From ee452a8d984f94fa8e894f003a52e776e4572881 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 15 Jul 2022 11:12:14 +0300
Subject: [PATCH] null_blk: fix ida error handling in null_add_dev()
Git-commit: ee452a8d984f94fa8e894f003a52e776e4572881
Patch-mainline: v6.0-rc1
References: git-fixes

There needs to be some error checking if ida_simple_get() fails.
Also call ida_free() if there are errors later.

(Coly Li: rebased for Linux v4.12 based SUSE kernel)

Fixes: 94bc02e30fb8 ("nullb: use ida to manage index")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YtEhXsr6vJeoiYhd@kili
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/block/null_blk.c |   14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -1814,8 +1814,13 @@ static int null_add_dev(struct nullb_dev
 	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
 
 	mutex_lock(&lock);
-	nullb->index = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
-	dev->index = nullb->index;
+	rv = ida_simple_get(&nullb_indexes, 0, 0, GFP_KERNEL);
+	if (rv < 0) {
+		mutex_unlock(&lock);
+		goto out_cleanup_blk_queue;
+	}
+	nullb->index = rv;
+	dev->index = rv;
 	mutex_unlock(&lock);
 
 	blk_queue_logical_block_size(nullb->q, dev->blocksize);
@@ -1827,13 +1832,16 @@ static int null_add_dev(struct nullb_dev
 
 	rv = null_gendisk_register(nullb);
 	if (rv)
-		goto out_cleanup_blk_queue;
+		goto out_ida_free;
 
 	mutex_lock(&lock);
 	list_add_tail(&nullb->list, &nullb_list);
 	mutex_unlock(&lock);
 
 	return 0;
+
+out_ida_free:
+	ida_free(&nullb_indexes, nullb->index);
 out_cleanup_blk_queue:
 	blk_cleanup_queue(nullb->q);
 out_cleanup_tags: