Commit d7fe1a67 authored by Dan Williams's avatar Dan Williams
Browse files

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: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 868f036f

drivers/dax/dax.c

+94 −0
Original line number Diff line number Diff line
@@ -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);

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