Commit a8e7d558 authored by Dan Williams's avatar Dan Williams
Browse files

cxl/region: Support empty uuids for non-pmem regions 



Shipping versions of the cxl-cli utility expect all regions to have a
'uuid' attribute. In preparation for 'ram' regions, update the 'uuid'
attribute to return an empty string which satisfies the current
expectations of 'cxl list -R'. Otherwise, 'cxl list -R' fails in the
presence of regions with the 'uuid' attribute missing. Force the
attribute to be read-only as there is no facility or expectation for a
'ram' region to recall its uuid from one boot to the next.

Reviewed-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Tested-by: default avatarFan Ni <fan.ni@samsung.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/167601994558.1924368.12612811533724694444.stgit@dwillia2-xfh.jf.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 7d505f98

Documentation/ABI/testing/sysfs-bus-cxl

+2 −1
Original line number Diff line number Diff line
@@ -317,7 +317,8 @@ Contact: linux-cxl@vger.kernel.org 
Description:

		(RW) Write a unique identifier for the region. This field must

		be set for persistent regions and it must not conflict with the

		UUID of another region.

		UUID of another region. For volatile ram regions this

		attribute is a read-only empty string.





What:		/sys/bus/cxl/devices/regionZ/interleave_granularity

drivers/cxl/core/region.c

+9 −2
Original line number Diff line number Diff line
@@ -45,6 +45,9 @@ static ssize_t uuid_show(struct device *dev, struct device_attribute *attr, 
	rc = down_read_interruptible(&cxl_region_rwsem);

	if (rc)

		return rc;

	if (cxlr->mode != CXL_DECODER_PMEM)

		rc = sysfs_emit(buf, "\n");

	else

		rc = sysfs_emit(buf, "%pUb\n", &p->uuid);

	up_read(&cxl_region_rwsem);
@@ -300,8 +303,12 @@ static umode_t cxl_region_visible(struct kobject *kobj, struct attribute *a, 
	struct device *dev = kobj_to_dev(kobj);

	struct cxl_region *cxlr = to_cxl_region(dev);



	/*

	 * Support tooling that expects to find a 'uuid' attribute for all

	 * regions regardless of mode.

	 */

	if (a == &dev_attr_uuid.attr && cxlr->mode != CXL_DECODER_PMEM)

		return 0;

		return 0444;

	return a->mode;

}