bcache: Convert gc to a kthread

We needed a dedicated rescuer workqueue for gc anyways... and gc was
conceptually a dedicated thread, just one that wasn't running all the
time. Switch it to a dedicated thread to make the code a bit more
straightforward.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 9 insertions, 11 deletions

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 84398a82fbe3..f89e2296bde1 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1342,6 +1342,9 @@ static void cache_set_flush(struct closure *cl)
         kobject_put(&c->internal);
         kobject_del(&c->kobj);
 
+        if (c->gc_thread)
+                kthread_stop(c->gc_thread);
+
         if (!IS_ERR_OR_NULL(c->root))
                 list_add(&c->root->list, &c->btree_cache);
 
@@ -1579,8 +1582,6 @@ static void run_cache_set(struct cache_set *c)
                 bch_journal_replay(c, &journal, &op);
         } else {
                 pr_notice("invalidating existing data");
-                /* Don't want invalidate_buckets() to queue a gc yet */
-                closure_lock(&c->gc, NULL);
 
                 for_each_cache(ca, c, i) {
                         unsigned j;
@@ -1606,12 +1607,12 @@ static void run_cache_set(struct cache_set *c)
 
                 err = "cannot allocate new UUID bucket";
                 if (__uuid_write(c))
-                        goto err_unlock_gc;
+                        goto err;
 
                 err = "cannot allocate new btree root";
                 c->root = bch_btree_node_alloc(c, 0);
                 if (IS_ERR_OR_NULL(c->root))
-                        goto err_unlock_gc;
+                        goto err;
 
                 bkey_copy_key(&c->root->key, &MAX_KEY);
                 bch_btree_node_write(c->root, &op.cl);
@@ -1628,12 +1629,12 @@ static void run_cache_set(struct cache_set *c)
 
                 bch_journal_next(&c->journal);
                 bch_journal_meta(c, &op.cl);
-
-                /* Unlock */
-                closure_set_stopped(&c->gc.cl);
-                closure_put(&c->gc.cl);
         }
 
+        err = "error starting gc thread";
+        if (bch_gc_thread_start(c))
+                goto err;
+
         closure_sync(&op.cl);
         c->sb.last_mount = get_seconds();
         bcache_write_super(c);
@@ -1644,9 +1645,6 @@ static void run_cache_set(struct cache_set *c)
         flash_devs_run(c);
 
         return;
-err_unlock_gc:
-        closure_set_stopped(&c->gc.cl);
-        closure_put(&c->gc.cl);
 err:
         closure_sync(&op.cl);
         /* XXX: test this, it's broken */