memremap: change devm_memremap_pages interface to use struct dev_pagemap

This new interface is similar to how struct device (and many others)
work. The caller initializes a 'struct dev_pagemap' as required
and calls 'devm_memremap_pages'. This allows the pagemap structure to
be embedded in another structure and thus container_of can be used. In
this way application specific members can be stored in a containing
struct.

This will be used by the P2P infrastructure and HMM could probably
be cleaned up to use it as well (instead of having it's own, similar
'hmm_devmem_pages_create' function).

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 15 insertions, 12 deletions

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 2adada1a5855..f5c4e8c6e29d 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -542,9 +542,10 @@ static unsigned long init_altmap_reserve(resource_size_t base)
 	return reserve;
 }
 
-static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
-		struct resource *res, struct vmem_altmap *altmap)
+static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
 {
+	struct resource *res = &pgmap->res;
+	struct vmem_altmap *altmap = &pgmap->altmap;
 	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 	u64 offset = le64_to_cpu(pfn_sb->dataoff);
 	u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
@@ -561,11 +562,13 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 	res->start += start_pad;
 	res->end -= end_trunc;
 
+	pgmap->type = MEMORY_DEVICE_HOST;
+
 	if (nd_pfn->mode == PFN_MODE_RAM) {
 		if (offset < SZ_8K)
-			return ERR_PTR(-EINVAL);
+			return -EINVAL;
 		nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
-		altmap = NULL;
+		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);
@@ -577,10 +580,11 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 		memcpy(altmap, &__altmap, sizeof(*altmap));
 		altmap->free = PHYS_PFN(offset - SZ_8K);
 		altmap->alloc = 0;
+		pgmap->altmap_valid = true;
 	} else
-		return ERR_PTR(-ENXIO);
+		return -ENXIO;
 
-	return altmap;
+	return 0;
 }
 
 static u64 phys_pmem_align_down(struct nd_pfn *nd_pfn, u64 phys)
@@ -708,19 +712,18 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
  * Determine the effective resource range and vmem_altmap from an nd_pfn
  * instance.
  */
-struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
-		struct resource *res, struct vmem_altmap *altmap)
+int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
 {
 	int rc;
 
 	if (!nd_pfn->uuid || !nd_pfn->ndns)
-		return ERR_PTR(-ENODEV);
+		return -ENODEV;
 
 	rc = nd_pfn_init(nd_pfn);
 	if (rc)
-		return ERR_PTR(rc);
+		return rc;
 
-	/* we need a valid pfn_sb before we can init a vmem_altmap */
-	return __nvdimm_setup_pfn(nd_pfn, res, altmap);
+	/* we need a valid pfn_sb before we can init a dev_pagemap */
+	return __nvdimm_setup_pfn(nd_pfn, pgmap);
 }
 EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);