[PATCH v4 05/14] cxl: Simplify cxl_root_ops allocation and handling

Robert Richter
2025-11-03T18:49:09Z

A root port's callback handlers are collected in struct cxl_root_ops.
The structure is dynamically allocated, though it contains only a
single pointer in it. This also requires to check two pointers to
check for the existance of a callback.

Simplify the allocation, release and handler check by embedding the
ops statical in struct cxl_root.

Signed-off-by: Robert Richter <rrichter@amd.com>
---
drivers/cxl/acpi.c | 7 ++-----
drivers/cxl/core/cdat.c | 8 ++++----
drivers/cxl/core/port.c | 9 ++-------
drivers/cxl/cxl.h | 19 ++++++++++---------
4 files changed, 18 insertions(+), 25 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index bd2e282ca93a..1ab780edf141 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -299,10 +299,6 @@ static int cxl_acpi_qos_class(struct cxl_root *cxl_root,
return cxl_acpi_evaluate_qtg_dsm(handle, coord, entries, qos_class);
}

-static const struct cxl_root_ops acpi_root_ops = {
- .qos_class = cxl_acpi_qos_class,
-};
-
static void del_cxl_resource(struct resource *res)
{
if (!res)
@@ -914,9 +910,10 @@ static int cxl_acpi_probe(struct platform_device *pdev)
cxl_res->end = -1;
cxl_res->flags = IORESOURCE_MEM;

- cxl_root = devm_cxl_add_root(host, &acpi_root_ops);
+ cxl_root = devm_cxl_add_root(host);
if (IS_ERR(cxl_root))
return PTR_ERR(cxl_root);
+ cxl_root->ops.qos_class = cxl_acpi_qos_class;
root_port = &cxl_root->port;

rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index c4bd6e8a0cf0..b84a9b52942c 100644
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -213,7 +213,7 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
if (!cxl_root)
return -ENODEV;

- if (!cxl_root->ops || !cxl_root->ops->qos_class)
+ if (!cxl_root->ops.qos_class)
return -EOPNOTSUPP;

xa_for_each(dsmas_xa, index, dent) {
@@ -221,9 +221,9 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,

cxl_coordinates_combine(dent->coord, dent->cdat_coord, ep_c);
dent->entries = 1;
- rc = cxl_root->ops->qos_class(cxl_root,
- &dent->coord[ACCESS_COORDINATE_CPU],
- 1, &qos_class);
+ rc = cxl_root->ops.qos_class(cxl_root,
+ &dent->coord[ACCESS_COORDINATE_CPU],
+ 1, &qos_class);
if (rc != 1)
continue;

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 8128fd2b5b31..2338d146577c 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -459,7 +459,6 @@ static void cxl_root_decoder_release(struct device *dev)
if (atomic_read(&cxlrd->region_id) >= 0)
memregion_free(atomic_read(&cxlrd->region_id));
__cxl_decoder_release(&cxlrd->cxlsd.cxld);
- kfree(cxlrd->ops);
kfree(cxlrd);
}

@@ -955,19 +954,15 @@ struct cxl_port *devm_cxl_add_port(struct device *host,
}
EXPORT_SYMBOL_NS_GPL(devm_cxl_add_port, "CXL");

-struct cxl_root *devm_cxl_add_root(struct device *host,
- const struct cxl_root_ops *ops)
+struct cxl_root *devm_cxl_add_root(struct device *host)
{
- struct cxl_root *cxl_root;
struct cxl_port *port;

port = devm_cxl_add_port(host, host, CXL_RESOURCE_NONE, NULL);
if (IS_ERR(port))
return ERR_CAST(port);

- cxl_root = to_cxl_root(port);
- cxl_root->ops = ops;
- return cxl_root;
+ return to_cxl_root(port);
}
EXPORT_SYMBOL_NS_GPL(devm_cxl_add_root, "CXL");

diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index b57cfa4273b9..9a381c827416 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -638,6 +638,14 @@ struct cxl_port {
resource_size_t component_reg_phys;
};

+struct cxl_root;
+
+struct cxl_root_ops {
+ int (*qos_class)(struct cxl_root *cxl_root,
+ struct access_coordinate *coord, int entries,
+ int *qos_class);
+};
+
/**
* struct cxl_root - logical collection of root cxl_port items
*
@@ -646,7 +654,7 @@ struct cxl_port {
*/
struct cxl_root {
struct cxl_port port;
- const struct cxl_root_ops *ops;
+ struct cxl_root_ops ops;
};

static inline struct cxl_root *
@@ -655,12 +663,6 @@ to_cxl_root(const struct cxl_port *port)
return container_of(port, struct cxl_root, port);
}

-struct cxl_root_ops {
- int (*qos_class)(struct cxl_root *cxl_root,
- struct access_coordinate *coord, int entries,
- int *qos_class);
-};
-
static inline struct cxl_dport *
cxl_find_dport_by_dev(struct cxl_port *port, const struct device *dport_dev)
{
@@ -755,8 +757,7 @@ struct cxl_port *devm_cxl_add_port(struct device *host,
struct device *uport_dev,
resource_size_t component_reg_phys,
struct cxl_dport *parent_dport);
-struct cxl_root *devm_cxl_add_root(struct device *host,
- const struct cxl_root_ops *ops);
+struct cxl_root *devm_cxl_add_root(struct device *host);
struct cxl_root *find_cxl_root(struct cxl_port *port);

DEFINE_FREE(put_cxl_root, struct cxl_root *, if (_T) put_device(&_T->port.dev))
--
2.47.3