On Fri, May 22, 2015 at 1:04 AM, Keith Busch <keith.bu...@intel.com> wrote: > On Thu, 21 May 2015, Parav Pandit wrote: >> >> Avoid diabling interrupt and holding q_lock for the queue >> which is just getting initialized. >> >> With this change, online_queues is also incremented without >> lock during queue setup stage. >> if Power management nvme_suspend() kicks in during queue setup time, >> per nvmeq based q_lock spinlock cannot protect device wide >> online_queues variable anyway. > > > The q_lock is held to protect polling from reading inconsistent data.
ah, yes. I can see the nvme_kthread can poll the CQ while its getting created through the nvme_resume(). I think this opens up other issue. nvme_kthread() should, Instead of, struct nvme_queue *nvmeq = dev->queues[i]; it should do, struct nvme_queue *nvmeq = rcu_dereference(dev->queues[i]); And, nvme_alloc_queue() dev->queues[qid] = nvmeq; should be, rcu_assign_pointer(dev->queues[qid], nvmeq); Otherwise nvme_kthread could get stale value for elements of nvmeq. I will send patch for fix. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
