[PATCH v5 0/3] pull region-specific logic into new files

[PATCH v5 0/3] pull region-specific logic into new files

[Gregory Price]

cxl/core/region.c presently contains logic to handle cxl_region,
cxl_pmem_region, and cxl_dax_region.  The cxl_pmem_region and
cxl_dax_region management code deserves new files to make it clear
that this logic applies to a specific types of regions.

This also breaks up development space so fewer conflicts can occur, and
it becomes clear where changes are actually happening.

I snuck in a cleanup.h fixup for devm_cxl_add_dax_region to tidy up some
of the existing functions.

v4 -> v5:  Ira test fixes
           Jonathan nit fixes

v3 -> v4:  address DJ's feedback on cleanup.h patch:
           move __free() declaration to assignment point
           restore local dev variable

v2 -> v3:  renamed from x_region to region_x because it's prettier
           added cleanup.h
           small nits asked for by Jonathan (commas)

Gregory Price (3):
  cxl/core/region: move pmem region driver logic into region_pmem.c
  cxl/core/region: move dax region device logic into region_dax.c
  cxl/core: use cleanup.h for devm_cxl_add_dax_region

 drivers/cxl/core/Makefile      |   2 +-
 drivers/cxl/core/core.h        |   2 +
 drivers/cxl/core/region.c      | 283 ---------------------------------
 drivers/cxl/core/region_dax.c  | 106 ++++++++++++
 drivers/cxl/core/region_pmem.c | 191 ++++++++++++++++++++++
 drivers/cxl/cxl.h              |   1 +
 tools/testing/cxl/Kbuild       |   2 +-
 7 files changed, 302 insertions(+), 285 deletions(-)
 create mode 100644 drivers/cxl/core/region_dax.c
 create mode 100644 drivers/cxl/core/region_pmem.c

-- 
2.53.0

[PATCH v5 1/3] cxl/core/region: move pmem region driver logic into region_pmem.c

[Gregory Price]

core/region.c is overloaded with per-region control logic (pmem, dax,
sysram, etc). Move the pmem region driver logic from region.c into
region_pmem.c make it clear that this code only applies to pmem regions.

No functional changes.

Signed-off-by: Gregory Price <gourry@gourry.net>
Co-developed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 drivers/cxl/core/Makefile      |   2 +-
 drivers/cxl/core/core.h        |   1 +
 drivers/cxl/core/region.c      | 184 -------------------------------
 drivers/cxl/core/region_pmem.c | 191 +++++++++++++++++++++++++++++++++
 tools/testing/cxl/Kbuild       |   2 +-
 5 files changed, 194 insertions(+), 186 deletions(-)
 create mode 100644 drivers/cxl/core/region_pmem.c

diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index a639a9499972..f73776fe323b 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -15,7 +15,7 @@ cxl_core-y += hdm.o
 cxl_core-y += pmu.o
 cxl_core-y += cdat.o
 cxl_core-$(CONFIG_TRACING) += trace.o
-cxl_core-$(CONFIG_CXL_REGION) += region.o
+cxl_core-$(CONFIG_CXL_REGION) += region.o region_pmem.o
 cxl_core-$(CONFIG_CXL_MCE) += mce.o
 cxl_core-$(CONFIG_CXL_FEATURES) += features.o
 cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += edac.o
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 5539e941782f..ef03966eeabd 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -50,6 +50,7 @@ int cxl_get_poison_by_endpoint(struct cxl_port *port);
 struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa);
 u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
 		   u64 dpa);
+int devm_cxl_add_pmem_region(struct cxl_region *cxlr);
 
 #else
 static inline u64 cxl_dpa_to_hpa(struct cxl_region *cxlr,
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index f24b7e754727..72aee1408efb 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2781,46 +2781,6 @@ static ssize_t delete_region_store(struct device *dev,
 }
 DEVICE_ATTR_WO(delete_region);
 
-static void cxl_pmem_region_release(struct device *dev)
-{
-	struct cxl_pmem_region *cxlr_pmem = to_cxl_pmem_region(dev);
-	int i;
-
-	for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
-		struct cxl_memdev *cxlmd = cxlr_pmem->mapping[i].cxlmd;
-
-		put_device(&cxlmd->dev);
-	}
-
-	kfree(cxlr_pmem);
-}
-
-static const struct attribute_group *cxl_pmem_region_attribute_groups[] = {
-	&cxl_base_attribute_group,
-	NULL,
-};
-
-const struct device_type cxl_pmem_region_type = {
-	.name = "cxl_pmem_region",
-	.release = cxl_pmem_region_release,
-	.groups = cxl_pmem_region_attribute_groups,
-};
-
-bool is_cxl_pmem_region(struct device *dev)
-{
-	return dev->type == &cxl_pmem_region_type;
-}
-EXPORT_SYMBOL_NS_GPL(is_cxl_pmem_region, "CXL");
-
-struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
-{
-	if (dev_WARN_ONCE(dev, !is_cxl_pmem_region(dev),
-			  "not a cxl_pmem_region device\n"))
-		return NULL;
-	return container_of(dev, struct cxl_pmem_region, dev);
-}
-EXPORT_SYMBOL_NS_GPL(to_cxl_pmem_region, "CXL");
-
 struct cxl_poison_context {
 	struct cxl_port *port;
 	int part;
@@ -3476,64 +3436,6 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
 	return -ENXIO;
 }
 
-static struct lock_class_key cxl_pmem_region_key;
-
-static int cxl_pmem_region_alloc(struct cxl_region *cxlr)
-{
-	struct cxl_region_params *p = &cxlr->params;
-	struct cxl_nvdimm_bridge *cxl_nvb;
-	struct device *dev;
-	int i;
-
-	guard(rwsem_read)(&cxl_rwsem.region);
-	if (p->state != CXL_CONFIG_COMMIT)
-		return -ENXIO;
-
-	struct cxl_pmem_region *cxlr_pmem __free(kfree) =
-		kzalloc_flex(*cxlr_pmem, mapping, p->nr_targets);
-	if (!cxlr_pmem)
-		return -ENOMEM;
-
-	cxlr_pmem->hpa_range.start = p->res->start;
-	cxlr_pmem->hpa_range.end = p->res->end;
-
-	/* Snapshot the region configuration underneath the cxl_rwsem.region */
-	cxlr_pmem->nr_mappings = p->nr_targets;
-	for (i = 0; i < p->nr_targets; i++) {
-		struct cxl_endpoint_decoder *cxled = p->targets[i];
-		struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
-		struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
-
-		/*
-		 * Regions never span CXL root devices, so by definition the
-		 * bridge for one device is the same for all.
-		 */
-		if (i == 0) {
-			cxl_nvb = cxl_find_nvdimm_bridge(cxlmd->endpoint);
-			if (!cxl_nvb)
-				return -ENODEV;
-			cxlr->cxl_nvb = cxl_nvb;
-		}
-		m->cxlmd = cxlmd;
-		get_device(&cxlmd->dev);
-		m->start = cxled->dpa_res->start;
-		m->size = resource_size(cxled->dpa_res);
-		m->position = i;
-	}
-
-	dev = &cxlr_pmem->dev;
-	device_initialize(dev);
-	lockdep_set_class(&dev->mutex, &cxl_pmem_region_key);
-	device_set_pm_not_required(dev);
-	dev->parent = &cxlr->dev;
-	dev->bus = &cxl_bus_type;
-	dev->type = &cxl_pmem_region_type;
-	cxlr_pmem->cxlr = cxlr;
-	cxlr->cxlr_pmem = no_free_ptr(cxlr_pmem);
-
-	return 0;
-}
-
 static void cxl_dax_region_release(struct device *dev)
 {
 	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
@@ -3597,92 +3499,6 @@ static struct cxl_dax_region *cxl_dax_region_alloc(struct cxl_region *cxlr)
 	return cxlr_dax;
 }
 
-static void cxlr_pmem_unregister(void *_cxlr_pmem)
-{
-	struct cxl_pmem_region *cxlr_pmem = _cxlr_pmem;
-	struct cxl_region *cxlr = cxlr_pmem->cxlr;
-	struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
-
-	/*
-	 * Either the bridge is in ->remove() context under the device_lock(),
-	 * or cxlr_release_nvdimm() is cancelling the bridge's release action
-	 * for @cxlr_pmem and doing it itself (while manually holding the bridge
-	 * lock).
-	 */
-	device_lock_assert(&cxl_nvb->dev);
-	cxlr->cxlr_pmem = NULL;
-	cxlr_pmem->cxlr = NULL;
-	device_unregister(&cxlr_pmem->dev);
-}
-
-static void cxlr_release_nvdimm(void *_cxlr)
-{
-	struct cxl_region *cxlr = _cxlr;
-	struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
-
-	scoped_guard(device, &cxl_nvb->dev) {
-		if (cxlr->cxlr_pmem)
-			devm_release_action(&cxl_nvb->dev, cxlr_pmem_unregister,
-					    cxlr->cxlr_pmem);
-	}
-	cxlr->cxl_nvb = NULL;
-	put_device(&cxl_nvb->dev);
-}
-
-/**
- * devm_cxl_add_pmem_region() - add a cxl_region-to-nd_region bridge
- * @cxlr: parent CXL region for this pmem region bridge device
- *
- * Return: 0 on success negative error code on failure.
- */
-static int devm_cxl_add_pmem_region(struct cxl_region *cxlr)
-{
-	struct cxl_pmem_region *cxlr_pmem;
-	struct cxl_nvdimm_bridge *cxl_nvb;
-	struct device *dev;
-	int rc;
-
-	rc = cxl_pmem_region_alloc(cxlr);
-	if (rc)
-		return rc;
-	cxlr_pmem = cxlr->cxlr_pmem;
-	cxl_nvb = cxlr->cxl_nvb;
-
-	dev = &cxlr_pmem->dev;
-	rc = dev_set_name(dev, "pmem_region%d", cxlr->id);
-	if (rc)
-		goto err;
-
-	rc = device_add(dev);
-	if (rc)
-		goto err;
-
-	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
-		dev_name(dev));
-
-	scoped_guard(device, &cxl_nvb->dev) {
-		if (cxl_nvb->dev.driver)
-			rc = devm_add_action_or_reset(&cxl_nvb->dev,
-						      cxlr_pmem_unregister,
-						      cxlr_pmem);
-		else
-			rc = -ENXIO;
-	}
-
-	if (rc)
-		goto err_bridge;
-
-	/* @cxlr carries a reference on @cxl_nvb until cxlr_release_nvdimm */
-	return devm_add_action_or_reset(&cxlr->dev, cxlr_release_nvdimm, cxlr);
-
-err:
-	put_device(dev);
-err_bridge:
-	put_device(&cxl_nvb->dev);
-	cxlr->cxl_nvb = NULL;
-	return rc;
-}
-
 static void cxlr_dax_unregister(void *_cxlr_dax)
 {
 	struct cxl_dax_region *cxlr_dax = _cxlr_dax;
diff --git a/drivers/cxl/core/region_pmem.c b/drivers/cxl/core/region_pmem.c
new file mode 100644
index 000000000000..b2f1e567d398
--- /dev/null
+++ b/drivers/cxl/core/region_pmem.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <cxlmem.h>
+#include <cxl.h>
+#include "core.h"
+
+static void cxl_pmem_region_release(struct device *dev)
+{
+	struct cxl_pmem_region *cxlr_pmem = to_cxl_pmem_region(dev);
+	int i;
+
+	for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
+		struct cxl_memdev *cxlmd = cxlr_pmem->mapping[i].cxlmd;
+
+		put_device(&cxlmd->dev);
+	}
+
+	kfree(cxlr_pmem);
+}
+
+static const struct attribute_group *cxl_pmem_region_attribute_groups[] = {
+	&cxl_base_attribute_group,
+	NULL
+};
+
+const struct device_type cxl_pmem_region_type = {
+	.name = "cxl_pmem_region",
+	.release = cxl_pmem_region_release,
+	.groups = cxl_pmem_region_attribute_groups,
+};
+
+bool is_cxl_pmem_region(struct device *dev)
+{
+	return dev->type == &cxl_pmem_region_type;
+}
+EXPORT_SYMBOL_NS_GPL(is_cxl_pmem_region, "CXL");
+
+struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
+{
+	if (dev_WARN_ONCE(dev, !is_cxl_pmem_region(dev),
+				"not a cxl_pmem_region device\n"))
+		return NULL;
+	return container_of(dev, struct cxl_pmem_region, dev);
+}
+EXPORT_SYMBOL_NS_GPL(to_cxl_pmem_region, "CXL");
+
+static struct lock_class_key cxl_pmem_region_key;
+
+static int cxl_pmem_region_alloc(struct cxl_region *cxlr)
+{
+	struct cxl_region_params *p = &cxlr->params;
+	struct cxl_nvdimm_bridge *cxl_nvb;
+	struct device *dev;
+	int i;
+
+	guard(rwsem_read)(&cxl_rwsem.region);
+	if (p->state != CXL_CONFIG_COMMIT)
+		return -ENXIO;
+
+	struct cxl_pmem_region *cxlr_pmem __free(kfree) =
+		kzalloc_flex(*cxlr_pmem, mapping, p->nr_targets);
+	if (!cxlr_pmem)
+		return -ENOMEM;
+
+	cxlr_pmem->hpa_range.start = p->res->start;
+	cxlr_pmem->hpa_range.end = p->res->end;
+
+	/* Snapshot the region configuration underneath the cxl_rwsem.region */
+	cxlr_pmem->nr_mappings = p->nr_targets;
+	for (i = 0; i < p->nr_targets; i++) {
+		struct cxl_endpoint_decoder *cxled = p->targets[i];
+		struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
+		struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
+
+		/*
+		 * Regions never span CXL root devices, so by definition the
+		 * bridge for one device is the same for all.
+		 */
+		if (i == 0) {
+			cxl_nvb = cxl_find_nvdimm_bridge(cxlmd->endpoint);
+			if (!cxl_nvb)
+				return -ENODEV;
+			cxlr->cxl_nvb = cxl_nvb;
+		}
+		m->cxlmd = cxlmd;
+		get_device(&cxlmd->dev);
+		m->start = cxled->dpa_res->start;
+		m->size = resource_size(cxled->dpa_res);
+		m->position = i;
+	}
+
+	dev = &cxlr_pmem->dev;
+	device_initialize(dev);
+	lockdep_set_class(&dev->mutex, &cxl_pmem_region_key);
+	device_set_pm_not_required(dev);
+	dev->parent = &cxlr->dev;
+	dev->bus = &cxl_bus_type;
+	dev->type = &cxl_pmem_region_type;
+	cxlr_pmem->cxlr = cxlr;
+	cxlr->cxlr_pmem = no_free_ptr(cxlr_pmem);
+
+	return 0;
+}
+
+static void cxlr_pmem_unregister(void *_cxlr_pmem)
+{
+	struct cxl_pmem_region *cxlr_pmem = _cxlr_pmem;
+	struct cxl_region *cxlr = cxlr_pmem->cxlr;
+	struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
+
+	/*
+	 * Either the bridge is in ->remove() context under the device_lock(),
+	 * or cxlr_release_nvdimm() is cancelling the bridge's release action
+	 * for @cxlr_pmem and doing it itself (while manually holding the bridge
+	 * lock).
+	 */
+	device_lock_assert(&cxl_nvb->dev);
+	cxlr->cxlr_pmem = NULL;
+	cxlr_pmem->cxlr = NULL;
+	device_unregister(&cxlr_pmem->dev);
+}
+
+static void cxlr_release_nvdimm(void *_cxlr)
+{
+	struct cxl_region *cxlr = _cxlr;
+	struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
+
+	scoped_guard(device, &cxl_nvb->dev) {
+		if (cxlr->cxlr_pmem)
+			devm_release_action(&cxl_nvb->dev, cxlr_pmem_unregister,
+					cxlr->cxlr_pmem);
+	}
+	cxlr->cxl_nvb = NULL;
+	put_device(&cxl_nvb->dev);
+}
+
+/**
+ * devm_cxl_add_pmem_region() - add a cxl_region-to-nd_region bridge
+ * @cxlr: parent CXL region for this pmem region bridge device
+ *
+ * Return: 0 on success negative error code on failure.
+ */
+int devm_cxl_add_pmem_region(struct cxl_region *cxlr)
+{
+	struct cxl_pmem_region *cxlr_pmem;
+	struct cxl_nvdimm_bridge *cxl_nvb;
+	struct device *dev;
+	int rc;
+
+	rc = cxl_pmem_region_alloc(cxlr);
+	if (rc)
+		return rc;
+	cxlr_pmem = cxlr->cxlr_pmem;
+	cxl_nvb = cxlr->cxl_nvb;
+
+	dev = &cxlr_pmem->dev;
+	rc = dev_set_name(dev, "pmem_region%d", cxlr->id);
+	if (rc)
+		goto err;
+
+	rc = device_add(dev);
+	if (rc)
+		goto err;
+
+	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
+			dev_name(dev));
+
+	scoped_guard(device, &cxl_nvb->dev) {
+		if (cxl_nvb->dev.driver)
+			rc = devm_add_action_or_reset(&cxl_nvb->dev,
+					cxlr_pmem_unregister,
+					cxlr_pmem);
+		else
+			rc = -ENXIO;
+	}
+
+	if (rc)
+		goto err_bridge;
+
+	/* @cxlr carries a reference on @cxl_nvb until cxlr_release_nvdimm */
+	return devm_add_action_or_reset(&cxlr->dev, cxlr_release_nvdimm, cxlr);
+
+err:
+	put_device(dev);
+err_bridge:
+	put_device(&cxl_nvb->dev);
+	cxlr->cxl_nvb = NULL;
+	return rc;
+}
diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
index 53d84a6874b7..f53d79a05661 100644
--- a/tools/testing/cxl/Kbuild
+++ b/tools/testing/cxl/Kbuild
@@ -59,7 +59,7 @@ cxl_core-y += $(CXL_CORE_SRC)/hdm.o
 cxl_core-y += $(CXL_CORE_SRC)/pmu.o
 cxl_core-y += $(CXL_CORE_SRC)/cdat.o
 cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
-cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o
+cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o $(CXL_CORE_SRC)/region_pmem.o
 cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
 cxl_core-$(CONFIG_CXL_FEATURES) += $(CXL_CORE_SRC)/features.o
 cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += $(CXL_CORE_SRC)/edac.o
-- 
2.53.0

Re: [PATCH v5 1/3] cxl/core/region: move pmem region driver logic into region_pmem.c

[Ira Weiny]

Gregory Price wrote:
> core/region.c is overloaded with per-region control logic (pmem, dax,
> sysram, etc). Move the pmem region driver logic from region.c into
> region_pmem.c make it clear that this code only applies to pmem regions.
> 
> No functional changes.
> 

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

> Signed-off-by: Gregory Price <gourry@gourry.net>
> Co-developed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---

[snip]

[PATCH v5 2/3] cxl/core/region: move dax region device logic into region_dax.c

[Gregory Price]

core/region.c is overloaded with per-region control logic (pmem, dax,
sysram, etc). Move the CXL DAX region device infrastructure from
region.c into a new region_dax.c file.

This will also allow us to add additional dax-driver integration paths
that don't further dirty the core region.c logic.

No functional changes.

Signed-off-by: Gregory Price <gourry@gourry.net>
Co-developed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 drivers/cxl/core/Makefile     |   2 +-
 drivers/cxl/core/core.h       |   1 +
 drivers/cxl/core/region.c     |  99 ------------------------------
 drivers/cxl/core/region_dax.c | 109 ++++++++++++++++++++++++++++++++++
 tools/testing/cxl/Kbuild      |   2 +-
 5 files changed, 112 insertions(+), 101 deletions(-)
 create mode 100644 drivers/cxl/core/region_dax.c

diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index f73776fe323b..ce7213818d3c 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -15,7 +15,7 @@ cxl_core-y += hdm.o
 cxl_core-y += pmu.o
 cxl_core-y += cdat.o
 cxl_core-$(CONFIG_TRACING) += trace.o
-cxl_core-$(CONFIG_CXL_REGION) += region.o region_pmem.o
+cxl_core-$(CONFIG_CXL_REGION) += region.o region_pmem.o region_dax.o
 cxl_core-$(CONFIG_CXL_MCE) += mce.o
 cxl_core-$(CONFIG_CXL_FEATURES) += features.o
 cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += edac.o
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index ef03966eeabd..82ca3a476708 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -50,6 +50,7 @@ int cxl_get_poison_by_endpoint(struct cxl_port *port);
 struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa);
 u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
 		   u64 dpa);
+int devm_cxl_add_dax_region(struct cxl_region *cxlr);
 int devm_cxl_add_pmem_region(struct cxl_region *cxlr);
 
 #else
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 72aee1408efb..6a2ef3475764 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3436,105 +3436,6 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
 	return -ENXIO;
 }
 
-static void cxl_dax_region_release(struct device *dev)
-{
-	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
-
-	kfree(cxlr_dax);
-}
-
-static const struct attribute_group *cxl_dax_region_attribute_groups[] = {
-	&cxl_base_attribute_group,
-	NULL,
-};
-
-const struct device_type cxl_dax_region_type = {
-	.name = "cxl_dax_region",
-	.release = cxl_dax_region_release,
-	.groups = cxl_dax_region_attribute_groups,
-};
-
-static bool is_cxl_dax_region(struct device *dev)
-{
-	return dev->type == &cxl_dax_region_type;
-}
-
-struct cxl_dax_region *to_cxl_dax_region(struct device *dev)
-{
-	if (dev_WARN_ONCE(dev, !is_cxl_dax_region(dev),
-			  "not a cxl_dax_region device\n"))
-		return NULL;
-	return container_of(dev, struct cxl_dax_region, dev);
-}
-EXPORT_SYMBOL_NS_GPL(to_cxl_dax_region, "CXL");
-
-static struct lock_class_key cxl_dax_region_key;
-
-static struct cxl_dax_region *cxl_dax_region_alloc(struct cxl_region *cxlr)
-{
-	struct cxl_region_params *p = &cxlr->params;
-	struct cxl_dax_region *cxlr_dax;
-	struct device *dev;
-
-	guard(rwsem_read)(&cxl_rwsem.region);
-	if (p->state != CXL_CONFIG_COMMIT)
-		return ERR_PTR(-ENXIO);
-
-	cxlr_dax = kzalloc_obj(*cxlr_dax);
-	if (!cxlr_dax)
-		return ERR_PTR(-ENOMEM);
-
-	cxlr_dax->hpa_range.start = p->res->start;
-	cxlr_dax->hpa_range.end = p->res->end;
-
-	dev = &cxlr_dax->dev;
-	cxlr_dax->cxlr = cxlr;
-	device_initialize(dev);
-	lockdep_set_class(&dev->mutex, &cxl_dax_region_key);
-	device_set_pm_not_required(dev);
-	dev->parent = &cxlr->dev;
-	dev->bus = &cxl_bus_type;
-	dev->type = &cxl_dax_region_type;
-
-	return cxlr_dax;
-}
-
-static void cxlr_dax_unregister(void *_cxlr_dax)
-{
-	struct cxl_dax_region *cxlr_dax = _cxlr_dax;
-
-	device_unregister(&cxlr_dax->dev);
-}
-
-static int devm_cxl_add_dax_region(struct cxl_region *cxlr)
-{
-	struct cxl_dax_region *cxlr_dax;
-	struct device *dev;
-	int rc;
-
-	cxlr_dax = cxl_dax_region_alloc(cxlr);
-	if (IS_ERR(cxlr_dax))
-		return PTR_ERR(cxlr_dax);
-
-	dev = &cxlr_dax->dev;
-	rc = dev_set_name(dev, "dax_region%d", cxlr->id);
-	if (rc)
-		goto err;
-
-	rc = device_add(dev);
-	if (rc)
-		goto err;
-
-	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
-		dev_name(dev));
-
-	return devm_add_action_or_reset(&cxlr->dev, cxlr_dax_unregister,
-					cxlr_dax);
-err:
-	put_device(dev);
-	return rc;
-}
-
 static int match_root_decoder(struct device *dev, const void *data)
 {
 	const struct range *r1, *r2 = data;
diff --git a/drivers/cxl/core/region_dax.c b/drivers/cxl/core/region_dax.c
new file mode 100644
index 000000000000..fe367759ac69
--- /dev/null
+++ b/drivers/cxl/core/region_dax.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright(c) 2022 Intel Corporation. All rights reserved.
+ * Copyright(c) 2026 Meta Technologies Inc. All rights reserved.
+ */
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <cxlmem.h>
+#include <cxl.h>
+#include "core.h"
+
+static void cxl_dax_region_release(struct device *dev)
+{
+	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
+
+	kfree(cxlr_dax);
+}
+
+static const struct attribute_group *cxl_dax_region_attribute_groups[] = {
+	&cxl_base_attribute_group,
+	NULL
+};
+
+const struct device_type cxl_dax_region_type = {
+	.name = "cxl_dax_region",
+	.release = cxl_dax_region_release,
+	.groups = cxl_dax_region_attribute_groups,
+};
+
+static bool is_cxl_dax_region(struct device *dev)
+{
+	return dev->type == &cxl_dax_region_type;
+}
+
+struct cxl_dax_region *to_cxl_dax_region(struct device *dev)
+{
+	if (dev_WARN_ONCE(dev, !is_cxl_dax_region(dev),
+			  "not a cxl_dax_region device\n"))
+		return NULL;
+	return container_of(dev, struct cxl_dax_region, dev);
+}
+EXPORT_SYMBOL_NS_GPL(to_cxl_dax_region, "CXL");
+
+static struct lock_class_key cxl_dax_region_key;
+
+static struct cxl_dax_region *cxl_dax_region_alloc(struct cxl_region *cxlr)
+{
+	struct cxl_region_params *p = &cxlr->params;
+	struct cxl_dax_region *cxlr_dax;
+	struct device *dev;
+
+	guard(rwsem_read)(&cxl_rwsem.region);
+	if (p->state != CXL_CONFIG_COMMIT)
+		return ERR_PTR(-ENXIO);
+
+	cxlr_dax = kzalloc_obj(*cxlr_dax);
+	if (!cxlr_dax)
+		return ERR_PTR(-ENOMEM);
+
+	cxlr_dax->hpa_range.start = p->res->start;
+	cxlr_dax->hpa_range.end = p->res->end;
+
+	dev = &cxlr_dax->dev;
+	cxlr_dax->cxlr = cxlr;
+	device_initialize(dev);
+	lockdep_set_class(&dev->mutex, &cxl_dax_region_key);
+	device_set_pm_not_required(dev);
+	dev->parent = &cxlr->dev;
+	dev->bus = &cxl_bus_type;
+	dev->type = &cxl_dax_region_type;
+
+	return cxlr_dax;
+}
+
+static void cxlr_dax_unregister(void *_cxlr_dax)
+{
+	struct cxl_dax_region *cxlr_dax = _cxlr_dax;
+
+	device_unregister(&cxlr_dax->dev);
+}
+
+int devm_cxl_add_dax_region(struct cxl_region *cxlr)
+{
+	struct cxl_dax_region *cxlr_dax;
+	struct device *dev;
+	int rc;
+
+	cxlr_dax = cxl_dax_region_alloc(cxlr);
+	if (IS_ERR(cxlr_dax))
+		return PTR_ERR(cxlr_dax);
+
+	dev = &cxlr_dax->dev;
+	rc = dev_set_name(dev, "dax_region%d", cxlr->id);
+	if (rc)
+		goto err;
+
+	rc = device_add(dev);
+	if (rc)
+		goto err;
+
+	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
+		dev_name(dev));
+
+	return devm_add_action_or_reset(&cxlr->dev, cxlr_dax_unregister,
+					cxlr_dax);
+err:
+	put_device(dev);
+	return rc;
+}
diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
index f53d79a05661..d2b291e5f842 100644
--- a/tools/testing/cxl/Kbuild
+++ b/tools/testing/cxl/Kbuild
@@ -59,7 +59,7 @@ cxl_core-y += $(CXL_CORE_SRC)/hdm.o
 cxl_core-y += $(CXL_CORE_SRC)/pmu.o
 cxl_core-y += $(CXL_CORE_SRC)/cdat.o
 cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
-cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o $(CXL_CORE_SRC)/region_pmem.o
+cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o $(CXL_CORE_SRC)/region_pmem.o $(CXL_CORE_SRC)/region_dax.o
 cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
 cxl_core-$(CONFIG_CXL_FEATURES) += $(CXL_CORE_SRC)/features.o
 cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += $(CXL_CORE_SRC)/edac.o
-- 
2.53.0

Re: [PATCH v5 2/3] cxl/core/region: move dax region device logic into region_dax.c

[Ira Weiny]

Gregory Price wrote:
> core/region.c is overloaded with per-region control logic (pmem, dax,
> sysram, etc). Move the CXL DAX region device infrastructure from
> region.c into a new region_dax.c file.
> 
> This will also allow us to add additional dax-driver integration paths
> that don't further dirty the core region.c logic.
> 
> No functional changes.
> 

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

> Signed-off-by: Gregory Price <gourry@gourry.net>
> Co-developed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---

[snip]

Re: [PATCH v5 2/3] cxl/core/region: move dax region device logic into region_dax.c

[Anisa Su]

On Thu, Mar 26, 2026 at 10:02:02PM -0400, Gregory Price wrote:
> core/region.c is overloaded with per-region control logic (pmem, dax,
> sysram, etc). Move the CXL DAX region device infrastructure from
> region.c into a new region_dax.c file.
> 
> This will also allow us to add additional dax-driver integration paths
> that don't further dirty the core region.c logic.
> 
> No functional changes.
> 
> Signed-off-by: Gregory Price <gourry@gourry.net>
> Co-developed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
>  drivers/cxl/core/Makefile     |   2 +-
>  drivers/cxl/core/core.h       |   1 +
>  drivers/cxl/core/region.c     |  99 ------------------------------
>  drivers/cxl/core/region_dax.c | 109 ++++++++++++++++++++++++++++++++++
>  tools/testing/cxl/Kbuild      |   2 +-
>  5 files changed, 112 insertions(+), 101 deletions(-)
>  create mode 100644 drivers/cxl/core/region_dax.c
> 
> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
> index f73776fe323b..ce7213818d3c 100644
> --- a/drivers/cxl/core/Makefile
> +++ b/drivers/cxl/core/Makefile
> @@ -15,7 +15,7 @@ cxl_core-y += hdm.o
>  cxl_core-y += pmu.o
>  cxl_core-y += cdat.o
>  cxl_core-$(CONFIG_TRACING) += trace.o
> -cxl_core-$(CONFIG_CXL_REGION) += region.o region_pmem.o
> +cxl_core-$(CONFIG_CXL_REGION) += region.o region_pmem.o region_dax.o
>  cxl_core-$(CONFIG_CXL_MCE) += mce.o
>  cxl_core-$(CONFIG_CXL_FEATURES) += features.o
>  cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += edac.o
> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
> index ef03966eeabd..82ca3a476708 100644
> --- a/drivers/cxl/core/core.h
> +++ b/drivers/cxl/core/core.h
> @@ -50,6 +50,7 @@ int cxl_get_poison_by_endpoint(struct cxl_port *port);
>  struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa);
>  u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
>  		   u64 dpa);
> +int devm_cxl_add_dax_region(struct cxl_region *cxlr);
>  int devm_cxl_add_pmem_region(struct cxl_region *cxlr);
>  
>  #else
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 72aee1408efb..6a2ef3475764 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3436,105 +3436,6 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
>  	return -ENXIO;
>  }
>  
> -static void cxl_dax_region_release(struct device *dev)
> -{
> -	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
> -
> -	kfree(cxlr_dax);
> -}
> -
> -static const struct attribute_group *cxl_dax_region_attribute_groups[] = {
> -	&cxl_base_attribute_group,
> -	NULL,
> -};
> -
> -const struct device_type cxl_dax_region_type = {
> -	.name = "cxl_dax_region",
> -	.release = cxl_dax_region_release,
> -	.groups = cxl_dax_region_attribute_groups,
> -};
> -
> -static bool is_cxl_dax_region(struct device *dev)
> -{
> -	return dev->type == &cxl_dax_region_type;
> -}
> -
> -struct cxl_dax_region *to_cxl_dax_region(struct device *dev)
> -{
> -	if (dev_WARN_ONCE(dev, !is_cxl_dax_region(dev),
> -			  "not a cxl_dax_region device\n"))
> -		return NULL;
> -	return container_of(dev, struct cxl_dax_region, dev);
> -}
> -EXPORT_SYMBOL_NS_GPL(to_cxl_dax_region, "CXL");
> -
> -static struct lock_class_key cxl_dax_region_key;
> -
> -static struct cxl_dax_region *cxl_dax_region_alloc(struct cxl_region *cxlr)
> -{
> -	struct cxl_region_params *p = &cxlr->params;
> -	struct cxl_dax_region *cxlr_dax;
> -	struct device *dev;
> -
> -	guard(rwsem_read)(&cxl_rwsem.region);
> -	if (p->state != CXL_CONFIG_COMMIT)
> -		return ERR_PTR(-ENXIO);
> -
> -	cxlr_dax = kzalloc_obj(*cxlr_dax);
> -	if (!cxlr_dax)
> -		return ERR_PTR(-ENOMEM);
> -
> -	cxlr_dax->hpa_range.start = p->res->start;
> -	cxlr_dax->hpa_range.end = p->res->end;
> -
> -	dev = &cxlr_dax->dev;
> -	cxlr_dax->cxlr = cxlr;
> -	device_initialize(dev);
> -	lockdep_set_class(&dev->mutex, &cxl_dax_region_key);
> -	device_set_pm_not_required(dev);
> -	dev->parent = &cxlr->dev;
> -	dev->bus = &cxl_bus_type;
> -	dev->type = &cxl_dax_region_type;
> -
> -	return cxlr_dax;
> -}
> -
> -static void cxlr_dax_unregister(void *_cxlr_dax)
> -{
> -	struct cxl_dax_region *cxlr_dax = _cxlr_dax;
> -
> -	device_unregister(&cxlr_dax->dev);
> -}
> -
> -static int devm_cxl_add_dax_region(struct cxl_region *cxlr)
> -{
> -	struct cxl_dax_region *cxlr_dax;
> -	struct device *dev;
> -	int rc;
> -
> -	cxlr_dax = cxl_dax_region_alloc(cxlr);
> -	if (IS_ERR(cxlr_dax))
> -		return PTR_ERR(cxlr_dax);
> -
> -	dev = &cxlr_dax->dev;
> -	rc = dev_set_name(dev, "dax_region%d", cxlr->id);
> -	if (rc)
> -		goto err;
> -
> -	rc = device_add(dev);
> -	if (rc)
> -		goto err;
> -
> -	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
> -		dev_name(dev));
> -
> -	return devm_add_action_or_reset(&cxlr->dev, cxlr_dax_unregister,
> -					cxlr_dax);
> -err:
> -	put_device(dev);
> -	return rc;
> -}
> -
>  static int match_root_decoder(struct device *dev, const void *data)
>  {
>  	const struct range *r1, *r2 = data;
> diff --git a/drivers/cxl/core/region_dax.c b/drivers/cxl/core/region_dax.c
> new file mode 100644
> index 000000000000..fe367759ac69
> --- /dev/null
> +++ b/drivers/cxl/core/region_dax.c
> @@ -0,0 +1,109 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright(c) 2022 Intel Corporation. All rights reserved.
> + * Copyright(c) 2026 Meta Technologies Inc. All rights reserved.
> + */
> +#include <linux/device.h>
> +#include <linux/slab.h>
> +#include <cxlmem.h>
> +#include <cxl.h>
> +#include "core.h"
> +
> +static void cxl_dax_region_release(struct device *dev)
> +{
> +	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
> +
> +	kfree(cxlr_dax);
> +}
> +
> +static const struct attribute_group *cxl_dax_region_attribute_groups[] = {
> +	&cxl_base_attribute_group,
> +	NULL
> +};
> +
> +const struct device_type cxl_dax_region_type = {
> +	.name = "cxl_dax_region",
> +	.release = cxl_dax_region_release,
> +	.groups = cxl_dax_region_attribute_groups,
> +};
> +
> +static bool is_cxl_dax_region(struct device *dev)
> +{
> +	return dev->type == &cxl_dax_region_type;
> +}
> +
> +struct cxl_dax_region *to_cxl_dax_region(struct device *dev)
> +{
> +	if (dev_WARN_ONCE(dev, !is_cxl_dax_region(dev),
> +			  "not a cxl_dax_region device\n"))
> +		return NULL;
> +	return container_of(dev, struct cxl_dax_region, dev);
> +}
> +EXPORT_SYMBOL_NS_GPL(to_cxl_dax_region, "CXL");
> +
> +static struct lock_class_key cxl_dax_region_key;
> +
> +static struct cxl_dax_region *cxl_dax_region_alloc(struct cxl_region *cxlr)
> +{
> +	struct cxl_region_params *p = &cxlr->params;
> +	struct cxl_dax_region *cxlr_dax;
> +	struct device *dev;
> +
> +	guard(rwsem_read)(&cxl_rwsem.region);
> +	if (p->state != CXL_CONFIG_COMMIT)
> +		return ERR_PTR(-ENXIO);
> +
> +	cxlr_dax = kzalloc_obj(*cxlr_dax);
> +	if (!cxlr_dax)
> +		return ERR_PTR(-ENOMEM);
> +
> +	cxlr_dax->hpa_range.start = p->res->start;
> +	cxlr_dax->hpa_range.end = p->res->end;
> +
> +	dev = &cxlr_dax->dev;
> +	cxlr_dax->cxlr = cxlr;
	cxlr->cxlr_dax = cxlr_dax;

Running into segfaults without this ^
> +	device_initialize(dev);
> +	lockdep_set_class(&dev->mutex, &cxl_dax_region_key);
> +	device_set_pm_not_required(dev);
> +	dev->parent = &cxlr->dev;
> +	dev->bus = &cxl_bus_type;
> +	dev->type = &cxl_dax_region_type;
> +
> +	return cxlr_dax;
> +}
> +
> +static void cxlr_dax_unregister(void *_cxlr_dax)
> +{
> +	struct cxl_dax_region *cxlr_dax = _cxlr_dax;
> +
> +	device_unregister(&cxlr_dax->dev);
> +}
> +
> +int devm_cxl_add_dax_region(struct cxl_region *cxlr)
> +{
> +	struct cxl_dax_region *cxlr_dax;
> +	struct device *dev;
> +	int rc;
> +
> +	cxlr_dax = cxl_dax_region_alloc(cxlr);
> +	if (IS_ERR(cxlr_dax))
> +		return PTR_ERR(cxlr_dax);
> +
> +	dev = &cxlr_dax->dev;
> +	rc = dev_set_name(dev, "dax_region%d", cxlr->id);
> +	if (rc)
> +		goto err;
> +
> +	rc = device_add(dev);
> +	if (rc)
> +		goto err;
> +
> +	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
> +		dev_name(dev));
> +
> +	return devm_add_action_or_reset(&cxlr->dev, cxlr_dax_unregister,
> +					cxlr_dax);
> +err:
> +	put_device(dev);
> +	return rc;
> +}
> diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
> index f53d79a05661..d2b291e5f842 100644
> --- a/tools/testing/cxl/Kbuild
> +++ b/tools/testing/cxl/Kbuild
> @@ -59,7 +59,7 @@ cxl_core-y += $(CXL_CORE_SRC)/hdm.o
>  cxl_core-y += $(CXL_CORE_SRC)/pmu.o
>  cxl_core-y += $(CXL_CORE_SRC)/cdat.o
>  cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
> -cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o $(CXL_CORE_SRC)/region_pmem.o
> +cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o $(CXL_CORE_SRC)/region_pmem.o $(CXL_CORE_SRC)/region_dax.o
>  cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
>  cxl_core-$(CONFIG_CXL_FEATURES) += $(CXL_CORE_SRC)/features.o
>  cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += $(CXL_CORE_SRC)/edac.o
> -- 
> 2.53.0
> 

Re: [PATCH v5 2/3] cxl/core/region: move dax region device logic into region_dax.c

[Dave Jiang]

On 4/10/26 5:02 PM, Anisa Su wrote:
> On Thu, Mar 26, 2026 at 10:02:02PM -0400, Gregory Price wrote:
>> core/region.c is overloaded with per-region control logic (pmem, dax,
>> sysram, etc). Move the CXL DAX region device infrastructure from
>> region.c into a new region_dax.c file.
>>
>> This will also allow us to add additional dax-driver integration paths
>> that don't further dirty the core region.c logic.
>>
>> No functional changes.
>>
>> Signed-off-by: Gregory Price <gourry@gourry.net>
>> Co-developed-by: Ira Weiny <ira.weiny@intel.com>
>> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
>> ---
>>  drivers/cxl/core/Makefile     |   2 +-
>>  drivers/cxl/core/core.h       |   1 +
>>  drivers/cxl/core/region.c     |  99 ------------------------------
>>  drivers/cxl/core/region_dax.c | 109 ++++++++++++++++++++++++++++++++++
>>  tools/testing/cxl/Kbuild      |   2 +-
>>  5 files changed, 112 insertions(+), 101 deletions(-)
>>  create mode 100644 drivers/cxl/core/region_dax.c
>>
>> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
>> index f73776fe323b..ce7213818d3c 100644
>> --- a/drivers/cxl/core/Makefile
>> +++ b/drivers/cxl/core/Makefile
>> @@ -15,7 +15,7 @@ cxl_core-y += hdm.o
>>  cxl_core-y += pmu.o
>>  cxl_core-y += cdat.o
>>  cxl_core-$(CONFIG_TRACING) += trace.o
>> -cxl_core-$(CONFIG_CXL_REGION) += region.o region_pmem.o
>> +cxl_core-$(CONFIG_CXL_REGION) += region.o region_pmem.o region_dax.o
>>  cxl_core-$(CONFIG_CXL_MCE) += mce.o
>>  cxl_core-$(CONFIG_CXL_FEATURES) += features.o
>>  cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += edac.o
>> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
>> index ef03966eeabd..82ca3a476708 100644
>> --- a/drivers/cxl/core/core.h
>> +++ b/drivers/cxl/core/core.h
>> @@ -50,6 +50,7 @@ int cxl_get_poison_by_endpoint(struct cxl_port *port);
>>  struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa);
>>  u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
>>  		   u64 dpa);
>> +int devm_cxl_add_dax_region(struct cxl_region *cxlr);
>>  int devm_cxl_add_pmem_region(struct cxl_region *cxlr);
>>  
>>  #else
>> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
>> index 72aee1408efb..6a2ef3475764 100644
>> --- a/drivers/cxl/core/region.c
>> +++ b/drivers/cxl/core/region.c
>> @@ -3436,105 +3436,6 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
>>  	return -ENXIO;
>>  }
>>  
>> -static void cxl_dax_region_release(struct device *dev)
>> -{
>> -	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
>> -
>> -	kfree(cxlr_dax);
>> -}
>> -
>> -static const struct attribute_group *cxl_dax_region_attribute_groups[] = {
>> -	&cxl_base_attribute_group,
>> -	NULL,
>> -};
>> -
>> -const struct device_type cxl_dax_region_type = {
>> -	.name = "cxl_dax_region",
>> -	.release = cxl_dax_region_release,
>> -	.groups = cxl_dax_region_attribute_groups,
>> -};
>> -
>> -static bool is_cxl_dax_region(struct device *dev)
>> -{
>> -	return dev->type == &cxl_dax_region_type;
>> -}
>> -
>> -struct cxl_dax_region *to_cxl_dax_region(struct device *dev)
>> -{
>> -	if (dev_WARN_ONCE(dev, !is_cxl_dax_region(dev),
>> -			  "not a cxl_dax_region device\n"))
>> -		return NULL;
>> -	return container_of(dev, struct cxl_dax_region, dev);
>> -}
>> -EXPORT_SYMBOL_NS_GPL(to_cxl_dax_region, "CXL");
>> -
>> -static struct lock_class_key cxl_dax_region_key;
>> -
>> -static struct cxl_dax_region *cxl_dax_region_alloc(struct cxl_region *cxlr)
>> -{
>> -	struct cxl_region_params *p = &cxlr->params;
>> -	struct cxl_dax_region *cxlr_dax;
>> -	struct device *dev;
>> -
>> -	guard(rwsem_read)(&cxl_rwsem.region);
>> -	if (p->state != CXL_CONFIG_COMMIT)
>> -		return ERR_PTR(-ENXIO);
>> -
>> -	cxlr_dax = kzalloc_obj(*cxlr_dax);
>> -	if (!cxlr_dax)
>> -		return ERR_PTR(-ENOMEM);
>> -
>> -	cxlr_dax->hpa_range.start = p->res->start;
>> -	cxlr_dax->hpa_range.end = p->res->end;
>> -
>> -	dev = &cxlr_dax->dev;
>> -	cxlr_dax->cxlr = cxlr;
>> -	device_initialize(dev);
>> -	lockdep_set_class(&dev->mutex, &cxl_dax_region_key);
>> -	device_set_pm_not_required(dev);
>> -	dev->parent = &cxlr->dev;
>> -	dev->bus = &cxl_bus_type;
>> -	dev->type = &cxl_dax_region_type;
>> -
>> -	return cxlr_dax;
>> -}
>> -
>> -static void cxlr_dax_unregister(void *_cxlr_dax)
>> -{
>> -	struct cxl_dax_region *cxlr_dax = _cxlr_dax;
>> -
>> -	device_unregister(&cxlr_dax->dev);
>> -}
>> -
>> -static int devm_cxl_add_dax_region(struct cxl_region *cxlr)
>> -{
>> -	struct cxl_dax_region *cxlr_dax;
>> -	struct device *dev;
>> -	int rc;
>> -
>> -	cxlr_dax = cxl_dax_region_alloc(cxlr);
>> -	if (IS_ERR(cxlr_dax))
>> -		return PTR_ERR(cxlr_dax);
>> -
>> -	dev = &cxlr_dax->dev;
>> -	rc = dev_set_name(dev, "dax_region%d", cxlr->id);
>> -	if (rc)
>> -		goto err;
>> -
>> -	rc = device_add(dev);
>> -	if (rc)
>> -		goto err;
>> -
>> -	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
>> -		dev_name(dev));
>> -
>> -	return devm_add_action_or_reset(&cxlr->dev, cxlr_dax_unregister,
>> -					cxlr_dax);
>> -err:
>> -	put_device(dev);
>> -	return rc;
>> -}
>> -
>>  static int match_root_decoder(struct device *dev, const void *data)
>>  {
>>  	const struct range *r1, *r2 = data;
>> diff --git a/drivers/cxl/core/region_dax.c b/drivers/cxl/core/region_dax.c
>> new file mode 100644
>> index 000000000000..fe367759ac69
>> --- /dev/null
>> +++ b/drivers/cxl/core/region_dax.c
>> @@ -0,0 +1,109 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright(c) 2022 Intel Corporation. All rights reserved.
>> + * Copyright(c) 2026 Meta Technologies Inc. All rights reserved.
>> + */
>> +#include <linux/device.h>
>> +#include <linux/slab.h>
>> +#include <cxlmem.h>
>> +#include <cxl.h>
>> +#include "core.h"
>> +
>> +static void cxl_dax_region_release(struct device *dev)
>> +{
>> +	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
>> +
>> +	kfree(cxlr_dax);
>> +}
>> +
>> +static const struct attribute_group *cxl_dax_region_attribute_groups[] = {
>> +	&cxl_base_attribute_group,
>> +	NULL
>> +};
>> +
>> +const struct device_type cxl_dax_region_type = {
>> +	.name = "cxl_dax_region",
>> +	.release = cxl_dax_region_release,
>> +	.groups = cxl_dax_region_attribute_groups,
>> +};
>> +
>> +static bool is_cxl_dax_region(struct device *dev)
>> +{
>> +	return dev->type == &cxl_dax_region_type;
>> +}
>> +
>> +struct cxl_dax_region *to_cxl_dax_region(struct device *dev)
>> +{
>> +	if (dev_WARN_ONCE(dev, !is_cxl_dax_region(dev),
>> +			  "not a cxl_dax_region device\n"))
>> +		return NULL;
>> +	return container_of(dev, struct cxl_dax_region, dev);
>> +}
>> +EXPORT_SYMBOL_NS_GPL(to_cxl_dax_region, "CXL");
>> +
>> +static struct lock_class_key cxl_dax_region_key;
>> +
>> +static struct cxl_dax_region *cxl_dax_region_alloc(struct cxl_region *cxlr)
>> +{
>> +	struct cxl_region_params *p = &cxlr->params;
>> +	struct cxl_dax_region *cxlr_dax;
>> +	struct device *dev;
>> +
>> +	guard(rwsem_read)(&cxl_rwsem.region);
>> +	if (p->state != CXL_CONFIG_COMMIT)
>> +		return ERR_PTR(-ENXIO);
>> +
>> +	cxlr_dax = kzalloc_obj(*cxlr_dax);
>> +	if (!cxlr_dax)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	cxlr_dax->hpa_range.start = p->res->start;
>> +	cxlr_dax->hpa_range.end = p->res->end;
>> +
>> +	dev = &cxlr_dax->dev;
>> +	cxlr_dax->cxlr = cxlr;
> 	cxlr->cxlr_dax = cxlr_dax;
> 
> Running into segfaults without this ^

Can you pls create a fixes patch?

DJ

>> +	device_initialize(dev);
>> +	lockdep_set_class(&dev->mutex, &cxl_dax_region_key);
>> +	device_set_pm_not_required(dev);
>> +	dev->parent = &cxlr->dev;
>> +	dev->bus = &cxl_bus_type;
>> +	dev->type = &cxl_dax_region_type;
>> +
>> +	return cxlr_dax;
>> +}
>> +
>> +static void cxlr_dax_unregister(void *_cxlr_dax)
>> +{
>> +	struct cxl_dax_region *cxlr_dax = _cxlr_dax;
>> +
>> +	device_unregister(&cxlr_dax->dev);
>> +}
>> +
>> +int devm_cxl_add_dax_region(struct cxl_region *cxlr)
>> +{
>> +	struct cxl_dax_region *cxlr_dax;
>> +	struct device *dev;
>> +	int rc;
>> +
>> +	cxlr_dax = cxl_dax_region_alloc(cxlr);
>> +	if (IS_ERR(cxlr_dax))
>> +		return PTR_ERR(cxlr_dax);
>> +
>> +	dev = &cxlr_dax->dev;
>> +	rc = dev_set_name(dev, "dax_region%d", cxlr->id);
>> +	if (rc)
>> +		goto err;
>> +
>> +	rc = device_add(dev);
>> +	if (rc)
>> +		goto err;
>> +
>> +	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
>> +		dev_name(dev));
>> +
>> +	return devm_add_action_or_reset(&cxlr->dev, cxlr_dax_unregister,
>> +					cxlr_dax);
>> +err:
>> +	put_device(dev);
>> +	return rc;
>> +}
>> diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
>> index f53d79a05661..d2b291e5f842 100644
>> --- a/tools/testing/cxl/Kbuild
>> +++ b/tools/testing/cxl/Kbuild
>> @@ -59,7 +59,7 @@ cxl_core-y += $(CXL_CORE_SRC)/hdm.o
>>  cxl_core-y += $(CXL_CORE_SRC)/pmu.o
>>  cxl_core-y += $(CXL_CORE_SRC)/cdat.o
>>  cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
>> -cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o $(CXL_CORE_SRC)/region_pmem.o
>> +cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o $(CXL_CORE_SRC)/region_pmem.o $(CXL_CORE_SRC)/region_dax.o
>>  cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
>>  cxl_core-$(CONFIG_CXL_FEATURES) += $(CXL_CORE_SRC)/features.o
>>  cxl_core-$(CONFIG_CXL_EDAC_MEM_FEATURES) += $(CXL_CORE_SRC)/edac.o
>> -- 
>> 2.53.0
>>

Re: [PATCH v5 2/3] cxl/core/region: move dax region device logic into region_dax.c

[Gregory Price]

On Fri, Apr 10, 2026 at 05:02:00PM -0700, Anisa Su wrote:
> > +
> > +	cxlr_dax->hpa_range.start = p->res->start;
> > +	cxlr_dax->hpa_range.end = p->res->end;
> > +
> > +	dev = &cxlr_dax->dev;
> > +	cxlr_dax->cxlr = cxlr;
> 	cxlr->cxlr_dax = cxlr_dax;
> 
> Running into segfaults without this ^

This should have been a purely non-functional change (the code is just
moving from A to B without changes).

That would mean the original code should run into this too unless I
mucked up the move.

~Gregory

Re: [PATCH v5 2/3] cxl/core/region: move dax region device logic into region_dax.c

[Dan Williams]

Gregory Price wrote:
> On Fri, Apr 10, 2026 at 05:02:00PM -0700, Anisa Su wrote:
> > > +
> > > +	cxlr_dax->hpa_range.start = p->res->start;
> > > +	cxlr_dax->hpa_range.end = p->res->end;
> > > +
> > > +	dev = &cxlr_dax->dev;
> > > +	cxlr_dax->cxlr = cxlr;
> > 	cxlr->cxlr_dax = cxlr_dax;
> > 
> > Running into segfaults without this ^
> 
> This should have been a purely non-functional change (the code is just
> moving from A to B without changes).
> 
> That would mean the original code should run into this too unless I
> mucked up the move.

I do not think you mucked anything up ->cxlr_dax does not exist in mainline.

Re: [PATCH v5 2/3] cxl/core/region: move dax region device logic into region_dax.c

[Anisa Su]

On Sat, Apr 11, 2026 at 01:09:13AM -0400, Gregory Price wrote:
> On Fri, Apr 10, 2026 at 05:02:00PM -0700, Anisa Su wrote:
> > > +
> > > +	cxlr_dax->hpa_range.start = p->res->start;
> > > +	cxlr_dax->hpa_range.end = p->res->end;
> > > +
> > > +	dev = &cxlr_dax->dev;
> > > +	cxlr_dax->cxlr = cxlr;
> > 	cxlr->cxlr_dax = cxlr_dax;
> > 
> > Running into segfaults without this ^
> 
> This should have been a purely non-functional change (the code is just
> moving from A to B without changes).
> 
> That would mean the original code should run into this too unless I
> mucked up the move.
> 
> ~Gregory

Wait no sorry I was wrong... I got confused by the merge conflict when I was
rebasing the dcd series

Pls ignore

- Anisa

[PATCH v5 3/3] cxl/core: use cleanup.h for devm_cxl_add_dax_region

[Gregory Price]

Cleanup the gotos in the function.  No functional change.

Signed-off-by: Gregory Price <gourry@gourry.net>
---
 drivers/cxl/core/region_dax.c | 13 +++++--------
 drivers/cxl/cxl.h             |  1 +
 2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/cxl/core/region_dax.c b/drivers/cxl/core/region_dax.c
index fe367759ac69..de04f78f6ad8 100644
--- a/drivers/cxl/core/region_dax.c
+++ b/drivers/cxl/core/region_dax.c
@@ -81,29 +81,26 @@ static void cxlr_dax_unregister(void *_cxlr_dax)
 
 int devm_cxl_add_dax_region(struct cxl_region *cxlr)
 {
-	struct cxl_dax_region *cxlr_dax;
 	struct device *dev;
 	int rc;
 
-	cxlr_dax = cxl_dax_region_alloc(cxlr);
+	struct cxl_dax_region *cxlr_dax __free(put_cxl_dax_region) =
+		cxl_dax_region_alloc(cxlr);
 	if (IS_ERR(cxlr_dax))
 		return PTR_ERR(cxlr_dax);
 
 	dev = &cxlr_dax->dev;
 	rc = dev_set_name(dev, "dax_region%d", cxlr->id);
 	if (rc)
-		goto err;
+		return rc;
 
 	rc = device_add(dev);
 	if (rc)
-		goto err;
+		return rc;
 
 	dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
 		dev_name(dev));
 
 	return devm_add_action_or_reset(&cxlr->dev, cxlr_dax_unregister,
-					cxlr_dax);
-err:
-	put_device(dev);
-	return rc;
+					no_free_ptr(cxlr_dax));
 }
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index f08be12e0e53..249a2f5ffc7b 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -712,6 +712,7 @@ DEFINE_FREE(put_cxl_root, struct cxl_root *, if (_T) put_device(&_T->port.dev))
 DEFINE_FREE(put_cxl_port, struct cxl_port *, if (!IS_ERR_OR_NULL(_T)) put_device(&_T->dev))
 DEFINE_FREE(put_cxl_root_decoder, struct cxl_root_decoder *, if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))
 DEFINE_FREE(put_cxl_region, struct cxl_region *, if (!IS_ERR_OR_NULL(_T)) put_device(&_T->dev))
+DEFINE_FREE(put_cxl_dax_region, struct cxl_dax_region *, if (!IS_ERR_OR_NULL(_T)) put_device(&_T->dev))
 
 int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd);
 void cxl_bus_rescan(void);
-- 
2.53.0

Re: [PATCH v5 3/3] cxl/core: use cleanup.h for devm_cxl_add_dax_region

[Ira Weiny]

Gregory Price wrote:
> Cleanup the gotos in the function.  No functional change.
> 
> Signed-off-by: Gregory Price <gourry@gourry.net>

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

[snip]

Re: [PATCH v5 0/3] pull region-specific logic into new files

[Dave Jiang]

On 3/26/26 7:02 PM, Gregory Price wrote:
> cxl/core/region.c presently contains logic to handle cxl_region,
> cxl_pmem_region, and cxl_dax_region.  The cxl_pmem_region and
> cxl_dax_region management code deserves new files to make it clear
> that this logic applies to a specific types of regions.
> 
> This also breaks up development space so fewer conflicts can occur, and
> it becomes clear where changes are actually happening.
> 
> I snuck in a cleanup.h fixup for devm_cxl_add_dax_region to tidy up some
> of the existing functions.
> 
> v4 -> v5:  Ira test fixes
>            Jonathan nit fixes
> 
> v3 -> v4:  address DJ's feedback on cleanup.h patch:
>            move __free() declaration to assignment point
>            restore local dev variable
> 
> v2 -> v3:  renamed from x_region to region_x because it's prettier
>            added cleanup.h
>            small nits asked for by Jonathan (commas)
> 
> Gregory Price (3):
>   cxl/core/region: move pmem region driver logic into region_pmem.c
>   cxl/core/region: move dax region device logic into region_dax.c
>   cxl/core: use cleanup.h for devm_cxl_add_dax_region
> 
>  drivers/cxl/core/Makefile      |   2 +-
>  drivers/cxl/core/core.h        |   2 +
>  drivers/cxl/core/region.c      | 283 ---------------------------------
>  drivers/cxl/core/region_dax.c  | 106 ++++++++++++
>  drivers/cxl/core/region_pmem.c | 191 ++++++++++++++++++++++
>  drivers/cxl/cxl.h              |   1 +
>  tools/testing/cxl/Kbuild       |   2 +-
>  7 files changed, 302 insertions(+), 285 deletions(-)
>  create mode 100644 drivers/cxl/core/region_dax.c
>  create mode 100644 drivers/cxl/core/region_pmem.c
> 

I applied to for-7.1/cxl-region-refactor branch and pushed to the cxl.git so it gets 0-day coverage. But I'm going hold off until the end to merge this in case of merge conflicts.

29990ab5cb40 cxl/core: use cleanup.h for devm_cxl_add_dax_region
d747cf98f091 cxl/core/region: move dax region device logic into region_dax.c
8a1ec5fb2360 cxl/core/region: move pmem region driver logic into region_pmem.c