 - various tidbits from the reviews
====================

Conflicts resolved by:
 - Keeping Ira's version of the code in swap.c
 - Using the delete for the section in hmm.rst
 - Using the delete for the devmap code in hmm.c and .h

* branch 'hmm-devmem-cleanup.4': (24 commits)
  mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR
  mm: remove the HMM config option
  mm: sort out the DEVICE_PRIVATE Kconfig mess
  mm: simplify ZONE_DEVICE page private data
  mm: remove hmm_devmem_add
  mm: remove hmm_vma_alloc_locked_page
  nouveau: use devm_memremap_pages directly
  nouveau: use alloc_page_vma directly
  PCI/P2PDMA: use the dev_pagemap internal refcount
  device-dax: use the dev_pagemap internal refcount
  memremap: provide an optional internal refcount in struct dev_pagemap
  memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
  memremap: remove the data field in struct dev_pagemap
  memremap: add a migrate_to_ram method to struct dev_pagemap_ops
  memremap: lift the devmap_enable manipulation into devm_memremap_pages
  memremap: pass a struct dev_pagemap to ->kill and ->cleanup
  memremap: move dev_pagemap callbacks into a separate structure
  memremap: validate the pagemap type passed to devm_memremap_pages
  mm: factor out a devm_request_free_mem_region helper
  mm: export alloc_pages_vma
  ...

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 39 insertions, 0 deletions

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"))