On Tue, Aug 2, 2016 at 7:21 PM, Jens Axboe <axboe@xxxxxxxxx> wrote:
> On 08/02/2016 06:58 AM, Jinpu Wang wrote:
>>
>> Hi Jens,
>>
>> I found in blk_mq_register_disk, we blk_mq_disable_hotplug which in
>> turn mutex_lock(&all_q_mutex);
>> queue_for_each_hw_ctx(q, hctx, i) {
>> ret = blk_mq_register_hctx(hctx);
>> if (ret)
>> break; /// if about error out, we will call
>> unregister below
>> }
>>
>> if (ret)
>> blk_mq_unregister_disk(disk);
>>
>> In blk_mq_unregister_disk, we will try to disable_hotplug again, which
>> leads to dead lock.
>>
>> Did I miss anything?
>
>
> Nope, your analysis looks correct. This should fix it:
>
> http://git.kernel.dk/cgit/linux-block/commit/?h=for-linus&id=6316338a94b2319abe9d3790eb9cdc56ef81ac1a
>
>
> --
> Jens Axboe
>
Thanks Jens, looks good to me!
--
Mit freundlichen Grüßen,
Best Regards,
Jack Wang
Linux Kernel Developer Storage
ProfitBricks GmbH The IaaS-Company.
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