[PATCH v5 0/6] CXL core reorganization

[PATCH v5 0/6] CXL core reorganization

[Dan Williams]

Changes since v4 [1]:
- Fix ARCH=um compile errors reported by 0day caused by header
  filename collisions with "mem.h", moved to "cxlmem.h"

- Improve kdoc note for @fops attribute of 'struct
  cdevm_file_operations' (Jonathan)

- Include core.h in memdev.c to fix "no prior declaration" warnings
  (kbuild robot)

- Collect reviewed-by's from Jonathan

[1]: https://lore.kernel.org/r/162774927110.4094313.9743731504096769799.stgit@dwillia2-desk3.amr.corp.intel.com

---

Original Cover from Ben:

The main motivation of the patch series is to establish the cxl_core driver in
its own directory and modularize it. Specifically, the patch series aims to
achieve three things:
1. Move existing core functionality to a new directory.
2. Split existing core functionality into multiple files.
3. Migrate memdev functionality into core.

#1 is trivially accomplished with git mv. The file itself is renamed back to
bus.c since the goal is to break up core functionality into multiple files, and
so the name core.c doesn't make sense in that context.

#2 is also trivially accomplished via cut/paste.

#3 is slightly invasive in that it has certain functional changes to improve the
existing interfaces and make them more generic. The rest of the change is
cut/paste. This is also the only part of the series which has runtime functional
change in that some interfaces are removed from cxl_pci, moved into cxl_core,
and exported for other drivers to use.

---

Ben Widawsky (3):
      cxl: Move cxl_core to new directory
      cxl/core: Improve CXL core kernel docs
      cxl/core: Move memdev management to core

Dan Williams (3):
      cxl/core: Move pmem functionality
      cxl/core: Move register mapping infrastructure
      cxl/pci: Introduce cdevm_file_operations


 Documentation/driver-api/cxl/memory-devices.rst |    8 
 drivers/cxl/Makefile                            |    4 
 drivers/cxl/core/Makefile                       |    8 
 drivers/cxl/core/bus.c                          |  464 +----------------------
 drivers/cxl/core/core.h                         |   20 +
 drivers/cxl/core/memdev.c                       |  246 ++++++++++++
 drivers/cxl/core/pmem.c                         |  204 ++++++++++
 drivers/cxl/core/regs.c                         |  235 ++++++++++++
 drivers/cxl/cxlmem.h                            |   26 +
 drivers/cxl/pci.c                               |  259 +------------
 drivers/cxl/pmem.c                              |    2 
 11 files changed, 795 insertions(+), 681 deletions(-)
 create mode 100644 drivers/cxl/core/Makefile
 rename drivers/cxl/{core.c => core/bus.c} (58%)
 create mode 100644 drivers/cxl/core/core.h
 create mode 100644 drivers/cxl/core/memdev.c
 create mode 100644 drivers/cxl/core/pmem.c
 create mode 100644 drivers/cxl/core/regs.c
 rename drivers/cxl/{mem.h => cxlmem.h} (76%)

base-commit: ff1176468d368232b684f75e82563369208bc371

[PATCH v5 1/6] cxl: Move cxl_core to new directory

[Dan Williams]

From: Ben Widawsky <ben.widawsky@intel.com>

CXL core is growing, and it's already arguably unmanageable. To support
future growth, move core functionality to a new directory and rename the
file to represent just bus support. Future work will remove non-bus
functionality.

Note that mem.h is renamed to cxlmem.h to avoid a namespace collision
with the global ARCH=um mem.h header.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 Documentation/driver-api/cxl/memory-devices.rst |    2 +-
 drivers/cxl/Makefile                            |    4 +---
 drivers/cxl/core/Makefile                       |    5 +++++
 drivers/cxl/core/bus.c                          |    4 ++--
 drivers/cxl/cxlmem.h                            |    0 
 drivers/cxl/pci.c                               |    2 +-
 drivers/cxl/pmem.c                              |    2 +-
 7 files changed, 11 insertions(+), 8 deletions(-)
 create mode 100644 drivers/cxl/core/Makefile
 rename drivers/cxl/{core.c => core/bus.c} (99%)
 rename drivers/cxl/{mem.h => cxlmem.h} (100%)

diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst
index 487ce4f41d77..a86e2c7c551a 100644
--- a/Documentation/driver-api/cxl/memory-devices.rst
+++ b/Documentation/driver-api/cxl/memory-devices.rst
@@ -36,7 +36,7 @@ CXL Core
 .. kernel-doc:: drivers/cxl/cxl.h
    :internal:
 
-.. kernel-doc:: drivers/cxl/core.c
+.. kernel-doc:: drivers/cxl/core/bus.c
    :doc: cxl core
 
 External Interfaces
diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile
index 32954059b37b..d1aaabc940f3 100644
--- a/drivers/cxl/Makefile
+++ b/drivers/cxl/Makefile
@@ -1,11 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0
-obj-$(CONFIG_CXL_BUS) += cxl_core.o
+obj-$(CONFIG_CXL_BUS) += core/
 obj-$(CONFIG_CXL_MEM) += cxl_pci.o
 obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o
 obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o
 
-ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL
-cxl_core-y := core.o
 cxl_pci-y := pci.o
 cxl_acpi-y := acpi.o
 cxl_pmem-y := pmem.o
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
new file mode 100644
index 000000000000..ad137f96e5c8
--- /dev/null
+++ b/drivers/cxl/core/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CXL_BUS) += cxl_core.o
+
+ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL -I$(srctree)/drivers/cxl
+cxl_core-y := bus.o
diff --git a/drivers/cxl/core.c b/drivers/cxl/core/bus.c
similarity index 99%
rename from drivers/cxl/core.c
rename to drivers/cxl/core/bus.c
index a2e4d54fc7bc..0815eec23944 100644
--- a/drivers/cxl/core.c
+++ b/drivers/cxl/core/bus.c
@@ -6,8 +6,8 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
-#include "cxl.h"
-#include "mem.h"
+#include <cxlmem.h>
+#include <cxl.h>
 
 /**
  * DOC: cxl core
diff --git a/drivers/cxl/mem.h b/drivers/cxl/cxlmem.h
similarity index 100%
rename from drivers/cxl/mem.h
rename to drivers/cxl/cxlmem.h
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 4cf351a3cf99..a945c5fda292 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -12,9 +12,9 @@
 #include <linux/pci.h>
 #include <linux/io.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
+#include "cxlmem.h"
 #include "pci.h"
 #include "cxl.h"
-#include "mem.h"
 
 /**
  * DOC: cxl pci
diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
index 0088e41dd2f3..9652c3ee41e7 100644
--- a/drivers/cxl/pmem.c
+++ b/drivers/cxl/pmem.c
@@ -6,7 +6,7 @@
 #include <linux/ndctl.h>
 #include <linux/async.h>
 #include <linux/slab.h>
-#include "mem.h"
+#include "cxlmem.h"
 #include "cxl.h"
 
 /*

[PATCH v5 2/6] cxl/core: Improve CXL core kernel docs

[Dan Williams]

From: Ben Widawsky <ben.widawsky@intel.com>

Now that CXL core's role is well understood, the documentation should
reflect that information.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/core/bus.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
index 0815eec23944..6ea69d70086b 100644
--- a/drivers/cxl/core/bus.c
+++ b/drivers/cxl/core/bus.c
@@ -12,8 +12,15 @@
 /**
  * DOC: cxl core
  *
- * The CXL core provides a sysfs hierarchy for control devices and a rendezvous
- * point for cross-device interleave coordination through cxl ports.
+ * The CXL core provides a set of interfaces that can be consumed by CXL aware
+ * drivers. The interfaces allow for creation, modification, and destruction of
+ * regions, memory devices, ports, and decoders. CXL aware drivers must register
+ * with the CXL core via these interfaces in order to be able to participate in
+ * cross-device interleave coordination. The CXL core also establishes and
+ * maintains the bridge to the nvdimm subsystem.
+ *
+ * CXL core introduces sysfs hierarchy to control the devices that are
+ * instantiated by the core.
  */
 
 static DEFINE_IDA(cxl_port_ida);

[PATCH v5 3/6] cxl/core: Move pmem functionality

[Dan Williams]

Refactor the pmem / nvdimm-bridge functionality from core/bus.c to
core/pmem.c. Introduce drivers/core/core.h to communicate data
structures and helpers between the core bus and other functionality that
registers devices on the bus.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 Documentation/driver-api/cxl/memory-devices.rst |    3 
 drivers/cxl/core/Makefile                       |    1 
 drivers/cxl/core/bus.c                          |  205 -----------------------
 drivers/cxl/core/core.h                         |   17 ++
 drivers/cxl/core/pmem.c                         |  204 +++++++++++++++++++++++
 5 files changed, 228 insertions(+), 202 deletions(-)
 create mode 100644 drivers/cxl/core/core.h
 create mode 100644 drivers/cxl/core/pmem.c

diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst
index a86e2c7c551a..e65c0ba82229 100644
--- a/Documentation/driver-api/cxl/memory-devices.rst
+++ b/Documentation/driver-api/cxl/memory-devices.rst
@@ -39,6 +39,9 @@ CXL Core
 .. kernel-doc:: drivers/cxl/core/bus.c
    :doc: cxl core
 
+.. kernel-doc:: drivers/cxl/core/pmem.c
+   :internal:
+
 External Interfaces
 ===================
 
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index ad137f96e5c8..e037521fe02b 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_CXL_BUS) += cxl_core.o
 
 ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL -I$(srctree)/drivers/cxl
 cxl_core-y := bus.o
+cxl_core-y += pmem.o
diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
index 6ea69d70086b..408654ad70db 100644
--- a/drivers/cxl/core/bus.c
+++ b/drivers/cxl/core/bus.c
@@ -8,6 +8,7 @@
 #include <linux/idr.h>
 #include <cxlmem.h>
 #include <cxl.h>
+#include "core.h"
 
 /**
  * DOC: cxl core
@@ -37,7 +38,7 @@ static struct attribute *cxl_base_attributes[] = {
 	NULL,
 };
 
-static struct attribute_group cxl_base_attribute_group = {
+struct attribute_group cxl_base_attribute_group = {
 	.attrs = cxl_base_attributes,
 };
 
@@ -514,11 +515,6 @@ cxl_decoder_alloc(struct cxl_port *port, int nr_targets, resource_size_t base,
 	return ERR_PTR(rc);
 }
 
-static void unregister_dev(void *dev)
-{
-	device_unregister(dev);
-}
-
 struct cxl_decoder *
 devm_cxl_add_decoder(struct device *host, struct cxl_port *port, int nr_targets,
 		     resource_size_t base, resource_size_t len,
@@ -543,7 +539,7 @@ devm_cxl_add_decoder(struct device *host, struct cxl_port *port, int nr_targets,
 	if (rc)
 		goto err;
 
-	rc = devm_add_action_or_reset(host, unregister_dev, dev);
+	rc = devm_add_action_or_reset(host, unregister_cxl_dev, dev);
 	if (rc)
 		return ERR_PTR(rc);
 	return cxld;
@@ -626,201 +622,6 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 }
 EXPORT_SYMBOL_GPL(cxl_probe_component_regs);
 
-static void cxl_nvdimm_bridge_release(struct device *dev)
-{
-	struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
-
-	kfree(cxl_nvb);
-}
-
-static const struct attribute_group *cxl_nvdimm_bridge_attribute_groups[] = {
-	&cxl_base_attribute_group,
-	NULL,
-};
-
-static const struct device_type cxl_nvdimm_bridge_type = {
-	.name = "cxl_nvdimm_bridge",
-	.release = cxl_nvdimm_bridge_release,
-	.groups = cxl_nvdimm_bridge_attribute_groups,
-};
-
-struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev)
-{
-	if (dev_WARN_ONCE(dev, dev->type != &cxl_nvdimm_bridge_type,
-			  "not a cxl_nvdimm_bridge device\n"))
-		return NULL;
-	return container_of(dev, struct cxl_nvdimm_bridge, dev);
-}
-EXPORT_SYMBOL_GPL(to_cxl_nvdimm_bridge);
-
-static struct cxl_nvdimm_bridge *
-cxl_nvdimm_bridge_alloc(struct cxl_port *port)
-{
-	struct cxl_nvdimm_bridge *cxl_nvb;
-	struct device *dev;
-
-	cxl_nvb = kzalloc(sizeof(*cxl_nvb), GFP_KERNEL);
-	if (!cxl_nvb)
-		return ERR_PTR(-ENOMEM);
-
-	dev = &cxl_nvb->dev;
-	cxl_nvb->port = port;
-	cxl_nvb->state = CXL_NVB_NEW;
-	device_initialize(dev);
-	device_set_pm_not_required(dev);
-	dev->parent = &port->dev;
-	dev->bus = &cxl_bus_type;
-	dev->type = &cxl_nvdimm_bridge_type;
-
-	return cxl_nvb;
-}
-
-static void unregister_nvb(void *_cxl_nvb)
-{
-	struct cxl_nvdimm_bridge *cxl_nvb = _cxl_nvb;
-	bool flush;
-
-	/*
-	 * If the bridge was ever activated then there might be in-flight state
-	 * work to flush. Once the state has been changed to 'dead' then no new
-	 * work can be queued by user-triggered bind.
-	 */
-	device_lock(&cxl_nvb->dev);
-	flush = cxl_nvb->state != CXL_NVB_NEW;
-	cxl_nvb->state = CXL_NVB_DEAD;
-	device_unlock(&cxl_nvb->dev);
-
-	/*
-	 * Even though the device core will trigger device_release_driver()
-	 * before the unregister, it does not know about the fact that
-	 * cxl_nvdimm_bridge_driver defers ->remove() work. So, do the driver
-	 * release not and flush it before tearing down the nvdimm device
-	 * hierarchy.
-	 */
-	device_release_driver(&cxl_nvb->dev);
-	if (flush)
-		flush_work(&cxl_nvb->state_work);
-	device_unregister(&cxl_nvb->dev);
-}
-
-struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
-						     struct cxl_port *port)
-{
-	struct cxl_nvdimm_bridge *cxl_nvb;
-	struct device *dev;
-	int rc;
-
-	if (!IS_ENABLED(CONFIG_CXL_PMEM))
-		return ERR_PTR(-ENXIO);
-
-	cxl_nvb = cxl_nvdimm_bridge_alloc(port);
-	if (IS_ERR(cxl_nvb))
-		return cxl_nvb;
-
-	dev = &cxl_nvb->dev;
-	rc = dev_set_name(dev, "nvdimm-bridge");
-	if (rc)
-		goto err;
-
-	rc = device_add(dev);
-	if (rc)
-		goto err;
-
-	rc = devm_add_action_or_reset(host, unregister_nvb, cxl_nvb);
-	if (rc)
-		return ERR_PTR(rc);
-
-	return cxl_nvb;
-
-err:
-	put_device(dev);
-	return ERR_PTR(rc);
-}
-EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm_bridge);
-
-static void cxl_nvdimm_release(struct device *dev)
-{
-	struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
-
-	kfree(cxl_nvd);
-}
-
-static const struct attribute_group *cxl_nvdimm_attribute_groups[] = {
-	&cxl_base_attribute_group,
-	NULL,
-};
-
-static const struct device_type cxl_nvdimm_type = {
-	.name = "cxl_nvdimm",
-	.release = cxl_nvdimm_release,
-	.groups = cxl_nvdimm_attribute_groups,
-};
-
-bool is_cxl_nvdimm(struct device *dev)
-{
-	return dev->type == &cxl_nvdimm_type;
-}
-EXPORT_SYMBOL_GPL(is_cxl_nvdimm);
-
-struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev)
-{
-	if (dev_WARN_ONCE(dev, !is_cxl_nvdimm(dev),
-			  "not a cxl_nvdimm device\n"))
-		return NULL;
-	return container_of(dev, struct cxl_nvdimm, dev);
-}
-EXPORT_SYMBOL_GPL(to_cxl_nvdimm);
-
-static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd)
-{
-	struct cxl_nvdimm *cxl_nvd;
-	struct device *dev;
-
-	cxl_nvd = kzalloc(sizeof(*cxl_nvd), GFP_KERNEL);
-	if (!cxl_nvd)
-		return ERR_PTR(-ENOMEM);
-
-	dev = &cxl_nvd->dev;
-	cxl_nvd->cxlmd = cxlmd;
-	device_initialize(dev);
-	device_set_pm_not_required(dev);
-	dev->parent = &cxlmd->dev;
-	dev->bus = &cxl_bus_type;
-	dev->type = &cxl_nvdimm_type;
-
-	return cxl_nvd;
-}
-
-int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd)
-{
-	struct cxl_nvdimm *cxl_nvd;
-	struct device *dev;
-	int rc;
-
-	cxl_nvd = cxl_nvdimm_alloc(cxlmd);
-	if (IS_ERR(cxl_nvd))
-		return PTR_ERR(cxl_nvd);
-
-	dev = &cxl_nvd->dev;
-	rc = dev_set_name(dev, "pmem%d", cxlmd->id);
-	if (rc)
-		goto err;
-
-	rc = device_add(dev);
-	if (rc)
-		goto err;
-
-	dev_dbg(host, "%s: register %s\n", dev_name(dev->parent),
-		dev_name(dev));
-
-	return devm_add_action_or_reset(host, unregister_dev, dev);
-
-err:
-	put_device(dev);
-	return rc;
-}
-EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm);
-
 /**
  * cxl_probe_device_regs() - Detect CXL Device register blocks
  * @dev: Host device of the @base mapping
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
new file mode 100644
index 000000000000..49045daf8bd7
--- /dev/null
+++ b/drivers/cxl/core/core.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2020 Intel Corporation. */
+
+#ifndef __CXL_CORE_H__
+#define __CXL_CORE_H__
+
+extern const struct device_type cxl_nvdimm_bridge_type;
+extern const struct device_type cxl_nvdimm_type;
+
+extern struct attribute_group cxl_base_attribute_group;
+
+static inline void unregister_cxl_dev(void *dev)
+{
+	device_unregister(dev);
+}
+
+#endif /* __CXL_CORE_H__ */
diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c
new file mode 100644
index 000000000000..69c97cc0d945
--- /dev/null
+++ b/drivers/cxl/core/pmem.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. */
+
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <cxlmem.h>
+#include <cxl.h>
+
+#include "core.h"
+
+static void cxl_nvdimm_bridge_release(struct device *dev)
+{
+	struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
+
+	kfree(cxl_nvb);
+}
+
+static const struct attribute_group *cxl_nvdimm_bridge_attribute_groups[] = {
+	&cxl_base_attribute_group,
+	NULL,
+};
+
+const struct device_type cxl_nvdimm_bridge_type = {
+	.name = "cxl_nvdimm_bridge",
+	.release = cxl_nvdimm_bridge_release,
+	.groups = cxl_nvdimm_bridge_attribute_groups,
+};
+
+struct cxl_nvdimm_bridge *to_cxl_nvdimm_bridge(struct device *dev)
+{
+	if (dev_WARN_ONCE(dev, dev->type != &cxl_nvdimm_bridge_type,
+			  "not a cxl_nvdimm_bridge device\n"))
+		return NULL;
+	return container_of(dev, struct cxl_nvdimm_bridge, dev);
+}
+EXPORT_SYMBOL_GPL(to_cxl_nvdimm_bridge);
+
+static struct cxl_nvdimm_bridge *
+cxl_nvdimm_bridge_alloc(struct cxl_port *port)
+{
+	struct cxl_nvdimm_bridge *cxl_nvb;
+	struct device *dev;
+
+	cxl_nvb = kzalloc(sizeof(*cxl_nvb), GFP_KERNEL);
+	if (!cxl_nvb)
+		return ERR_PTR(-ENOMEM);
+
+	dev = &cxl_nvb->dev;
+	cxl_nvb->port = port;
+	cxl_nvb->state = CXL_NVB_NEW;
+	device_initialize(dev);
+	device_set_pm_not_required(dev);
+	dev->parent = &port->dev;
+	dev->bus = &cxl_bus_type;
+	dev->type = &cxl_nvdimm_bridge_type;
+
+	return cxl_nvb;
+}
+
+static void unregister_nvb(void *_cxl_nvb)
+{
+	struct cxl_nvdimm_bridge *cxl_nvb = _cxl_nvb;
+	bool flush;
+
+	/*
+	 * If the bridge was ever activated then there might be in-flight state
+	 * work to flush. Once the state has been changed to 'dead' then no new
+	 * work can be queued by user-triggered bind.
+	 */
+	device_lock(&cxl_nvb->dev);
+	flush = cxl_nvb->state != CXL_NVB_NEW;
+	cxl_nvb->state = CXL_NVB_DEAD;
+	device_unlock(&cxl_nvb->dev);
+
+	/*
+	 * Even though the device core will trigger device_release_driver()
+	 * before the unregister, it does not know about the fact that
+	 * cxl_nvdimm_bridge_driver defers ->remove() work. So, do the driver
+	 * release not and flush it before tearing down the nvdimm device
+	 * hierarchy.
+	 */
+	device_release_driver(&cxl_nvb->dev);
+	if (flush)
+		flush_work(&cxl_nvb->state_work);
+	device_unregister(&cxl_nvb->dev);
+}
+
+struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
+						     struct cxl_port *port)
+{
+	struct cxl_nvdimm_bridge *cxl_nvb;
+	struct device *dev;
+	int rc;
+
+	if (!IS_ENABLED(CONFIG_CXL_PMEM))
+		return ERR_PTR(-ENXIO);
+
+	cxl_nvb = cxl_nvdimm_bridge_alloc(port);
+	if (IS_ERR(cxl_nvb))
+		return cxl_nvb;
+
+	dev = &cxl_nvb->dev;
+	rc = dev_set_name(dev, "nvdimm-bridge");
+	if (rc)
+		goto err;
+
+	rc = device_add(dev);
+	if (rc)
+		goto err;
+
+	rc = devm_add_action_or_reset(host, unregister_nvb, cxl_nvb);
+	if (rc)
+		return ERR_PTR(rc);
+
+	return cxl_nvb;
+
+err:
+	put_device(dev);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm_bridge);
+
+static void cxl_nvdimm_release(struct device *dev)
+{
+	struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
+
+	kfree(cxl_nvd);
+}
+
+static const struct attribute_group *cxl_nvdimm_attribute_groups[] = {
+	&cxl_base_attribute_group,
+	NULL,
+};
+
+const struct device_type cxl_nvdimm_type = {
+	.name = "cxl_nvdimm",
+	.release = cxl_nvdimm_release,
+	.groups = cxl_nvdimm_attribute_groups,
+};
+
+bool is_cxl_nvdimm(struct device *dev)
+{
+	return dev->type == &cxl_nvdimm_type;
+}
+EXPORT_SYMBOL_GPL(is_cxl_nvdimm);
+
+struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev)
+{
+	if (dev_WARN_ONCE(dev, !is_cxl_nvdimm(dev),
+			  "not a cxl_nvdimm device\n"))
+		return NULL;
+	return container_of(dev, struct cxl_nvdimm, dev);
+}
+EXPORT_SYMBOL_GPL(to_cxl_nvdimm);
+
+static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd)
+{
+	struct cxl_nvdimm *cxl_nvd;
+	struct device *dev;
+
+	cxl_nvd = kzalloc(sizeof(*cxl_nvd), GFP_KERNEL);
+	if (!cxl_nvd)
+		return ERR_PTR(-ENOMEM);
+
+	dev = &cxl_nvd->dev;
+	cxl_nvd->cxlmd = cxlmd;
+	device_initialize(dev);
+	device_set_pm_not_required(dev);
+	dev->parent = &cxlmd->dev;
+	dev->bus = &cxl_bus_type;
+	dev->type = &cxl_nvdimm_type;
+
+	return cxl_nvd;
+}
+
+int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd)
+{
+	struct cxl_nvdimm *cxl_nvd;
+	struct device *dev;
+	int rc;
+
+	cxl_nvd = cxl_nvdimm_alloc(cxlmd);
+	if (IS_ERR(cxl_nvd))
+		return PTR_ERR(cxl_nvd);
+
+	dev = &cxl_nvd->dev;
+	rc = dev_set_name(dev, "pmem%d", cxlmd->id);
+	if (rc)
+		goto err;
+
+	rc = device_add(dev);
+	if (rc)
+		goto err;
+
+	dev_dbg(host, "%s: register %s\n", dev_name(dev->parent),
+		dev_name(dev));
+
+	return devm_add_action_or_reset(host, unregister_cxl_dev, dev);
+
+err:
+	put_device(dev);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_nvdimm);

[PATCH v5 4/6] cxl/core: Move register mapping infrastructure

[Dan Williams]

The register mapping infrastructure is large enough to move to its own
compilation unit. This also cleans up an unnecessary include of <mem.h>
core/bus.c.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 Documentation/driver-api/cxl/memory-devices.rst |    3 
 drivers/cxl/core/Makefile                       |    1 
 drivers/cxl/core/bus.c                          |  228 ----------------------
 drivers/cxl/core/regs.c                         |  235 +++++++++++++++++++++++
 4 files changed, 239 insertions(+), 228 deletions(-)
 create mode 100644 drivers/cxl/core/regs.c

diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst
index e65c0ba82229..46847d8c70a0 100644
--- a/Documentation/driver-api/cxl/memory-devices.rst
+++ b/Documentation/driver-api/cxl/memory-devices.rst
@@ -42,6 +42,9 @@ CXL Core
 .. kernel-doc:: drivers/cxl/core/pmem.c
    :internal:
 
+.. kernel-doc:: drivers/cxl/core/regs.c
+   :internal:
+
 External Interfaces
 ===================
 
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index e037521fe02b..a3522d2fbf5b 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_CXL_BUS) += cxl_core.o
 ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL -I$(srctree)/drivers/cxl
 cxl_core-y := bus.o
 cxl_core-y += pmem.o
+cxl_core-y += regs.o
diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
index 408654ad70db..c938d8590c9f 100644
--- a/drivers/cxl/core/bus.c
+++ b/drivers/cxl/core/bus.c
@@ -550,234 +550,6 @@ devm_cxl_add_decoder(struct device *host, struct cxl_port *port, int nr_targets,
 }
 EXPORT_SYMBOL_GPL(devm_cxl_add_decoder);
 
-/**
- * cxl_probe_component_regs() - Detect CXL Component register blocks
- * @dev: Host device of the @base mapping
- * @base: Mapping containing the HDM Decoder Capability Header
- * @map: Map object describing the register block information found
- *
- * See CXL 2.0 8.2.4 Component Register Layout and Definition
- * See CXL 2.0 8.2.5.5 CXL Device Register Interface
- *
- * Probe for component register information and return it in map object.
- */
-void cxl_probe_component_regs(struct device *dev, void __iomem *base,
-			      struct cxl_component_reg_map *map)
-{
-	int cap, cap_count;
-	u64 cap_array;
-
-	*map = (struct cxl_component_reg_map) { 0 };
-
-	/*
-	 * CXL.cache and CXL.mem registers are at offset 0x1000 as defined in
-	 * CXL 2.0 8.2.4 Table 141.
-	 */
-	base += CXL_CM_OFFSET;
-
-	cap_array = readq(base + CXL_CM_CAP_HDR_OFFSET);
-
-	if (FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, cap_array) != CM_CAP_HDR_CAP_ID) {
-		dev_err(dev,
-			"Couldn't locate the CXL.cache and CXL.mem capability array header./n");
-		return;
-	}
-
-	/* It's assumed that future versions will be backward compatible */
-	cap_count = FIELD_GET(CXL_CM_CAP_HDR_ARRAY_SIZE_MASK, cap_array);
-
-	for (cap = 1; cap <= cap_count; cap++) {
-		void __iomem *register_block;
-		u32 hdr;
-		int decoder_cnt;
-		u16 cap_id, offset;
-		u32 length;
-
-		hdr = readl(base + cap * 0x4);
-
-		cap_id = FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, hdr);
-		offset = FIELD_GET(CXL_CM_CAP_PTR_MASK, hdr);
-		register_block = base + offset;
-
-		switch (cap_id) {
-		case CXL_CM_CAP_CAP_ID_HDM:
-			dev_dbg(dev, "found HDM decoder capability (0x%x)\n",
-				offset);
-
-			hdr = readl(register_block);
-
-			decoder_cnt = cxl_hdm_decoder_count(hdr);
-			length = 0x20 * decoder_cnt + 0x10;
-
-			map->hdm_decoder.valid = true;
-			map->hdm_decoder.offset = CXL_CM_OFFSET + offset;
-			map->hdm_decoder.size = length;
-			break;
-		default:
-			dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id,
-				offset);
-			break;
-		}
-	}
-}
-EXPORT_SYMBOL_GPL(cxl_probe_component_regs);
-
-/**
- * cxl_probe_device_regs() - Detect CXL Device register blocks
- * @dev: Host device of the @base mapping
- * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface
- * @map: Map object describing the register block information found
- *
- * Probe for device register information and return it in map object.
- */
-void cxl_probe_device_regs(struct device *dev, void __iomem *base,
-			   struct cxl_device_reg_map *map)
-{
-	int cap, cap_count;
-	u64 cap_array;
-
-	*map = (struct cxl_device_reg_map){ 0 };
-
-	cap_array = readq(base + CXLDEV_CAP_ARRAY_OFFSET);
-	if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
-	    CXLDEV_CAP_ARRAY_CAP_ID)
-		return;
-
-	cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array);
-
-	for (cap = 1; cap <= cap_count; cap++) {
-		u32 offset, length;
-		u16 cap_id;
-
-		cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK,
-				   readl(base + cap * 0x10));
-		offset = readl(base + cap * 0x10 + 0x4);
-		length = readl(base + cap * 0x10 + 0x8);
-
-		switch (cap_id) {
-		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
-			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
-
-			map->status.valid = true;
-			map->status.offset = offset;
-			map->status.size = length;
-			break;
-		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
-			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
-			map->mbox.valid = true;
-			map->mbox.offset = offset;
-			map->mbox.size = length;
-			break;
-		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
-			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
-			break;
-		case CXLDEV_CAP_CAP_ID_MEMDEV:
-			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
-			map->memdev.valid = true;
-			map->memdev.offset = offset;
-			map->memdev.size = length;
-			break;
-		default:
-			if (cap_id >= 0x8000)
-				dev_dbg(dev, "Vendor cap ID: %#x offset: %#x\n", cap_id, offset);
-			else
-				dev_dbg(dev, "Unknown cap ID: %#x offset: %#x\n", cap_id, offset);
-			break;
-		}
-	}
-}
-EXPORT_SYMBOL_GPL(cxl_probe_device_regs);
-
-static void __iomem *devm_cxl_iomap_block(struct device *dev,
-					  resource_size_t addr,
-					  resource_size_t length)
-{
-	void __iomem *ret_val;
-	struct resource *res;
-
-	res = devm_request_mem_region(dev, addr, length, dev_name(dev));
-	if (!res) {
-		resource_size_t end = addr + length - 1;
-
-		dev_err(dev, "Failed to request region %pa-%pa\n", &addr, &end);
-		return NULL;
-	}
-
-	ret_val = devm_ioremap(dev, addr, length);
-	if (!ret_val)
-		dev_err(dev, "Failed to map region %pr\n", res);
-
-	return ret_val;
-}
-
-int cxl_map_component_regs(struct pci_dev *pdev,
-			   struct cxl_component_regs *regs,
-			   struct cxl_register_map *map)
-{
-	struct device *dev = &pdev->dev;
-	resource_size_t phys_addr;
-	resource_size_t length;
-
-	phys_addr = pci_resource_start(pdev, map->barno);
-	phys_addr += map->block_offset;
-
-	phys_addr += map->component_map.hdm_decoder.offset;
-	length = map->component_map.hdm_decoder.size;
-	regs->hdm_decoder = devm_cxl_iomap_block(dev, phys_addr, length);
-	if (!regs->hdm_decoder)
-		return -ENOMEM;
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(cxl_map_component_regs);
-
-int cxl_map_device_regs(struct pci_dev *pdev,
-			struct cxl_device_regs *regs,
-			struct cxl_register_map *map)
-{
-	struct device *dev = &pdev->dev;
-	resource_size_t phys_addr;
-
-	phys_addr = pci_resource_start(pdev, map->barno);
-	phys_addr += map->block_offset;
-
-	if (map->device_map.status.valid) {
-		resource_size_t addr;
-		resource_size_t length;
-
-		addr = phys_addr + map->device_map.status.offset;
-		length = map->device_map.status.size;
-		regs->status = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->status)
-			return -ENOMEM;
-	}
-
-	if (map->device_map.mbox.valid) {
-		resource_size_t addr;
-		resource_size_t length;
-
-		addr = phys_addr + map->device_map.mbox.offset;
-		length = map->device_map.mbox.size;
-		regs->mbox = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->mbox)
-			return -ENOMEM;
-	}
-
-	if (map->device_map.memdev.valid) {
-		resource_size_t addr;
-		resource_size_t length;
-
-		addr = phys_addr + map->device_map.memdev.offset;
-		length = map->device_map.memdev.size;
-		regs->memdev = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->memdev)
-			return -ENOMEM;
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(cxl_map_device_regs);
-
 /**
  * __cxl_driver_register - register a driver for the cxl bus
  * @cxl_drv: cxl driver structure to attach
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
new file mode 100644
index 000000000000..d196536b347f
--- /dev/null
+++ b/drivers/cxl/core/regs.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. */
+
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <cxlmem.h>
+
+/**
+ * cxl_probe_component_regs() - Detect CXL Component register blocks
+ * @dev: Host device of the @base mapping
+ * @base: Mapping containing the HDM Decoder Capability Header
+ * @map: Map object describing the register block information found
+ *
+ * See CXL 2.0 8.2.4 Component Register Layout and Definition
+ * See CXL 2.0 8.2.5.5 CXL Device Register Interface
+ *
+ * Probe for component register information and return it in map object.
+ */
+void cxl_probe_component_regs(struct device *dev, void __iomem *base,
+			      struct cxl_component_reg_map *map)
+{
+	int cap, cap_count;
+	u64 cap_array;
+
+	*map = (struct cxl_component_reg_map) { 0 };
+
+	/*
+	 * CXL.cache and CXL.mem registers are at offset 0x1000 as defined in
+	 * CXL 2.0 8.2.4 Table 141.
+	 */
+	base += CXL_CM_OFFSET;
+
+	cap_array = readq(base + CXL_CM_CAP_HDR_OFFSET);
+
+	if (FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, cap_array) != CM_CAP_HDR_CAP_ID) {
+		dev_err(dev,
+			"Couldn't locate the CXL.cache and CXL.mem capability array header./n");
+		return;
+	}
+
+	/* It's assumed that future versions will be backward compatible */
+	cap_count = FIELD_GET(CXL_CM_CAP_HDR_ARRAY_SIZE_MASK, cap_array);
+
+	for (cap = 1; cap <= cap_count; cap++) {
+		void __iomem *register_block;
+		u32 hdr;
+		int decoder_cnt;
+		u16 cap_id, offset;
+		u32 length;
+
+		hdr = readl(base + cap * 0x4);
+
+		cap_id = FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, hdr);
+		offset = FIELD_GET(CXL_CM_CAP_PTR_MASK, hdr);
+		register_block = base + offset;
+
+		switch (cap_id) {
+		case CXL_CM_CAP_CAP_ID_HDM:
+			dev_dbg(dev, "found HDM decoder capability (0x%x)\n",
+				offset);
+
+			hdr = readl(register_block);
+
+			decoder_cnt = cxl_hdm_decoder_count(hdr);
+			length = 0x20 * decoder_cnt + 0x10;
+
+			map->hdm_decoder.valid = true;
+			map->hdm_decoder.offset = CXL_CM_OFFSET + offset;
+			map->hdm_decoder.size = length;
+			break;
+		default:
+			dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id,
+				offset);
+			break;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(cxl_probe_component_regs);
+
+/**
+ * cxl_probe_device_regs() - Detect CXL Device register blocks
+ * @dev: Host device of the @base mapping
+ * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface
+ * @map: Map object describing the register block information found
+ *
+ * Probe for device register information and return it in map object.
+ */
+void cxl_probe_device_regs(struct device *dev, void __iomem *base,
+			   struct cxl_device_reg_map *map)
+{
+	int cap, cap_count;
+	u64 cap_array;
+
+	*map = (struct cxl_device_reg_map){ 0 };
+
+	cap_array = readq(base + CXLDEV_CAP_ARRAY_OFFSET);
+	if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
+	    CXLDEV_CAP_ARRAY_CAP_ID)
+		return;
+
+	cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array);
+
+	for (cap = 1; cap <= cap_count; cap++) {
+		u32 offset, length;
+		u16 cap_id;
+
+		cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK,
+				   readl(base + cap * 0x10));
+		offset = readl(base + cap * 0x10 + 0x4);
+		length = readl(base + cap * 0x10 + 0x8);
+
+		switch (cap_id) {
+		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
+			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
+
+			map->status.valid = true;
+			map->status.offset = offset;
+			map->status.size = length;
+			break;
+		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
+			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
+			map->mbox.valid = true;
+			map->mbox.offset = offset;
+			map->mbox.size = length;
+			break;
+		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
+			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
+			break;
+		case CXLDEV_CAP_CAP_ID_MEMDEV:
+			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
+			map->memdev.valid = true;
+			map->memdev.offset = offset;
+			map->memdev.size = length;
+			break;
+		default:
+			if (cap_id >= 0x8000)
+				dev_dbg(dev, "Vendor cap ID: %#x offset: %#x\n", cap_id, offset);
+			else
+				dev_dbg(dev, "Unknown cap ID: %#x offset: %#x\n", cap_id, offset);
+			break;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(cxl_probe_device_regs);
+
+static void __iomem *devm_cxl_iomap_block(struct device *dev,
+					  resource_size_t addr,
+					  resource_size_t length)
+{
+	void __iomem *ret_val;
+	struct resource *res;
+
+	res = devm_request_mem_region(dev, addr, length, dev_name(dev));
+	if (!res) {
+		resource_size_t end = addr + length - 1;
+
+		dev_err(dev, "Failed to request region %pa-%pa\n", &addr, &end);
+		return NULL;
+	}
+
+	ret_val = devm_ioremap(dev, addr, length);
+	if (!ret_val)
+		dev_err(dev, "Failed to map region %pr\n", res);
+
+	return ret_val;
+}
+
+int cxl_map_component_regs(struct pci_dev *pdev,
+			   struct cxl_component_regs *regs,
+			   struct cxl_register_map *map)
+{
+	struct device *dev = &pdev->dev;
+	resource_size_t phys_addr;
+	resource_size_t length;
+
+	phys_addr = pci_resource_start(pdev, map->barno);
+	phys_addr += map->block_offset;
+
+	phys_addr += map->component_map.hdm_decoder.offset;
+	length = map->component_map.hdm_decoder.size;
+	regs->hdm_decoder = devm_cxl_iomap_block(dev, phys_addr, length);
+	if (!regs->hdm_decoder)
+		return -ENOMEM;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_map_component_regs);
+
+int cxl_map_device_regs(struct pci_dev *pdev,
+			struct cxl_device_regs *regs,
+			struct cxl_register_map *map)
+{
+	struct device *dev = &pdev->dev;
+	resource_size_t phys_addr;
+
+	phys_addr = pci_resource_start(pdev, map->barno);
+	phys_addr += map->block_offset;
+
+	if (map->device_map.status.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.status.offset;
+		length = map->device_map.status.size;
+		regs->status = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->status)
+			return -ENOMEM;
+	}
+
+	if (map->device_map.mbox.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.mbox.offset;
+		length = map->device_map.mbox.size;
+		regs->mbox = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->mbox)
+			return -ENOMEM;
+	}
+
+	if (map->device_map.memdev.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.memdev.offset;
+		length = map->device_map.memdev.size;
+		regs->memdev = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->memdev)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_map_device_regs);

[PATCH v6 4/6] cxl/core: Move register mapping infrastructure

[Dan Williams]

The register mapping infrastructure is large enough to move to its own
compilation unit. This also cleans up an unnecessary include of <mem.h>
core/bus.c.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
Changes since v5:

- Fix missing include of io-64-nonatomic-lo-hi.h

 Documentation/driver-api/cxl/memory-devices.rst |    3 
 drivers/cxl/core/Makefile                       |    1 
 drivers/cxl/core/bus.c                          |  228 ----------------------
 drivers/cxl/core/regs.c                         |  236 +++++++++++++++++++++++
 4 files changed, 240 insertions(+), 228 deletions(-)
 create mode 100644 drivers/cxl/core/regs.c

diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst
index e65c0ba82229..46847d8c70a0 100644
--- a/Documentation/driver-api/cxl/memory-devices.rst
+++ b/Documentation/driver-api/cxl/memory-devices.rst
@@ -42,6 +42,9 @@ CXL Core
 .. kernel-doc:: drivers/cxl/core/pmem.c
    :internal:
 
+.. kernel-doc:: drivers/cxl/core/regs.c
+   :internal:
+
 External Interfaces
 ===================
 
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index e037521fe02b..a3522d2fbf5b 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_CXL_BUS) += cxl_core.o
 ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL -I$(srctree)/drivers/cxl
 cxl_core-y := bus.o
 cxl_core-y += pmem.o
+cxl_core-y += regs.o
diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
index 408654ad70db..c938d8590c9f 100644
--- a/drivers/cxl/core/bus.c
+++ b/drivers/cxl/core/bus.c
@@ -550,234 +550,6 @@ devm_cxl_add_decoder(struct device *host, struct cxl_port *port, int nr_targets,
 }
 EXPORT_SYMBOL_GPL(devm_cxl_add_decoder);
 
-/**
- * cxl_probe_component_regs() - Detect CXL Component register blocks
- * @dev: Host device of the @base mapping
- * @base: Mapping containing the HDM Decoder Capability Header
- * @map: Map object describing the register block information found
- *
- * See CXL 2.0 8.2.4 Component Register Layout and Definition
- * See CXL 2.0 8.2.5.5 CXL Device Register Interface
- *
- * Probe for component register information and return it in map object.
- */
-void cxl_probe_component_regs(struct device *dev, void __iomem *base,
-			      struct cxl_component_reg_map *map)
-{
-	int cap, cap_count;
-	u64 cap_array;
-
-	*map = (struct cxl_component_reg_map) { 0 };
-
-	/*
-	 * CXL.cache and CXL.mem registers are at offset 0x1000 as defined in
-	 * CXL 2.0 8.2.4 Table 141.
-	 */
-	base += CXL_CM_OFFSET;
-
-	cap_array = readq(base + CXL_CM_CAP_HDR_OFFSET);
-
-	if (FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, cap_array) != CM_CAP_HDR_CAP_ID) {
-		dev_err(dev,
-			"Couldn't locate the CXL.cache and CXL.mem capability array header./n");
-		return;
-	}
-
-	/* It's assumed that future versions will be backward compatible */
-	cap_count = FIELD_GET(CXL_CM_CAP_HDR_ARRAY_SIZE_MASK, cap_array);
-
-	for (cap = 1; cap <= cap_count; cap++) {
-		void __iomem *register_block;
-		u32 hdr;
-		int decoder_cnt;
-		u16 cap_id, offset;
-		u32 length;
-
-		hdr = readl(base + cap * 0x4);
-
-		cap_id = FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, hdr);
-		offset = FIELD_GET(CXL_CM_CAP_PTR_MASK, hdr);
-		register_block = base + offset;
-
-		switch (cap_id) {
-		case CXL_CM_CAP_CAP_ID_HDM:
-			dev_dbg(dev, "found HDM decoder capability (0x%x)\n",
-				offset);
-
-			hdr = readl(register_block);
-
-			decoder_cnt = cxl_hdm_decoder_count(hdr);
-			length = 0x20 * decoder_cnt + 0x10;
-
-			map->hdm_decoder.valid = true;
-			map->hdm_decoder.offset = CXL_CM_OFFSET + offset;
-			map->hdm_decoder.size = length;
-			break;
-		default:
-			dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id,
-				offset);
-			break;
-		}
-	}
-}
-EXPORT_SYMBOL_GPL(cxl_probe_component_regs);
-
-/**
- * cxl_probe_device_regs() - Detect CXL Device register blocks
- * @dev: Host device of the @base mapping
- * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface
- * @map: Map object describing the register block information found
- *
- * Probe for device register information and return it in map object.
- */
-void cxl_probe_device_regs(struct device *dev, void __iomem *base,
-			   struct cxl_device_reg_map *map)
-{
-	int cap, cap_count;
-	u64 cap_array;
-
-	*map = (struct cxl_device_reg_map){ 0 };
-
-	cap_array = readq(base + CXLDEV_CAP_ARRAY_OFFSET);
-	if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
-	    CXLDEV_CAP_ARRAY_CAP_ID)
-		return;
-
-	cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array);
-
-	for (cap = 1; cap <= cap_count; cap++) {
-		u32 offset, length;
-		u16 cap_id;
-
-		cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK,
-				   readl(base + cap * 0x10));
-		offset = readl(base + cap * 0x10 + 0x4);
-		length = readl(base + cap * 0x10 + 0x8);
-
-		switch (cap_id) {
-		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
-			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
-
-			map->status.valid = true;
-			map->status.offset = offset;
-			map->status.size = length;
-			break;
-		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
-			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
-			map->mbox.valid = true;
-			map->mbox.offset = offset;
-			map->mbox.size = length;
-			break;
-		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
-			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
-			break;
-		case CXLDEV_CAP_CAP_ID_MEMDEV:
-			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
-			map->memdev.valid = true;
-			map->memdev.offset = offset;
-			map->memdev.size = length;
-			break;
-		default:
-			if (cap_id >= 0x8000)
-				dev_dbg(dev, "Vendor cap ID: %#x offset: %#x\n", cap_id, offset);
-			else
-				dev_dbg(dev, "Unknown cap ID: %#x offset: %#x\n", cap_id, offset);
-			break;
-		}
-	}
-}
-EXPORT_SYMBOL_GPL(cxl_probe_device_regs);
-
-static void __iomem *devm_cxl_iomap_block(struct device *dev,
-					  resource_size_t addr,
-					  resource_size_t length)
-{
-	void __iomem *ret_val;
-	struct resource *res;
-
-	res = devm_request_mem_region(dev, addr, length, dev_name(dev));
-	if (!res) {
-		resource_size_t end = addr + length - 1;
-
-		dev_err(dev, "Failed to request region %pa-%pa\n", &addr, &end);
-		return NULL;
-	}
-
-	ret_val = devm_ioremap(dev, addr, length);
-	if (!ret_val)
-		dev_err(dev, "Failed to map region %pr\n", res);
-
-	return ret_val;
-}
-
-int cxl_map_component_regs(struct pci_dev *pdev,
-			   struct cxl_component_regs *regs,
-			   struct cxl_register_map *map)
-{
-	struct device *dev = &pdev->dev;
-	resource_size_t phys_addr;
-	resource_size_t length;
-
-	phys_addr = pci_resource_start(pdev, map->barno);
-	phys_addr += map->block_offset;
-
-	phys_addr += map->component_map.hdm_decoder.offset;
-	length = map->component_map.hdm_decoder.size;
-	regs->hdm_decoder = devm_cxl_iomap_block(dev, phys_addr, length);
-	if (!regs->hdm_decoder)
-		return -ENOMEM;
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(cxl_map_component_regs);
-
-int cxl_map_device_regs(struct pci_dev *pdev,
-			struct cxl_device_regs *regs,
-			struct cxl_register_map *map)
-{
-	struct device *dev = &pdev->dev;
-	resource_size_t phys_addr;
-
-	phys_addr = pci_resource_start(pdev, map->barno);
-	phys_addr += map->block_offset;
-
-	if (map->device_map.status.valid) {
-		resource_size_t addr;
-		resource_size_t length;
-
-		addr = phys_addr + map->device_map.status.offset;
-		length = map->device_map.status.size;
-		regs->status = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->status)
-			return -ENOMEM;
-	}
-
-	if (map->device_map.mbox.valid) {
-		resource_size_t addr;
-		resource_size_t length;
-
-		addr = phys_addr + map->device_map.mbox.offset;
-		length = map->device_map.mbox.size;
-		regs->mbox = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->mbox)
-			return -ENOMEM;
-	}
-
-	if (map->device_map.memdev.valid) {
-		resource_size_t addr;
-		resource_size_t length;
-
-		addr = phys_addr + map->device_map.memdev.offset;
-		length = map->device_map.memdev.size;
-		regs->memdev = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->memdev)
-			return -ENOMEM;
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(cxl_map_device_regs);
-
 /**
  * __cxl_driver_register - register a driver for the cxl bus
  * @cxl_drv: cxl driver structure to attach
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
new file mode 100644
index 000000000000..8535a7b94f28
--- /dev/null
+++ b/drivers/cxl/core/regs.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. */
+
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <cxlmem.h>
+
+/**
+ * cxl_probe_component_regs() - Detect CXL Component register blocks
+ * @dev: Host device of the @base mapping
+ * @base: Mapping containing the HDM Decoder Capability Header
+ * @map: Map object describing the register block information found
+ *
+ * See CXL 2.0 8.2.4 Component Register Layout and Definition
+ * See CXL 2.0 8.2.5.5 CXL Device Register Interface
+ *
+ * Probe for component register information and return it in map object.
+ */
+void cxl_probe_component_regs(struct device *dev, void __iomem *base,
+			      struct cxl_component_reg_map *map)
+{
+	int cap, cap_count;
+	u64 cap_array;
+
+	*map = (struct cxl_component_reg_map) { 0 };
+
+	/*
+	 * CXL.cache and CXL.mem registers are at offset 0x1000 as defined in
+	 * CXL 2.0 8.2.4 Table 141.
+	 */
+	base += CXL_CM_OFFSET;
+
+	cap_array = readq(base + CXL_CM_CAP_HDR_OFFSET);
+
+	if (FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, cap_array) != CM_CAP_HDR_CAP_ID) {
+		dev_err(dev,
+			"Couldn't locate the CXL.cache and CXL.mem capability array header./n");
+		return;
+	}
+
+	/* It's assumed that future versions will be backward compatible */
+	cap_count = FIELD_GET(CXL_CM_CAP_HDR_ARRAY_SIZE_MASK, cap_array);
+
+	for (cap = 1; cap <= cap_count; cap++) {
+		void __iomem *register_block;
+		u32 hdr;
+		int decoder_cnt;
+		u16 cap_id, offset;
+		u32 length;
+
+		hdr = readl(base + cap * 0x4);
+
+		cap_id = FIELD_GET(CXL_CM_CAP_HDR_ID_MASK, hdr);
+		offset = FIELD_GET(CXL_CM_CAP_PTR_MASK, hdr);
+		register_block = base + offset;
+
+		switch (cap_id) {
+		case CXL_CM_CAP_CAP_ID_HDM:
+			dev_dbg(dev, "found HDM decoder capability (0x%x)\n",
+				offset);
+
+			hdr = readl(register_block);
+
+			decoder_cnt = cxl_hdm_decoder_count(hdr);
+			length = 0x20 * decoder_cnt + 0x10;
+
+			map->hdm_decoder.valid = true;
+			map->hdm_decoder.offset = CXL_CM_OFFSET + offset;
+			map->hdm_decoder.size = length;
+			break;
+		default:
+			dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id,
+				offset);
+			break;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(cxl_probe_component_regs);
+
+/**
+ * cxl_probe_device_regs() - Detect CXL Device register blocks
+ * @dev: Host device of the @base mapping
+ * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface
+ * @map: Map object describing the register block information found
+ *
+ * Probe for device register information and return it in map object.
+ */
+void cxl_probe_device_regs(struct device *dev, void __iomem *base,
+			   struct cxl_device_reg_map *map)
+{
+	int cap, cap_count;
+	u64 cap_array;
+
+	*map = (struct cxl_device_reg_map){ 0 };
+
+	cap_array = readq(base + CXLDEV_CAP_ARRAY_OFFSET);
+	if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
+	    CXLDEV_CAP_ARRAY_CAP_ID)
+		return;
+
+	cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array);
+
+	for (cap = 1; cap <= cap_count; cap++) {
+		u32 offset, length;
+		u16 cap_id;
+
+		cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK,
+				   readl(base + cap * 0x10));
+		offset = readl(base + cap * 0x10 + 0x4);
+		length = readl(base + cap * 0x10 + 0x8);
+
+		switch (cap_id) {
+		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
+			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
+
+			map->status.valid = true;
+			map->status.offset = offset;
+			map->status.size = length;
+			break;
+		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
+			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
+			map->mbox.valid = true;
+			map->mbox.offset = offset;
+			map->mbox.size = length;
+			break;
+		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
+			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
+			break;
+		case CXLDEV_CAP_CAP_ID_MEMDEV:
+			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
+			map->memdev.valid = true;
+			map->memdev.offset = offset;
+			map->memdev.size = length;
+			break;
+		default:
+			if (cap_id >= 0x8000)
+				dev_dbg(dev, "Vendor cap ID: %#x offset: %#x\n", cap_id, offset);
+			else
+				dev_dbg(dev, "Unknown cap ID: %#x offset: %#x\n", cap_id, offset);
+			break;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(cxl_probe_device_regs);
+
+static void __iomem *devm_cxl_iomap_block(struct device *dev,
+					  resource_size_t addr,
+					  resource_size_t length)
+{
+	void __iomem *ret_val;
+	struct resource *res;
+
+	res = devm_request_mem_region(dev, addr, length, dev_name(dev));
+	if (!res) {
+		resource_size_t end = addr + length - 1;
+
+		dev_err(dev, "Failed to request region %pa-%pa\n", &addr, &end);
+		return NULL;
+	}
+
+	ret_val = devm_ioremap(dev, addr, length);
+	if (!ret_val)
+		dev_err(dev, "Failed to map region %pr\n", res);
+
+	return ret_val;
+}
+
+int cxl_map_component_regs(struct pci_dev *pdev,
+			   struct cxl_component_regs *regs,
+			   struct cxl_register_map *map)
+{
+	struct device *dev = &pdev->dev;
+	resource_size_t phys_addr;
+	resource_size_t length;
+
+	phys_addr = pci_resource_start(pdev, map->barno);
+	phys_addr += map->block_offset;
+
+	phys_addr += map->component_map.hdm_decoder.offset;
+	length = map->component_map.hdm_decoder.size;
+	regs->hdm_decoder = devm_cxl_iomap_block(dev, phys_addr, length);
+	if (!regs->hdm_decoder)
+		return -ENOMEM;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_map_component_regs);
+
+int cxl_map_device_regs(struct pci_dev *pdev,
+			struct cxl_device_regs *regs,
+			struct cxl_register_map *map)
+{
+	struct device *dev = &pdev->dev;
+	resource_size_t phys_addr;
+
+	phys_addr = pci_resource_start(pdev, map->barno);
+	phys_addr += map->block_offset;
+
+	if (map->device_map.status.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.status.offset;
+		length = map->device_map.status.size;
+		regs->status = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->status)
+			return -ENOMEM;
+	}
+
+	if (map->device_map.mbox.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.mbox.offset;
+		length = map->device_map.mbox.size;
+		regs->mbox = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->mbox)
+			return -ENOMEM;
+	}
+
+	if (map->device_map.memdev.valid) {
+		resource_size_t addr;
+		resource_size_t length;
+
+		addr = phys_addr + map->device_map.memdev.offset;
+		length = map->device_map.memdev.size;
+		regs->memdev = devm_cxl_iomap_block(dev, addr, length);
+		if (!regs->memdev)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_map_device_regs);

[PATCH v5 5/6] cxl/pci: Introduce cdevm_file_operations

[Dan Williams]

In preparation for moving cxl_memdev allocation to the core, introduce
cdevm_file_operations to coordinate file operations shutdown relative to
driver data release.

The motivation for moving cxl_memdev allocation to the core (beyond
better file organization of sysfs attributes in core/ and drivers in
cxl/), is that device lifetime is longer than module lifetime. The cxl_pci
module should be free to come and go without needing to coordinate with
devices that need the text associated with cxl_memdev_release() to stay
resident. The move will fix a use after free bug when looping driver
load / unload with CONFIG_DEBUG_KOBJECT_RELEASE=y.

Another motivation for passing in file_operations to the core cxl_memdev
creation flow is to allow for alternate drivers, like unit test code, to
define their own ioctl backends.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/cxlmem.h |   15 ++++++++++++
 drivers/cxl/pci.c    |   65 +++++++++++++++++++++++++++++---------------------
 2 files changed, 53 insertions(+), 27 deletions(-)

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 8f02d02b26b4..0cd463de1342 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -34,6 +34,21 @@
  */
 #define CXL_MEM_MAX_DEVS 65536
 
+/**
+ * struct cdevm_file_operations - devm coordinated cdev file operations
+ * @fops: file operations that are synchronized against @shutdown
+ * @shutdown: disconnect driver data
+ *
+ * @shutdown is invoked in the devres release path to disconnect any
+ * driver instance data from @dev. It assumes synchronization with any
+ * fops operation that requires driver data. After @shutdown an
+ * operation may only reference @device data.
+ */
+struct cdevm_file_operations {
+	struct file_operations fops;
+	void (*shutdown)(struct device *dev);
+};
+
 /**
  * struct cxl_memdev - CXL bus object representing a Type-3 Memory Device
  * @dev: driver core device object
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index a945c5fda292..f7a5ad5e1f4a 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -806,13 +806,30 @@ static int cxl_memdev_release_file(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static const struct file_operations cxl_memdev_fops = {
-	.owner = THIS_MODULE,
-	.unlocked_ioctl = cxl_memdev_ioctl,
-	.open = cxl_memdev_open,
-	.release = cxl_memdev_release_file,
-	.compat_ioctl = compat_ptr_ioctl,
-	.llseek = noop_llseek,
+static struct cxl_memdev *to_cxl_memdev(struct device *dev)
+{
+	return container_of(dev, struct cxl_memdev, dev);
+}
+
+static void cxl_memdev_shutdown(struct device *dev)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+
+	down_write(&cxl_memdev_rwsem);
+	cxlmd->cxlm = NULL;
+	up_write(&cxl_memdev_rwsem);
+}
+
+static const struct cdevm_file_operations cxl_memdev_fops = {
+	.fops = {
+		.owner = THIS_MODULE,
+		.unlocked_ioctl = cxl_memdev_ioctl,
+		.open = cxl_memdev_open,
+		.release = cxl_memdev_release_file,
+		.compat_ioctl = compat_ptr_ioctl,
+		.llseek = noop_llseek,
+	},
+	.shutdown = cxl_memdev_shutdown,
 };
 
 static inline struct cxl_mem_command *cxl_mem_find_command(u16 opcode)
@@ -1161,11 +1178,6 @@ static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
 	return ret;
 }
 
-static struct cxl_memdev *to_cxl_memdev(struct device *dev)
-{
-	return container_of(dev, struct cxl_memdev, dev);
-}
-
 static void cxl_memdev_release(struct device *dev)
 {
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
@@ -1281,24 +1293,22 @@ static const struct device_type cxl_memdev_type = {
 	.groups = cxl_memdev_attribute_groups,
 };
 
-static void cxl_memdev_shutdown(struct cxl_memdev *cxlmd)
-{
-	down_write(&cxl_memdev_rwsem);
-	cxlmd->cxlm = NULL;
-	up_write(&cxl_memdev_rwsem);
-}
-
 static void cxl_memdev_unregister(void *_cxlmd)
 {
 	struct cxl_memdev *cxlmd = _cxlmd;
 	struct device *dev = &cxlmd->dev;
+	struct cdev *cdev = &cxlmd->cdev;
+	const struct cdevm_file_operations *cdevm_fops;
+
+	cdevm_fops = container_of(cdev->ops, typeof(*cdevm_fops), fops);
+	cdevm_fops->shutdown(dev);
 
 	cdev_device_del(&cxlmd->cdev, dev);
-	cxl_memdev_shutdown(cxlmd);
 	put_device(dev);
 }
 
-static struct cxl_memdev *cxl_memdev_alloc(struct cxl_mem *cxlm)
+static struct cxl_memdev *cxl_memdev_alloc(struct cxl_mem *cxlm,
+					   const struct file_operations *fops)
 {
 	struct pci_dev *pdev = cxlm->pdev;
 	struct cxl_memdev *cxlmd;
@@ -1324,7 +1334,7 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_mem *cxlm)
 	device_set_pm_not_required(dev);
 
 	cdev = &cxlmd->cdev;
-	cdev_init(cdev, &cxl_memdev_fops);
+	cdev_init(cdev, fops);
 	return cxlmd;
 
 err:
@@ -1332,15 +1342,16 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_mem *cxlm)
 	return ERR_PTR(rc);
 }
 
-static struct cxl_memdev *devm_cxl_add_memdev(struct device *host,
-					      struct cxl_mem *cxlm)
+static struct cxl_memdev *
+devm_cxl_add_memdev(struct device *host, struct cxl_mem *cxlm,
+		    const struct cdevm_file_operations *cdevm_fops)
 {
 	struct cxl_memdev *cxlmd;
 	struct device *dev;
 	struct cdev *cdev;
 	int rc;
 
-	cxlmd = cxl_memdev_alloc(cxlm);
+	cxlmd = cxl_memdev_alloc(cxlm, &cdevm_fops->fops);
 	if (IS_ERR(cxlmd))
 		return cxlmd;
 
@@ -1370,7 +1381,7 @@ static struct cxl_memdev *devm_cxl_add_memdev(struct device *host,
 	 * The cdev was briefly live, shutdown any ioctl operations that
 	 * saw that state.
 	 */
-	cxl_memdev_shutdown(cxlmd);
+	cdevm_fops->shutdown(dev);
 	put_device(dev);
 	return ERR_PTR(rc);
 }
@@ -1611,7 +1622,7 @@ static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (rc)
 		return rc;
 
-	cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlm);
+	cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlm, &cxl_memdev_fops);
 	if (IS_ERR(cxlmd))
 		return PTR_ERR(cxlmd);
 

[PATCH v5 6/6] cxl/core: Move memdev management to core

[Dan Williams]

From: Ben Widawsky <ben.widawsky@intel.com>

The motivation for moving cxl_memdev allocation to the core (beyond
better file organization of sysfs attributes in core/ and drivers in
cxl/), is that device lifetime is longer than module lifetime. The cxl_pci
module should be free to come and go without needing to coordinate with
devices that need the text associated with cxl_memdev_release() to stay
resident. The move fixes a use after free bug when looping driver
load / unload with CONFIG_DEBUG_KOBJECT_RELEASE=y.

Another motivation for disconnecting cxl_memdev creation from cxl_pci is
to enable other drivers, like a unit test driver, to registers memdevs.

Fixes: b39cb1052a5c ("cxl/mem: Register CXL memX devices")
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/core/Makefile |    1 
 drivers/cxl/core/bus.c    |   16 +++
 drivers/cxl/core/core.h   |    3 +
 drivers/cxl/core/memdev.c |  246 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/cxl/cxlmem.h      |   15 ++-
 drivers/cxl/pci.c         |  228 ------------------------------------------
 6 files changed, 275 insertions(+), 234 deletions(-)
 create mode 100644 drivers/cxl/core/memdev.c

diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index a3522d2fbf5b..0fdbf3c6ac1a 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -5,3 +5,4 @@ ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL -I$(srctree)/drivers/cxl
 cxl_core-y := bus.o
 cxl_core-y += pmem.o
 cxl_core-y += regs.o
+cxl_core-y += memdev.o
diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
index c938d8590c9f..37b87adaa33f 100644
--- a/drivers/cxl/core/bus.c
+++ b/drivers/cxl/core/bus.c
@@ -634,12 +634,26 @@ EXPORT_SYMBOL_GPL(cxl_bus_type);
 
 static __init int cxl_core_init(void)
 {
-	return bus_register(&cxl_bus_type);
+	int rc;
+
+	rc = cxl_memdev_init();
+	if (rc)
+		return rc;
+
+	rc = bus_register(&cxl_bus_type);
+	if (rc)
+		goto err;
+	return 0;
+
+err:
+	cxl_memdev_exit();
+	return rc;
 }
 
 static void cxl_core_exit(void)
 {
 	bus_unregister(&cxl_bus_type);
+	cxl_memdev_exit();
 }
 
 module_init(cxl_core_init);
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 49045daf8bd7..036a3c8106b4 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -14,4 +14,7 @@ static inline void unregister_cxl_dev(void *dev)
 	device_unregister(dev);
 }
 
+int cxl_memdev_init(void);
+void cxl_memdev_exit(void);
+
 #endif /* __CXL_CORE_H__ */
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
new file mode 100644
index 000000000000..a9c317e32010
--- /dev/null
+++ b/drivers/cxl/core/memdev.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. */
+
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <linux/pci.h>
+#include <cxlmem.h>
+#include "core.h"
+
+/*
+ * An entire PCI topology full of devices should be enough for any
+ * config
+ */
+#define CXL_MEM_MAX_DEVS 65536
+
+static int cxl_mem_major;
+static DEFINE_IDA(cxl_memdev_ida);
+
+static void cxl_memdev_release(struct device *dev)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+
+	ida_free(&cxl_memdev_ida, cxlmd->id);
+	kfree(cxlmd);
+}
+
+static char *cxl_memdev_devnode(struct device *dev, umode_t *mode, kuid_t *uid,
+				kgid_t *gid)
+{
+	return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
+}
+
+static ssize_t firmware_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+
+	return sysfs_emit(buf, "%.16s\n", cxlm->firmware_version);
+}
+static DEVICE_ATTR_RO(firmware_version);
+
+static ssize_t payload_max_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+
+	return sysfs_emit(buf, "%zu\n", cxlm->payload_size);
+}
+static DEVICE_ATTR_RO(payload_max);
+
+static ssize_t label_storage_size_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+
+	return sysfs_emit(buf, "%zu\n", cxlm->lsa_size);
+}
+static DEVICE_ATTR_RO(label_storage_size);
+
+static ssize_t ram_size_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+	unsigned long long len = range_len(&cxlm->ram_range);
+
+	return sysfs_emit(buf, "%#llx\n", len);
+}
+
+static struct device_attribute dev_attr_ram_size =
+	__ATTR(size, 0444, ram_size_show, NULL);
+
+static ssize_t pmem_size_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+	unsigned long long len = range_len(&cxlm->pmem_range);
+
+	return sysfs_emit(buf, "%#llx\n", len);
+}
+
+static struct device_attribute dev_attr_pmem_size =
+	__ATTR(size, 0444, pmem_size_show, NULL);
+
+static struct attribute *cxl_memdev_attributes[] = {
+	&dev_attr_firmware_version.attr,
+	&dev_attr_payload_max.attr,
+	&dev_attr_label_storage_size.attr,
+	NULL,
+};
+
+static struct attribute *cxl_memdev_pmem_attributes[] = {
+	&dev_attr_pmem_size.attr,
+	NULL,
+};
+
+static struct attribute *cxl_memdev_ram_attributes[] = {
+	&dev_attr_ram_size.attr,
+	NULL,
+};
+
+static struct attribute_group cxl_memdev_attribute_group = {
+	.attrs = cxl_memdev_attributes,
+};
+
+static struct attribute_group cxl_memdev_ram_attribute_group = {
+	.name = "ram",
+	.attrs = cxl_memdev_ram_attributes,
+};
+
+static struct attribute_group cxl_memdev_pmem_attribute_group = {
+	.name = "pmem",
+	.attrs = cxl_memdev_pmem_attributes,
+};
+
+static const struct attribute_group *cxl_memdev_attribute_groups[] = {
+	&cxl_memdev_attribute_group,
+	&cxl_memdev_ram_attribute_group,
+	&cxl_memdev_pmem_attribute_group,
+	NULL,
+};
+
+static const struct device_type cxl_memdev_type = {
+	.name = "cxl_memdev",
+	.release = cxl_memdev_release,
+	.devnode = cxl_memdev_devnode,
+	.groups = cxl_memdev_attribute_groups,
+};
+
+static void cxl_memdev_unregister(void *_cxlmd)
+{
+	struct cxl_memdev *cxlmd = _cxlmd;
+	struct device *dev = &cxlmd->dev;
+	struct cdev *cdev = &cxlmd->cdev;
+	const struct cdevm_file_operations *cdevm_fops;
+
+	cdevm_fops = container_of(cdev->ops, typeof(*cdevm_fops), fops);
+	cdevm_fops->shutdown(dev);
+
+	cdev_device_del(&cxlmd->cdev, dev);
+	put_device(dev);
+}
+
+static struct cxl_memdev *cxl_memdev_alloc(struct cxl_mem *cxlm,
+					   const struct file_operations *fops)
+{
+	struct pci_dev *pdev = cxlm->pdev;
+	struct cxl_memdev *cxlmd;
+	struct device *dev;
+	struct cdev *cdev;
+	int rc;
+
+	cxlmd = kzalloc(sizeof(*cxlmd), GFP_KERNEL);
+	if (!cxlmd)
+		return ERR_PTR(-ENOMEM);
+
+	rc = ida_alloc_range(&cxl_memdev_ida, 0, CXL_MEM_MAX_DEVS, GFP_KERNEL);
+	if (rc < 0)
+		goto err;
+	cxlmd->id = rc;
+
+	dev = &cxlmd->dev;
+	device_initialize(dev);
+	dev->parent = &pdev->dev;
+	dev->bus = &cxl_bus_type;
+	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
+	dev->type = &cxl_memdev_type;
+	device_set_pm_not_required(dev);
+
+	cdev = &cxlmd->cdev;
+	cdev_init(cdev, fops);
+	return cxlmd;
+
+err:
+	kfree(cxlmd);
+	return ERR_PTR(rc);
+}
+
+struct cxl_memdev *
+devm_cxl_add_memdev(struct device *host, struct cxl_mem *cxlm,
+		    const struct cdevm_file_operations *cdevm_fops)
+{
+	struct cxl_memdev *cxlmd;
+	struct device *dev;
+	struct cdev *cdev;
+	int rc;
+
+	cxlmd = cxl_memdev_alloc(cxlm, &cdevm_fops->fops);
+	if (IS_ERR(cxlmd))
+		return cxlmd;
+
+	dev = &cxlmd->dev;
+	rc = dev_set_name(dev, "mem%d", cxlmd->id);
+	if (rc)
+		goto err;
+
+	/*
+	 * Activate ioctl operations, no cxl_memdev_rwsem manipulation
+	 * needed as this is ordered with cdev_add() publishing the device.
+	 */
+	cxlmd->cxlm = cxlm;
+
+	cdev = &cxlmd->cdev;
+	rc = cdev_device_add(cdev, dev);
+	if (rc)
+		goto err;
+
+	rc = devm_add_action_or_reset(host, cxl_memdev_unregister, cxlmd);
+	if (rc)
+		return ERR_PTR(rc);
+	return cxlmd;
+
+err:
+	/*
+	 * The cdev was briefly live, shutdown any ioctl operations that
+	 * saw that state.
+	 */
+	cdevm_fops->shutdown(dev);
+	put_device(dev);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(devm_cxl_add_memdev);
+
+__init int cxl_memdev_init(void)
+{
+	dev_t devt;
+	int rc;
+
+	rc = alloc_chrdev_region(&devt, 0, CXL_MEM_MAX_DEVS, "cxl");
+	if (rc)
+		return rc;
+
+	cxl_mem_major = MAJOR(devt);
+
+	return 0;
+}
+
+void cxl_memdev_exit(void)
+{
+	unregister_chrdev_region(MKDEV(cxl_mem_major, 0), CXL_MEM_MAX_DEVS);
+}
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 0cd463de1342..25345ece25f8 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -28,12 +28,6 @@
 	(FIELD_GET(CXLMDEV_RESET_NEEDED_MASK, status) !=                       \
 	 CXLMDEV_RESET_NEEDED_NOT)
 
-/*
- * An entire PCI topology full of devices should be enough for any
- * config
- */
-#define CXL_MEM_MAX_DEVS 65536
-
 /**
  * struct cdevm_file_operations - devm coordinated cdev file operations
  * @fops: file operations that are synchronized against @shutdown
@@ -63,6 +57,15 @@ struct cxl_memdev {
 	int id;
 };
 
+static inline struct cxl_memdev *to_cxl_memdev(struct device *dev)
+{
+	return container_of(dev, struct cxl_memdev, dev);
+}
+
+struct cxl_memdev *
+devm_cxl_add_memdev(struct device *host, struct cxl_mem *cxlm,
+		    const struct cdevm_file_operations *cdevm_fops);
+
 /**
  * struct cxl_mem - A CXL memory device
  * @pdev: The PCI device associated with this CXL device.
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index f7a5ad5e1f4a..193983e6edce 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -94,8 +94,6 @@ struct mbox_cmd {
 #define CXL_MBOX_SUCCESS 0
 };
 
-static int cxl_mem_major;
-static DEFINE_IDA(cxl_memdev_ida);
 static DECLARE_RWSEM(cxl_memdev_rwsem);
 static struct dentry *cxl_debugfs;
 static bool cxl_raw_allow_all;
@@ -806,11 +804,6 @@ static int cxl_memdev_release_file(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static struct cxl_memdev *to_cxl_memdev(struct device *dev)
-{
-	return container_of(dev, struct cxl_memdev, dev);
-}
-
 static void cxl_memdev_shutdown(struct device *dev)
 {
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
@@ -1178,214 +1171,6 @@ static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
 	return ret;
 }
 
-static void cxl_memdev_release(struct device *dev)
-{
-	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-
-	ida_free(&cxl_memdev_ida, cxlmd->id);
-	kfree(cxlmd);
-}
-
-static char *cxl_memdev_devnode(struct device *dev, umode_t *mode, kuid_t *uid,
-				kgid_t *gid)
-{
-	return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
-}
-
-static ssize_t firmware_version_show(struct device *dev,
-				     struct device_attribute *attr, char *buf)
-{
-	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_mem *cxlm = cxlmd->cxlm;
-
-	return sysfs_emit(buf, "%.16s\n", cxlm->firmware_version);
-}
-static DEVICE_ATTR_RO(firmware_version);
-
-static ssize_t payload_max_show(struct device *dev,
-				struct device_attribute *attr, char *buf)
-{
-	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_mem *cxlm = cxlmd->cxlm;
-
-	return sysfs_emit(buf, "%zu\n", cxlm->payload_size);
-}
-static DEVICE_ATTR_RO(payload_max);
-
-static ssize_t label_storage_size_show(struct device *dev,
-				struct device_attribute *attr, char *buf)
-{
-	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_mem *cxlm = cxlmd->cxlm;
-
-	return sysfs_emit(buf, "%zu\n", cxlm->lsa_size);
-}
-static DEVICE_ATTR_RO(label_storage_size);
-
-static ssize_t ram_size_show(struct device *dev, struct device_attribute *attr,
-			     char *buf)
-{
-	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_mem *cxlm = cxlmd->cxlm;
-	unsigned long long len = range_len(&cxlm->ram_range);
-
-	return sysfs_emit(buf, "%#llx\n", len);
-}
-
-static struct device_attribute dev_attr_ram_size =
-	__ATTR(size, 0444, ram_size_show, NULL);
-
-static ssize_t pmem_size_show(struct device *dev, struct device_attribute *attr,
-			      char *buf)
-{
-	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
-	struct cxl_mem *cxlm = cxlmd->cxlm;
-	unsigned long long len = range_len(&cxlm->pmem_range);
-
-	return sysfs_emit(buf, "%#llx\n", len);
-}
-
-static struct device_attribute dev_attr_pmem_size =
-	__ATTR(size, 0444, pmem_size_show, NULL);
-
-static struct attribute *cxl_memdev_attributes[] = {
-	&dev_attr_firmware_version.attr,
-	&dev_attr_payload_max.attr,
-	&dev_attr_label_storage_size.attr,
-	NULL,
-};
-
-static struct attribute *cxl_memdev_pmem_attributes[] = {
-	&dev_attr_pmem_size.attr,
-	NULL,
-};
-
-static struct attribute *cxl_memdev_ram_attributes[] = {
-	&dev_attr_ram_size.attr,
-	NULL,
-};
-
-static struct attribute_group cxl_memdev_attribute_group = {
-	.attrs = cxl_memdev_attributes,
-};
-
-static struct attribute_group cxl_memdev_ram_attribute_group = {
-	.name = "ram",
-	.attrs = cxl_memdev_ram_attributes,
-};
-
-static struct attribute_group cxl_memdev_pmem_attribute_group = {
-	.name = "pmem",
-	.attrs = cxl_memdev_pmem_attributes,
-};
-
-static const struct attribute_group *cxl_memdev_attribute_groups[] = {
-	&cxl_memdev_attribute_group,
-	&cxl_memdev_ram_attribute_group,
-	&cxl_memdev_pmem_attribute_group,
-	NULL,
-};
-
-static const struct device_type cxl_memdev_type = {
-	.name = "cxl_memdev",
-	.release = cxl_memdev_release,
-	.devnode = cxl_memdev_devnode,
-	.groups = cxl_memdev_attribute_groups,
-};
-
-static void cxl_memdev_unregister(void *_cxlmd)
-{
-	struct cxl_memdev *cxlmd = _cxlmd;
-	struct device *dev = &cxlmd->dev;
-	struct cdev *cdev = &cxlmd->cdev;
-	const struct cdevm_file_operations *cdevm_fops;
-
-	cdevm_fops = container_of(cdev->ops, typeof(*cdevm_fops), fops);
-	cdevm_fops->shutdown(dev);
-
-	cdev_device_del(&cxlmd->cdev, dev);
-	put_device(dev);
-}
-
-static struct cxl_memdev *cxl_memdev_alloc(struct cxl_mem *cxlm,
-					   const struct file_operations *fops)
-{
-	struct pci_dev *pdev = cxlm->pdev;
-	struct cxl_memdev *cxlmd;
-	struct device *dev;
-	struct cdev *cdev;
-	int rc;
-
-	cxlmd = kzalloc(sizeof(*cxlmd), GFP_KERNEL);
-	if (!cxlmd)
-		return ERR_PTR(-ENOMEM);
-
-	rc = ida_alloc_range(&cxl_memdev_ida, 0, CXL_MEM_MAX_DEVS, GFP_KERNEL);
-	if (rc < 0)
-		goto err;
-	cxlmd->id = rc;
-
-	dev = &cxlmd->dev;
-	device_initialize(dev);
-	dev->parent = &pdev->dev;
-	dev->bus = &cxl_bus_type;
-	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
-	dev->type = &cxl_memdev_type;
-	device_set_pm_not_required(dev);
-
-	cdev = &cxlmd->cdev;
-	cdev_init(cdev, fops);
-	return cxlmd;
-
-err:
-	kfree(cxlmd);
-	return ERR_PTR(rc);
-}
-
-static struct cxl_memdev *
-devm_cxl_add_memdev(struct device *host, struct cxl_mem *cxlm,
-		    const struct cdevm_file_operations *cdevm_fops)
-{
-	struct cxl_memdev *cxlmd;
-	struct device *dev;
-	struct cdev *cdev;
-	int rc;
-
-	cxlmd = cxl_memdev_alloc(cxlm, &cdevm_fops->fops);
-	if (IS_ERR(cxlmd))
-		return cxlmd;
-
-	dev = &cxlmd->dev;
-	rc = dev_set_name(dev, "mem%d", cxlmd->id);
-	if (rc)
-		goto err;
-
-	/*
-	 * Activate ioctl operations, no cxl_memdev_rwsem manipulation
-	 * needed as this is ordered with cdev_add() publishing the device.
-	 */
-	cxlmd->cxlm = cxlm;
-
-	cdev = &cxlmd->cdev;
-	rc = cdev_device_add(cdev, dev);
-	if (rc)
-		goto err;
-
-	rc = devm_add_action_or_reset(host, cxl_memdev_unregister, cxlmd);
-	if (rc)
-		return ERR_PTR(rc);
-	return cxlmd;
-
-err:
-	/*
-	 * The cdev was briefly live, shutdown any ioctl operations that
-	 * saw that state.
-	 */
-	cdevm_fops->shutdown(dev);
-	put_device(dev);
-	return ERR_PTR(rc);
-}
-
 static int cxl_xfer_log(struct cxl_mem *cxlm, uuid_t *uuid, u32 size, u8 *out)
 {
 	u32 remaining = size;
@@ -1651,25 +1436,15 @@ static struct pci_driver cxl_mem_driver = {
 static __init int cxl_mem_init(void)
 {
 	struct dentry *mbox_debugfs;
-	dev_t devt;
 	int rc;
 
 	/* Double check the anonymous union trickery in struct cxl_regs */
 	BUILD_BUG_ON(offsetof(struct cxl_regs, memdev) !=
 		     offsetof(struct cxl_regs, device_regs.memdev));
 
-	rc = alloc_chrdev_region(&devt, 0, CXL_MEM_MAX_DEVS, "cxl");
-	if (rc)
-		return rc;
-
-	cxl_mem_major = MAJOR(devt);
-
 	rc = pci_register_driver(&cxl_mem_driver);
-	if (rc) {
-		unregister_chrdev_region(MKDEV(cxl_mem_major, 0),
-					 CXL_MEM_MAX_DEVS);
+	if (rc)
 		return rc;
-	}
 
 	cxl_debugfs = debugfs_create_dir("cxl", NULL);
 	mbox_debugfs = debugfs_create_dir("mbox", cxl_debugfs);
@@ -1683,7 +1458,6 @@ static __exit void cxl_mem_exit(void)
 {
 	debugfs_remove_recursive(cxl_debugfs);
 	pci_unregister_driver(&cxl_mem_driver);
-	unregister_chrdev_region(MKDEV(cxl_mem_major, 0), CXL_MEM_MAX_DEVS);
 }
 
 MODULE_LICENSE("GPL v2");