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

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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: Vishal Verma <vishal.l.verma@intel.com>
Tested-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/167601994558.1924368.12612811533724694444.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2023-02-10 01:05:45 -08:00
parent 7d505f982f
commit a8e7d558f7
2 changed files with 11 additions and 3 deletions
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3
Documentation/ABI/testing/sysfs-bus-cxl
View File

@ -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

11
drivers/cxl/core/region.c
View File

@ -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;
@ -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;
}