Re: [PATCH v13 net-next 6/9] octeontx2: cn20k: Coordinate default rules with NIX LF lifecycle

[Ratheesh Kannoth <rkannoth@marvell.com>]

On 2026-05-11 at 09:09:20, Ratheesh Kannoth (rkannoth@marvell.com) wrote:
> Add NIX_LF_DONT_FREE_DFT_IDXS so the PF can send NIX LF free during hw
> reinit or teardown without the AF freeing CN20K default NPC rule indexes
> while the driver still owns that state (otx2_init_hw_resources and
> otx2_free_hw_resources).

>> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
>> --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
>> +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
>[ ... ]
>> @@ -1684,10 +1691,16 @@ int rvu_mbox_handler_nix_lf_alloc(struct rvu *rvu,
>>  	if (is_sdp_pfvf(rvu, pcifunc))
>>  		intf = NIX_INTF_TYPE_SDP;
>>
>> -	err = nix_interface_init(rvu, pcifunc, intf, nixlf, rsp,
>> -				 !!(req->flags & NIX_LF_LBK_BLK_SEL));
>> -	if (err)
>> -		goto free_mem;
>> +	if (is_cn20k(rvu->pdev)) {
>> +		rc = npc_cn20k_dft_rules_alloc(rvu, pcifunc);
>> +		if (rc)
>> +			goto free_mem;
>> +	}
>Can this error path wipe out user-configured MCAM rules?
No. Default rules are configured first soon after nix_lf alloc. So there is no
rule before it.

>> -			__func__, pcifunc);
>> +
>> +	/* In cn20k, default rules are freed before detach rsrc */
>> +	if (ucast_idx < 0)
>>  		return;
>> -	}
>Does this unconditionally remove the error log and mask legitimate errors on
>older silicon?
>If npc_get_nixlf_mcam_index() fails on non-CN20K platforms due to an internal
>error or missing entry, the failure is now silently ignored, degrading
>debuggability. Should this dev_err() be preserved and wrapped in an
>is_cn20k() check instead?
nix_lf_detach() will be called first and then rvu_npc_clear_ucast_entry().
In cn20k, since npc mcam entries are allocated/deallocated dynamically, ucast_idx
will be negative. Remove the unnecessary log.

>
> On CN20K, allocate default NPC rules from NIX LF alloc before
> nix_interface_init, roll back with npc_cn20k_dft_rules_free on failure,
> and free from NIX LF free when the new flag is not set. Tighten
> rvu_mbox_handler_nix_lf_alloc error handling: use a single rc, propagate
> qmem_alloc and other errors, and set -ENOMEM only when kcalloc fails
> (remove the blanket -ENOMEM at the free_mem path).
>
> Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
> ---
>  .../net/ethernet/marvell/octeontx2/af/mbox.h  |  1 +
>  .../ethernet/marvell/octeontx2/af/rvu_nix.c   | 69 ++++++++++++-------
>  .../ethernet/marvell/octeontx2/af/rvu_npc.c   | 20 ++++--
>  .../ethernet/marvell/octeontx2/nic/otx2_pf.c  |  6 +-
>  4 files changed, 61 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/mbox.h b/drivers/net/ethernet/marvell/octeontx2/af/mbox.h
> index dc42c81c0942..e07fbf842b94 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/af/mbox.h
> +++ b/drivers/net/ethernet/marvell/octeontx2/af/mbox.h