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, 6 insertions, 7 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d66bc8abe0af..c0e031c52db5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5853,6 +5853,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
 {
 	unsigned long pfn, end_pfn = start_pfn + size;
 	struct pglist_data *pgdat = zone->zone_pgdat;
+	struct vmem_altmap *altmap = pgmap_altmap(pgmap);
 	unsigned long zone_idx = zone_idx(zone);
 	unsigned long start = jiffies;
 	int nid = pgdat->node_id;
@@ -5865,9 +5866,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
 	 * of the pages reserved for the memmap, so we can just jump to
 	 * the end of that region and start processing the device pages.
 	 */
-	if (pgmap->altmap_valid) {
-		struct vmem_altmap *altmap = &pgmap->altmap;
-
+	if (altmap) {
 		start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
 		size = end_pfn - start_pfn;
 	}
@@ -5887,12 +5886,12 @@ void __ref memmap_init_zone_device(struct zone *zone,
 		__SetPageReserved(page);
 
 		/*
-		 * ZONE_DEVICE pages union ->lru with a ->pgmap back
-		 * pointer and hmm_data.  It is a bug if a ZONE_DEVICE
-		 * page is ever freed or placed on a driver-private list.
+		 * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
+		 * and zone_device_data.  It is a bug if a ZONE_DEVICE page is
+		 * ever freed or placed on a driver-private list.
 		 */
 		page->pgmap = pgmap;
-		page->hmm_data = 0;
+		page->zone_device_data = NULL;
 
 		/*
 		 * Mark the block movable so that blocks are reserved for