From 5c2a634cbfaf1971cb6453fe5f86d83585257790 Mon Sep 17 00:00:00 2001
From: Coly Li <colyli@suse.de>
Date: Fri, 28 Jun 2019 19:59:45 +0800
Subject: [PATCH] bcache: stop writeback kthread and kworker when
 bch_cached_dev_run() failed
Git-commit: 5c2a634cbfaf1971cb6453fe5f86d83585257790
References: bsc#1140652
Patch-mainline: v5.3-rc1

In bch_cached_dev_attach() after bch_cached_dev_writeback_start()
called, the wrireback kthread and writeback rate update kworker of the
cached device are created, if the following bch_cached_dev_run()
failed, bch_cached_dev_attach() will return with -ENOMEM without
stopping the writeback related kthread and kworker.

This patch stops writeback kthread and writeback rate update kworker
before returning -ENOMEM if bch_cached_dev_run() returns error.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

---
 drivers/md/bcache/super.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index c4c4b2d99dc2..791cb930b353 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1189,6 +1189,14 @@ int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c,
 	ret = bch_cached_dev_run(dc);
 	if (ret && (ret != -EBUSY)) {
 		up_write(&dc->writeback_lock);
+		/*
+		 * bch_register_lock is held, bcache_device_stop() is not
+		 * able to be directly called. The kthread and kworker
+		 * created previously in bch_cached_dev_writeback_start()
+		 * have to be stopped manually here.
+		 */
+		kthread_stop(dc->writeback_thread);
+		cancel_writeback_rate_update_dwork(dc);
 		pr_err("Couldn't run cached device %s",
 		       dc->backing_dev_name);
 		return ret;
-- 
2.16.4