Introduce md_cluster_operations to handle cluster functions

This allows dynamic registering of cluster hooks.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index c8d2bac4e28b..57ecb51ec5fd 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -53,6 +53,7 @@
 #include <linux/slab.h>
 #include "md.h"
 #include "bitmap.h"
+#include "md-cluster.h"
 
 #ifndef MODULE
 static void autostart_arrays(int part);
@@ -66,6 +67,10 @@ static void autostart_arrays(int part);
 static LIST_HEAD(pers_list);
 static DEFINE_SPINLOCK(pers_lock);
 
+struct md_cluster_operations *md_cluster_ops;
+struct module *md_cluster_mod;
+EXPORT_SYMBOL(md_cluster_mod);
+
 static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
 static struct workqueue_struct *md_wq;
 static struct workqueue_struct *md_misc_wq;
@@ -7231,6 +7236,53 @@ int unregister_md_personality(struct md_personality *p)
 }
 EXPORT_SYMBOL(unregister_md_personality);
 
+int register_md_cluster_operations(struct md_cluster_operations *ops, struct module *module)
+{
+        if (md_cluster_ops != NULL)
+                return -EALREADY;
+        spin_lock(&pers_lock);
+        md_cluster_ops = ops;
+        md_cluster_mod = module;
+        spin_unlock(&pers_lock);
+        return 0;
+}
+EXPORT_SYMBOL(register_md_cluster_operations);
+
+int unregister_md_cluster_operations(void)
+{
+        spin_lock(&pers_lock);
+        md_cluster_ops = NULL;
+        spin_unlock(&pers_lock);
+        return 0;
+}
+EXPORT_SYMBOL(unregister_md_cluster_operations);
+
+int md_setup_cluster(struct mddev *mddev, int nodes)
+{
+        int err;
+
+        err = request_module("md-cluster");
+        if (err) {
+                pr_err("md-cluster module not found.\n");
+                return err;
+        }
+
+        spin_lock(&pers_lock);
+        if (!md_cluster_ops || !try_module_get(md_cluster_mod)) {
+                spin_unlock(&pers_lock);
+                return -ENOENT;
+        }
+        spin_unlock(&pers_lock);
+
+        return md_cluster_ops->join(mddev);
+}
+
+void md_cluster_stop(struct mddev *mddev)
+{
+        md_cluster_ops->leave(mddev);
+        module_put(md_cluster_mod);
+}
+
 static int is_mddev_idle(struct mddev *mddev, int init)
 {
         struct md_rdev *rdev;