[PATCH v2] dev-dax: add support to display badblocks in sysfs for dev-dax

[PATCH v2] dev-dax: add support to display badblocks in sysfs for dev-dax

[Dave Jiang]

Adding support to show badblocks in the pmem region that's provided
by the poison_list. This should show up in
/sys/class/dax/daxN.N/badblocks as read only. Currently we only support
a single resource and we do not support badblocks for seeds. Additional
support code will be implemented to support.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dax/dax.c  |   25 +++++++++++++++++++++----
 drivers/dax/dax.h  |    8 +++++++-
 drivers/dax/pmem.c |   37 ++++++++++++++++++++++++++++++++++++-
 3 files changed, 64 insertions(+), 6 deletions(-)

diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index ed4843a9..6580f85 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -79,6 +79,7 @@ struct dax_dev {
 	int id;
 	int num_resources;
 	struct resource **res;
+	void *private;
 };
 
 #define for_each_dax_region_resource(dax_region, res) \
@@ -336,6 +337,20 @@ static struct dax_dev *to_dax_dev(struct device *dev)
 	return container_of(dev, struct dax_dev, dev);
 }
 
+void *dax_dev_get_private(struct device *dev)
+{
+	struct dax_dev *dax_dev = to_dax_dev(dev);
+
+	return dax_dev->private;
+}
+EXPORT_SYMBOL_GPL(dax_dev_get_private);
+
+void dax_dev_set_private(struct dax_dev *dax_dev, void *priv)
+{
+	dax_dev->private = priv;
+}
+EXPORT_SYMBOL_GPL(dax_dev_set_private);
+
 static ssize_t size_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -355,9 +370,10 @@ static struct attribute *dax_device_attributes[] = {
 	NULL,
 };
 
-static const struct attribute_group dax_device_attribute_group = {
+struct attribute_group dax_device_attribute_group = {
 	.attrs = dax_device_attributes,
 };
+EXPORT_SYMBOL_GPL(dax_device_attribute_group);
 
 static const struct attribute_group *dax_attribute_groups[] = {
 	&dax_device_attribute_group,
@@ -676,7 +692,8 @@ static void unregister_dax_dev(void *dev)
 }
 
 struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
-		struct resource *res, int count)
+		struct resource *res, int count,
+		const struct attribute_group **groups)
 {
 	struct device *parent = dax_region->dev;
 	struct dax_dev *dax_dev;
@@ -757,7 +774,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
 	dev->devt = dev_t;
 	dev->class = dax_class;
 	dev->parent = parent;
-	dev->groups = dax_attribute_groups;
+	dev->groups = groups ? groups : dax_attribute_groups;
 	dev->release = dax_dev_release;
 	dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
 	/* update resource names now that the owner device is named */
@@ -777,7 +794,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
 	if (atomic_inc_return(&dax_region->child_count) == 1) {
 		struct dax_dev *seed;
 
-		seed = devm_create_dax_dev(dax_region, NULL, 0);
+		seed = devm_create_dax_dev(dax_region, NULL, 0, NULL);
 		if (IS_ERR(seed))
 			dev_warn(parent, "failed to create region seed\n");
 		else
diff --git a/drivers/dax/dax.h b/drivers/dax/dax.h
index ddd829a..c23c7ac 100644
--- a/drivers/dax/dax.h
+++ b/drivers/dax/dax.h
@@ -16,10 +16,16 @@ struct device;
 struct dax_dev;
 struct resource;
 struct dax_region;
+extern struct attribute_group dax_device_attribute_group;
+
 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,
 		void *addr, unsigned long flags);
 struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
-		struct resource *res, int count);
+		struct resource *res, int count,
+		const struct attribute_group **groups);
+void *dax_dev_get_private(struct device *dev);
+void dax_dev_set_private(struct dax_dev *dax_dev, void *priv);
+
 #endif /* __DAX_H__ */
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index 9630d88..56282a9 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -14,6 +14,7 @@
 #include <linux/memremap.h>
 #include <linux/module.h>
 #include <linux/pfn_t.h>
+#include <linux/badblocks.h>
 #include "../nvdimm/pfn.h"
 #include "../nvdimm/nd.h"
 #include "dax.h"
@@ -22,6 +23,32 @@ struct dax_pmem {
 	struct device *dev;
 	struct percpu_ref ref;
 	struct completion cmp;
+	struct badblocks bb;
+};
+
+static ssize_t dax_pmem_badblocks_show(struct device *dev,
+		struct device_attribute *attr, char *page)
+{
+	struct dax_pmem *dax_pmem =
+		(struct dax_pmem *)dax_dev_get_private(dev);
+
+	return badblocks_show(&dax_pmem->bb, page, 0);
+}
+static DEVICE_ATTR(badblocks, S_IRUGO, dax_pmem_badblocks_show, NULL);
+
+static struct attribute *dax_pmem_badblock_attributes[] = {
+	&dev_attr_badblocks.attr,
+	NULL,
+};
+
+static struct attribute_group dax_pmem_badblock_attribute_group = {
+	.attrs = dax_pmem_badblock_attributes,
+};
+
+static const struct attribute_group *dax_pmem_attribute_groups[] = {
+	&dax_device_attribute_group,
+	&dax_pmem_badblock_attribute_group,
+	NULL,
 };
 
 static struct dax_pmem *to_dax_pmem(struct percpu_ref *ref)
@@ -127,7 +154,15 @@ static int dax_pmem_probe(struct device *dev)
 		return -ENOMEM;
 
 	/* TODO: support for subdividing a dax region... */
-	dax_dev = devm_create_dax_dev(dax_region, &res, 1);
+	dax_dev = devm_create_dax_dev(dax_region, &res, 1,
+			dax_pmem_attribute_groups);
+	dax_dev_set_private(dax_dev, dax_pmem);
+
+	rc = devm_init_badblocks(dev, &dax_pmem->bb);
+	if (rc)
+		return rc;
+
+	nvdimm_badblocks_populate(nd_region, &dax_pmem->bb, &res);
 
 	/* child dax_dev instances now own the lifetime of the dax_region */
 	dax_region_put(dax_region);

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