Re: [PATCH v2] nbd: Fix NULL pointer in flush_workqueue

hi，Markus

在 2021/2/2 3:05, Markus Elfring 写道:

…

quoted

+++ b/drivers/block/nbd.c

@@ -2011,12 +2011,14 @@ static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
  		       index);
  		return -EINVAL;
  	}
+	mutex_lock(&nbd->config_lock);
  	if (!refcount_inc_not_zero(&nbd->refs)) {
-		mutex_unlock(&nbd_index_mutex);
-		printk(KERN_ERR "nbd: device at index %d is going down\n",
-		       index);
-		return -EINVAL;
+		goto unlock;
  	}
+	if (!nbd->recv_workq) {
+		goto unlock;
+	}

How do you think about to use the following patch variant
(so that unwanted curly brackets would be avoided for proposed single statements
in two if branches)?

+	mutex_lock(&nbd->config_lock);
-	if (!refcount_inc_not_zero(&nbd->refs)) {
+	if (!refcount_inc_not_zero(&nbd->refs) || !nbd->recv_workq) {
+		mutex_unlock(&nbd->config_lock);
  		mutex_unlock(&nbd_index_mutex);
  		printk(KERN_ERR "nbd: device at index %d is going down\n",tter
  		       index);
  		return -EINVAL;
  	}

It looks better,  thanks for your suggestion.

By the way:
Would you like to replace the following two statements by the statement
“goto put_nbd;” in another update step for this function implementation?

		nbd_put(nbd);
		return 0;

Sure, I will do it.

Regards,
Markus

Thanks,

Sun Ke

.