Re: [PATCH net-next v2] net: airoha: Implement BQL support

[Jakub Kicinski <kuba@kernel.org>]

On Tue, 15 Oct 2024 16:39:08 +0200 Lorenzo Bianconi wrote:
> On Oct 15, Jakub Kicinski wrote:
> > On Sat, 12 Oct 2024 11:01:11 +0200 Lorenzo Bianconi wrote:  
> > > Introduce BQL support in the airoha_eth driver reporting to the kernel
> > > info about tx hw DMA queues in order to avoid bufferbloat and keep the
> > > latency small.  
> > 
> > TBH I haven't looked at the code again, but when I looked at v1 I was
> > surprised you don't have a reset in airoha_qdma_cleanup_tx_queue().
> > Are you sure it's okay? It's a common bug not to reset the BQL state
> > when queue is purged while stopping the interface.  
> 
> So far airoha_qdma_cleanup_tx_queue() is called just in airoha_hw_cleanup()
> that in turn runs just when the module is removed (airoha_remove()).
> Do we need it?

Oh, thought its called on stop. In that case we're probably good
from BQL perspective.

But does it mean potentially very stale packets can sit on the Tx
ring when the device is stopped, until it's started again?