[PATCH v4 0/4] cxl: Fix memdev qos_class sysfs attributes

[PATCH v4 0/4] cxl: Fix memdev qos_class sysfs attributes

[Dave Jiang]

v4:
- Fix resetting of dpa_perf (Wonjae)
- Change cxl_qos_match() to return bool. (Jonathan)
- Remove unnecessary void * casting. (Jonathan)
- Replace open code with sysfs_update_groups() helper. (Jonathan)

This series provides fixes to the memdev qos_class sysfs attributes. The
current code emits duplicate sysfs attribute under the same directory and
the ram qos_class clobbers the pmem qos_class. Move the attributes under
static definitions and allow the attributes to show up under ram and pmem
directory individually.

The series also adds cxl_test support in order to allow CXL CLI add a unit
test for qos_class attributes.

[PATCH v4 1/4] cxl: Change 'struct cxl_memdev_state' *_perf_list to single 'struct cxl_dpa_perf'

[Dave Jiang]

In order to address the issue with being able to expose qos_class sysfs
attributes under 'ram' and 'pmem' sub-directories, the attributes must
be defined as static attributes rather than under driver->dev_groups.
To avoid implementing locking for accessing the 'struct cxl_dpa_perf`
lists, convert the list to a single 'struct cxl_dpa_perf' entry in
preparation to move the attributes to statically defined.

While theoretically a partition may have multiple qos_class via CDAT, this
has not been encountered with testing on available hardware. The code is
simplified for now to not support the complex case until a use case is
needed to support that.

Link: https://lore.kernel.org/linux-cxl/65b200ba228f_2d43c29468@dwillia2-mobl3.amr.corp.intel.com.notmuch/
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
v4:
- Fix resetting of dpa_perf. (Wonjae)
- Change cxl_qos_match() to return bool. (Jonathan)
---
 drivers/cxl/core/cdat.c | 82 ++++++++++++-----------------------------
 drivers/cxl/core/mbox.c |  4 +-
 drivers/cxl/cxlmem.h    | 10 ++---
 drivers/cxl/mem.c       | 28 ++------------
 4 files changed, 34 insertions(+), 90 deletions(-)

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index 6fe11546889f..d66acc917dac 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -210,19 +210,12 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
 	return 0;
 }
 
-static void add_perf_entry(struct device *dev, struct dsmas_entry *dent,
-			   struct list_head *list)
+static void update_perf_entry(struct device *dev, struct dsmas_entry *dent,
+			      struct cxl_dpa_perf *dpa_perf)
 {
-	struct cxl_dpa_perf *dpa_perf;
-
-	dpa_perf = kzalloc(sizeof(*dpa_perf), GFP_KERNEL);
-	if (!dpa_perf)
-		return;
-
 	dpa_perf->dpa_range = dent->dpa_range;
 	dpa_perf->coord = dent->coord;
 	dpa_perf->qos_class = dent->qos_class;
-	list_add_tail(&dpa_perf->list, list);
 	dev_dbg(dev,
 		"DSMAS: dpa: %#llx qos: %d read_bw: %d write_bw %d read_lat: %d write_lat: %d\n",
 		dent->dpa_range.start, dpa_perf->qos_class,
@@ -230,20 +223,6 @@ static void add_perf_entry(struct device *dev, struct dsmas_entry *dent,
 		dent->coord.read_latency, dent->coord.write_latency);
 }
 
-static void free_perf_ents(void *data)
-{
-	struct cxl_memdev_state *mds = data;
-	struct cxl_dpa_perf *dpa_perf, *n;
-	LIST_HEAD(discard);
-
-	list_splice_tail_init(&mds->ram_perf_list, &discard);
-	list_splice_tail_init(&mds->pmem_perf_list, &discard);
-	list_for_each_entry_safe(dpa_perf, n, &discard, list) {
-		list_del(&dpa_perf->list);
-		kfree(dpa_perf);
-	}
-}
-
 static void cxl_memdev_set_qos_class(struct cxl_dev_state *cxlds,
 				     struct xarray *dsmas_xa)
 {
@@ -263,16 +242,14 @@ static void cxl_memdev_set_qos_class(struct cxl_dev_state *cxlds,
 	xa_for_each(dsmas_xa, index, dent) {
 		if (resource_size(&cxlds->ram_res) &&
 		    range_contains(&ram_range, &dent->dpa_range))
-			add_perf_entry(dev, dent, &mds->ram_perf_list);
+			update_perf_entry(dev, dent, &mds->ram_perf);
 		else if (resource_size(&cxlds->pmem_res) &&
 			 range_contains(&pmem_range, &dent->dpa_range))
-			add_perf_entry(dev, dent, &mds->pmem_perf_list);
+			update_perf_entry(dev, dent, &mds->pmem_perf);
 		else
 			dev_dbg(dev, "no partition for dsmas dpa: %#llx\n",
 				dent->dpa_range.start);
 	}
-
-	devm_add_action_or_reset(&cxlds->cxlmd->dev, free_perf_ents, mds);
 }
 
 static int match_cxlrd_qos_class(struct device *dev, void *data)
@@ -293,24 +270,24 @@ static int match_cxlrd_qos_class(struct device *dev, void *data)
 	return 0;
 }
 
-static void cxl_qos_match(struct cxl_port *root_port,
-			  struct list_head *work_list,
-			  struct list_head *discard_list)
+static void reset_dpa_perf(struct cxl_dpa_perf *dpa_perf)
 {
-	struct cxl_dpa_perf *dpa_perf, *n;
+	*dpa_perf = (struct cxl_dpa_perf) {
+		.qos_class = CXL_QOS_CLASS_INVALID,
+	};
+}
 
-	list_for_each_entry_safe(dpa_perf, n, work_list, list) {
-		int rc;
+static bool cxl_qos_match(struct cxl_port *root_port,
+			  struct cxl_dpa_perf *dpa_perf)
+{
+	if (dpa_perf->qos_class == CXL_QOS_CLASS_INVALID)
+		return false;
 
-		if (dpa_perf->qos_class == CXL_QOS_CLASS_INVALID)
-			return;
+	if (!device_for_each_child(&root_port->dev, &dpa_perf->qos_class,
+				   match_cxlrd_qos_class))
+		return false;
 
-		rc = device_for_each_child(&root_port->dev,
-					   (void *)&dpa_perf->qos_class,
-					   match_cxlrd_qos_class);
-		if (!rc)
-			list_move_tail(&dpa_perf->list, discard_list);
-	}
+	return true;
 }
 
 static int match_cxlrd_hb(struct device *dev, void *data)
@@ -334,23 +311,10 @@ static int match_cxlrd_hb(struct device *dev, void *data)
 	return 0;
 }
 
-static void discard_dpa_perf(struct list_head *list)
-{
-	struct cxl_dpa_perf *dpa_perf, *n;
-
-	list_for_each_entry_safe(dpa_perf, n, list, list) {
-		list_del(&dpa_perf->list);
-		kfree(dpa_perf);
-	}
-}
-DEFINE_FREE(dpa_perf, struct list_head *, if (!list_empty(_T)) discard_dpa_perf(_T))
-
 static int cxl_qos_class_verify(struct cxl_memdev *cxlmd)
 {
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-	LIST_HEAD(__discard);
-	struct list_head *discard __free(dpa_perf) = &__discard;
 	struct cxl_port *root_port;
 	int rc;
 
@@ -363,16 +327,18 @@ static int cxl_qos_class_verify(struct cxl_memdev *cxlmd)
 	root_port = &cxl_root->port;
 
 	/* Check that the QTG IDs are all sane between end device and root decoders */
-	cxl_qos_match(root_port, &mds->ram_perf_list, discard);
-	cxl_qos_match(root_port, &mds->pmem_perf_list, discard);
+	if (!cxl_qos_match(root_port, &mds->ram_perf))
+		reset_dpa_perf(&mds->ram_perf);
+	if (!cxl_qos_match(root_port, &mds->pmem_perf))
+		reset_dpa_perf(&mds->pmem_perf);
 
 	/* Check to make sure that the device's host bridge is under a root decoder */
 	rc = device_for_each_child(&root_port->dev,
 				   (void *)cxlmd->endpoint->host_bridge,
 				   match_cxlrd_hb);
 	if (!rc) {
-		list_splice_tail_init(&mds->ram_perf_list, discard);
-		list_splice_tail_init(&mds->pmem_perf_list, discard);
+		reset_dpa_perf(&mds->ram_perf);
+		reset_dpa_perf(&mds->pmem_perf);
 	}
 
 	return rc;
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 27166a411705..9adda4795eb7 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -1391,8 +1391,8 @@ struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev)
 	mds->cxlds.reg_map.host = dev;
 	mds->cxlds.reg_map.resource = CXL_RESOURCE_NONE;
 	mds->cxlds.type = CXL_DEVTYPE_CLASSMEM;
-	INIT_LIST_HEAD(&mds->ram_perf_list);
-	INIT_LIST_HEAD(&mds->pmem_perf_list);
+	mds->ram_perf.qos_class = CXL_QOS_CLASS_INVALID;
+	mds->pmem_perf.qos_class = CXL_QOS_CLASS_INVALID;
 
 	return mds;
 }
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 5303d6942b88..20fb3b35e89e 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -395,13 +395,11 @@ enum cxl_devtype {
 
 /**
  * struct cxl_dpa_perf - DPA performance property entry
- * @list - list entry
  * @dpa_range - range for DPA address
  * @coord - QoS performance data (i.e. latency, bandwidth)
  * @qos_class - QoS Class cookies
  */
 struct cxl_dpa_perf {
-	struct list_head list;
 	struct range dpa_range;
 	struct access_coordinate coord;
 	int qos_class;
@@ -471,8 +469,8 @@ struct cxl_dev_state {
  * @security: security driver state info
  * @fw: firmware upload / activation state
  * @mbox_send: @dev specific transport for transmitting mailbox commands
- * @ram_perf_list: performance data entries matched to RAM
- * @pmem_perf_list: performance data entries matched to PMEM
+ * @ram_perf: performance data entry matched to RAM partition
+ * @pmem_perf: performance data entry matched to PMEM partition
  *
  * See CXL 3.0 8.2.9.8.2 Capacity Configuration and Label Storage for
  * details on capacity parameters.
@@ -494,8 +492,8 @@ struct cxl_memdev_state {
 	u64 next_volatile_bytes;
 	u64 next_persistent_bytes;
 
-	struct list_head ram_perf_list;
-	struct list_head pmem_perf_list;
+	struct cxl_dpa_perf ram_perf;
+	struct cxl_dpa_perf pmem_perf;
 
 	struct cxl_event_state event;
 	struct cxl_poison_state poison;
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index c5c9d8e0d88d..547f5a145fc5 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -221,18 +221,8 @@ static ssize_t ram_qos_class_show(struct device *dev,
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-	struct cxl_dpa_perf *dpa_perf;
 
-	if (!dev->driver)
-		return -ENOENT;
-
-	if (list_empty(&mds->ram_perf_list))
-		return -ENOENT;
-
-	dpa_perf = list_first_entry(&mds->ram_perf_list, struct cxl_dpa_perf,
-				    list);
-
-	return sysfs_emit(buf, "%d\n", dpa_perf->qos_class);
+	return sysfs_emit(buf, "%d\n", mds->ram_perf.qos_class);
 }
 
 static struct device_attribute dev_attr_ram_qos_class =
@@ -244,18 +234,8 @@ static ssize_t pmem_qos_class_show(struct device *dev,
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-	struct cxl_dpa_perf *dpa_perf;
 
-	if (!dev->driver)
-		return -ENOENT;
-
-	if (list_empty(&mds->pmem_perf_list))
-		return -ENOENT;
-
-	dpa_perf = list_first_entry(&mds->pmem_perf_list, struct cxl_dpa_perf,
-				    list);
-
-	return sysfs_emit(buf, "%d\n", dpa_perf->qos_class);
+	return sysfs_emit(buf, "%d\n", mds->pmem_perf.qos_class);
 }
 
 static struct device_attribute dev_attr_pmem_qos_class =
@@ -273,11 +253,11 @@ static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
 			return 0;
 
 	if (a == &dev_attr_pmem_qos_class.attr)
-		if (list_empty(&mds->pmem_perf_list))
+		if (mds->pmem_perf.qos_class == CXL_QOS_CLASS_INVALID)
 			return 0;
 
 	if (a == &dev_attr_ram_qos_class.attr)
-		if (list_empty(&mds->ram_perf_list))
+		if (mds->ram_perf.qos_class == CXL_QOS_CLASS_INVALID)
 			return 0;
 
 	return a->mode;
-- 
2.43.0

[PATCH v4 2/4] cxl: Remove unnecessary type cast in cxl_qos_class_verify()

[Dave Jiang]

The passed in host bridge parameter for device_for_each_child() has
unnecessary void * type cast. Remove the type cast.

Suggested-by: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/cxl/core/cdat.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index d66acc917dac..ecbd209ca70a 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -334,8 +334,7 @@ static int cxl_qos_class_verify(struct cxl_memdev *cxlmd)
 
 	/* Check to make sure that the device's host bridge is under a root decoder */
 	rc = device_for_each_child(&root_port->dev,
-				   (void *)cxlmd->endpoint->host_bridge,
-				   match_cxlrd_hb);
+				   cxlmd->endpoint->host_bridge, match_cxlrd_hb);
 	if (!rc) {
 		reset_dpa_perf(&mds->ram_perf);
 		reset_dpa_perf(&mds->pmem_perf);
-- 
2.43.0

[PATCH v4 3/4] cxl: Fix sysfs export of qos_class for memdev

[Dave Jiang]

Current implementation exports only to
/sys/bus/cxl/devices/.../memN/qos_class. With both ram and pmem exposed,
the second registered sysfs attribute is rejected as duplicate. It's not
possible to create qos_class under the dev_groups via the driver due to
the ram and pmem sysfs sub-directories already created by the device sysfs
groups. Move the ram and pmem qos_class to the device sysfs groups and add
a call to sysfs_update() after the perf data are validated so the
qos_class can be visible. The end results should be
/sys/bus/cxl/devices/.../memN/ram/qos_class and
/sys/bus/cxl/devices/.../memN/pmem/qos_class.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
v4:
- Replace open code with sysfs_update_groups() helper. (Jonathan)
---
 drivers/cxl/core/cdat.c   |  1 +
 drivers/cxl/core/memdev.c | 66 +++++++++++++++++++++++++++++++++++++++
 drivers/cxl/cxl.h         |  2 ++
 drivers/cxl/mem.c         | 36 ---------------------
 4 files changed, 69 insertions(+), 36 deletions(-)

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index ecbd209ca70a..f5bebc7e7ccf 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -382,6 +382,7 @@ void cxl_endpoint_parse_cdat(struct cxl_port *port)
 
 	cxl_memdev_set_qos_class(cxlds, dsmas_xa);
 	cxl_qos_class_verify(cxlmd);
+	cxl_memdev_update_attribute_groups(cxlmd);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_endpoint_parse_cdat, CXL);
 
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index dae8802ecdb0..c81f2cd4bcc6 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -447,13 +447,41 @@ static struct attribute *cxl_memdev_attributes[] = {
 	NULL,
 };
 
+static ssize_t pmem_qos_class_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
+
+	return sysfs_emit(buf, "%d\n", mds->pmem_perf.qos_class);
+}
+
+static struct device_attribute dev_attr_pmem_qos_class =
+	__ATTR(qos_class, 0444, pmem_qos_class_show, NULL);
+
 static struct attribute *cxl_memdev_pmem_attributes[] = {
 	&dev_attr_pmem_size.attr,
+	&dev_attr_pmem_qos_class.attr,
 	NULL,
 };
 
+static ssize_t ram_qos_class_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
+
+	return sysfs_emit(buf, "%d\n", mds->ram_perf.qos_class);
+}
+
+static struct device_attribute dev_attr_ram_qos_class =
+	__ATTR(qos_class, 0444, ram_qos_class_show, NULL);
+
 static struct attribute *cxl_memdev_ram_attributes[] = {
 	&dev_attr_ram_size.attr,
+	&dev_attr_ram_qos_class.attr,
 	NULL,
 };
 
@@ -477,14 +505,42 @@ static struct attribute_group cxl_memdev_attribute_group = {
 	.is_visible = cxl_memdev_visible,
 };
 
+static umode_t cxl_ram_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
+
+	if (a == &dev_attr_ram_qos_class.attr)
+		if (mds->ram_perf.qos_class == CXL_QOS_CLASS_INVALID)
+			return 0;
+
+	return a->mode;
+}
+
 static struct attribute_group cxl_memdev_ram_attribute_group = {
 	.name = "ram",
 	.attrs = cxl_memdev_ram_attributes,
+	.is_visible = cxl_ram_visible,
 };
 
+static umode_t cxl_pmem_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
+
+	if (a == &dev_attr_pmem_qos_class.attr)
+		if (mds->pmem_perf.qos_class == CXL_QOS_CLASS_INVALID)
+			return 0;
+
+	return a->mode;
+}
+
 static struct attribute_group cxl_memdev_pmem_attribute_group = {
 	.name = "pmem",
 	.attrs = cxl_memdev_pmem_attributes,
+	.is_visible = cxl_pmem_visible,
 };
 
 static umode_t cxl_memdev_security_visible(struct kobject *kobj,
@@ -519,6 +575,16 @@ static const struct attribute_group *cxl_memdev_attribute_groups[] = {
 	NULL,
 };
 
+void cxl_memdev_update_attribute_groups(struct cxl_memdev *cxlmd)
+{
+	int rc;
+
+	rc = sysfs_update_groups(&cxlmd->dev.kobj, cxl_memdev_attribute_groups);
+	if (rc)
+		dev_dbg(&cxlmd->dev, "Unable to update memdev attribute group.\n");
+}
+EXPORT_SYMBOL_NS_GPL(cxl_memdev_update_attribute_groups, CXL);
+
 static const struct device_type cxl_memdev_type = {
 	.name = "cxl_memdev",
 	.release = cxl_memdev_release,
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index b6017c0c57b4..1f630b30d845 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -880,6 +880,8 @@ void cxl_switch_parse_cdat(struct cxl_port *port);
 int cxl_endpoint_get_perf_coordinates(struct cxl_port *port,
 				      struct access_coordinate *coord);
 
+void cxl_memdev_update_attribute_groups(struct cxl_memdev *cxlmd);
+
 /*
  * Unit test builds overrides this to __weak, find the 'strong' version
  * of these symbols in tools/testing/cxl/.
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 547f5a145fc5..0c79d9ce877c 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -215,32 +215,6 @@ static ssize_t trigger_poison_list_store(struct device *dev,
 }
 static DEVICE_ATTR_WO(trigger_poison_list);
 
-static ssize_t ram_qos_class_show(struct device *dev,
-				  struct device_attribute *attr, char *buf)
-{
-	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_dev_state *cxlds = cxlmd->cxlds;
-	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-
-	return sysfs_emit(buf, "%d\n", mds->ram_perf.qos_class);
-}
-
-static struct device_attribute dev_attr_ram_qos_class =
-	__ATTR(qos_class, 0444, ram_qos_class_show, NULL);
-
-static ssize_t pmem_qos_class_show(struct device *dev,
-				   struct device_attribute *attr, char *buf)
-{
-	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_dev_state *cxlds = cxlmd->cxlds;
-	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-
-	return sysfs_emit(buf, "%d\n", mds->pmem_perf.qos_class);
-}
-
-static struct device_attribute dev_attr_pmem_qos_class =
-	__ATTR(qos_class, 0444, pmem_qos_class_show, NULL);
-
 static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
 {
 	struct device *dev = kobj_to_dev(kobj);
@@ -252,21 +226,11 @@ static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
 			      mds->poison.enabled_cmds))
 			return 0;
 
-	if (a == &dev_attr_pmem_qos_class.attr)
-		if (mds->pmem_perf.qos_class == CXL_QOS_CLASS_INVALID)
-			return 0;
-
-	if (a == &dev_attr_ram_qos_class.attr)
-		if (mds->ram_perf.qos_class == CXL_QOS_CLASS_INVALID)
-			return 0;
-
 	return a->mode;
 }
 
 static struct attribute *cxl_mem_attrs[] = {
 	&dev_attr_trigger_poison_list.attr,
-	&dev_attr_ram_qos_class.attr,
-	&dev_attr_pmem_qos_class.attr,
 	NULL
 };
 
-- 
2.43.0

[PATCH v4 4/4] cxl/test: Add support for qos_class checking

[Dave Jiang]

Set a fake qos_class to a unique value in order to do simple testing of
qos_class for root decoders and mem devs via user cxl_test. A mock
function is added to set the fake qos_class values for memory device
and overrides cxl_endpoint_parse_cdat() in cxl driver code.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 tools/testing/cxl/Kbuild      |  1 +
 tools/testing/cxl/test/cxl.c  | 63 ++++++++++++++++++++++++++++++-----
 tools/testing/cxl/test/mock.c | 14 ++++++++
 tools/testing/cxl/test/mock.h |  1 +
 4 files changed, 70 insertions(+), 9 deletions(-)

diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
index caff3834671f..030b388800f0 100644
--- a/tools/testing/cxl/Kbuild
+++ b/tools/testing/cxl/Kbuild
@@ -13,6 +13,7 @@ ldflags-y += --wrap=cxl_hdm_decode_init
 ldflags-y += --wrap=cxl_dvsec_rr_decode
 ldflags-y += --wrap=devm_cxl_add_rch_dport
 ldflags-y += --wrap=cxl_rcd_component_reg_phys
+ldflags-y += --wrap=cxl_endpoint_parse_cdat
 
 DRIVERS := ../../../drivers
 CXL_SRC := $(DRIVERS)/cxl
diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index a3cdbb2be038..59dc28bfcb5e 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -15,6 +15,8 @@
 
 static int interleave_arithmetic;
 
+#define FAKE_QTG_ID	42
+
 #define NR_CXL_HOST_BRIDGES 2
 #define NR_CXL_SINGLE_HOST 1
 #define NR_CXL_RCH 1
@@ -209,7 +211,7 @@ static struct {
 			.granularity = 4,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_VOLATILE,
-			.qtg_id = 0,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M * 4UL,
 		},
 		.target = { 0 },
@@ -224,7 +226,7 @@ static struct {
 			.granularity = 4,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_VOLATILE,
-			.qtg_id = 1,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M * 8UL,
 		},
 		.target = { 0, 1, },
@@ -239,7 +241,7 @@ static struct {
 			.granularity = 4,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_PMEM,
-			.qtg_id = 2,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M * 4UL,
 		},
 		.target = { 0 },
@@ -254,7 +256,7 @@ static struct {
 			.granularity = 4,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_PMEM,
-			.qtg_id = 3,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M * 8UL,
 		},
 		.target = { 0, 1, },
@@ -269,7 +271,7 @@ static struct {
 			.granularity = 4,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_PMEM,
-			.qtg_id = 4,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M * 4UL,
 		},
 		.target = { 2 },
@@ -284,7 +286,7 @@ static struct {
 			.granularity = 4,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_VOLATILE,
-			.qtg_id = 5,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M,
 		},
 		.target = { 3 },
@@ -301,7 +303,7 @@ static struct {
 			.granularity = 4,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_PMEM,
-			.qtg_id = 0,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M * 8UL,
 		},
 		.target = { 0, },
@@ -317,7 +319,7 @@ static struct {
 			.granularity = 0,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_PMEM,
-			.qtg_id = 1,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M * 8UL,
 		},
 		.target = { 0, 1, },
@@ -333,7 +335,7 @@ static struct {
 			.granularity = 0,
 			.restrictions = ACPI_CEDT_CFMWS_RESTRICT_TYPE3 |
 					ACPI_CEDT_CFMWS_RESTRICT_PMEM,
-			.qtg_id = 0,
+			.qtg_id = FAKE_QTG_ID,
 			.window_size = SZ_256M * 16UL,
 		},
 		.target = { 0, 1, 0, 1, },
@@ -976,6 +978,48 @@ static int mock_cxl_port_enumerate_dports(struct cxl_port *port)
 	return 0;
 }
 
+/*
+ * Faking the cxl_dpa_perf for the memdev when appropriate.
+ */
+static void dpa_perf_setup(struct cxl_port *endpoint, struct range *range,
+			   struct cxl_dpa_perf *dpa_perf)
+{
+	dpa_perf->qos_class = FAKE_QTG_ID;
+	dpa_perf->dpa_range = *range;
+	dpa_perf->coord.read_latency = 500;
+	dpa_perf->coord.write_latency = 500;
+	dpa_perf->coord.read_bandwidth = 1000;
+	dpa_perf->coord.write_bandwidth = 1000;
+}
+
+static void mock_cxl_endpoint_parse_cdat(struct cxl_port *port)
+{
+	struct cxl_root *cxl_root __free(put_cxl_root) =
+		find_cxl_root(port);
+	struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
+	struct range pmem_range = {
+		.start = cxlds->pmem_res.start,
+		.end = cxlds->pmem_res.end,
+	};
+	struct range ram_range = {
+		.start = cxlds->ram_res.start,
+		.end = cxlds->ram_res.end,
+	};
+
+	if (!cxl_root)
+		return;
+
+	if (range_len(&ram_range))
+		dpa_perf_setup(port, &ram_range, &mds->ram_perf);
+
+	if (range_len(&pmem_range))
+		dpa_perf_setup(port, &pmem_range, &mds->pmem_perf);
+
+	cxl_memdev_update_attribute_groups(cxlmd);
+}
+
 static struct cxl_mock_ops cxl_mock_ops = {
 	.is_mock_adev = is_mock_adev,
 	.is_mock_bridge = is_mock_bridge,
@@ -989,6 +1033,7 @@ static struct cxl_mock_ops cxl_mock_ops = {
 	.devm_cxl_setup_hdm = mock_cxl_setup_hdm,
 	.devm_cxl_add_passthrough_decoder = mock_cxl_add_passthrough_decoder,
 	.devm_cxl_enumerate_decoders = mock_cxl_enumerate_decoders,
+	.cxl_endpoint_parse_cdat = mock_cxl_endpoint_parse_cdat,
 	.list = LIST_HEAD_INIT(cxl_mock_ops.list),
 };
 
diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
index 1a61e68e3095..6f737941dc0e 100644
--- a/tools/testing/cxl/test/mock.c
+++ b/tools/testing/cxl/test/mock.c
@@ -285,6 +285,20 @@ resource_size_t __wrap_cxl_rcd_component_reg_phys(struct device *dev,
 }
 EXPORT_SYMBOL_NS_GPL(__wrap_cxl_rcd_component_reg_phys, CXL);
 
+void __wrap_cxl_endpoint_parse_cdat(struct cxl_port *port)
+{
+	int index;
+	struct cxl_mock_ops *ops = get_cxl_mock_ops(&index);
+	struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev);
+
+	if (ops && ops->is_mock_dev(cxlmd->dev.parent))
+		ops->cxl_endpoint_parse_cdat(port);
+	else
+		cxl_endpoint_parse_cdat(port);
+	put_cxl_mock_ops(index);
+}
+EXPORT_SYMBOL_NS_GPL(__wrap_cxl_endpoint_parse_cdat, CXL);
+
 MODULE_LICENSE("GPL v2");
 MODULE_IMPORT_NS(ACPI);
 MODULE_IMPORT_NS(CXL);
diff --git a/tools/testing/cxl/test/mock.h b/tools/testing/cxl/test/mock.h
index a94223750346..d1b0271d2822 100644
--- a/tools/testing/cxl/test/mock.h
+++ b/tools/testing/cxl/test/mock.h
@@ -25,6 +25,7 @@ struct cxl_mock_ops {
 	int (*devm_cxl_add_passthrough_decoder)(struct cxl_port *port);
 	int (*devm_cxl_enumerate_decoders)(
 		struct cxl_hdm *hdm, struct cxl_endpoint_dvsec_info *info);
+	void (*cxl_endpoint_parse_cdat)(struct cxl_port *port);
 };
 
 void register_cxl_mock_ops(struct cxl_mock_ops *ops);
-- 
2.43.0

RE: [PATCH v4 3/4] cxl: Fix sysfs export of qos_class for memdev

[Dan Williams]

Dave Jiang wrote:
> Current implementation exports only to
> /sys/bus/cxl/devices/.../memN/qos_class. With both ram and pmem exposed,
> the second registered sysfs attribute is rejected as duplicate. It's not
> possible to create qos_class under the dev_groups via the driver due to
> the ram and pmem sysfs sub-directories already created by the device sysfs
> groups. Move the ram and pmem qos_class to the device sysfs groups and add
> a call to sysfs_update() after the perf data are validated so the
> qos_class can be visible. The end results should be
> /sys/bus/cxl/devices/.../memN/ram/qos_class and
> /sys/bus/cxl/devices/.../memN/pmem/qos_class.
> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
> v4:
> - Replace open code with sysfs_update_groups() helper. (Jonathan)
> ---
>  drivers/cxl/core/cdat.c   |  1 +
>  drivers/cxl/core/memdev.c | 66 +++++++++++++++++++++++++++++++++++++++
>  drivers/cxl/cxl.h         |  2 ++
>  drivers/cxl/mem.c         | 36 ---------------------
>  4 files changed, 69 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
> index ecbd209ca70a..f5bebc7e7ccf 100644
> --- a/drivers/cxl/core/cdat.c
> +++ b/drivers/cxl/core/cdat.c
> @@ -382,6 +382,7 @@ void cxl_endpoint_parse_cdat(struct cxl_port *port)
>  
>  	cxl_memdev_set_qos_class(cxlds, dsmas_xa);
>  	cxl_qos_class_verify(cxlmd);
> +	cxl_memdev_update_attribute_groups(cxlmd);
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_endpoint_parse_cdat, CXL);
>  
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index dae8802ecdb0..c81f2cd4bcc6 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -447,13 +447,41 @@ static struct attribute *cxl_memdev_attributes[] = {
>  	NULL,
>  };
>  
> +static ssize_t pmem_qos_class_show(struct device *dev,
> +				   struct device_attribute *attr, char *buf)
> +{
> +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> +	struct cxl_dev_state *cxlds = cxlmd->cxlds;
> +	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
> +
> +	return sysfs_emit(buf, "%d\n", mds->pmem_perf.qos_class);
> +}
> +
> +static struct device_attribute dev_attr_pmem_qos_class =
> +	__ATTR(qos_class, 0444, pmem_qos_class_show, NULL);
> +
>  static struct attribute *cxl_memdev_pmem_attributes[] = {
>  	&dev_attr_pmem_size.attr,
> +	&dev_attr_pmem_qos_class.attr,
>  	NULL,
>  };
>  
> +static ssize_t ram_qos_class_show(struct device *dev,
> +				  struct device_attribute *attr, char *buf)
> +{
> +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> +	struct cxl_dev_state *cxlds = cxlmd->cxlds;
> +	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
> +
> +	return sysfs_emit(buf, "%d\n", mds->ram_perf.qos_class);
> +}
> +
> +static struct device_attribute dev_attr_ram_qos_class =
> +	__ATTR(qos_class, 0444, ram_qos_class_show, NULL);
> +
>  static struct attribute *cxl_memdev_ram_attributes[] = {
>  	&dev_attr_ram_size.attr,
> +	&dev_attr_ram_qos_class.attr,
>  	NULL,
>  };
>  
> @@ -477,14 +505,42 @@ static struct attribute_group cxl_memdev_attribute_group = {
>  	.is_visible = cxl_memdev_visible,
>  };
>  
> +static umode_t cxl_ram_visible(struct kobject *kobj, struct attribute *a, int n)
> +{
> +	struct device *dev = kobj_to_dev(kobj);
> +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> +	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
> +
> +	if (a == &dev_attr_ram_qos_class.attr)
> +		if (mds->ram_perf.qos_class == CXL_QOS_CLASS_INVALID)
> +			return 0;
> +
> +	return a->mode;
> +}
> +
>  static struct attribute_group cxl_memdev_ram_attribute_group = {
>  	.name = "ram",
>  	.attrs = cxl_memdev_ram_attributes,
> +	.is_visible = cxl_ram_visible,
>  };
>  
> +static umode_t cxl_pmem_visible(struct kobject *kobj, struct attribute *a, int n)
> +{
> +	struct device *dev = kobj_to_dev(kobj);
> +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> +	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
> +
> +	if (a == &dev_attr_pmem_qos_class.attr)
> +		if (mds->pmem_perf.qos_class == CXL_QOS_CLASS_INVALID)
> +			return 0;
> +
> +	return a->mode;
> +}
> +
>  static struct attribute_group cxl_memdev_pmem_attribute_group = {
>  	.name = "pmem",
>  	.attrs = cxl_memdev_pmem_attributes,
> +	.is_visible = cxl_pmem_visible,
>  };
>  
>  static umode_t cxl_memdev_security_visible(struct kobject *kobj,
> @@ -519,6 +575,16 @@ static const struct attribute_group *cxl_memdev_attribute_groups[] = {
>  	NULL,
>  };
>  
> +void cxl_memdev_update_attribute_groups(struct cxl_memdev *cxlmd)
> +{
> +	int rc;
> +
> +	rc = sysfs_update_groups(&cxlmd->dev.kobj, cxl_memdev_attribute_groups);
> +	if (rc)
> +		dev_dbg(&cxlmd->dev, "Unable to update memdev attribute group.\n");
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_memdev_update_attribute_groups, CXL);

So I appreciate that Jonathan pointed out this helper as a replacement
for the hand coded loop over all the attribute groups, but I don't
understand why all the groups need to be revisited when the groups to
update are known? It is also a red-flag to handle the result of a
__must_check helper with a silent dev_dbg() statement.

Given this qos-class support is optional, sysfs_update_groups(), with
its violent "tear it all down on failure" semantic, is too heavyweight.
The failure can not really be handled from the endpoint port code
because the side-effect tears down all groups even the ones registered
before the endpoint port driver loads.

Instead, just do something like this:

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index c81f2cd4bcc6..d4e259f3a7e9 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -575,15 +575,12 @@ static const struct attribute_group *cxl_memdev_attribute_groups[] = {
        NULL,
 };
 
-void cxl_memdev_update_attribute_groups(struct cxl_memdev *cxlmd)
+void cxl_memdev_update_perf(struct cxl_memdev *cxlmd)
 {
-       int rc;
-
-       rc = sysfs_update_groups(&cxlmd->dev.kobj, cxl_memdev_attribute_groups);
-       if (rc)
-               dev_dbg(&cxlmd->dev, "Unable to update memdev attribute group.\n");
+       sysfs_update_group(&cxlmd->dev.kobj, &cxl_memdev_ram_attribute_group);
+       sysfs_update_group(&cxlmd->dev.kobj, &cxl_memdev_pmem_attribute_group);
 }
-EXPORT_SYMBOL_NS_GPL(cxl_memdev_update_attribute_groups, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_memdev_update_perf, CXL);
 
 static const struct device_type cxl_memdev_type = {
        .name = "cxl_memdev",

...where failures are truly ignored.

Re: [PATCH v4 3/4] cxl: Fix sysfs export of qos_class for memdev

[Dave Jiang]

On 2/5/24 1:38 PM, Dan Williams wrote:
> Dave Jiang wrote:
>> Current implementation exports only to
>> /sys/bus/cxl/devices/.../memN/qos_class. With both ram and pmem exposed,
>> the second registered sysfs attribute is rejected as duplicate. It's not
>> possible to create qos_class under the dev_groups via the driver due to
>> the ram and pmem sysfs sub-directories already created by the device sysfs
>> groups. Move the ram and pmem qos_class to the device sysfs groups and add
>> a call to sysfs_update() after the perf data are validated so the
>> qos_class can be visible. The end results should be
>> /sys/bus/cxl/devices/.../memN/ram/qos_class and
>> /sys/bus/cxl/devices/.../memN/pmem/qos_class.
>>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>> v4:
>> - Replace open code with sysfs_update_groups() helper. (Jonathan)
>> ---
>>  drivers/cxl/core/cdat.c   |  1 +
>>  drivers/cxl/core/memdev.c | 66 +++++++++++++++++++++++++++++++++++++++
>>  drivers/cxl/cxl.h         |  2 ++
>>  drivers/cxl/mem.c         | 36 ---------------------
>>  4 files changed, 69 insertions(+), 36 deletions(-)
>>
>> diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
>> index ecbd209ca70a..f5bebc7e7ccf 100644
>> --- a/drivers/cxl/core/cdat.c
>> +++ b/drivers/cxl/core/cdat.c
>> @@ -382,6 +382,7 @@ void cxl_endpoint_parse_cdat(struct cxl_port *port)
>>  
>>  	cxl_memdev_set_qos_class(cxlds, dsmas_xa);
>>  	cxl_qos_class_verify(cxlmd);
>> +	cxl_memdev_update_attribute_groups(cxlmd);
>>  }
>>  EXPORT_SYMBOL_NS_GPL(cxl_endpoint_parse_cdat, CXL);
>>  
>> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
>> index dae8802ecdb0..c81f2cd4bcc6 100644
>> --- a/drivers/cxl/core/memdev.c
>> +++ b/drivers/cxl/core/memdev.c
>> @@ -447,13 +447,41 @@ static struct attribute *cxl_memdev_attributes[] = {
>>  	NULL,
>>  };
>>  
>> +static ssize_t pmem_qos_class_show(struct device *dev,
>> +				   struct device_attribute *attr, char *buf)
>> +{
>> +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>> +	struct cxl_dev_state *cxlds = cxlmd->cxlds;
>> +	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>> +
>> +	return sysfs_emit(buf, "%d\n", mds->pmem_perf.qos_class);
>> +}
>> +
>> +static struct device_attribute dev_attr_pmem_qos_class =
>> +	__ATTR(qos_class, 0444, pmem_qos_class_show, NULL);
>> +
>>  static struct attribute *cxl_memdev_pmem_attributes[] = {
>>  	&dev_attr_pmem_size.attr,
>> +	&dev_attr_pmem_qos_class.attr,
>>  	NULL,
>>  };
>>  
>> +static ssize_t ram_qos_class_show(struct device *dev,
>> +				  struct device_attribute *attr, char *buf)
>> +{
>> +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>> +	struct cxl_dev_state *cxlds = cxlmd->cxlds;
>> +	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>> +
>> +	return sysfs_emit(buf, "%d\n", mds->ram_perf.qos_class);
>> +}
>> +
>> +static struct device_attribute dev_attr_ram_qos_class =
>> +	__ATTR(qos_class, 0444, ram_qos_class_show, NULL);
>> +
>>  static struct attribute *cxl_memdev_ram_attributes[] = {
>>  	&dev_attr_ram_size.attr,
>> +	&dev_attr_ram_qos_class.attr,
>>  	NULL,
>>  };
>>  
>> @@ -477,14 +505,42 @@ static struct attribute_group cxl_memdev_attribute_group = {
>>  	.is_visible = cxl_memdev_visible,
>>  };
>>  
>> +static umode_t cxl_ram_visible(struct kobject *kobj, struct attribute *a, int n)
>> +{
>> +	struct device *dev = kobj_to_dev(kobj);
>> +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>> +	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>> +
>> +	if (a == &dev_attr_ram_qos_class.attr)
>> +		if (mds->ram_perf.qos_class == CXL_QOS_CLASS_INVALID)
>> +			return 0;
>> +
>> +	return a->mode;
>> +}
>> +
>>  static struct attribute_group cxl_memdev_ram_attribute_group = {
>>  	.name = "ram",
>>  	.attrs = cxl_memdev_ram_attributes,
>> +	.is_visible = cxl_ram_visible,
>>  };
>>  
>> +static umode_t cxl_pmem_visible(struct kobject *kobj, struct attribute *a, int n)
>> +{
>> +	struct device *dev = kobj_to_dev(kobj);
>> +	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>> +	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>> +
>> +	if (a == &dev_attr_pmem_qos_class.attr)
>> +		if (mds->pmem_perf.qos_class == CXL_QOS_CLASS_INVALID)
>> +			return 0;
>> +
>> +	return a->mode;
>> +}
>> +
>>  static struct attribute_group cxl_memdev_pmem_attribute_group = {
>>  	.name = "pmem",
>>  	.attrs = cxl_memdev_pmem_attributes,
>> +	.is_visible = cxl_pmem_visible,
>>  };
>>  
>>  static umode_t cxl_memdev_security_visible(struct kobject *kobj,
>> @@ -519,6 +575,16 @@ static const struct attribute_group *cxl_memdev_attribute_groups[] = {
>>  	NULL,
>>  };
>>  
>> +void cxl_memdev_update_attribute_groups(struct cxl_memdev *cxlmd)
>> +{
>> +	int rc;
>> +
>> +	rc = sysfs_update_groups(&cxlmd->dev.kobj, cxl_memdev_attribute_groups);
>> +	if (rc)
>> +		dev_dbg(&cxlmd->dev, "Unable to update memdev attribute group.\n");
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_memdev_update_attribute_groups, CXL);
> 
> So I appreciate that Jonathan pointed out this helper as a replacement
> for the hand coded loop over all the attribute groups, but I don't
> understand why all the groups need to be revisited when the groups to
> update are known? It is also a red-flag to handle the result of a
> __must_check helper with a silent dev_dbg() statement.

For some reason I had it stuck in my head that you wanted a caller that updated all the groups.

> 
> Given this qos-class support is optional, sysfs_update_groups(), with
> its violent "tear it all down on failure" semantic, is too heavyweight.
> The failure can not really be handled from the endpoint port code
> because the side-effect tears down all groups even the ones registered
> before the endpoint port driver loads.
> 
> Instead, just do something like this:
> 
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index c81f2cd4bcc6..d4e259f3a7e9 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -575,15 +575,12 @@ static const struct attribute_group *cxl_memdev_attribute_groups[] = {
>         NULL,
>  };
>  
> -void cxl_memdev_update_attribute_groups(struct cxl_memdev *cxlmd)
> +void cxl_memdev_update_perf(struct cxl_memdev *cxlmd)
>  {
> -       int rc;
> -
> -       rc = sysfs_update_groups(&cxlmd->dev.kobj, cxl_memdev_attribute_groups);
> -       if (rc)
> -               dev_dbg(&cxlmd->dev, "Unable to update memdev attribute group.\n");
> +       sysfs_update_group(&cxlmd->dev.kobj, &cxl_memdev_ram_attribute_group);
> +       sysfs_update_group(&cxlmd->dev.kobj, &cxl_memdev_pmem_attribute_group);
>  }
> -EXPORT_SYMBOL_NS_GPL(cxl_memdev_update_attribute_groups, CXL);
> +EXPORT_SYMBOL_NS_GPL(cxl_memdev_update_perf, CXL);
>  
>  static const struct device_type cxl_memdev_type = {
>         .name = "cxl_memdev",
> 
> ...where failures are truly ignored.

Re: [PATCH v4 1/4] cxl: Change 'struct cxl_memdev_state' *_perf_list to single 'struct cxl_dpa_perf'

[Jonathan Cameron]

> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 5303d6942b88..20fb3b35e89e 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -395,13 +395,11 @@ enum cxl_devtype {
>  
>  /**
>   * struct cxl_dpa_perf - DPA performance property entry
> - * @list - list entry
>   * @dpa_range - range for DPA address
>   * @coord - QoS performance data (i.e. latency, bandwidth)
>   * @qos_class - QoS Class cookies
>   */
>  struct cxl_dpa_perf {
> -	struct list_head list;
>  	struct range dpa_range;
>  	struct access_coordinate coord;
>  	int qos_class;
> @@ -471,8 +469,8 @@ struct cxl_dev_state {
>   * @security: security driver state info
>   * @fw: firmware upload / activation state
>   * @mbox_send: @dev specific transport for transmitting mailbox commands
> - * @ram_perf_list: performance data entries matched to RAM
> - * @pmem_perf_list: performance data entries matched to PMEM
> + * @ram_perf: performance data entry matched to RAM partition
> + * @pmem_perf: performance data entry matched to PMEM partition

Just noticed in review of DCD but these are in wrong place in docs.
Intentional or accident?

>   *
>   * See CXL 3.0 8.2.9.8.2 Capacity Configuration and Label Storage for
>   * details on capacity parameters.
> @@ -494,8 +492,8 @@ struct cxl_memdev_state {
>  	u64 next_volatile_bytes;
>  	u64 next_persistent_bytes;
>  
> -	struct list_head ram_perf_list;
> -	struct list_head pmem_perf_list;
> +	struct cxl_dpa_perf ram_perf;
> +	struct cxl_dpa_perf pmem_perf;
>  
>  	struct cxl_event_state event;
>  	struct cxl_poison_state poison;

Re: [PATCH v4 1/4] cxl: Change 'struct cxl_memdev_state' *_perf_list to single 'struct cxl_dpa_perf'

[Dave Jiang]

On 3/25/24 10:10 AM, Jonathan Cameron wrote:
> 
>> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
>> index 5303d6942b88..20fb3b35e89e 100644
>> --- a/drivers/cxl/cxlmem.h
>> +++ b/drivers/cxl/cxlmem.h
>> @@ -395,13 +395,11 @@ enum cxl_devtype {
>>  
>>  /**
>>   * struct cxl_dpa_perf - DPA performance property entry
>> - * @list - list entry
>>   * @dpa_range - range for DPA address
>>   * @coord - QoS performance data (i.e. latency, bandwidth)
>>   * @qos_class - QoS Class cookies
>>   */
>>  struct cxl_dpa_perf {
>> -	struct list_head list;
>>  	struct range dpa_range;
>>  	struct access_coordinate coord;
>>  	int qos_class;
>> @@ -471,8 +469,8 @@ struct cxl_dev_state {
>>   * @security: security driver state info
>>   * @fw: firmware upload / activation state
>>   * @mbox_send: @dev specific transport for transmitting mailbox commands
>> - * @ram_perf_list: performance data entries matched to RAM
>> - * @pmem_perf_list: performance data entries matched to PMEM
>> + * @ram_perf: performance data entry matched to RAM partition
>> + * @pmem_perf: performance data entry matched to PMEM partition
> 
> Just noticed in review of DCD but these are in wrong place in docs.
> Intentional or accident?

Most likely accidental from moving code around.

> 
>>   *
>>   * See CXL 3.0 8.2.9.8.2 Capacity Configuration and Label Storage for
>>   * details on capacity parameters.
>> @@ -494,8 +492,8 @@ struct cxl_memdev_state {
>>  	u64 next_volatile_bytes;
>>  	u64 next_persistent_bytes;
>>  
>> -	struct list_head ram_perf_list;
>> -	struct list_head pmem_perf_list;
>> +	struct cxl_dpa_perf ram_perf;
>> +	struct cxl_dpa_perf pmem_perf;
>>  
>>  	struct cxl_event_state event;
>>  	struct cxl_poison_state poison;