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2db05cd199
We need to ensure there is enough headroom to push extra header, but we also need to check if we are allowed to change headers. skb_cow_head() is the proper helper to deal with this. Fixes Ethernet<->WiFi bridge for Raspberry Pi and probably other devices. Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
44 lines
1.4 KiB
Diff
44 lines
1.4 KiB
Diff
From 39fba7835aacda65284a86e611774cbba71dac20 Mon Sep 17 00:00:00 2001
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From: Eric Dumazet <edumazet@google.com>
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Date: Wed, 19 Apr 2017 09:59:26 -0700
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Subject: [PATCH] kaweth: use skb_cow_head() to deal with cloned skbs
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We can use skb_cow_head() to properly deal with clones,
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especially the ones coming from TCP stack that allow their head being
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modified. This avoids a copy.
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Signed-off-by: Eric Dumazet <edumazet@google.com>
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Cc: James Hughes <james.hughes@raspberrypi.org>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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drivers/net/usb/kaweth.c | 18 ++++++------------
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1 file changed, 6 insertions(+), 12 deletions(-)
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--- a/drivers/net/usb/kaweth.c
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+++ b/drivers/net/usb/kaweth.c
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@@ -812,18 +812,12 @@ static netdev_tx_t kaweth_start_xmit(str
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}
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/* We now decide whether we can put our special header into the sk_buff */
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- if (skb_cloned(skb) || skb_headroom(skb) < 2) {
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- /* no such luck - we make our own */
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- struct sk_buff *copied_skb;
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- copied_skb = skb_copy_expand(skb, 2, 0, GFP_ATOMIC);
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- dev_kfree_skb_irq(skb);
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- skb = copied_skb;
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- if (!copied_skb) {
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- kaweth->stats.tx_errors++;
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- netif_start_queue(net);
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- spin_unlock_irq(&kaweth->device_lock);
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- return NETDEV_TX_OK;
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- }
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+ if (skb_cow_head(skb, 2)) {
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+ kaweth->stats.tx_errors++;
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+ netif_start_queue(net);
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+ spin_unlock_irq(&kaweth->device_lock);
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+ dev_kfree_skb_any(skb);
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+ return NETDEV_TX_OK;
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}
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private_header = (__le16 *)__skb_push(skb, 2);
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