Re: [PATCH V2]nvme-pci: Fixes EEH failure on ppc

[Sagi Grimberg]

> > @@ -1189,6 +1183,12 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
> >   	struct nvme_command cmd;
> >   	u32 csts = readl(dev->bar + NVME_REG_CSTS);
> >   
> > +	/* If PCI error recovery process is happening, we cannot reset or
> > +	 * the recovery mechanism will surely fail.
> > +	 */
> > +	if (pci_channel_offline(to_pci_dev(dev->dev)))
> > +		return BLK_EH_RESET_TIMER;
>
> So reading csts is what triggers EEH to be detected and get the channel
> set offline? If so, don't we need a memory barrier before calling
> pci_channel_offline? Otherwise it looks like the compiler optimization
> could reorder these.

I think you're right.