[PATCH] dm: Check kthread_run's return value

[Minfei Huang]

kthread function is used to process kthread_work. And there is no return
value checking during create this thread. Add this checking to fix this
issue.

Signed-off-by: Minfei Huang <mngh...@gmail.com>
Signed-off-by: Minfei Huang <minfei....@alibaba-inc.com>
---
 drivers/md/dm.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 1b2f962..d68b9d2 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2654,12 +2654,15 @@ struct queue_limits *dm_get_queue_limits(struct 
mapped_device *md)
 }
 EXPORT_SYMBOL_GPL(dm_get_queue_limits);
 
-static void dm_old_init_rq_based_worker_thread(struct mapped_device *md)
+static int dm_old_init_rq_based_worker_thread(struct mapped_device *md)
 {
        /* Initialize the request-based DM worker thread */
        init_kthread_worker(&md->kworker);
        md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
                                       "kdmwork-%s", dm_device_name(md));
+       if (IS_ERR(md->kworker_task))
+               return -ENOMEM;
+       return 0;
 }
 
 /*
@@ -2667,6 +2670,8 @@ static void dm_old_init_rq_based_worker_thread(struct 
mapped_device *md)
  */
 static int dm_old_init_request_queue(struct mapped_device *md)
 {
+       int ret;
+
        /* Fully initialize the queue */
        if (!blk_init_allocated_queue(md->queue, dm_request_fn, NULL))
                return -EINVAL;
@@ -2678,7 +2683,9 @@ static int dm_old_init_request_queue(struct mapped_device 
*md)
        blk_queue_softirq_done(md->queue, dm_softirq_done);
        blk_queue_prep_rq(md->queue, dm_old_prep_fn);
 
-       dm_old_init_rq_based_worker_thread(md);
+       ret = dm_old_init_rq_based_worker_thread(md);
+       if (ret < 0)
+               return ret;
 
        elv_register_queue(md->queue);
 
-- 
2.7.4 (Apple Git-66)