Commit 7ab89b17 authored by Ilan Tayari's avatar Ilan Tayari Committed by Greg Kroah-Hartman

gso: Validate assumption of frag_list segementation

[ Upstream commit 43170c4e ]

Commit 07b26c94 ("gso: Support partial splitting at the frag_list
pointer") assumes that all SKBs in a frag_list (except maybe the last
one) contain the same amount of GSO payload.

This assumption is not always correct, resulting in the following
warning message in the log:
    skb_segment: too many frags

For example, mlx5 driver in Striding RQ mode creates some RX SKBs with
one frag, and some with 2 frags.
After GRO, the frag_list SKBs end up having different amounts of payload.
If this frag_list SKB is then forwarded, the aforementioned assumption
is violated.

Validate the assumption, and fall back to software GSO if it not true.

Change-Id: Ia03983f4a47b6534dd987d7a2aad96d54d46d212
Fixes: 07b26c94 ("gso: Support partial splitting at the frag_list pointer")
Signed-off-by: default avatarIlan Tayari <ilant@mellanox.com>
Signed-off-by: default avatarIlya Lesokhin <ilyal@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fcbf5a71
......@@ -3076,22 +3076,32 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb,
if (sg && csum && (mss != GSO_BY_FRAGS)) {
if (!(features & NETIF_F_GSO_PARTIAL)) {
struct sk_buff *iter;
unsigned int frag_len;
if (!list_skb ||
!net_gso_ok(features, skb_shinfo(head_skb)->gso_type))
goto normal;
/* Split the buffer at the frag_list pointer.
* This is based on the assumption that all
* buffers in the chain excluding the last
* containing the same amount of data.
/* If we get here then all the required
* GSO features except frag_list are supported.
* Try to split the SKB to multiple GSO SKBs
* with no frag_list.
* Currently we can do that only when the buffers don't
* have a linear part and all the buffers except
* the last are of the same length.
*/
frag_len = list_skb->len;
skb_walk_frags(head_skb, iter) {
if (frag_len != iter->len && iter->next)
goto normal;
if (skb_headlen(iter))
goto normal;
len -= iter->len;
}
if (len != frag_len)
goto normal;
}
/* GSO partial only requires that we trim off any excess that
......
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