[PATCH v2 06/20] libnvdimm, pfn, pmem: allocate memmap array in persistent memory

[Dan Williams <dan.j.williams@xxxxxxxxx>]

Use the new vmem_altmap capability to enable the pmem driver to arrange
for a struct page memmap to be established in persistent memory.

Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/nvdimm/pfn_devs.c |    3 +--
 drivers/nvdimm/pmem.c     |   19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 71805a1aa0f3..a642cfacee07 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -83,8 +83,7 @@ static ssize_t mode_store(struct device *dev,
 
 		if (strncmp(buf, "pmem\n", n) == 0
 				|| strncmp(buf, "pmem", n) == 0) {
-			/* TODO: allocate from PMEM support */
-			rc = -ENOTTY;
+			nd_pfn->mode = PFN_MODE_PMEM;
 		} else if (strncmp(buf, "ram\n", n) == 0
 				|| strncmp(buf, "ram", n) == 0)
 			nd_pfn->mode = PFN_MODE_RAM;
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 3c5b8f585441..bb66158c0505 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -322,12 +322,16 @@ static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
 	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 	struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
 	struct device *dev = &nd_pfn->dev;
-	struct vmem_altmap *altmap;
 	struct nd_region *nd_region;
+	struct vmem_altmap *altmap;
 	struct nd_pfn_sb *pfn_sb;
 	struct pmem_device *pmem;
 	phys_addr_t offset;
 	int rc;
+	struct vmem_altmap __altmap = {
+		.base_pfn = __phys_to_pfn(nsio->res.start),
+		.reserve = __phys_to_pfn(SZ_8K),
+	};
 
 	if (!nd_pfn->uuid || !nd_pfn->ndns)
 		return -ENODEV;
@@ -355,6 +359,17 @@ static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
 			return -EINVAL;
 		nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 		altmap = NULL;
+	} else if (nd_pfn->mode == PFN_MODE_PMEM) {
+		nd_pfn->npfns = (resource_size(&nsio->res) - offset)
+			/ PAGE_SIZE;
+		if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
+			dev_info(&nd_pfn->dev,
+					"number of pfns truncated from %lld to %ld\n",
+					le64_to_cpu(nd_pfn->pfn_sb->npfns),
+					nd_pfn->npfns);
+		altmap = & __altmap;
+		altmap->free = __phys_to_pfn(offset - SZ_8K);
+		altmap->alloc = 0;
 	} else {
 		rc = -ENXIO;
 		goto err;
@@ -364,7 +379,7 @@ static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
 	pmem = dev_get_drvdata(dev);
 	devm_memunmap(dev, (void __force *) pmem->virt_addr);
 	pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res,
-			NULL);
+			altmap);
 	if (IS_ERR(pmem->virt_addr)) {
 		rc = PTR_ERR(pmem->virt_addr);
 		goto err;

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