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([2a0d:3344:2706:e010:b099:aac6:4e70:6198]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-441b8a2874asm162916855e9.26.2025.05.06.03.36.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 06 May 2025 03:37:01 -0700 (PDT) Message-ID: <61ebe754-d895-47cb-a4b2-bb2650b9ff7b@redhat.com> Date: Tue, 6 May 2025 12:36:57 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [net-next v11 4/7] net: mtip: The L2 switch driver for imx287 To: Lukasz Majewski , Andrew Lunn , davem@davemloft.net, Eric Dumazet , Jakub Kicinski , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Shawn Guo Cc: Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Richard Cochran , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Stefan Wahren , Simon Horman , Andrew Lunn References: <20250504145538.3881294-1-lukma@denx.de> <20250504145538.3881294-5-lukma@denx.de> Content-Language: en-US From: Paolo Abeni In-Reply-To: <20250504145538.3881294-5-lukma@denx.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/4/25 4:55 PM, Lukasz Majewski wrote: > + /* This does 16 byte alignment, exactly what we need. > + * The packet length includes FCS, but we don't want to > + * include that when passing upstream as it messes up > + * bridging applications. > + */ > + skb = netdev_alloc_skb(pndev, pkt_len + NET_IP_ALIGN); > + if (unlikely(!skb)) { > + dev_dbg(&fep->pdev->dev, > + "%s: Memory squeeze, dropping packet.\n", > + pndev->name); > + pndev->stats.rx_dropped++; > + goto err_mem; > + } else { > + skb_reserve(skb, NET_IP_ALIGN); > + skb_put(skb, pkt_len); /* Make room */ > + skb_copy_to_linear_data(skb, data, pkt_len); > + skb->protocol = eth_type_trans(skb, pndev); > + napi_gro_receive(&fep->napi, skb); > + } > + > + bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, data, > + bdp->cbd_datlen, > + DMA_FROM_DEVICE); > + if (unlikely(dma_mapping_error(&fep->pdev->dev, > + bdp->cbd_bufaddr))) { > + dev_err(&fep->pdev->dev, > + "Failed to map descriptor rx buffer\n"); > + pndev->stats.rx_errors++; > + pndev->stats.rx_dropped++; > + dev_kfree_skb_any(skb); > + goto err_mem; > + } This is doing the mapping and ev. dropping the skb _after_ pushing the skb up the stack, you must attempt the mapping first. > +static void mtip_free_buffers(struct net_device *dev) > +{ > + struct mtip_ndev_priv *priv = netdev_priv(dev); > + struct switch_enet_private *fep = priv->fep; > + struct sk_buff *skb; > + struct cbd_t *bdp; > + int i; > + > + bdp = fep->rx_bd_base; > + for (i = 0; i < RX_RING_SIZE; i++) { > + skb = fep->rx_skbuff[i]; > + > + if (bdp->cbd_bufaddr) > + dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr, > + MTIP_SWITCH_RX_FRSIZE, > + DMA_FROM_DEVICE); > + if (skb) > + dev_kfree_skb(skb); I suspect that on error paths mtip_free_buffers() can be invoked multiple consecutive times with any successful allocation in between: skb will be freed twice. Likely you need to clear fep->rx_skbuff[i] here. Side note: this patch is way too big for a proper review: you need to break it in multiple smaller ones, introducing the basic features separately. Cheers, Paolo