Re: [PATCH] md: bcache: check the return value of mempool_alloc() in bch_btree_node_read_done()

[Coly Li <colyli@suse.de>]

On 2/25/22 4:28 PM, Jia-Ju Bai wrote:
> The function mempool_alloc() in bch_btree_node_read_done() can fail, so
> its return value should be checked.
>
> Fixes: d19936a26658 ("bcache: convert to bioset_init()/mempool_init()")
> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
>   drivers/md/bcache/btree.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
> index 88c573eeb598..fb8b7dd6bcc2 100644
> --- a/drivers/md/bcache/btree.c
> +++ b/drivers/md/bcache/btree.c
> @@ -157,6 +157,8 @@ void bch_btree_node_read_done(struct btree *b)
>   	 * See the comment arount cache_set->fill_iter.
>   	 */
>   	iter = mempool_alloc(&b->c->fill_iter, GFP_NOIO);
> +	if (!iter)
> +		return;


This is unnecessary, mempool_alloc() doesn't return NULL in this condition.


Coly Li



>   	iter->size = b->c->cache->sb.bucket_size / b->c->cache->sb.block_size;
>   	iter->used = 0;
>