On Thu, Jul 23, 2026 at 12:18:22PM +0200, Paolo Abeni wrote:
> On 7/11/26 6:10 AM, Dipayaan Roy wrote:
> > When mana_attach() fails during ethtool ring size or channel count
> > changes, the port is left in a broken state with no recovery
> > mechanism, requiring manual intervention to bring the port back up.
> > 
> > On VM SKUs without a netvsc fallback interface, this results in
> > complete loss of network connectivity to the VM.
> > 
> > Fix by scheduling queue_reset_work when mana_attach() fails. The
> > preceding patch ensures mana_detach() always completes its full
> > teardown (netif_device_detach + cleanup), so the reset handler's
> > mana_detach() takes the "already detached" early return, preserving
> > port_st_save for a successful mana_attach() recovery.
> > 
> > When mana_attach() fails, choose retry values that maximize recovery
> > chances: if the operation was an increase, fall back to the previous
> > working values; if it was a decrease but still above default, fall
> > back to defaults; otherwise use the minimum supported values.
> > 
> > Reviewed-by: Haiyang Zhang <[email protected]>
> > Tested-by: Aditya Garg <[email protected]>
> > Signed-off-by: Dipayaan Roy <[email protected]>
> sashiko gemini sees quite a bit of problem with the above approach:
> 
> https://sashiko.dev/#/patchset/20260711041415.3008868-1-dipayanroy%40linux.microsoft.com
> 
> Also, changing user-setting in case of fallback is quite a bad thing to
> be avoided.
> 
> Skimming over the code, it looks like than pre-allocate all the
> resources and to a replace instead of detach/attach() looks feasible. I
> suggest investigating such path. I also think that this last patch (and
> possibly 2/4) could/should be in separate series.
> 
> Finally and most relevant thing; AI review comments should be explicitly
> acknowledged by either debating them or addressing them. In both cases a
> reply on the ML is expected.
> 
> /P

Hi Paolo,

Thank you for the review.

Accepting the feedback on 4/4 and working on the
pre-allocate-and-replace approach you suggested. We are discussing with
the HW/NIC team and investigating pre-allocating the queue resources from HW
while a set already exists, as with this patch we are trying to handle
and recover from failures caused due to HW/NIC resource exhaustion for
queues.

I will drop 4/4 from this series in v13 and stick to only the ethtool
private flag changes. Will send out a separate series for the problem
currently discussed in 4/4 once all the above points are concluded.

For 2/4 I will send it as a fixes patch to net as it will be common for
all functions calling mana_detach.

Regards
Dipayaan Roy

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