Re: [PATCH] NVMe: do not touch sq door bell if nvmeq has been suspended

[Keith Busch]

On Tue, Feb 09, 2016 at 11:22:04AM +0000, Wenbo Wang wrote:
> In most cases, rcu read lock is just a preempt_disable, which is what get_cpu does. I don't see any risk.

Yes, many rcu_read_lock cases expand similarly to get_cpu. What about
the other cases?

FWIW, I don't think we'll hit the problem with the proposed rcu sync.
Heck, we don't even have a synchronize today and we don't hit the
theoretical problem.