Re: [PATCH 0/4] Rework NVMe abort handling

[Christoph Hellwig]

On Thu, Jul 19, 2018 at 04:35:34PM +0200, Johannes Thumshirn wrote:
> > No with the the code following what we have in PCIe that just means
> > we'll eventually controller reset after the I/O command times out
> > the second time as we still won't have seen a completion for it.
> 
> Exactly that was my intention.

Which means the only thing you do for your use case is to delay
recovery even further.

> OK, let me see where I'm stuck here. We're issuing a command, it gets
> lost due to $REASON and I'm aborting it. The upper layers then
> eventually retry the command and it arrives at the target side. But so
> does the old command as well and we have a duplicate. Correct?

The upper layer is only going to retry after tearing down the transport
connection.  And a tear down of the connection MUST clear all pending
commands on the way.  If it doesn't we are in deep, deep trouble.

A NVMe abort has no chance of clearing things at the transport layer.