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>

2 files changed, 20 insertions, 34 deletions

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 0f81fc56bbfd..55fb6b7433ed 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -622,7 +622,6 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
 		if (offset < reserve)
 			return -EINVAL;
 		nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
-		pgmap->altmap_valid = false;
 	} else if (nd_pfn->mode == PFN_MODE_PMEM) {
 		nd_pfn->npfns = PFN_SECTION_ALIGN_UP((resource_size(res)
 					- offset) / PAGE_SIZE);
@@ -634,7 +633,7 @@ static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
 		memcpy(altmap, &__altmap, sizeof(*altmap));
 		altmap->free = PHYS_PFN(offset - reserve);
 		altmap->alloc = 0;
-		pgmap->altmap_valid = true;
+		pgmap->flags |= PGMAP_ALTMAP_VALID;
 	} else
 		return -ENXIO;
 
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 24d7fe7c74ed..e7d8cc9f41e8 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -303,24 +303,24 @@ static const struct attribute_group *pmem_attribute_groups[] = {
 	NULL,
 };
 
-static void __pmem_release_queue(struct percpu_ref *ref)
+static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap)
 {
-	struct request_queue *q;
+	struct request_queue *q =
+		container_of(pgmap->ref, struct request_queue, q_usage_counter);
 
-	q = container_of(ref, typeof(*q), q_usage_counter);
 	blk_cleanup_queue(q);
 }
 
-static void pmem_release_queue(void *ref)
+static void pmem_release_queue(void *pgmap)
 {
-	__pmem_release_queue(ref);
+	pmem_pagemap_cleanup(pgmap);
 }
 
-static void pmem_freeze_queue(struct percpu_ref *ref)
+static void pmem_pagemap_kill(struct dev_pagemap *pgmap)
 {
-	struct request_queue *q;
+	struct request_queue *q =
+		container_of(pgmap->ref, struct request_queue, q_usage_counter);
 
-	q = container_of(ref, typeof(*q), q_usage_counter);
 	blk_freeze_queue_start(q);
 }
 
@@ -334,26 +334,16 @@ static void pmem_release_disk(void *__pmem)
 	put_disk(pmem->disk);
 }
 
-static void pmem_release_pgmap_ops(void *__pgmap)
-{
-	dev_pagemap_put_ops();
-}
-
-static void fsdax_pagefree(struct page *page, void *data)
+static void pmem_pagemap_page_free(struct page *page)
 {
 	wake_up_var(&page->_refcount);
 }
 
-static int setup_pagemap_fsdax(struct device *dev, struct dev_pagemap *pgmap)
-{
-	dev_pagemap_get_ops();
-	if (devm_add_action_or_reset(dev, pmem_release_pgmap_ops, pgmap))
-		return -ENOMEM;
-	pgmap->type = MEMORY_DEVICE_FS_DAX;
-	pgmap->page_free = fsdax_pagefree;
-
-	return 0;
-}
+static const struct dev_pagemap_ops fsdax_pagemap_ops = {
+	.page_free		= pmem_pagemap_page_free,
+	.kill			= pmem_pagemap_kill,
+	.cleanup		= pmem_pagemap_cleanup,
+};
 
 static int pmem_attach_disk(struct device *dev,
 		struct nd_namespace_common *ndns)
@@ -409,11 +399,9 @@ static int pmem_attach_disk(struct device *dev,
 
 	pmem->pfn_flags = PFN_DEV;
 	pmem->pgmap.ref = &q->q_usage_counter;
-	pmem->pgmap.kill = pmem_freeze_queue;
-	pmem->pgmap.cleanup = __pmem_release_queue;
 	if (is_nd_pfn(dev)) {
-		if (setup_pagemap_fsdax(dev, &pmem->pgmap))
-			return -ENOMEM;
+		pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
+		pmem->pgmap.ops = &fsdax_pagemap_ops;
 		addr = devm_memremap_pages(dev, &pmem->pgmap);
 		pfn_sb = nd_pfn->pfn_sb;
 		pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
@@ -424,15 +412,14 @@ static int pmem_attach_disk(struct device *dev,
 		bb_res.start += pmem->data_offset;
 	} else if (pmem_should_map_pages(dev)) {
 		memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));
-		pmem->pgmap.altmap_valid = false;
-		if (setup_pagemap_fsdax(dev, &pmem->pgmap))
-			return -ENOMEM;
+		pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
+		pmem->pgmap.ops = &fsdax_pagemap_ops;
 		addr = devm_memremap_pages(dev, &pmem->pgmap);
 		pmem->pfn_flags |= PFN_MAP;
 		memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
 	} else {
 		if (devm_add_action_or_reset(dev, pmem_release_queue,
-					&q->q_usage_counter))
+					&pmem->pgmap))
 			return -ENOMEM;
 		addr = devm_memremap(dev, pmem->phys_addr,
 				pmem->size, ARCH_MEMREMAP_PMEM);