Re: [PATCH v9 13/27] cxl: prepare memdev creation for type2

From: Alejandro Lucero <redacted>

Current cxl core is relying on a CXL_DEVTYPE_CLASSMEM type device when
creating a memdev leading to problems when obtaining cxl_memdev_state
references from a CXL_DEVTYPE_DEVMEM type. This last device type is
managed by a specific vendor driver and does not need same sysfs files
since not userspace intervention is expected.

Create a new cxl_mem device type with no attributes for Type2.

Avoid debugfs files relying on existence of cxl_memdev_state.

Make devm_cxl_add_memdev accesible from a accel driver.

Signed-off-by: Alejandro Lucero <redacted>
---
 drivers/cxl/core/cdat.c   |  3 +++
 drivers/cxl/core/memdev.c | 14 ++++++++++++--
 drivers/cxl/core/region.c |  3 ++-
 drivers/cxl/cxlmem.h      |  2 --
 drivers/cxl/mem.c         | 25 +++++++++++++++++++------
 include/cxl/cxl.h         |  2 ++
 6 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index 8153f8d83a16..c57bc83e79ee 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c

@@ -577,6 +577,9 @@ static struct cxl_dpa_perf *cxled_get_dpa_perf(struct cxl_endpoint_decoder *cxle
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
 	struct cxl_dpa_perf *perf;
 
+	if (!mds)
+		return ERR_PTR(-EINVAL);
+

 	switch (mode) {
 	case CXL_DECODER_RAM:
 		perf = &mds->ram_perf;

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 836db4a462b3..f91feca586dd 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c

@@ -547,9 +547,16 @@ static const struct device_type cxl_memdev_type = {
 	.groups = cxl_memdev_attribute_groups,
 };
 
+static const struct device_type cxl_accel_memdev_type = {
+	.name = "cxl_accel_memdev",
+	.release = cxl_memdev_release,
+	.devnode = cxl_memdev_devnode,
+};
+
 bool is_cxl_memdev(const struct device *dev)
 {
-	return dev->type == &cxl_memdev_type;
+	return (dev->type == &cxl_memdev_type ||
+		dev->type == &cxl_accel_memdev_type);

 }
 EXPORT_SYMBOL_NS_GPL(is_cxl_memdev, "CXL");
 

@@ -660,7 +667,10 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,
 	dev->parent = cxlds->dev;
 	dev->bus = &cxl_bus_type;
 	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
-	dev->type = &cxl_memdev_type;
+	if (cxlds->type == CXL_DEVTYPE_DEVMEM)
+		dev->type = &cxl_accel_memdev_type;
+	else
+		dev->type = &cxl_memdev_type;
 	device_set_pm_not_required(dev);
 	INIT_WORK(&cxlmd->detach_work, detach_memdev);
 

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index d77899650798..967132b49832 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c

@@ -1948,7 +1948,8 @@ static int cxl_region_attach(struct cxl_region *cxlr,
 		return -EINVAL;
 	}
 
-	cxl_region_perf_data_calculate(cxlr, cxled);
+	if (cxlr->type == CXL_DECODER_HOSTONLYMEM)
+		cxl_region_perf_data_calculate(cxlr, cxled);

 	if (test_bit(CXL_REGION_F_AUTO, &cxlr->flags)) {
 		int i;

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 4c1c53c29544..360d3728f492 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h

@@ -87,8 +87,6 @@ static inline bool is_cxl_endpoint(struct cxl_port *port)
 	return is_cxl_memdev(port->uport_dev);
 }
 
-struct cxl_memdev *devm_cxl_add_memdev(struct device *host,
-				       struct cxl_dev_state *cxlds);
 int devm_cxl_sanitize_setup_notifier(struct device *host,
 				     struct cxl_memdev *cxlmd);
 struct cxl_memdev_state;

diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 2f03a4d5606e..93106a43990b 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c

@@ -130,12 +130,18 @@ static int cxl_mem_probe(struct device *dev)
 	dentry = cxl_debugfs_create_dir(dev_name(dev));
 	debugfs_create_devm_seqfile(dev, "dpamem", dentry, cxl_mem_dpa_show);
 
-	if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
-		debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
-				    &cxl_poison_inject_fops);
-	if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
-		debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
-				    &cxl_poison_clear_fops);
+	/*
+	 * Avoid poison debugfs files for Type2 devices as they rely on
+	 * cxl_memdev_state.
+	 */
+	if (mds) {
+		if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
+			debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
+					    &cxl_poison_inject_fops);
+		if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
+			debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
+					    &cxl_poison_clear_fops);
+	}
 
 	rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
 	if (rc)

@@ -219,6 +225,13 @@ static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
 
+	/*
+	 * Avoid poison sysfs files for Type2 devices as they rely on
+	 * cxl_memdev_state.
+	 */
+	if (!mds)
+		return 0;