From 14b20704a18062249903a7a930e27c4452bc56bc Mon Sep 17 00:00:00 2001 From: Xie He Date: Sat, 31 Oct 2020 11:10:40 -0700 Subject: [PATCH] net: hdlc_fr: Change the use of "dev" in fr_rx to make the code cleaner The eth_type_trans function is called when we receive frames carrying Ethernet frames. This function expects a non-NULL pointer as an argument, and assigns it directly to skb->dev. However, the code handling other types of frames first assigns the pointer to "dev", and then at the end checks whether the value is NULL, and if it is not NULL, assigns it to skb->dev. The two flows are different. Mixing them in this function makes the code messy. It's better that we convert the second flow to align with how eth_type_trans does things. So this patch changes the code to: first make sure the pointer is not NULL, then assign it directly to skb->dev. "dev" is no longer needed until the end where we use it to update stats. Cc: Krzysztof Halasa Cc: Willem de Bruijn Signed-off-by: Xie He Signed-off-by: Jakub Kicinski --- drivers/net/wan/hdlc_fr.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c index 4db0e01b96a9..71ee9b60d91b 100644 --- a/drivers/net/wan/hdlc_fr.c +++ b/drivers/net/wan/hdlc_fr.c @@ -880,7 +880,7 @@ static int fr_rx(struct sk_buff *skb) u8 *data = skb->data; u16 dlci; struct pvc_device *pvc; - struct net_device *dev = NULL; + struct net_device *dev; if (skb->len <= 4 || fh->ea1 || data[2] != FR_UI) goto rx_error; @@ -930,13 +930,17 @@ static int fr_rx(struct sk_buff *skb) } if (data[3] == NLPID_IP) { + if (!pvc->main) + goto rx_drop; skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */ - dev = pvc->main; + skb->dev = pvc->main; skb->protocol = htons(ETH_P_IP); } else if (data[3] == NLPID_IPV6) { + if (!pvc->main) + goto rx_drop; skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */ - dev = pvc->main; + skb->dev = pvc->main; skb->protocol = htons(ETH_P_IPV6); } else if (skb->len > 10 && data[3] == FR_PAD && @@ -950,13 +954,16 @@ static int fr_rx(struct sk_buff *skb) case ETH_P_IPX: case ETH_P_IP: /* a long variant */ case ETH_P_IPV6: - dev = pvc->main; + if (!pvc->main) + goto rx_drop; + skb->dev = pvc->main; skb->protocol = htons(pid); break; case 0x80C20007: /* bridged Ethernet frame */ - if ((dev = pvc->ether) != NULL) - skb->protocol = eth_type_trans(skb, dev); + if (!pvc->ether) + goto rx_drop; + skb->protocol = eth_type_trans(skb, pvc->ether); break; default: @@ -970,17 +977,13 @@ static int fr_rx(struct sk_buff *skb) goto rx_drop; } - if (dev) { - dev->stats.rx_packets++; /* PVC traffic */ - dev->stats.rx_bytes += skb->len; - if (pvc->state.becn) - dev->stats.rx_compressed++; - skb->dev = dev; - netif_rx(skb); - return NET_RX_SUCCESS; - } else { - goto rx_drop; - } + dev = skb->dev; + dev->stats.rx_packets++; /* PVC traffic */ + dev->stats.rx_bytes += skb->len; + if (pvc->state.becn) + dev->stats.rx_compressed++; + netif_rx(skb); + return NET_RX_SUCCESS; rx_error: frad->stats.rx_errors++; /* Mark error */ -- 2.11.0