RAS: Export helper to get ras_debugfs_dir

Export a getter instead of the debugfs node directly so that, other
in-tree-only RAS modules can use it.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20240301143748.854090-2-yazen.ghannam@amd.com

drivers/ras/cec.c

@@ -480,9 +480,15 @@ DEFINE_SHOW_ATTRIBUTE(array);
 
 static int __init create_debugfs_nodes(void)
 {
-	struct dentry *d, *pfn, *decay, *count, *array;
+	struct dentry *d, *pfn, *decay, *count, *array, *dfs;
 
-	d = debugfs_create_dir("cec", ras_debugfs_dir);
+	dfs = ras_get_debugfs_root();
+	if (!dfs) {
+		pr_warn("Error getting RAS debugfs root!\n");
+		return -1;
+	}
+
+	d = debugfs_create_dir("cec", dfs);
 	if (!d) {
 		pr_warn("Error creating cec debugfs node!\n");
 		return -1;

drivers/ras/debugfs.c

@@ -3,10 +3,16 @@
 #include <linux/ras.h>
 #include "debugfs.h"
 
-struct dentry *ras_debugfs_dir;
+static struct dentry *ras_debugfs_dir;
 
 static atomic_t trace_count = ATOMIC_INIT(0);
 
+struct dentry *ras_get_debugfs_root(void)
+{
+	return ras_debugfs_dir;
+}
+EXPORT_SYMBOL_GPL(ras_get_debugfs_root);
+
 int ras_userspace_consumers(void)
 {
 	return atomic_read(&trace_count);

drivers/ras/debugfs.h

@@ -4,6 +4,6 @@
 
 #include <linux/debugfs.h>
 
-extern struct dentry *ras_debugfs_dir;
+struct dentry *ras_get_debugfs_root(void);
 
 #endif /* __RAS_DEBUGFS_H__ */