[PATCH v2 3/4] dax: Update hmem resource/device registration

Nathan Fontenot
2025-01-16T17:43:25Z

In order to handle registering hmem devices for SOFT RESERVE reources
that are added late in boot update the hmem_register_resource(),
hmem_register_device(), and walk_hmem_resources() interfaces.

Remove the target_nid arg to hmem_register_resource(). The target nid
value is calculated from the resource start address and not used until
registering a device for the resource. Move the target nid calculation
to hmem_register_device().

To allow for registering hmem devices outside of the hmem dax driver
probe routine save the dax hmem platform driver during probe. The
hmem_register_device() interface can then drop the host and target
nid parameters.

There should be no functional changes.

Signed-off-by: Nathan Fontenot <nathan.fontenot@amd.com>
---
drivers/acpi/numa/hmat.c | 7 ++-----
drivers/dax/hmem/device.c | 14 ++++++--------
drivers/dax/hmem/hmem.c | 12 ++++++++----
include/linux/dax.h | 9 ++++-----
4 files changed, 20 insertions(+), 22 deletions(-)

diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c
index 1a902a02390f..23d4b3ad6d88 100644
--- a/drivers/acpi/numa/hmat.c
+++ b/drivers/acpi/numa/hmat.c
@@ -857,11 +857,8 @@ static void hmat_register_target_devices(struct memory_target *target)
if (!IS_ENABLED(CONFIG_DEV_DAX_HMEM))
return;

- for (res = target->memregions.child; res; res = res->sibling) {
- int target_nid = pxm_to_node(target->memory_pxm);
-
- hmem_register_resource(target_nid, res);
- }
+ for (res = target->memregions.child; res; res = res->sibling)
+ hmem_register_resource(res);
}

static void hmat_register_target(struct memory_target *target)
diff --git a/drivers/dax/hmem/device.c b/drivers/dax/hmem/device.c
index f9e1a76a04a9..ae25e08a636f 100644
--- a/drivers/dax/hmem/device.c
+++ b/drivers/dax/hmem/device.c
@@ -17,14 +17,14 @@ static struct resource hmem_active = {
.flags = IORESOURCE_MEM,
};

-int walk_hmem_resources(struct device *host, walk_hmem_fn fn)
+int walk_hmem_resources(walk_hmem_fn fn)
{
struct resource *res;
int rc = 0;

mutex_lock(&hmem_resource_lock);
for (res = hmem_active.child; res; res = res->sibling) {
- rc = fn(host, (int) res->desc, res);
+ rc = fn(res);
if (rc)
break;
}
@@ -33,7 +33,7 @@ int walk_hmem_resources(struct device *host, walk_hmem_fn fn)
}
EXPORT_SYMBOL_GPL(walk_hmem_resources);

-static void __hmem_register_resource(int target_nid, struct resource *res)
+static void __hmem_register_resource(struct resource *res)
{
struct platform_device *pdev;
struct resource *new;
@@ -46,8 +46,6 @@ static void __hmem_register_resource(int target_nid, struct resource *res)
return;
}

- new->desc = target_nid;
-
if (platform_initialized)
return;

@@ -64,19 +62,19 @@ static void __hmem_register_resource(int target_nid, struct resource *res)
platform_initialized = true;
}

-void hmem_register_resource(int target_nid, struct resource *res)
+void hmem_register_resource(struct resource *res)
{
if (nohmem)
return;

mutex_lock(&hmem_resource_lock);
- __hmem_register_resource(target_nid, res);
+ __hmem_register_resource(res);
mutex_unlock(&hmem_resource_lock);
}

static __init int hmem_register_one(struct resource *res, void *data)
{
- hmem_register_resource(phys_to_target_node(res->start), res);
+ hmem_register_resource(res);

return 0;
}
diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c
index 5e7c53f18491..088f4060d4d5 100644
--- a/drivers/dax/hmem/hmem.c
+++ b/drivers/dax/hmem/hmem.c
@@ -9,6 +9,8 @@
static bool region_idle;
module_param_named(region_idle, region_idle, bool, 0644);

+static struct platform_device *dax_hmem_pdev;
+
static int dax_hmem_probe(struct platform_device *pdev)
{
unsigned long flags = IORESOURCE_DAX_KMEM;
@@ -59,13 +61,13 @@ static void release_hmem(void *pdev)
platform_device_unregister(pdev);
}

-static int hmem_register_device(struct device *host, int target_nid,
- const struct resource *res)
+static int hmem_register_device(const struct resource *res)
{
+ struct device *host = &dax_hmem_pdev->dev;
struct platform_device *pdev;
struct memregion_info info;
+ int target_nid, rc;
long id;
- int rc;

if (IS_ENABLED(CONFIG_CXL_REGION) &&
region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
@@ -94,6 +96,7 @@ static int hmem_register_device(struct device *host, int target_nid,
return -ENOMEM;
}

+ target_nid = phys_to_target_node(res->start);
pdev->dev.numa_node = numa_map_to_online_node(target_nid);
info = (struct memregion_info) {
.target_node = target_nid,
@@ -125,7 +128,8 @@ static int hmem_register_device(struct device *host, int target_nid,

static int dax_hmem_platform_probe(struct platform_device *pdev)
{
- return walk_hmem_resources(&pdev->dev, hmem_register_device);
+ dax_hmem_pdev = pdev;
+ return walk_hmem_resources(hmem_register_device);
}

static struct platform_driver dax_hmem_platform_driver = {
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 9d3e3327af4c..beaa4bcb515c 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -276,14 +276,13 @@ static inline int dax_mem2blk_err(int err)
}

#ifdef CONFIG_DEV_DAX_HMEM_DEVICES
-void hmem_register_resource(int target_nid, struct resource *r);
+void hmem_register_resource(struct resource *r);
#else
-static inline void hmem_register_resource(int target_nid, struct resource *r)
+static inline void hmem_register_resource(struct resource *r)
{
}
#endif

-typedef int (*walk_hmem_fn)(struct device *dev, int target_nid,
- const struct resource *res);
-int walk_hmem_resources(struct device *dev, walk_hmem_fn fn);
+typedef int (*walk_hmem_fn)(const struct resource *res);
+int walk_hmem_resources(walk_hmem_fn fn);
#endif
--
2.43.0