Re: [PATCH v8 17/18] scsi: megaraid_sas: Added support for shared host tagset for cpuhotplug

[Ming Lei]

On Wed, Nov 11, 2020 at 09:42:17AM -0500, Qian Cai wrote:
> On Wed, 2020-11-11 at 17:27 +0800, Ming Lei wrote:
> > Can this issue disappear by applying the following change?
> 
> This makes the system boot again as well.

OK, actually it isn't necessary to register one new lock key for each
hctx(blk_flush_queue) instance, and the current way is really over-kill
because there can be lots of hw queues in one system.

The original lockdep warning can be avoided by setting one nvme_loop
specific lock class simply. If nvme_loop is backed against another nvme_loop,
we still can avoid the warning by killing the direct end io chain, or
assign another lock class.

Will prepare one formal patch tomorrow.

Thanks,
Ming