[PATCH 1/5] net/iavf: discard empty AdminQ descriptors on reset

[Loftus, Ciara]

> Subject: [PATCH 1/5] net/iavf: discard empty AdminQ descriptors on reset
> 
> During PF-initiated resets iavf_clean_arq_element() has been observed
> to return success with a fully zeroed descriptor (opcode 0).
> These fell through to the default arm of the dispatch switch and
> produced a "Request 0 is not supported yet" log flood in the field.
> 
> Skip descriptors with opcode 0 so they are silently discarded and do not
> flood log.
> 
> Signed-off-by: Anurag Mandal <anurag.mandal at intel.com>
> ---
>  drivers/net/intel/iavf/iavf_vchnl.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/net/intel/iavf/iavf_vchnl.c
> b/drivers/net/intel/iavf/iavf_vchnl.c
> index f346837bf1..56918ebcc1 100644
> --- a/drivers/net/intel/iavf/iavf_vchnl.c
> +++ b/drivers/net/intel/iavf/iavf_vchnl.c
> @@ -614,6 +614,19 @@ iavf_handle_virtchnl_msg(struct rte_eth_dev *dev)
>  			break;
>  		}
>  		aq_opc = rte_le_to_cpu_16(info.desc.opcode);
> +
> +		/*
> +		 * During PF-initiated resets, iavf_clean_arq_element() has
> +		 * been observed to return IAVF_SUCCESS with a fully zeroed
> +		 * descriptor (opcode 0).
> +		 * Without this guard, such descriptors would fall through
> +		 * to the default case of the dispatch switch below and the
> +		 * "Request 0 is not supported yet" log flood reported in
> +		 * the field would be produced. These are discarded now.
> +		 */

This comment is too lengthy. This information is captured appropriately in
the commit message.

Something like "opcode 0 means the descriptor is empty so it can be
skipped" or similar. Assuming an opcode of zero always means an
empty/zeroed descriptor?

> +		if (aq_opc == 0)
> +			continue;
> +
>  		/* For the message sent from pf to vf, opcode is stored in
>  		 * cookie_high of struct iavf_aq_desc, while return error code
>  		 * are stored in cookie_low, Which is done by PF driver.
> --
> 2.34.1