[PATCH] loop: check loop_add's return value

[weiping zhang]

do cleanup if loop_add fail.

Signed-off-by: weiping zhang <zhangweip...@didichuxing.com>
---
 drivers/block/loop.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index bc8e61506968..9bea70a7da16 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1987,6 +1987,14 @@ static struct miscdevice loop_misc = {
 MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR);
 MODULE_ALIAS("devname:loop-control");
 
+static int loop_exit_cb(int id, void *ptr, void *data)
+{
+       struct loop_device *lo = ptr;
+
+       loop_remove(lo);
+       return 0;
+}
+
 static int __init loop_init(void)
 {
        int i, nr;
@@ -2050,27 +2058,29 @@ static int __init loop_init(void)
 
        /* pre-create number of devices given by config or max_loop */
        mutex_lock(&loop_index_mutex);
-       for (i = 0; i < nr; i++)
-               loop_add(&lo, i);
+       for (i = 0; i < nr; i++) {
+               err = loop_add(&lo, i);
+               if (err < 0) {
+                       mutex_unlock(&loop_index_mutex);
+                       goto err_blk;
+               }
+       }
        mutex_unlock(&loop_index_mutex);
 
        printk(KERN_INFO "loop: module loaded\n");
        return 0;
 
+err_blk:
+       idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
+       idr_destroy(&loop_index_idr);
+       blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range);
+       unregister_blkdev(LOOP_MAJOR, "loop");
 misc_out:
        misc_deregister(&loop_misc);
 err_out:
        return err;
 }
 
-static int loop_exit_cb(int id, void *ptr, void *data)
-{
-       struct loop_device *lo = ptr;
-
-       loop_remove(lo);
-       return 0;
-}
-
 static void __exit loop_exit(void)
 {
        unsigned long range;
-- 
2.14.2