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Subject[PATCH 6/8] device-dax: Move resource pinning+mapping into the common driver
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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/bus.c | 6 ++-
drivers/dax/bus.h | 3 +
drivers/dax/dax-private.h | 9 ++++
drivers/dax/device.c | 65 ++++++++++++++++++++++++++++++
drivers/dax/pmem.c | 98 ++++++---------------------------------------
5 files changed, 94 insertions(+), 87 deletions(-)

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 0cff32102c4c..69aae2cbd45f 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2017-2018 Intel Corporation. All rights reserved. */
+#include <linux/memremap.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/dax.h>
@@ -206,7 +207,8 @@ static void unregister_dev_dax(void *dev)
put_device(dev);
}

-struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, int id)
+struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, int id,
+ struct dev_pagemap *pgmap)
{
struct device *parent = dax_region->dev;
struct dax_device *dax_dev;
@@ -222,6 +224,8 @@ struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, int id)
if (!dev_dax)
return ERR_PTR(-ENOMEM);

+ memcpy(&dev_dax->pgmap, pgmap, sizeof(*pgmap));
+
/*
* No 'host' or dax_operations since there is no access to this
* device outside of mmap of the resulting character device.
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index ea509504df3a..e08e0c394983 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -10,7 +10,8 @@ struct dax_region;
void dax_region_put(struct dax_region *dax_region);
struct dax_region *alloc_dax_region(struct device *parent, int region_id,
struct resource *res, unsigned int align, unsigned long flags);
-struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, int id);
+struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, int id,
+ struct dev_pagemap *pgmap);
int __dax_driver_register(struct device_driver *drv,
struct module *module, const char *mod_name);
#define dax_driver_register(driver) \
diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index c3a121700837..a82ce48f5884 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -42,15 +42,22 @@ struct dax_region {
};

/**
- * struct dev_dax - instance data for a subdivision of a dax region
+ * struct dev_dax - instance data for a subdivision of a dax region, and
+ * data while the device is activated in the driver.
* @region - parent region
* @dax_dev - core dax functionality
* @dev - device core
+ * @pgmap - pgmap for memmap setup / lifetime (driver owned)
+ * @ref: pgmap reference count (driver owned)
+ * @cmp: @ref final put completion (driver owned)
*/
struct dev_dax {
struct dax_region *region;
struct dax_device *dax_dev;
struct device dev;
+ struct dev_pagemap pgmap;
+ struct percpu_ref ref;
+ struct completion cmp;
};

static inline struct dev_dax *to_dev_dax(struct device *dev)
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index f55829404a24..967bab097013 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016-2018 Intel Corporation. All rights reserved. */
+#include <linux/memremap.h>
#include <linux/pagemap.h>
#include <linux/module.h>
#include <linux/device.h>
@@ -13,6 +14,38 @@
#include "dax-private.h"
#include "bus.h"

+static struct dev_dax *ref_to_dev_dax(struct percpu_ref *ref)
+{
+ return container_of(ref, struct dev_dax, ref);
+}
+
+static void dev_dax_percpu_release(struct percpu_ref *ref)
+{
+ struct dev_dax *dev_dax = ref_to_dev_dax(ref);
+
+ dev_dbg(&dev_dax->dev, "%s\n", __func__);
+ complete(&dev_dax->cmp);
+}
+
+static void dev_dax_percpu_exit(void *data)
+{
+ struct percpu_ref *ref = data;
+ struct dev_dax *dev_dax = ref_to_dev_dax(ref);
+
+ dev_dbg(&dev_dax->dev, "%s\n", __func__);
+ wait_for_completion(&dev_dax->cmp);
+ percpu_ref_exit(ref);
+}
+
+static void dev_dax_percpu_kill(void *data)
+{
+ struct percpu_ref *ref = data;
+ struct dev_dax *dev_dax = ref_to_dev_dax(ref);
+
+ dev_dbg(&dev_dax->dev, "%s\n", __func__);
+ percpu_ref_kill(ref);
+}
+
static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
const char *func)
{
@@ -416,10 +449,42 @@ static int dev_dax_probe(struct device *dev)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
struct dax_device *dax_dev = dev_dax->dax_dev;
+ struct resource *res = &dev_dax->region->res;
struct inode *inode;
struct cdev *cdev;
+ void *addr;
int rc;

+ /* 1:1 map region resource range to device-dax instance range */
+ if (!devm_request_mem_region(dev, res->start, resource_size(res),
+ dev_name(dev))) {
+ dev_warn(dev, "could not reserve region %pR\n", res);
+ return -EBUSY;
+ }
+
+ init_completion(&dev_dax->cmp);
+ rc = percpu_ref_init(&dev_dax->ref, dev_dax_percpu_release, 0,
+ GFP_KERNEL);
+ if (rc)
+ return rc;
+
+ rc = devm_add_action_or_reset(dev, dev_dax_percpu_exit, &dev_dax->ref);
+ if (rc)
+ return rc;
+
+ dev_dax->pgmap.ref = &dev_dax->ref;
+ addr = devm_memremap_pages(dev, &dev_dax->pgmap);
+ if (IS_ERR(addr)) {
+ devm_remove_action(dev, dev_dax_percpu_exit, &dev_dax->ref);
+ percpu_ref_exit(&dev_dax->ref);
+ return PTR_ERR(addr);
+ }
+
+ rc = devm_add_action_or_reset(dev, dev_dax_percpu_kill,
+ &dev_dax->ref);
+ if (rc)
+ return rc;
+
inode = dax_inode(dax_dev);
cdev = inode->i_cdev;
cdev_init(cdev, &dax_fops);
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index c94f17e662bd..d3cefa7868ac 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -18,55 +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(void *data)
-{
- struct percpu_ref *ref = data;
- 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;
@@ -76,68 +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;
- addr = devm_memremap_pages(dev, &dax_pmem->pgmap);
- if (IS_ERR(addr)) {
- devm_remove_action(dev, dax_pmem_percpu_exit, &dax_pmem->ref);
- percpu_ref_exit(&dax_pmem->ref);
- return PTR_ERR(addr);
- }
-
- rc = devm_add_action_or_reset(dev, dax_pmem_percpu_kill,
- &dax_pmem->ref);
- if (rc)
- return rc;
-
- /* 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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