block: null_blk: Cleanup device creation and deletion

Introduce the null_create_dev() and null_destroy_dev() helper functions
to respectivel create nullb devices on modprobe and destroy them on
rmmod. The null_destroy_dev() helper avoids duplicated code in the
null_init() and null_exit() functions for deleting devices.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220420005718.3780004-3-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 5528551..b0841f1 100644 (file)
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -2086,12 +2086,37 @@ out:
        return rv;
 }
 
+static int null_create_dev(void)
+{
+       struct nullb_device *dev;
+       int ret;
+
+       dev = null_alloc_dev();
+       if (!dev)
+               return -ENOMEM;
+
+       ret = null_add_dev(dev);
+       if (ret) {
+               null_free_dev(dev);
+               return ret;
+       }
+
+       return 0;
+}
+
+static void null_destroy_dev(struct nullb *nullb)
+{
+       struct nullb_device *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) {
                pr_warn("invalid block size\n");
@@ -2149,16 +2174,9 @@ static int __init null_init(void)
        }
 
        for (i = 0; i < nr_devices; i++) {
-               dev = null_alloc_dev();
-               if (!dev) {
-                       ret = -ENOMEM;
-                       goto err_dev;
-               }
-               ret = null_add_dev(dev);
-               if (ret) {
-                       null_free_dev(dev);
+               ret = null_create_dev();
+               if (ret)
                        goto err_dev;
-               }
        }
 
        pr_info("module loaded\n");
@@ -2167,9 +2185,7 @@ static int __init null_init(void)
 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_destroy_dev(nullb);
        }
        unregister_blkdev(null_major, "nullb");
 err_conf:
@@ -2190,12 +2206,8 @@ static void __exit null_exit(void)
 
        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_destroy_dev(nullb);
        }
        mutex_unlock(&lock);