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Subject: Re: [PATCH 7/8] nvme: use blk_mq_queue_tag_busy_iter
To:     James Smart <jsmart2021@gmail.com>,
        Jianchao Wang <jianchao.w.wang@oracle.com>, axboe@kernel.dk
Cc:     linux-block@vger.kernel.org, sagi@grimberg.me,
        josef@toxicpanda.com, linux-nvme@lists.infradead.org,
        linux-kernel@vger.kernel.org, keith.busch@intel.com, hare@suse.de,
        jthumshirn@suse.de, hch@lst.de, bvanassche@acm.org
References: <1552640264-26101-1-git-send-email-jianchao.w.wang@oracle.com>
 <1552640264-26101-8-git-send-email-jianchao.w.wang@oracle.com>
 <62de99e8-0d8d-910a-bfdc-649f734b152c@gmail.com>
From:   James Smart <james.smart@broadcom.com>
Message-ID: <f284663c-ad13-65ea-5ce0-9b305ca91d3c@broadcom.com>
Date:   Fri, 15 Mar 2019 09:39:45 -0700
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On 3/15/2019 9:33 AM, James Smart wrote:
> On 3/15/2019 1:57 AM, Jianchao Wang wrote:
>> blk_mq_tagset_busy_iter is not safe that it could get stale request
>> in tags->rqs[]. Use blk_mq_queue_tag_busy_iter here. A new helper
>> interface nvme_iterate_inflight_rqs is introduced to iterate
>> all of the ns under a ctrl.
>>
>> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
>> ---
>>   drivers/nvme/host/core.c   | 12 ++++++++++++
>>   drivers/nvme/host/fc.c     | 12 ++++++------
>>   drivers/nvme/host/nvme.h   |  2 ++
>>   drivers/nvme/host/pci.c    |  5 +++--
>>   drivers/nvme/host/rdma.c   |  6 +++---
>>   drivers/nvme/host/tcp.c    |  5 +++--
>>   drivers/nvme/target/loop.c |  6 +++---
>>   7 files changed, 32 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>> index 6a9dd68..5760fad 100644
>> --- a/drivers/nvme/host/core.c
>> +++ b/drivers/nvme/host/core.c
>> @@ -3816,6 +3816,18 @@ void nvme_start_queues(struct nvme_ctrl *ctrl)
>>   }
>>   EXPORT_SYMBOL_GPL(nvme_start_queues);
>>   +void nvme_iterate_inflight_rqs(struct nvme_ctrl *ctrl,
>> +        busy_iter_fn *fn, void *data)
>> +{
>> +    struct nvme_ns *ns;
>> +
>> +    down_read(&ctrl->namespaces_rwsem);
>> +    list_for_each_entry(ns, &ctrl->namespaces, list)
>> +        blk_mq_queue_tag_busy_iter(ns->queue, fn, data, true);
>> +    up_read(&ctrl->namespaces_rwsem);
>> +}
>> +EXPORT_SYMBOL_GPL(nvme_iterate_inflight_rqs);
>
> Hmm... so this aborts ios for namespaces. How about ios that aren't 
> for a namespace but rather for the controller itself.  For example, 
> anything on the admin queue ?   Rather critical for those ios be 
> terminated as well.
NVM - didn't look at which tag set.  but it does highlight - doesn't 
cover anything issued by core/transport on the io queues.

-- james