42 lines
1.7 KiB
Diff
42 lines
1.7 KiB
Diff
From: Sven Eckelmann <sven@narfation.org>
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Date: Thu, 26 Nov 2020 18:24:49 +0100
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Subject: batman-adv: Don't always reallocate the fragmentation skb head
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When a packet is fragmented by batman-adv, the original batman-adv header
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is not modified. Only a new fragmentation is inserted between the original
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one and the ethernet header. The code must therefore make sure that it has
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a writable region of this size in the skbuff head.
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But it is not useful to always reallocate the skbuff by this size even when
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there would be more than enough headroom still in the skb. The reallocation
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is just to costly during in this codepath.
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Fixes: db56e4ecf5c2 ("batman-adv: Fragment and send skbs larger than mtu")
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Signed-off-by: Sven Eckelmann <sven@narfation.org>
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Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/3e3ff987876d3be70d928561acbefe5a48ab1654
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diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
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index f1d202ff396cd69949915a9e90e763f3a68255b7..0da90e73c79bffe86072f0d704f0777d76b35f4c 100644
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--- a/net/batman-adv/fragmentation.c
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+++ b/net/batman-adv/fragmentation.c
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@@ -527,13 +527,14 @@ int batadv_frag_send_packet(struct sk_buff *skb,
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frag_header.no++;
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}
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- /* Make room for the fragment header. */
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- if (batadv_skb_head_push(skb, header_size) < 0 ||
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- pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0) {
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- ret = -ENOMEM;
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+ /* make sure that there is at least enough head for the fragmentation
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+ * and ethernet headers
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+ */
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+ ret = skb_cow_head(skb, ETH_HLEN + header_size);
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+ if (ret < 0)
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goto put_primary_if;
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- }
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+ skb_push(skb, header_size);
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memcpy(skb->data, &frag_header, header_size);
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/* Send the last fragment */
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