[V2] null_blk: add helper for deleting the nullb_list

Commit Message

Chaitanya Kulkarni July 2, 2020, 12:49 a.m. UTC

The nullb_list is destroyed when error occurs in the null_init() and
when removing the module in null_exit(). The identical code is repeated
in those functions which can be a part of helper function. This also
removes the extra variable struct nullb *nullb in the both functions.

Signed-off-by: Chaitanya Kulkarni <[e-mail]>
Reviewed-by: Johannes Thumshirn <[e-mail]>
---

* Changes from V1: -
--------------------

1. Add missing sign-off and reviewed-by tag.

---
 drivers/block/null_blk_main.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

Comments

Jens Axboe July 2, 2020, 4:22 a.m. UTC | #1

On 7/1/20 6:49 PM, Chaitanya Kulkarni wrote:
> diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
> index 907c6858aec0..3f5ff75fcb3d 100644
> --- a/drivers/block/null_blk_main.c
> +++ b/drivers/block/null_blk_main.c
> @@ -1868,11 +1868,23 @@ static int null_add_dev(struct nullb_device *dev)
>  	return rv;
>  }
>  
> +static void null_delete_nullb_list(void)
> +{
> +	struct nullb_device *dev;
> +	struct nullb *nullb;
> +
> +	while (!list_empty(&nullb_list)) {
> +		nullb = list_entry(nullb_list.next, struct nullb, list);
> +		dev = nullb->dev;
> +		null_del_dev(nullb);
> +		null_free_dev(dev);
> +	}
> +}

Since we're making the cleanup anyway, this should use list_first_entry()

Patch

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 907c6858aec0..3f5ff75fcb3d 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1868,11 +1868,23 @@  static int null_add_dev(struct nullb_device *dev)
 	return rv;
 }
 
+static void null_delete_nullb_list(void)
+{
+	struct nullb_device *dev;
+	struct nullb *nullb;
+
+	while (!list_empty(&nullb_list)) {
+		nullb = list_entry(nullb_list.next, struct nullb, list);
+		dev = nullb->dev;
+		null_del_dev(nullb);
+		null_free_dev(dev);
+	}
+}
+
 static int __init null_init(void)
 {
 	int ret = 0;
 	unsigned int i;
-	struct nullb *nullb;
 	struct nullb_device *dev;
 
 	if (g_bs > PAGE_SIZE) {
@@ -1939,12 +1951,7 @@  static int __init null_init(void)
 	return 0;
 
 err_dev:
-	while (!list_empty(&nullb_list)) {
-		nullb = list_entry(nullb_list.next, struct nullb, list);
-		dev = nullb->dev;
-		null_del_dev(nullb);
-		null_free_dev(dev);
-	}
+	null_delete_nullb_list();
 	unregister_blkdev(null_major, "nullb");
 err_conf:
 	configfs_unregister_subsystem(&nullb_subsys);
@@ -1956,21 +1963,12 @@  static int __init null_init(void)
 
 static void __exit null_exit(void)
 {
-	struct nullb *nullb;
-
 	configfs_unregister_subsystem(&nullb_subsys);
 
 	unregister_blkdev(null_major, "nullb");
 
 	mutex_lock(&lock);
-	while (!list_empty(&nullb_list)) {
-		struct nullb_device *dev;
-
-		nullb = list_entry(nullb_list.next, struct nullb, list);
-		dev = nullb->dev;
-		null_del_dev(nullb);
-		null_free_dev(dev);
-	}
+	null_delete_nullb_list();
 	mutex_unlock(&lock);
 
 	if (g_queue_mode == NULL_Q_MQ && shared_tags)