@@ -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
@@ -45,7 +45,10 @@ static ssize_t uuid_show(struct device *dev, struct device_attribute *attr,
rc = down_read_interruptible(&cxl_region_rwsem);
if (rc)
return rc;
- rc = sysfs_emit(buf, "%pUb\n", &p->uuid);
+ 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);
return rc;
@@ -301,7 +304,7 @@ static umode_t cxl_region_visible(struct kobject *kobj, struct attribute *a,
struct cxl_region *cxlr = to_cxl_region(dev);
if (a == &dev_attr_uuid.attr && cxlr->mode != CXL_DECODER_PMEM)
- return 0;
+ return 0444;
return a->mode;
}
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. Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- Documentation/ABI/testing/sysfs-bus-cxl | 3 ++- drivers/cxl/core/region.c | 7 +++++-- 2 files changed, 7 insertions(+), 3 deletions(-)