dax: add region 'id', 'size', and 'align' attributes
While this information is available by looking at the nvdimm parent
device that may not always be the case when/if we add support for other
memory regions. Tooling should not depend on walking a given ancestor
topology that is not guaranteed by the device's class. For example, a
device-dax instance will always have a dax_region parent, but it may not
always have a libnvdimm "dax" device as a grandparent.
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index 0e499bf..369fccd 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -75,6 +75,73 @@ struct dax_dev {
struct resource res[0];
};
+static ssize_t id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dax_region *dax_region;
+ ssize_t rc = -ENXIO;
+
+ device_lock(dev);
+ dax_region = dev_get_drvdata(dev);
+ if (dax_region)
+ rc = sprintf(buf, "%d\n", dax_region->id);
+ device_unlock(dev);
+
+ return rc;
+}
+static DEVICE_ATTR_RO(id);
+
+static ssize_t region_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dax_region *dax_region;
+ ssize_t rc = -ENXIO;
+
+ device_lock(dev);
+ dax_region = dev_get_drvdata(dev);
+ if (dax_region)
+ rc = sprintf(buf, "%llu\n", (unsigned long long)
+ resource_size(&dax_region->res));
+ device_unlock(dev);
+
+ return rc;
+}
+static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
+ region_size_show, NULL);
+
+static ssize_t align_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dax_region *dax_region;
+ ssize_t rc = -ENXIO;
+
+ device_lock(dev);
+ dax_region = dev_get_drvdata(dev);
+ if (dax_region)
+ rc = sprintf(buf, "%u\n", dax_region->align);
+ device_unlock(dev);
+
+ return rc;
+}
+static DEVICE_ATTR_RO(align);
+
+static struct attribute *dax_region_attributes[] = {
+ &dev_attr_region_size.attr,
+ &dev_attr_align.attr,
+ &dev_attr_id.attr,
+ NULL,
+};
+
+static const struct attribute_group dax_region_attribute_group = {
+ .name = "dax_region",
+ .attrs = dax_region_attributes,
+};
+
+static const struct attribute_group *dax_region_attribute_groups[] = {
+ &dax_region_attribute_group,
+ NULL,
+};
+
static struct inode *dax_alloc_inode(struct super_block *sb)
{
return kmem_cache_alloc(dax_cache, GFP_KERNEL);
@@ -200,12 +267,31 @@ void dax_region_put(struct dax_region *dax_region)
}
EXPORT_SYMBOL_GPL(dax_region_put);
+static void dax_region_unregister(void *region)
+{
+ struct dax_region *dax_region = region;
+
+ sysfs_remove_groups(&dax_region->dev->kobj,
+ dax_region_attribute_groups);
+ dax_region_put(dax_region);
+}
+
struct dax_region *alloc_dax_region(struct device *parent, int region_id,
struct resource *res, unsigned int align, void *addr,
unsigned long pfn_flags)
{
struct dax_region *dax_region;
+ /*
+ * The DAX core assumes that it can store its private data in
+ * parent->driver_data. This WARN is a reminder / safeguard for
+ * developers of device-dax drivers.
+ */
+ if (dev_get_drvdata(parent)) {
+ dev_WARN(parent, "dax core failed to setup private data\n");
+ return NULL;
+ }
+
if (!IS_ALIGNED(res->start, align)
|| !IS_ALIGNED(resource_size(res), align))
return NULL;
@@ -214,6 +300,7 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
if (!dax_region)
return NULL;
+ dev_set_drvdata(parent, dax_region);
memcpy(&dax_region->res, res, sizeof(*res));
dax_region->pfn_flags = pfn_flags;
kref_init(&dax_region->kref);
@@ -222,7 +309,14 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
dax_region->align = align;
dax_region->dev = parent;
dax_region->base = addr;
+ if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
+ kfree(dax_region);
+ return NULL;;
+ }
+ kref_get(&dax_region->kref);
+ if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
+ return NULL;
return dax_region;
}
EXPORT_SYMBOL_GPL(alloc_dax_region);
