Re: [PATCH v2 2/2] RDMA/cm: Optimise rbtree searching

["Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>]

On 2021/5/12 20:50, Jason Gunthorpe wrote:
> On Wed, May 12, 2021 at 06:05:37PM +0800, Zhen Lei wrote:
>>  static struct cm_id_private *cm_find_listen(struct ib_device *device,
>> @@ -686,22 +687,23 @@ static struct cm_id_private *cm_find_listen(struct ib_device *device,
>>  
>>  	while (node) {
>>  		cm_id_priv = rb_entry(node, struct cm_id_private, service_node);
>> -		if ((cm_id_priv->id.service_mask & service_id) ==
>> -		     cm_id_priv->id.service_id &&
>> -		    (cm_id_priv->id.device == device)) {
>> -			refcount_inc(&cm_id_priv->refcount);
>> -			return cm_id_priv;
>> -		}
>> +
>>  		if (device < cm_id_priv->id.device)
>>  			node = node->rb_left;
>>  		else if (device > cm_id_priv->id.device)
>>  			node = node->rb_right;
>> +		else if ((cm_id_priv->id.service_mask & service_id) == cm_id_priv->id.service_id)
>> +			goto found;
>>  		else if (be64_lt(service_id, cm_id_priv->id.service_id))
>>  			node = node->rb_left;
>>  		else
>>  			node = node->rb_right;
>>  	}
> 
> This is not the pattern I showed you. Drop the first patch and rely on
> the implicit equality in the final else.

Do you mean treate the "found" process as the else branch?

But ((cm_id_priv->id.service_mask & service_id) == cm_id_priv->id.service_id) is different from
(service_id == cm_id_priv->id.service_id)，I'm just worried that it might change the original logic.

> 
> Jason
> 
> .
>