From 89ec9f2cfa36cc5fca2fb445ed221bb9add7b536 Mon Sep 17 00:00:00 2001
From: Dan Williams
Date: Mon, 29 Oct 2018 15:52:42 -0700
Subject: device-dax: Move resource pinning+mapping into the common driver

Move the responsibility of calling devm_request_resource() and
devm_memremap_pages() into the common device-dax driver. This is another
preparatory step to allowing an alternate personality driver for a
device-dax range.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>---
 drivers/dax/pmem.c | 90 +++++++++---------------------------------------------
 1 file changed, 14 insertions(+), 76 deletions(-)

(limited to 'drivers/dax/pmem.c')

diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index e1b50d8fd1f8..d3cefa7868ac 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -18,54 +18,16 @@
 #include "../nvdimm/nd.h"
 #include "bus.h"
 
-struct dax_pmem {
-	struct device *dev;
-	struct percpu_ref ref;
-	struct dev_pagemap pgmap;
-	struct completion cmp;
-};
-
-static struct dax_pmem *to_dax_pmem(struct percpu_ref *ref)
-{
-	return container_of(ref, struct dax_pmem, ref);
-}
-
-static void dax_pmem_percpu_release(struct percpu_ref *ref)
-{
-	struct dax_pmem *dax_pmem = to_dax_pmem(ref);
-
-	dev_dbg(dax_pmem->dev, "trace\n");
-	complete(&dax_pmem->cmp);
-}
-
-static void dax_pmem_percpu_exit(void *data)
-{
-	struct percpu_ref *ref = data;
-	struct dax_pmem *dax_pmem = to_dax_pmem(ref);
-
-	dev_dbg(dax_pmem->dev, "trace\n");
-	wait_for_completion(&dax_pmem->cmp);
-	percpu_ref_exit(ref);
-}
-
-static void dax_pmem_percpu_kill(struct percpu_ref *ref)
-{
-	struct dax_pmem *dax_pmem = to_dax_pmem(ref);
-
-	dev_dbg(dax_pmem->dev, "trace\n");
-	percpu_ref_kill(ref);
-}
-
 static int dax_pmem_probe(struct device *dev)
 {
-	void *addr;
 	struct resource res;
 	int rc, id, region_id;
+	resource_size_t offset;
 	struct nd_pfn_sb *pfn_sb;
 	struct dev_dax *dev_dax;
-	struct dax_pmem *dax_pmem;
 	struct nd_namespace_io *nsio;
 	struct dax_region *dax_region;
+	struct dev_pagemap pgmap = { 0 };
 	struct nd_namespace_common *ndns;
 	struct nd_dax *nd_dax = to_nd_dax(dev);
 	struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;
@@ -75,61 +37,37 @@ static int dax_pmem_probe(struct device *dev)
 		return PTR_ERR(ndns);
 	nsio = to_nd_namespace_io(&ndns->dev);
 
-	dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL);
-	if (!dax_pmem)
-		return -ENOMEM;
-
 	/* parse the 'pfn' info block via ->rw_bytes */
 	rc = devm_nsio_enable(dev, nsio);
 	if (rc)
 		return rc;
-	rc = nvdimm_setup_pfn(nd_pfn, &dax_pmem->pgmap);
+	rc = nvdimm_setup_pfn(nd_pfn, &pgmap);
 	if (rc)
 		return rc;
 	devm_nsio_disable(dev, nsio);
 
-	pfn_sb = nd_pfn->pfn_sb;
-
-	if (!devm_request_mem_region(dev, nsio->res.start,
-				resource_size(&nsio->res),
+	/* reserve the metadata area, device-dax will reserve the data */
+        pfn_sb = nd_pfn->pfn_sb;
+	offset = le64_to_cpu(pfn_sb->dataoff);
+	if (!devm_request_mem_region(dev, nsio->res.start, offset,
 				dev_name(&ndns->dev))) {
-		dev_warn(dev, "could not reserve region %pR\n", &nsio->res);
-		return -EBUSY;
-	}
-
-	dax_pmem->dev = dev;
-	init_completion(&dax_pmem->cmp);
-	rc = percpu_ref_init(&dax_pmem->ref, dax_pmem_percpu_release, 0,
-			GFP_KERNEL);
-	if (rc)
-		return rc;
-
-	rc = devm_add_action(dev, dax_pmem_percpu_exit, &dax_pmem->ref);
-	if (rc) {
-		percpu_ref_exit(&dax_pmem->ref);
-		return rc;
-	}
-
-	dax_pmem->pgmap.ref = &dax_pmem->ref;
-	dax_pmem->pgmap.kill = dax_pmem_percpu_kill;
-	addr = devm_memremap_pages(dev, &dax_pmem->pgmap);
-	if (IS_ERR(addr))
-		return PTR_ERR(addr);
-
-	/* adjust the dax_region resource to the start of data */
-	memcpy(&res, &dax_pmem->pgmap.res, sizeof(res));
-	res.start += le64_to_cpu(pfn_sb->dataoff);
+                dev_warn(dev, "could not reserve metadata\n");
+                return -EBUSY;
+        }
 
 	rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
 	if (rc != 2)
 		return -EINVAL;
 
+	/* adjust the dax_region resource to the start of data */
+	memcpy(&res, &pgmap.res, sizeof(res));
+	res.start += offset;
 	dax_region = alloc_dax_region(dev, region_id, &res,
 			le32_to_cpu(pfn_sb->align), PFN_DEV|PFN_MAP);
 	if (!dax_region)
 		return -ENOMEM;
 
-	dev_dax = devm_create_dev_dax(dax_region, id);
+	dev_dax = devm_create_dev_dax(dax_region, id, &pgmap);
 
 	/* child dev_dax instances now own the lifetime of the dax_region */
 	dax_region_put(dax_region);
-- 
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