cxl/region: Factor out code into cxl_region_setup_poison()

Poison injection setup code is embedded in cxl_region_probe(). For
improved encapsulation, readability, and maintainability, factor out
code into function cxl_region_setup_poison().

This patch is a prerequisite to disable poison by region offset for
Normalized Addressing.

No functional changes.

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Robert Richter <rrichter@amd.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20260114164837.1076338-13-rrichter@amd.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Author: Robert Richter

drivers/cxl/core/region.c

@@ -3916,6 +3916,31 @@ static int cxl_region_debugfs_poison_clear(void *data, u64 offset)
 DEFINE_DEBUGFS_ATTRIBUTE(cxl_poison_clear_fops, NULL,
 			 cxl_region_debugfs_poison_clear, "%llx\n");
 
+static int cxl_region_setup_poison(struct cxl_region *cxlr)
+{
+	struct device *dev = &cxlr->dev;
+	struct cxl_region_params *p = &cxlr->params;
+	struct dentry *dentry;
+
+	/* Create poison attributes if all memdevs support the capabilities */
+	for (int i = 0; i < p->nr_targets; i++) {
+		struct cxl_endpoint_decoder *cxled = p->targets[i];
+		struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
+
+		if (!cxl_memdev_has_poison_cmd(cxlmd, CXL_POISON_ENABLED_INJECT) ||
+		    !cxl_memdev_has_poison_cmd(cxlmd, CXL_POISON_ENABLED_CLEAR))
+			return 0;
+	}
+
+	dentry = cxl_debugfs_create_dir(dev_name(dev));
+	debugfs_create_file("inject_poison", 0200, dentry, cxlr,
+			    &cxl_poison_inject_fops);
+	debugfs_create_file("clear_poison", 0200, dentry, cxlr,
+			    &cxl_poison_clear_fops);
+
+	return devm_add_action_or_reset(dev, remove_debugfs, dentry);
+}
+
 static int cxl_region_can_probe(struct cxl_region *cxlr)
 {
 	struct cxl_region_params *p = &cxlr->params;
@@ -3945,7 +3970,6 @@ static int cxl_region_probe(struct device *dev)
 {
 	struct cxl_region *cxlr = to_cxl_region(dev);
 	struct cxl_region_params *p = &cxlr->params;
-	bool poison_supported = true;
 	int rc;
 
 	rc = cxl_region_can_probe(cxlr);
@@ -3969,30 +3993,9 @@ static int cxl_region_probe(struct device *dev)
 	if (rc)
 		return rc;
 
-	/* Create poison attributes if all memdevs support the capabilities */
-	for (int i = 0; i < p->nr_targets; i++) {
-		struct cxl_endpoint_decoder *cxled = p->targets[i];
-		struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
-
-		if (!cxl_memdev_has_poison_cmd(cxlmd, CXL_POISON_ENABLED_INJECT) ||
-		    !cxl_memdev_has_poison_cmd(cxlmd, CXL_POISON_ENABLED_CLEAR)) {
-			poison_supported = false;
-			break;
-		}
-	}
-
-	if (poison_supported) {
-		struct dentry *dentry;
-
-		dentry = cxl_debugfs_create_dir(dev_name(dev));
-		debugfs_create_file("inject_poison", 0200, dentry, cxlr,
-				    &cxl_poison_inject_fops);
-		debugfs_create_file("clear_poison", 0200, dentry, cxlr,
-				    &cxl_poison_clear_fops);
-		rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
-		if (rc)
-			return rc;
-	}
+	rc = cxl_region_setup_poison(cxlr);
+	if (rc)
+		return rc;
 
 	switch (cxlr->mode) {
 	case CXL_PARTMODE_PMEM: