On 2021/6/9 1:55, Jason Gunthorpe wrote:
> On Fri, May 28, 2021 at 05:37:37PM +0800, Weihang Li wrote:
>> @@ -565,8 +565,11 @@ static struct mcast_group *acquire_group(struct mcast_port *port,
>> if (!is_mgid0) {
>> spin_lock_irqsave(&port->lock, flags);
>> group = mcast_find(port, mgid);
>> - if (group)
>> + if (group) {
>> + refcount_inc(&group->refcount);
>> goto found;
>> + }
>> +
>> spin_unlock_irqrestore(&port->lock, flags);
>> }
>>
>> @@ -590,8 +593,10 @@ static struct mcast_group *acquire_group(struct mcast_port *port,
>> group = cur_group;
>> } else
>> refcount_inc(&port->refcount);
>> +
>> + refcount_set(&group->refcount, 1);
>> +
>
> This isn't right, when mcast_insert() returns an existing group we
> need to incr not set the refcount. Change it like this:
>
Thanks, I will modify it.
Weihang
> diff --git a/drivers/infiniband/core/multicast.c b/drivers/infiniband/core/multicast.c
> index 17abc212b87d05..cf99e17b81ce79 100644
> --- a/drivers/infiniband/core/multicast.c
> +++ b/drivers/infiniband/core/multicast.c
> @@ -585,17 +585,17 @@ static struct mcast_group *acquire_group(struct mcast_port *port,
> INIT_LIST_HEAD(&group->active_list);
> INIT_WORK(&group->work, mcast_work_handler);
> spin_lock_init(&group->lock);
> + refcount_set(&group->refcount, 1);
>
> spin_lock_irqsave(&port->lock, flags);
> cur_group = mcast_insert(port, group, is_mgid0);
> if (cur_group) {
> kfree(group);
> group = cur_group;
> + refcount_inc(&group->refcount);
> } else
> refcount_inc(&port->refcount);
>
> - refcount_set(&group->refcount, 1);
> -
> found:
> spin_unlock_irqrestore(&port->lock, flags);
> return group;
>
