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authorDan Williams <[email protected]>2023-02-10 01:05:45 -0800
committerDan Williams <[email protected]>2023-02-10 17:32:01 -0800
commita8e7d558f7e9c2921de8b487baa01d23f068aa93 (patch)
tree2985b1bdc4b95f5fb0bc61c289deb4c41ba4d286
parent7d505f982f53189da819581ad4cc13c8cef76803 (diff)
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: Vishal Verma <[email protected]> Tested-by: Fan Ni <[email protected]> Reviewed-by: Ira Weiny <[email protected]> Reviewed-by: Jonathan Cameron <[email protected]> Link: https://lore.kernel.org/r/167601994558.1924368.12612811533724694444.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <[email protected]>
-rw-r--r--Documentation/ABI/testing/sysfs-bus-cxl3
-rw-r--r--drivers/cxl/core/region.c11
2 files changed, 11 insertions, 3 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl
index 058b0c45001f..4c4e1cbb1169 100644
--- a/Documentation/ABI/testing/sysfs-bus-cxl
+++ b/Documentation/ABI/testing/sysfs-bus-cxl
@@ -317,7 +317,8 @@ Contact: [email protected]
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
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 17d2d0c12725..0fc80478ff6b 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -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;
}