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net: hdlc_fr: Change the use of "dev" in fr_rx to make the code cleaner

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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 <khc@pm.waw.pl>
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Xie He 2020-10-31 11:10:40 -07:00 committed by Jakub Kicinski
parent 583d5333ed
commit 14b20704a1
1 changed files with 20 additions and 17 deletions
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37
drivers/net/wan/hdlc_fr.c
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@ -880,7 +880,7 @@ static int fr_rx(struct sk_buff *skb)
u8 *data = skb->data; u8 *data = skb->data;
u16 dlci; u16 dlci;
struct pvc_device *pvc; struct pvc_device *pvc;
struct net_device *dev = NULL; struct net_device *dev;
if (skb->len <= 4 || fh->ea1 || data[2] != FR_UI) if (skb->len <= 4 || fh->ea1 || data[2] != FR_UI)
goto rx_error; goto rx_error;
@ -930,13 +930,17 @@ static int fr_rx(struct sk_buff *skb)
} }
if (data[3] == NLPID_IP) { if (data[3] == NLPID_IP) {
if (!pvc->main)
goto rx_drop;
skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */ skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */
dev = pvc->main; skb->dev = pvc->main;
skb->protocol = htons(ETH_P_IP); skb->protocol = htons(ETH_P_IP);
} else if (data[3] == NLPID_IPV6) { } else if (data[3] == NLPID_IPV6) {
if (!pvc->main)
goto rx_drop;
skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */ skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */
dev = pvc->main; skb->dev = pvc->main;
skb->protocol = htons(ETH_P_IPV6); skb->protocol = htons(ETH_P_IPV6);
} else if (skb->len > 10 && data[3] == FR_PAD && } 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_IPX:
case ETH_P_IP: /* a long variant */ case ETH_P_IP: /* a long variant */
case ETH_P_IPV6: case ETH_P_IPV6:
dev = pvc->main; if (!pvc->main)
goto rx_drop;
skb->dev = pvc->main;
skb->protocol = htons(pid); skb->protocol = htons(pid);
break; break;
case 0x80C20007: /* bridged Ethernet frame */ case 0x80C20007: /* bridged Ethernet frame */
if ((dev = pvc->ether) != NULL) if (!pvc->ether)
skb->protocol = eth_type_trans(skb, dev); goto rx_drop;
skb->protocol = eth_type_trans(skb, pvc->ether);
break; break;
default: default:
@ -970,17 +977,13 @@ static int fr_rx(struct sk_buff *skb)
goto rx_drop; goto rx_drop;
} }
if (dev) { dev = skb->dev;
dev->stats.rx_packets++; /* PVC traffic */ dev->stats.rx_packets++; /* PVC traffic */
dev->stats.rx_bytes += skb->len; dev->stats.rx_bytes += skb->len;
if (pvc->state.becn) if (pvc->state.becn)
dev->stats.rx_compressed++; dev->stats.rx_compressed++;
skb->dev = dev; netif_rx(skb);
netif_rx(skb); return NET_RX_SUCCESS;
return NET_RX_SUCCESS;
} else {
goto rx_drop;
}
rx_error: rx_error:
frad->stats.rx_errors++; /* Mark error */ frad->stats.rx_errors++; /* Mark error */