[PATCH 3/5] nvme: track shared namespaces

[Christoph Hellwig]

On Thu, Nov 09, 2017 at 01:37:43PM +0200, Sagi Grimberg wrote:
>
>> To allow lockless path lookup the list of nvme_ns structures per
>> nvme_ns_head is protected by SRCU, which requires freeing the nvme_ns
>> structure through call_srcu.
>
> Can you remind me why isn't rcu sufficient? Can looking up a
> path (ns from head->list) block?

blk_mq_make_request can block.