Re: [PATCH 2/7] block: Remove bio->bi_ioc

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 2018/11/21 11:11, Jens Axboe wrote:
> On 11/20/18 4:58 PM, Damien Le Moal wrote:
>> On 2018/11/21 2:31, Jens Axboe wrote:
>>> I think the below should fix it, we haven't necessarily setup an
>>> ioc if we're just doing as passthrough request.
>>>
>>>
>>> diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
>>> index 13b8dc332541..f096d8989773 100644
>>> --- a/block/blk-mq-sched.c
>>> +++ b/block/blk-mq-sched.c
>>> @@ -34,9 +34,16 @@ EXPORT_SYMBOL_GPL(blk_mq_sched_free_hctx_data);
>>>  void blk_mq_sched_assign_ioc(struct request *rq)
>>>  {
>>>  	struct request_queue *q = rq->q;
>>> -	struct io_context *ioc = current->io_context;
>>> +	struct io_context *ioc;
>>>  	struct io_cq *icq;
>>>  
>>> +	/*
>>> +	 * May not have an IO context if it's a passthrough request
>>> +	 */
>>> +	ioc = current->io_context;
>>> +	if (!ioc)
>>> +		return;
>>> +
>>>  	spin_lock_irq(&q->queue_lock);
>>>  	icq = ioc_lookup_icq(ioc, q);
>>>  	spin_unlock_irq(&q->queue_lock);
>>
>> This seems reasonable to me, but I wonder why this problem was not triggering
>> before. The previous code getting the ioc with the rq_ioc(bio) call was
>> essentially the same and there was no "if (!ioc) return;" in
>> blk_mq_sched_assign_ioc() before the patch.
>> Any idea why this is popping up now ?
>>
>> Ming,
>>
>> Is this a new test your are running ? If this same problem triggers on stable
>> kernels, Jens patch needs to go to stable too.
> 
> No, it's definitely introduced in your patches:
> 
> -                       if (e->type->icq_cache && rq_ioc(bio))
> -                               blk_mq_sched_assign_ioc(rq, bio);
> +                       if (e->type->icq_cache)
> +                               blk_mq_sched_assign_ioc(rq);

Arg ! Yes, I missed this. My apologies.

> Please run blktests on a series. Always. There's no excuse not to.

I did run my usual tests exercising drives with various fio workloads. But I did
not run blktests itself. I will fix my workflow to include it.

Thanks.


-- 
Damien Le Moal
Western Digital Research




[Index of Archives]     [Linux RAID]     [Linux SCSI]     [Linux ATA RAID]     [IDE]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Device Mapper]

  Powered by Linux