[PATCH] cxl/dax: assign target node to cxl memdev during dax region probe

[liuqiqi]

From: liuqiqi <liuqiqi@xxxxxxxxxx>

When a cxl_dax_region is probed, set the numa_node of associated
cxl_memdev devices to match the target node derived from the region's
address range.
The cxl_dax_region_probe function computes the correct target node (nid)
via phys_to_target_node() but does not propagate this information to
the underlying cxl_memdev devices. This can cause memory allocations
to use an incorrect NUMA node.

Environment: node0/node1 = DRAM, node2 = CXL memory.
Before this fix:
  # cat /sys/bus/cxl/devices/mem0/numa_node
  1
After this fix:
  # cat /sys/bus/cxl/devices/mem0/numa_node
  2

Signed-off-by: liuqiqi <liuqiqi@xxxxxxxxxx>
---
 drivers/dax/cxl.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c
index 3ab39b77843d..a62af46ec31e 100644
--- a/drivers/dax/cxl.c
+++ b/drivers/dax/cxl.c
@@ -4,8 +4,27 @@
 #include <linux/dax.h>
 
 #include "../cxl/cxl.h"
+#include "../cxl/cxlmem.h"
 #include "bus.h"
 
+static void cxl_dax_set_numa_node(struct cxl_region *cxlr, int nid)
+{
+	struct cxl_region_params *p;
+	struct cxl_endpoint_decoder *cxled;
+	struct cxl_memdev *cxlmd;
+	int i;
+
+	p = &cxlr->params;
+	for (i = 0; i < p->nr_targets; i++) {
+		cxled = p->targets[i];
+		if (!cxled)
+			continue;
+
+		cxlmd = cxled_to_memdev(cxled);
+		set_dev_node(&cxlmd->dev, nid);
+	}
+}
+
 static int cxl_dax_region_probe(struct device *dev)
 {
 	struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
@@ -28,6 +47,7 @@ static int cxl_dax_region_probe(struct device *dev)
 		.size = range_len(&cxlr_dax->hpa_range),
 		.memmap_on_memory = true,
 	};
+	cxl_dax_set_numa_node(cxlr, nid);
 
 	return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));
 }
-- 
2.25.1