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device-dax: Add a 'resource' attribute 

device-dax based devices were missing a 'resource' attribute to indicate
the physical address range contributed by the device in question. This
information is desirable to userspace tooling that may want to use the
dax device as system-ram, and wants to selectively hotplug and online
the memory blocks associated with a given device.

Without this, the tooling would have to parse /proc/iomem for the memory
ranges contributed by dax devices, which can be a workaround, but it is
far easier to provide this information in the sysfs hierarchy.

Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Vishal Verma 2019-06-20 18:40:38 -06:00 committed by Dan Williams
parent 9e0babf2c0
commit 40cdc60ac1
1 changed files with 19 additions and 0 deletions
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19
drivers/dax/bus.c
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@ -295,6 +295,22 @@ static ssize_t target_node_show(struct device *dev,
}
static DEVICE_ATTR_RO(target_node);
static unsigned long long dev_dax_resource(struct dev_dax *dev_dax)
{
struct dax_region *dax_region = dev_dax->region;
return dax_region->res.start;
}
static ssize_t resource_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
return sprintf(buf, "%#llx\n", dev_dax_resource(dev_dax));
}
static DEVICE_ATTR_RO(resource);
static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@ -313,6 +329,8 @@ static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n)
if (a == &dev_attr_target_node.attr && dev_dax_target_node(dev_dax) < 0)
return 0;
if (a == &dev_attr_resource.attr)
return 0400;
return a->mode;
}
@ -320,6 +338,7 @@ static struct attribute *dev_dax_attributes[] = {
&dev_attr_modalias.attr,
&dev_attr_size.attr,
&dev_attr_target_node.attr,
&dev_attr_resource.attr,
NULL,
};