[PATCH] nvme-core: reduce io pause time when fail over

[Sagi Grimberg]

>> +       /* all namespaces share hctxs, so sync just once */
>> +       blk_mq_quiesce_queue_sync(ns->queue);
> 
> They don't share hctx's. An hctx is a property of a specific
> request_queue, and each namespace has their own.

ugh, right...

But I still think that we should wait for all the srcus together...

Perhaps we should do call_srcu on all and wait for all in one pass.
But I don't want the driver to do this without a proper blk-mq
interface..