Re: [PATCH net-next v4 14/14] ibmveth: Fix MQ RX poll and shutdown hangs after queue resize

[Jakub Kicinski <kuba@kernel.org>]

On Thu, 30 Jul 2026 17:47:17 -0700 Mingming Cao wrote:
> After aggressive ethtool -L cycling, PHYP can leave a VALID RX descriptor
> with a correlator that no longer matches the per-queue buffer pools. Poll
> treated this as fatal: ibmveth_rxq_get_buffer() WARNed and returned NULL
> without advancing the ring, then restart_poll retried the same slot
> forever.
> 
> Advance past bad correlators instead of spinning: validate correlators
> without WARN_ON, skip invalid slots in poll (count as invalid_buffers),
> and advance the RX ring when remove_buffer_from_pool cannot map the
> correlator. Rate-limit the bad correlator message.
> 
> Complete NAPI when the interface is down or napi_disable is pending so
> close/quiesce can finish. Do not restart_poll in that window. Close
> keeps hypervisor IRQ disable before napi_disable (via
> cleanup_rx_interrupts() / related cleanup helpers).
> 
> Also validate descriptor length against skb tailroom before skb_put(),
> and after napi_complete_done() on the budget-exhausted shutdown path
> return a value less than budget so NAPI does not immediately reschedule.

This patch looks very odd, like there's a bug somewhere and instead of
fixing it we're making the rx path more resilient. BTW minor coding
note - you're adding a bunch of heavily indented code to an already
long function. Please consider factoring things out. Similar comment
can be applied to other patches.