[PATCH] nvme-pci: fix sleeping function called from interrupt context

[Keith Busch]

On Mon, Dec 18, 2023 at 10:43:45AM -0700, Keith Busch wrote:
> On Mon, Dec 18, 2023 at 04:11:38PM +0100, Maurizio Lombardi wrote:
> > p'a 15. 12. 2023 v 18:25 odes'ilatel Keith Busch <kbusch at kernel.org> napsal:
> > > What async event occured to cause this? It looks like the only AEN
> > > handling that cancels anything is the FW activation one, but that only
> > > applies to fabrics, not pci. Still, that AEN hanlder sets the state to
> > > "RESETTING", but we only cancel work when transitioning to "LIVE" from a
> > > CONNECTING state.
> > 
> > It looks like the stack trace is a bit imprecise.
> > It's not the call to nvme_change_ctrl_state() that triggers the error
> > because, as
> > you correctly noticed, moving the controller to the resetting state
> > doesn't block.
> > 
> > The problem is the call to nvme_auth_stop().
> > 
> >         case NVME_AER_NOTICE_FW_ACT_STARTING:
> >                 /*
> >                  * We are (ab)using the RESETTING state to prevent subsequent
> >                  * recovery actions from interfering with the controller's
> >                  * firmware activation.
> >                  */
> >                 if (nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING)) {
> >                         nvme_auth_stop(ctrl);     <----------------
> >                         requeue = false;
> >                         queue_work(nvme_wq, &ctrl->fw_act_work);
> >                 }
> > 
> > void nvme_auth_stop(struct nvme_ctrl *ctrl)
> > {
> >         cancel_work_sync(&ctrl->dhchap_auth_work);
> > }
> 
> Oh, got it; thank you for clarifying.
> 
> In that case, let's move the nvme_auth_stop() call to fw_act_work. The
> AER handler doesn't depend on auth_work being sync'ed.

I also want to mention nvme_auth_stop() ought to be a no-op for PCI,
right? The nvme_ctrl struct seems a bit overburdened at this point, I'll
take a shot at splitting optional transport specifics out of it.