Re: [PATCH] cfq-iosched: Fix update_vdisktime logic

[Gui Jianfeng <guijianfeng@cn.fujitsu.com>]

Vivek Goyal wrote:
> On Tue, Jan 25, 2011 at 11:27:19AM +0800, Gui Jianfeng wrote:
>> The update_vdisktime logic is broken since commit b54ce60eb7f61f8e314b8b241b0469eda3bb1d42,
>> st->min_vdisktime never makes a progress. Fix it.
>>
>> Thanks Vivek for pointing it out.
>>
>> Signed-off-by: Gui Jianfeng <guijianfen@cn.fujitsu.com>
> 
> Thanks Gui. Looks good to me.
> 
> Acked-by: Vivek Goyal <vgoyal@redhat.com>

Jens, Would you pick up this fix?

Thanks,
Gui

> 
> Thanks
> Vivek
> 
>> ---
>>  block/cfq-iosched.c |    6 ++----
>>  1 files changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
>> index f083bda..8c28f56 100644
>> --- a/block/cfq-iosched.c
>> +++ b/block/cfq-iosched.c
>> @@ -558,15 +558,13 @@ static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime)
>>  
>>  static void update_min_vdisktime(struct cfq_rb_root *st)
>>  {
>> -	u64 vdisktime = st->min_vdisktime;
>>  	struct cfq_group *cfqg;
>>  
>>  	if (st->left) {
>>  		cfqg = rb_entry_cfqg(st->left);
>> -		vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime);
>> +		st->min_vdisktime = max_vdisktime(st->min_vdisktime,
>> +						  cfqg->vdisktime);
>>  	}
>> -
>> -	st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime);
>>  }
>>  
>>  /*
>> -- 
>> 1.7.1
>