Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Alexander Lobakin <alexandr.lobakin@intel.com>
To:     Horatiu Vultur <horatiu.vultur@microchip.com>
Cc:     Alexander Lobakin <alexandr.lobakin@intel.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, ast@kernel.org,
        daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com,
        UNGLinuxDriver@microchip.com
Subject: Re: [PATCH net-next v3 4/7] net: lan966x: Update rxq memory model
Date:   Tue, 22 Nov 2022 12:38:51 +0100
Message-Id: <20221122113851.418993-1-alexandr.lobakin@intel.com>
In-Reply-To: <20221121212850.3212649-5-horatiu.vultur@microchip.com>
References: <20221121212850.3212649-1-horatiu.vultur@microchip.com> <20221121212850.3212649-5-horatiu.vultur@microchip.com>
MIME-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Horatiu Vultur <horatiu.vultur@microchip.com>
Date: Mon, 21 Nov 2022 22:28:47 +0100

> By default the rxq memory model is MEM_TYPE_PAGE_SHARED but to be able
> to reuse pages on the TX side, when the XDP action XDP_TX it is required
> to update the memory model to PAGE_POOL.
> 
> Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
> ---
>  .../net/ethernet/microchip/lan966x/lan966x_fdma.c  | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
> index 384ed34197d58..483d1470c8362 100644
> --- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
> +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
> @@ -78,8 +78,22 @@ static int lan966x_fdma_rx_alloc_page_pool(struct lan966x_rx *rx)
>  		.max_len = rx->max_mtu -
>  			   SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
>  	};
> +	struct lan966x_port *port;
> +	int i;
>  
>  	rx->page_pool = page_pool_create(&pp_params);
> +
> +	for (i = 0; i < lan966x->num_phys_ports; ++i) {
> +		if (!lan966x->ports[i])
> +			continue;
> +
> +		port = lan966x->ports[i];
> +
> +		xdp_rxq_info_unreg_mem_model(&port->xdp_rxq);

xdp_rxq_info_unreg_mem_model() can emit a splat if currently the
corresponding xdp_rxq_info is not registered[0]. Can't we face it
here if called from lan966x_fdma_init()?

> +		xdp_rxq_info_reg_mem_model(&port->xdp_rxq, MEM_TYPE_PAGE_POOL,
> +					   rx->page_pool);
> +	}
> +
>  	return PTR_ERR_OR_ZERO(rx->page_pool);
>  }
>  
> -- 
> 2.38.0

Thanks,
Olek