NVMe induced NULL deref in bt_iter()

Ming Lei ming.lei at redhat.com
Tue Jul 4 01:08:19 PDT 2017

On Tue, Jul 04, 2017 at 10:56:23AM +0300, Sagi Grimberg wrote:
> > There are at least one case in which we have to use stop queues:
> > 
> > 	- when QUEUE_BUSY(now it becomes BLK_STS_RESOURCE) happens, some drivers
> > 	need to stop queues for avoiding to hurt CPU, such as virtio-blk, ...
> Why isn't virtio_blk using blk_mq_delay_run_hw_queue like scsi does?

IMO it shouldn't be easy to figure out one perfect delay time, and it
should have been self-adaptive.

Also I think it might be possible to move this kind of stop action into
blk-mq core code, and not let drivers touch stop state. Finally we
may kill all stopping in drivers.


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