[PATCH v4 12/14] cxl: Simplify cxl_rd_ops allocation and handling

Robert Richter
2025-11-03T18:49:51Z

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

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

Implementation is equivalent to how struct cxl_root_ops handles the
callbacks.

Signed-off-by: Robert Richter <rrichter@amd.com>
---
drivers/cxl/acpi.c | 8 ++------
drivers/cxl/core/region.c | 20 +++++---------------
drivers/cxl/cxl.h | 2 +-
3 files changed, 8 insertions(+), 22 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index f9bbc77f3ec2..778ee29430ea 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -471,12 +471,8 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
cxlrd->qos_class = cfmws->qtg_id;

if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_XOR) {
- cxlrd->ops = kzalloc(sizeof(*cxlrd->ops), GFP_KERNEL);
- if (!cxlrd->ops)
- return -ENOMEM;
-
- cxlrd->ops->hpa_to_spa = cxl_apply_xor_maps;
- cxlrd->ops->spa_to_hpa = cxl_apply_xor_maps;
+ cxlrd->ops.hpa_to_spa = cxl_apply_xor_maps;
+ cxlrd->ops.spa_to_hpa = cxl_apply_xor_maps;
}

rc = cxl_decoder_add(cxld);
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 379a67cc8e31..dec003084521 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2932,16 +2932,6 @@ static bool cxl_is_hpa_in_chunk(u64 hpa, struct cxl_region *cxlr, int pos)
return false;
}

-static bool has_hpa_to_spa(struct cxl_root_decoder *cxlrd)
-{
- return cxlrd->ops && cxlrd->ops->hpa_to_spa;
-}
-
-static bool has_spa_to_hpa(struct cxl_root_decoder *cxlrd)
-{
- return cxlrd->ops && cxlrd->ops->spa_to_hpa;
-}
-
u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
u64 dpa)
{
@@ -2996,8 +2986,8 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
hpa = hpa_offset + p->res->start + p->cache_size;

/* Root decoder translation overrides typical modulo decode */
- if (has_hpa_to_spa(cxlrd))
- hpa = cxlrd->ops->hpa_to_spa(cxlrd, hpa);
+ if (cxlrd->ops.hpa_to_spa)
+ hpa = cxlrd->ops.hpa_to_spa(cxlrd, hpa);

if (!cxl_resource_contains_addr(p->res, hpa)) {
dev_dbg(&cxlr->dev,
@@ -3006,7 +2996,7 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
}

/* Simple chunk check, by pos & gran, only applies to modulo decodes */
- if (!has_hpa_to_spa(cxlrd) && (!cxl_is_hpa_in_chunk(hpa, cxlr, pos)))
+ if (!cxlrd->ops.hpa_to_spa && !cxl_is_hpa_in_chunk(hpa, cxlr, pos))
return ULLONG_MAX;

return hpa;
@@ -3041,8 +3031,8 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
* If the root decoder has SPA to CXL HPA callback, use it. Otherwise
* CXL HPA is assumed to equal SPA.
*/
- if (has_spa_to_hpa(cxlrd)) {
- hpa = cxlrd->ops->spa_to_hpa(cxlrd, p->res->start + offset);
+ if (cxlrd->ops.spa_to_hpa) {
+ hpa = cxlrd->ops.spa_to_hpa(cxlrd, p->res->start + offset);
hpa_offset = hpa - p->res->start;
} else {
hpa_offset = offset;
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 0af46d1b0abc..75fd45ddca38 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -451,7 +451,7 @@ struct cxl_root_decoder {
void *platform_data;
struct mutex range_lock;
int qos_class;
- struct cxl_rd_ops *ops;
+ struct cxl_rd_ops ops;
struct cxl_switch_decoder cxlsd;
};

--
2.47.3