[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.